* [PATCH v3 00/13] crypto: Documentation of kernel crypto API
@ 2014-11-12 4:22 Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 01/13] crypto: Documentation - crypto API high level spec Stephan Mueller
` (13 more replies)
0 siblings, 14 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:22 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
Hi,
The following patch set adds documentation files under Documentation/crypto/
covering the high-level description of the API. In addition, it contains
source code comments added to the header files of the kernel crypto API
documenting the API functions.
The documentation is provided in a DocBook whose output can be reviewed at:
http://www.chronox.de/crypto-API/index.html
Changes v2:
* Split out the user space documentation into separate document including
the user space example code
* Change the license of the user space interface code to match the license
of the code that I used as a reference.
* Addition of a precise pointer to the user space interface code reference
code.
* Add a missing memset(0) to the user space example code.
* Move the API function call documentation into the header files in the hope
for a better maintainability.
* Merge the developer-related documentation from Marek Vasut
Changes v3:
* Replaced user space example code with reference to libkcapi as a reference
implementation and a simple library hiding the Netlink details.
* Converted all kernel documentation into a basis for a DocBook as suggested
by Jonathan Corbet
* Included (hopefully) all suggestions provided over the last two weeks
Stephan Mueller (13):
crypto: Documentation - crypto API high level spec
crypto: Documentation - compile crypto API spec
crypto: Documentation - userspace interface spec
crypto: Documentation - RNG API documentation
crypto: Documentation - hash data structures
crypto: Documentation - AHASH API documentation
crypto: Documentation - SHASH API documentation
crypto: Documentation - cipher data structures
crypto: Documentation - ABLKCIPHER API documentation
crypto: Documentation - AEAD API documentation
crypto: Documentation - BLKCIPHER API documentation
crypto: Documentation - CIPHER API documentation
crypto: Documentation - HASH API documentation
Documentation/DocBook/Makefile | 2 +-
Documentation/DocBook/crypto-API.tmpl | 1253 +++++++++++++++++++++++++
Documentation/crypto/crypto-API-userspace.txt | 205 ++++
include/crypto/hash.h | 487 ++++++++++
include/crypto/rng.h | 80 ++
include/linux/crypto.h | 1099 +++++++++++++++++++++-
6 files changed, 3122 insertions(+), 4 deletions(-)
create mode 100644 Documentation/DocBook/crypto-API.tmpl
create mode 100644 Documentation/crypto/crypto-API-userspace.txt
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 01/13] crypto: Documentation - crypto API high level spec
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
@ 2014-11-12 4:24 ` Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 02/13] crypto: Documentation - compile crypto API spec Stephan Mueller
` (12 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:24 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The design of the kernel crypto API as well as hints to program with
the kernel crypto API are given.
The documentation contains:
* design aspects of crypto API
* develper specific hints
* references to the API function description
* source code examples
CC: Marek Vasut <marex@denx.de>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
Documentation/DocBook/crypto-API.tmpl | 1253 +++++++++++++++++++++++++++++++++
1 file changed, 1253 insertions(+)
create mode 100644 Documentation/DocBook/crypto-API.tmpl
diff --git a/Documentation/DocBook/crypto-API.tmpl b/Documentation/DocBook/crypto-API.tmpl
new file mode 100644
index 0000000..c763d30
--- /dev/null
+++ b/Documentation/DocBook/crypto-API.tmpl
@@ -0,0 +1,1253 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
+ "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
+
+<book id="KernelCryptoAPI">
+ <bookinfo>
+ <title>Linux Kernel Crypto API</title>
+
+ <authorgroup>
+ <author>
+ <firstname>Stephan</firstname>
+ <surname>Mueller</surname>
+ <affiliation>
+ <address>
+ <email>smueller@chronox.de</email>
+ </address>
+ </affiliation>
+ </author>
+ <author>
+ <firstname>Marek</firstname>
+ <surname>Vasut</surname>
+ <affiliation>
+ <address>
+ <email>marek@denx.de</email>
+ </address>
+ </affiliation>
+ </author>
+ </authorgroup>
+
+ <copyright>
+ <year>2014</year>
+ <holder>Stephan Mueller</holder>
+ </copyright>
+
+
+ <legalnotice>
+ <para>
+ This documentation is free software; you can redistribute
+ it and/or modify it under the terms of the GNU General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later
+ version.
+ </para>
+
+ <para>
+ This program is distributed in the hope that it will be
+ useful, but WITHOUT ANY WARRANTY; without even the implied
+ warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ See the GNU General Public License for more details.
+ </para>
+
+ <para>
+ You should have received a copy of the GNU General Public
+ License along with this program; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ MA 02111-1307 USA
+ </para>
+
+ <para>
+ For more details see the file COPYING in the source
+ distribution of Linux.
+ </para>
+ </legalnotice>
+ </bookinfo>
+
+ <toc></toc>
+
+ <chapter id="Intro">
+ <title>Kernel Crypto API Interface Specification</title>
+
+ <sect1><title>Introduction</title>
+
+ <para>
+ The kernel crypto API offers a rich set of cryptographic ciphers as
+ well as other data transformation mechanisms and methods to invoke
+ these. This document contains a description of the API and provides
+ example code.
+ </para>
+
+ <para>
+ To understand and properly use the kernel crypto API a brief
+ explanation of its structure is given. Based on the architecture,
+ the API can be separated into different components. Following the
+ architecture specification, hints to developers of ciphers are
+ provided. Pointers to the API function call documentation are
+ given at the end.
+ </para>
+
+ <para>
+ The kernel crypto API refers to all algorithms as "transformations".
+ Therefore, a cipher handle variable usually has the name "tfm".
+ Besides cryptographic operations, the kernel crypto API also knows
+ compression transformations and handles them the same way as ciphers.
+ </para>
+
+ <para>
+ The kernel crypto API serves the following entity types:
+
+ <itemizedlist>
+ <listitem>
+ <para>consumers requesting cryptographic services</para>
+ </listitem>
+ <listitem>
+ <para>data transformation implementations (typically ciphers)
+ that can be called by consumers using the kernel crypto
+ API</para>
+ </listitem>
+ </itemizedlist>
+ </para>
+
+ <para>
+ This specification is intended for consumers of the kernel crypto
+ API as well as for developers implementing ciphers. This API
+ specification, however, does not discusses all API calls available
+ to data transformation implementations (i.e. implementations of
+ ciphers and other transformations (such as CRC or even compression
+ algorithms) that can register with the kernel crypto API).
+ </para>
+
+ <para>
+ Note: The terms "transformation" and cipher algorithm are used
+ interchangably.
+ </para>
+ </sect1>
+
+ <sect1><title>Terminology</title>
+ <para>
+ The transformation implementation is an actual code or interface
+ to hardware which implements a certain transformation with precisely
+ defined behavior.
+ </para>
+
+ <para>
+ The transformation object (TFM) is an instance of a transformation
+ implementation. There can be multiple transformation objects
+ associated with a single transformation implementation. Each of
+ those transformation objects is held by a crypto API consumer or
+ another transformation. Transformation object is allocated when a
+ crypto API consumer requests a transformation implementation.
+ The consumer is then provided with a structure, which contains
+ a transformation object (TFM).
+ </para>
+
+ <para>
+ The structure that contains transformation objects may also be
+ referred to as a "cipher handle". Such a cipher handle is always
+ subject to the following phases that are reflected in the API calls
+ applicable to such a cipher handle:
+ </para>
+
+ <orderedlist>
+ <listitem>
+ <para>Initialization of a cipher handle.</para>
+ </listitem>
+ <listitem>
+ <para>Execution of all intended cipher operations applicable
+ for the handle where the cipher handle must be furnished to
+ every API call.</para>
+ </listitem>
+ <listitem>
+ <para>Destruction of a cipher handle.</para>
+ </listitem>
+ </orderedlist>
+
+ <para>
+ When using the initialization API calls, a cipher handle is
+ created and returned to the consumer. Therefore, please refer
+ to all initialization API calls that refer to the data
+ structure type a consumer is expected to receive and subsequently
+ to use. The initialization API calls have all the same naming
+ conventions of crypto_alloc_*.
+ </para>
+
+ <para>
+ The transformation context is private data associated with
+ the transformation object.
+ </para>
+ </sect1>
+ </chapter>
+
+ <chapter id="Architecture"><title>Kernel Crypto API Architecture</title>
+ <sect1><title>Cipher algorithm types</title>
+ <para>
+ The kernel crypto API provides different API calls for the
+ following cipher types:
+
+ <itemizedlist>
+ <listitem><para>Symmetric ciphers</para></listitem>
+ <listitem><para>AEAD ciphers</para></listitem>
+ <listitem><para>Message digest, including keyed message digest</para></listitem>
+ <listitem><para>Random number generation</para></listitem>
+ <listitem><para>User space interface</para></listitem>
+ </itemizedlist>
+ </para>
+ </sect1>
+
+ <sect1><title>Ciphers And Templates</title>
+ <para>
+ The kernel crypto API provides implementations of single block
+ ciphers and message digests. In addition, the kernel crypto API
+ provides numerous "templates" that can be used in conjunction
+ with the single block ciphers and message digests. Templates
+ include all types of block chaining mode, the HMAC mechanism, etc.
+ </para>
+
+ <para>
+ Single block ciphers and message digests can either be directly
+ used by a caller or invoked together with a template to form
+ multi-block ciphers or keyed message digests.
+ </para>
+
+ <para>
+ A single block cipher may even be called with multiple templates.
+ However, templates cannot be used without a single cipher.
+ </para>
+
+ <para>
+ See /proc/crypto and search for "name". For example:
+
+ <itemizedlist>
+ <listitem><para>aes</para></listitem>
+ <listitem><para>ecb(aes)</para></listitem>
+ <listitem><para>cmac(aes)</para></listitem>
+ <listitem><para>ccm(aes)</para></listitem>
+ <listitem><para>rfc4106(gcm(aes))</para></listitem>
+ <listitem><para>sha1</para></listitem>
+ <listitem><para>hmac(sha1)</para></listitem>
+ <listitem><para>authenc(hmac(sha1),cbc(aes))</para></listitem>
+ </itemizedlist>
+ </para>
+
+ <para>
+ In these examples, "aes" and "sha1" are the ciphers and all
+ others are the templates.
+ </para>
+ </sect1>
+
+ <sect1><title>Synchronous And Asynchronous Operation</title>
+ <para>
+ The kernel crypto API provides synchronous and asynchronous
+ API operations.
+ </para>
+
+ <para>
+ When using the synchronous API operation, the caller invokes
+ a cipher operation which is performed synchronously by the
+ kernel crypto API. That means, the caller waits until the
+ cipher operation completes. Therefore, the kernel crypto API
+ calls work like regular function calls. For synchronous
+ operation, the set of API calls is small and conceptually
+ similar to any other crypto library.
+ </para>
+
+ <para>
+ Asynchronous operation is provided by the kernel crypto API
+ which implies that the invocation of a cipher operation will
+ complete almost instantly. That invocation triggers the
+ cipher operation but it does not signal its completion. Before
+ invoking a cipher operation, the caller must provide a callback
+ function the kernel crypto API can invoke to signal the
+ completion of the cipher operation. Furthermore, the caller
+ must ensure it can handle such asynchronous events by applying
+ appropriate locking around its data. The kernel crypto API
+ does not perform any special serialization operation to protect
+ the caller's data integrity.
+ </para>
+ </sect1>
+
+ <sect1><title>Crypto API Cipher References And Priority</title>
+ <para>
+ A cipher is referenced by the caller with a string. That string
+ has the following semantics:
+
+ <programlisting>
+ template(single block cipher)
+ </programlisting>
+
+ where "template" and "single block cipher" is the aforementioned
+ template and single block cipher, respectively. If applicable,
+ additional templates may enclose other templates, such as
+
+ <programlisting>
+ template1(template2(single block cipher)))
+ </programlisting>
+ </para>
+
+ <para>
+ The kernel crypto API may provide multiple implementations of a
+ template or a single block cipher. For example, AES on newer
+ Intel hardware has the following implementations: AES-NI,
+ assembler implementation, or straight C. Now, when using the
+ string "aes" with the kernel crypto API, which cipher
+ implementation is used? The answer to that question is the
+ priority number assigned to each cipher implementation by the
+ kernel crypto API. When a caller uses the string to refer to a
+ cipher during initialization of a cipher handle, the kernel
+ crypto API looks up all implementations providing an
+ implementation with that name and selects the implementation
+ with the highest priority.
+ </para>
+
+ <para>
+ Now, a caller may have the need to refer to a specific cipher
+ implementation and thus does not want to rely on the
+ priority-based selection. To accommodate this scenario, the
+ kernel crypto API allows the cipher implementation to register
+ a unique name in addition to common names. When using that
+ unique name, a caller is therefore always sure to refer to
+ the intended cipher implementation.
+ </para>
+
+ <para>
+ The list of available ciphers is given in /proc/crypto. However,
+ that list does not specify all possible permutations of
+ templates and ciphers. Each block listed in /proc/crypto may
+ contain the following information -- if one of the components
+ listed as follows are not applicable to a cipher, it is not
+ displayed:
+ </para>
+
+ <itemizedlist>
+ <listitem>
+ <para>name: the generic name of the cipher that is subject
+ to the priority-based selection -- this name can be used by
+ the cipher allocation API calls (all names listed above are
+ examples for such generic names)</para>
+ </listitem>
+ <listitem>
+ <para>driver: the unique name of the cipher -- this name can
+ be used by the cipher allocation API calls</para>
+ </listitem>
+ <listitem>
+ <para>module: the kernel module providing the cipher
+ implementation (or "kernel" for statically linked ciphers)</para>
+ </listitem>
+ <listitem>
+ <para>priority: the priority value of the cipher implementation</para>
+ </listitem>
+ <listitem>
+ <para>refcnt: the reference count of the respective cipher
+ (i.e. the number of current consumers of this cipher)</para>
+ </listitem>
+ <listitem>
+ <para>selftest: specification whether the self test for the
+ cipher passed</para>
+ </listitem>
+ <listitem>
+ <para>type:
+ <itemizedlist>
+ <listitem>
+ <para>blkcipher for synchronous block ciphers</para>
+ </listitem>
+ <listitem>
+ <para>ablkcipher for asynchronous block ciphers</para>
+ </listitem>
+ <listitem>
+ <para>cipher for single block ciphers that may be used with
+ an additional template</para>
+ </listitem>
+ <listitem>
+ <para>shash for synchronous message digest</para>
+ </listitem>
+ <listitem>
+ <para>ahash for asynchronous message digest</para>
+ </listitem>
+ <listitem>
+ <para>aead for AEAD cipher type</para>
+ </listitem>
+ <listitem>
+ <para>compression for compression type transformations</para>
+ </listitem>
+ <listitem>
+ <para>rng for random number generator</para>
+ </listitem>
+ <listitem>
+ <para>givcipher for cipher with associated IV generator
+ (see the geniv entry below for the specification of the
+ IV generator type used by the cipher implementation)</para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ </listitem>
+ <listitem>
+ <para>blocksize: blocksize of cipher in bytes</para>
+ </listitem>
+ <listitem>
+ <para>keysize: key size in bytes</para>
+ </listitem>
+ <listitem>
+ <para>ivsize: IV size in bytes</para>
+ </listitem>
+ <listitem>
+ <para>seedsize: required size of seed data for random number
+ generator</para>
+ </listitem>
+ <listitem>
+ <para>digestsize: output size of the message digest</para>
+ </listitem>
+ <listitem>
+ <para>geniv: IV generation type:
+ <itemizedlist>
+ <listitem>
+ <para>eseqiv for encrypted sequence number based IV
+ generation</para>
+ </listitem>
+ <listitem>
+ <para>seqiv for sequence number based IV generation</para>
+ </listitem>
+ <listitem>
+ <para>chainiv for chain iv generation</para>
+ </listitem>
+ <listitem>
+ <para><builtin> is a marker that the cipher implements
+ IV generation and handling as it is specific to the given
+ cipher</para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ </listitem>
+ </itemizedlist>
+ </sect1>
+
+ <sect1><title>Key Sizes</title>
+ <para>
+ When allocating a cipher handle, the caller only specifies the
+ cipher type. Symmetric ciphers, however, typically support
+ multiple key sizes (e.g. AES-128 vs. AES-192 vs. AES-256).
+ These key sizes are determined with the length of the provided
+ key. Thus, the kernel crypto API does not provide a separate
+ way to select the particular symmetric cipher key size.
+ </para>
+ </sect1>
+
+ <sect1><title>Cipher Allocation Type And Masks</title>
+ <para>
+ The different cipher handle allocation functions allow the
+ specification of a type and mask flag. Both parameters have
+ the following meaning (and are therefore not covered in the
+ subsequent sections).
+ </para>
+
+ <para>
+ The type flag specifies the type of the cipher algorithm.
+ The caller usually provides a 0 when the caller wants the
+ default handling. Otherwise, the caller may provide the
+ following selections which match the the aforementioned
+ cipher types:
+ </para>
+
+ <itemizedlist>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_CIPHER Single block cipher</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_COMPRESS Compression</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_AEAD Authenticated Encryption with
+ Associated Data (MAC)</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_BLKCIPHER Synchronous multi-block cipher</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_ABLKCIPHER Asynchronous multi-block cipher</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_GIVCIPHER Asynchronous multi-block
+ cipher packed together with an IV generator (see geniv field
+ in the /proc/crypto listing for the known IV generators)</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_DIGEST Raw message digest</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_HASH Alias for CRYPTO_ALG_TYPE_DIGEST</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_SHASH Synchronous multi-block hash</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_AHASH Asynchronous multi-block hash</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_RNG Random Number Generation</para>
+ </listitem>
+ <listitem>
+ <para>CRYPTO_ALG_TYPE_PCOMPRESS Enhanced version of
+ CRYPTO_ALG_TYPE_COMPRESS allowing for segmented compression /
+ decompression instead of performing the operation on one
+ segment only. CRYPTO_ALG_TYPE_PCOMPRESS is intended to replace
+ CRYPTO_ALG_TYPE_COMPRESS once existing consumers are converted.</para>
+ </listitem>
+ </itemizedlist>
+
+ <para>
+ The mask flag restricts the type of cipher. The only allowed
+ flag is CRYPTO_ALG_ASYNC to restrict the cipher lookup function
+ to asynchronous ciphers. Usually, a caller provides a 0 for the
+ mask flag.
+ </para>
+
+ <para>
+ When the caller provides a mask and type specification, the
+ caller limits the search the kernel crypto API can perform for
+ a suitable cipher implementation for the given cipher name.
+ That means, even when a caller uses a cipher name that exists
+ during its initialization call, the kernel crypto API may not
+ select it due to the used type and mask field.
+ </para>
+ </sect1>
+ </chapter>
+
+ <chapter id="Development"><title>Developing Cipher Algorithms</title>
+ <sect1><title>Registering And Unregistering Transformation</title>
+ <para>
+ There are three distinct types of registration functions in
+ the Crypto API. One is used to register a generic cryptographic
+ transformation, while the other two are specific to HASH
+ transformations and COMPRESSion. We will discuss the latter
+ two in a separate chapter, here we will only look at the
+ generic ones.
+ </para>
+
+ <para>
+ Before discussing the register functions, the data structure
+ to be filled with each, struct crypto_alg, must be considered
+ -- see below for a description of this data structure.
+ </para>
+
+ <para>
+ The generic registration functions can be found in
+ include/linux/crypto.h and their definition can be seen below.
+ The former function registers a single transformation, while
+ the latter works on an array of transformation descriptions.
+ The latter is useful when registering transformations in bulk.
+ </para>
+
+ <programlisting>
+ int crypto_register_alg(struct crypto_alg *alg);
+ int crypto_register_algs(struct crypto_alg *algs, int count);
+ </programlisting>
+
+ <para>
+ The counterparts to those functions are listed below.
+ </para>
+
+ <programlisting>
+ int crypto_unregister_alg(struct crypto_alg *alg);
+ int crypto_unregister_algs(struct crypto_alg *algs, int count);
+ </programlisting>
+
+ <para>
+ Notice that both registration and unregistration functions
+ do return a value, so make sure to handle errors. A return
+ code of zero implies success. Any return code < 0 implies
+ an error.
+ </para>
+
+ <para>
+ The bulk registration / unregistration functions require
+ that struct crypto_alg is an array of count size. These
+ functions simply loop over that array and register /
+ unregister each individual algorithm. If an error occurs,
+ the loop is terminated at the offending algorithm definition.
+ That means, the algorithms prior to the offending algorithm
+ are successfully registered. Note, the caller has no way of
+ knowing which cipher implementations have successfully
+ registered. If this is important to know, the caller should
+ loop through the different implementations using the single
+ instance *_alg functions for each individual implementation.
+ </para>
+ </sect1>
+
+ <sect1><title>Single-Block Symmetric Ciphers [CIPHER]</title>
+ <para>
+ Example of transformations: aes, arc4, ...
+ </para>
+
+ <para>
+ This section describes the simplest of all transformation
+ implementations, that being the CIPHER type used for symmetric
+ ciphers. The CIPHER type is used for transformations which
+ operate on exactly one block at a time and there are no
+ dependencies between blocks at all.
+ </para>
+
+ <sect2><title>Registration specifics</title>
+ <para>
+ The registration of [CIPHER] algorithm is specific in that
+ struct crypto_alg field .cra_type is empty. The .cra_u.cipher
+ has to be filled in with proper callbacks to implement this
+ transformation.
+ </para>
+
+ <para>
+ See struct cipher_alg below.
+ </para>
+ </sect2>
+
+ <sect2><title>Cipher Definition With struct cipher_alg</title>
+ <para>
+ Struct cipher_alg defines a single block cipher.
+ </para>
+
+ <para>
+ Here are schematics of how these functions are called when
+ operated from other part of the kernel. Note that the
+ .cia_setkey() call might happen before or after any of these
+ schematics happen, but must not happen during any of these
+ are in-flight.
+ </para>
+
+ <para>
+ <programlisting>
+ KEY ---. PLAINTEXT ---.
+ v v
+ .cia_setkey() -> .cia_encrypt()
+ |
+ '-----> CIPHERTEXT
+ </programlisting>
+ </para>
+
+ <para>
+ Please note that a pattern where .cia_setkey() is called
+ multiple times is also valid:
+ </para>
+
+ <para>
+ <programlisting>
+
+ KEY1 --. PLAINTEXT1 --. KEY2 --. PLAINTEXT2 --.
+ v v v v
+ .cia_setkey() -> .cia_encrypt() -> .cia_setkey() -> .cia_encrypt()
+ | |
+ '---> CIPHERTEXT1 '---> CIPHERTEXT2
+ </programlisting>
+ </para>
+
+ </sect2>
+ </sect1>
+
+ <sect1><title>Multi-Block Ciphers [BLKCIPHER] [ABLKCIPHER]</title>
+ <para>
+ Example of transformations: cbc(aes), ecb(arc4), ...
+ </para>
+
+ <para>
+ This section describes the multi-block cipher transformation
+ implementations for both synchronous [BLKCIPHER] and
+ asynchronous [ABLKCIPHER] case. The multi-block ciphers are
+ used for transformations which operate on scatterlists of
+ data supplied to the transformation functions. They output
+ the result into a scatterlist of data as well.
+ </para>
+
+ <sect2><title>Registration Specifics</title>
+
+ <para>
+ The registration of [BLKCIPHER] or [ABLKCIPHER] algorithms
+ is one of the most standard procedures throughout the crypto API.
+ </para>
+
+ <para>
+ Note, if a cipher implementation requires a proper alignment
+ of data, the caller should use the functions of
+ crypto_blkcipher_alignmask() or crypto_ablkcipher_alignmask()
+ respectively to identify a memory alignment mask. The kernel
+ crypto API is able to process requests that are unaligned.
+ This implies, however, additional overhead as the kernel
+ crypto API needs to perform the realignment of the data which
+ may imply moving of data.
+ </para>
+ </sect2>
+
+ <sect2><title>Cipher Definition With struct blkcipher_alg and ablkcipher_alg</title>
+ <para>
+ Struct blkcipher_alg defines a synchronous block cipher whereas
+ struct ablkcipher_alg defines an asynchronous block cipher.
+ </para>
+
+ <para>
+ Please refer to the single block cipher description for schematics
+ of the block cipher usage. The usage patterns are exactly the same
+ for [ABLKCIPHER] and [BLKCIPHER] as they are for plain [CIPHER].
+ </para>
+ </sect2>
+
+ <sect2><title>Specifics Of Asynchronous Multi-Block Cipher</title>
+ <para>
+ There are a couple of specifics to the [ABLKCIPHER] interface.
+ </para>
+
+ <para>
+ First of all, some of the drivers will want to use the
+ Generic ScatterWalk in case the hardware needs to be fed
+ separate chunks of the scatterlist which contains the
+ plaintext and will contain the ciphertext. Please refer
+ to the ScatterWalk interface offered by the Linux kernel
+ scatter / gather list implementation.
+ </para>
+ </sect2>
+ </sect1>
+
+ <sect1><title>Hashing [HASH]</title>
+
+ <para>
+ Example of transformations: crc32, md5, sha1, sha256,...
+ </para>
+
+ <sect2><title>Registering And Unregistering The Transformation</title>
+
+ <para>
+ There are multiple ways to register a HASH transformation,
+ depending on whether the transformation is synchronous [SHASH]
+ or asynchronous [AHASH] and the amount of HASH transformations
+ we are registering. You can find the prototypes defined in
+ include/crypto/internal/hash.h:
+ </para>
+
+ <programlisting>
+ int crypto_register_ahash(struct ahash_alg *alg);
+
+ int crypto_register_shash(struct shash_alg *alg);
+ int crypto_register_shashes(struct shash_alg *algs, int count);
+ </programlisting>
+
+ <para>
+ The respective counterparts for unregistering the HASH
+ transformation are as follows:
+ </para>
+
+ <programlisting>
+ int crypto_unregister_ahash(struct ahash_alg *alg);
+
+ int crypto_unregister_shash(struct shash_alg *alg);
+ int crypto_unregister_shashes(struct shash_alg *algs, int count);
+ </programlisting>
+ </sect2>
+
+ <sect2><title>Cipher Definition With struct shash_alg and ahash_alg</title>
+ <para>
+ Here are schematics of how these functions are called when
+ operated from other part of the kernel. Note that the .setkey()
+ call might happen before or after any of these schematics happen,
+ but must not happen during any of these are in-flight. Please note
+ that calling .init() followed immediately by .finish() is also a
+ perfectly valid transformation.
+ </para>
+
+ <programlisting>
+ I) DATA -----------.
+ v
+ .init() -> .update() -> .final() ! .update() might not be called
+ ^ | | at all in this scenario.
+ '----' '---> HASH
+
+ II) DATA -----------.-----------.
+ v v
+ .init() -> .update() -> .finup() ! .update() may not be called
+ ^ | | at all in this scenario.
+ '----' '---> HASH
+
+ III) DATA -----------.
+ v
+ .digest() ! The entire process is handled
+ | by the .digest() call.
+ '---------------> HASH
+ </programlisting>
+
+ <para>
+ Here is a schematic of how the .export()/.import() functions are
+ called when used from another part of the kernel.
+ </para>
+
+ <programlisting>
+ KEY--. DATA--.
+ v v ! .update() may not be called
+ .setkey() -> .init() -> .update() -> .export() at all in this scenario.
+ ^ | |
+ '-----' '--> PARTIAL_HASH
+
+ ----------- other transformations happen here -----------
+
+ PARTIAL_HASH--. DATA1--.
+ v v
+ .import -> .update() -> .final() ! .update() may not be called
+ ^ | | at all in this scenario.
+ '----' '--> HASH1
+
+ PARTIAL_HASH--. DATA2-.
+ v v
+ .import -> .finup()
+ |
+ '---------------> HASH2
+ </programlisting>
+ </sect2>
+
+ <sect2><title>Specifics Of Asynchronous HASH Transformation</title>
+ <para>
+ Some of the drivers will want to use the Generic ScatterWalk
+ in case the implementation needs to be fed separate chunks of the
+ scatterlist which contains the input data. The buffer containing
+ the resulting hash will always be properly aligned to
+ .cra_alignmask so there is no need to worry about this.
+ </para>
+ </sect2>
+ </sect1>
+ </chapter>
+
+ <chapter id="API"><title>Programming Interface</title>
+ <sect1><title>Block Cipher Context Data Structures</title>
+!Pinclude/linux/crypto.h Block Cipher Context Data Structures
+!Finclude/linux/crypto.h aead_request
+ </sect1>
+ <sect1><title>Block Cipher Algorithm Definitions</title>
+!Pinclude/linux/crypto.h Block Cipher Algorithm Definitions
+!Finclude/linux/crypto.h crypto_alg
+!Finclude/linux/crypto.h ablkcipher_alg
+!Finclude/linux/crypto.h aead_alg
+!Finclude/linux/crypto.h blkcipher_alg
+!Finclude/linux/crypto.h cipher_alg
+!Finclude/linux/crypto.h rng_alg
+ </sect1>
+ <sect1><title>Asynchronous Block Cipher API</title>
+!Pinclude/linux/crypto.h Asynchronous Block Cipher API
+!Finclude/linux/crypto.h crypto_alloc_ablkcipher
+!Finclude/linux/crypto.h crypto_free_ablkcipher
+!Finclude/linux/crypto.h crypto_has_ablkcipher
+!Finclude/linux/crypto.h crypto_ablkcipher_ivsize
+!Finclude/linux/crypto.h crypto_ablkcipher_blocksize
+!Finclude/linux/crypto.h crypto_ablkcipher_setkey
+!Finclude/linux/crypto.h crypto_ablkcipher_reqtfm
+!Finclude/linux/crypto.h crypto_ablkcipher_encrypt
+!Finclude/linux/crypto.h crypto_ablkcipher_decrypt
+ </sect1>
+ <sect1><title>Asynchronous Cipher Request Handle</title>
+!Pinclude/linux/crypto.h Asynchronous Cipher Request Handle
+!Finclude/linux/crypto.h crypto_ablkcipher_reqsize
+!Finclude/linux/crypto.h ablkcipher_request_set_tfm
+!Finclude/linux/crypto.h ablkcipher_request_alloc
+!Finclude/linux/crypto.h ablkcipher_request_free
+!Finclude/linux/crypto.h ablkcipher_request_set_callback
+!Finclude/linux/crypto.h ablkcipher_request_set_crypt
+ </sect1>
+ <sect1><title>Authenticated Encryption With Associated Data (AEAD) Cipher API</title>
+!Pinclude/linux/crypto.h Authenticated Encryption With Associated Data (AEAD) Cipher API
+!Finclude/linux/crypto.h crypto_alloc_aead
+!Finclude/linux/crypto.h crypto_free_aead
+!Finclude/linux/crypto.h crypto_aead_ivsize
+!Finclude/linux/crypto.h crypto_aead_authsize
+!Finclude/linux/crypto.h crypto_aead_blocksize
+!Finclude/linux/crypto.h crypto_aead_setkey
+!Finclude/linux/crypto.h crypto_aead_setauthsize
+!Finclude/linux/crypto.h crypto_aead_encrypt
+!Finclude/linux/crypto.h crypto_aead_decrypt
+ </sect1>
+ <sect1><title>Asynchronous AEAD Request Handle</title>
+!Pinclude/linux/crypto.h Asynchronous AEAD Request Handle
+!Finclude/linux/crypto.h crypto_aead_reqsize
+!Finclude/linux/crypto.h aead_request_set_tfm
+!Finclude/linux/crypto.h aead_request_alloc
+!Finclude/linux/crypto.h aead_request_free
+!Finclude/linux/crypto.h aead_request_set_callback
+!Finclude/linux/crypto.h aead_request_set_crypt
+!Finclude/linux/crypto.h aead_request_set_assoc
+ </sect1>
+ <sect1><title>Synchronous Block Cipher API</title>
+!Pinclude/linux/crypto.h Synchronous Block Cipher API
+!Finclude/linux/crypto.h crypto_alloc_blkcipher
+!Finclude/linux/crypto.h crypto_free_blkcipher
+!Finclude/linux/crypto.h crypto_has_blkcipher
+!Finclude/linux/crypto.h crypto_blkcipher_name
+!Finclude/linux/crypto.h crypto_blkcipher_ivsize
+!Finclude/linux/crypto.h crypto_blkcipher_blocksize
+!Finclude/linux/crypto.h crypto_blkcipher_setkey
+!Finclude/linux/crypto.h crypto_blkcipher_encrypt
+!Finclude/linux/crypto.h crypto_blkcipher_encrypt_iv
+!Finclude/linux/crypto.h crypto_blkcipher_decrypt
+!Finclude/linux/crypto.h crypto_blkcipher_decrypt_iv
+!Finclude/linux/crypto.h crypto_blkcipher_set_iv
+!Finclude/linux/crypto.h crypto_blkcipher_get_iv
+ </sect1>
+ <sect1><title>Single Block Cipher API</title>
+!Pinclude/linux/crypto.h Single Block Cipher API
+!Finclude/linux/crypto.h crypto_alloc_cipher
+!Finclude/linux/crypto.h crypto_free_cipher
+!Finclude/linux/crypto.h crypto_has_cipher
+!Finclude/linux/crypto.h crypto_cipher_blocksize
+!Finclude/linux/crypto.h crypto_cipher_setkey
+!Finclude/linux/crypto.h crypto_cipher_encrypt_one
+!Finclude/linux/crypto.h crypto_cipher_decrypt_one
+ </sect1>
+ <sect1><title>Synchronous Message Digest API</title>
+!Pinclude/linux/crypto.h Synchronous Message Digest API
+!Finclude/linux/crypto.h crypto_alloc_hash
+!Finclude/linux/crypto.h crypto_free_hash
+!Finclude/linux/crypto.h crypto_has_hash
+!Finclude/linux/crypto.h crypto_hash_blocksize
+!Finclude/linux/crypto.h crypto_hash_digestsize
+!Finclude/linux/crypto.h crypto_hash_init
+!Finclude/linux/crypto.h crypto_hash_update
+!Finclude/linux/crypto.h crypto_hash_final
+!Finclude/linux/crypto.h crypto_hash_digest
+!Finclude/linux/crypto.h crypto_hash_setkey
+ </sect1>
+ <sect1><title>Message Digest Algorithm Definitions</title>
+!Pinclude/crypto/hash.h Message Digest Algorithm Definitions
+!Finclude/crypto/hash.h hash_alg_common
+!Finclude/crypto/hash.h ahash_alg
+!Finclude/crypto/hash.h shash_alg
+ </sect1>
+ <sect1><title>Asynchronous Message Digest API</title>
+!Pinclude/crypto/hash.h Asynchronous Message Digest API
+!Finclude/crypto/hash.h crypto_alloc_ahash
+!Finclude/crypto/hash.h crypto_free_ahash
+!Finclude/crypto/hash.h crypto_ahash_init
+!Finclude/crypto/hash.h crypto_ahash_digestsize
+!Finclude/crypto/hash.h crypto_ahash_reqtfm
+!Finclude/crypto/hash.h crypto_ahash_reqsize
+!Finclude/crypto/hash.h crypto_ahash_setkey
+!Finclude/crypto/hash.h crypto_ahash_finup
+!Finclude/crypto/hash.h crypto_ahash_final
+!Finclude/crypto/hash.h crypto_ahash_digest
+!Finclude/crypto/hash.h crypto_ahash_export
+!Finclude/crypto/hash.h crypto_ahash_import
+ </sect1>
+ <sect1><title>Asynchronous Hash Request Handle</title>
+!Pinclude/crypto/hash.h Asynchronous Hash Request Handle
+!Finclude/crypto/hash.h ahash_request_set_tfm
+!Finclude/crypto/hash.h ahash_request_alloc
+!Finclude/crypto/hash.h ahash_request_free
+!Finclude/crypto/hash.h ahash_request_set_callback
+!Finclude/crypto/hash.h ahash_request_set_crypt
+ </sect1>
+ <sect1><title>Synchronous Message Digest API</title>
+!Pinclude/crypto/hash.h Synchronous Message Digest API
+!Finclude/crypto/hash.h crypto_alloc_shash
+!Finclude/crypto/hash.h crypto_free_shash
+!Finclude/crypto/hash.h crypto_shash_blocksize
+!Finclude/crypto/hash.h crypto_shash_digestsize
+!Finclude/crypto/hash.h crypto_shash_descsize
+!Finclude/crypto/hash.h crypto_shash_setkey
+!Finclude/crypto/hash.h crypto_shash_digest
+!Finclude/crypto/hash.h crypto_shash_export
+!Finclude/crypto/hash.h crypto_shash_import
+!Finclude/crypto/hash.h crypto_shash_init
+!Finclude/crypto/hash.h crypto_shash_update
+!Finclude/crypto/hash.h crypto_shash_final
+!Finclude/crypto/hash.h crypto_shash_finup
+ </sect1>
+ <sect1><title>Crypto API Random Number API</title>
+!Pinclude/crypto/rng.h Random number generator API
+!Finclude/crypto/rng.h crypto_alloc_rng
+!Finclude/crypto/rng.h crypto_rng_alg
+!Finclude/crypto/rng.h crypto_free_rng
+!Finclude/crypto/rng.h crypto_rng_get_bytes
+!Finclude/crypto/rng.h crypto_rng_reset
+!Finclude/crypto/rng.h crypto_rng_seedsize
+!Cinclude/crypto/rng.h
+ </sect1>
+ </chapter>
+
+ <chapter id="Code"><title>Code Examples</title>
+ <sect1><title>Code Example For Asynchronous Block Cipher Operation</title>
+ <programlisting>
+
+struct tcrypt_result {
+ struct completion completion;
+ int err;
+};
+
+/* tie all data structures together */
+struct ablkcipher_def {
+ struct scatterlist sg;
+ struct crypto_ablkcipher *tfm;
+ struct ablkcipher_request *req;
+ struct tcrypt_result result;
+};
+
+/* Callback function */
+static void test_ablkcipher_cb(struct crypto_async_request *req, int error)
+{
+ struct tcrypt_result *result = req->data;
+
+ if (error == -EINPROGRESS)
+ return;
+ result->err = error;
+ complete(&result->completion);
+ pr_info("Encryption finished successfully\n");
+}
+
+/* Perform cipher operation */
+static unsigned int test_ablkcipher_encdec(struct ablkcipher_def *ablk,
+ int enc)
+{
+ int rc = 0;
+
+ if (enc)
+ rc = crypto_ablkcipher_encrypt(ablk->req);
+ else
+ rc = crypto_ablkcipher_decrypt(ablk->req);
+
+ switch (rc) {
+ case 0:
+ break;
+ case -EINPROGRESS:
+ case -EBUSY:
+ rc = wait_for_completion_interruptible(
+ &ablk->result.completion);
+ if (!rc && !ablk->result.err) {
+ reinit_completion(&ablk->result.completion);
+ break;
+ }
+ default:
+ pr_info("ablkcipher encrypt returned with %d result %d\n",
+ rc, ablk->result.err);
+ break;
+ }
+ init_completion(&ablk->result.completion);
+
+ return rc;
+}
+
+/* Initialize and trigger cipher operation */
+static int test_ablkcipher(void)
+{
+ struct ablkcipher_def ablk;
+ struct crypto_ablkcipher *ablkcipher = NULL;
+ struct ablkcipher_request *req = NULL;
+ char *scratchpad = NULL;
+ char *ivdata = NULL;
+ unsigned char key[32];
+ int ret = -EFAULT;
+
+ ablkcipher = crypto_alloc_ablkcipher("cbc-aes-aesni", 0, 0);
+ if (IS_ERR(ablkcipher)) {
+ pr_info("could not allocate ablkcipher handle\n");
+ return PTR_ERR(ablkcipher);
+ }
+
+ req = ablkcipher_request_alloc(ablkcipher, GFP_KERNEL);
+ if (IS_ERR(req)) {
+ pr_info("could not allocate request queue\n");
+ ret = PTR_ERR(req);
+ goto out;
+ }
+
+ ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ test_ablkcipher_cb,
+ &ablk.result);
+
+ /* AES 256 with random key */
+ get_random_bytes(&key, 32);
+ if (crypto_ablkcipher_setkey(ablkcipher, key, 32)) {
+ pr_info("key could not be set\n");
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ /* IV will be random */
+ ivdata = kmalloc(16, GFP_KERNEL);
+ if (!ivdata) {
+ pr_info("could not allocate ivdata\n");
+ goto out;
+ }
+ get_random_bytes(ivdata, 16);
+
+ /* Input data will be random */
+ scratchpad = kmalloc(16, GFP_KERNEL);
+ if (!scratchpad) {
+ pr_info("could not allocate scratchpad\n");
+ goto out;
+ }
+ get_random_bytes(scratchpad, 16);
+
+ ablk.tfm = ablkcipher;
+ ablk.req = req;
+
+ /* We encrypt one block */
+ sg_init_one(&ablk.sg, scratchpad, 16);
+ ablkcipher_request_set_crypt(req, &ablk.sg, &ablk.sg, 16, ivdata);
+ init_completion(&ablk.result.completion);
+
+ /* encrypt data */
+ ret = test_ablkcipher_encdec(&ablk, 1);
+ if (ret)
+ goto out;
+
+ pr_info("Encryption triggered successfully\n");
+
+out:
+ if (ablkcipher)
+ crypto_free_ablkcipher(ablkcipher);
+ if (req)
+ ablkcipher_request_free(req);
+ if (ivdata)
+ kfree(ivdata);
+ if (scratchpad)
+ kfree(scratchpad);
+ return ret;
+}
+ </programlisting>
+ </sect1>
+
+ <sect1><title>Code Example For Synchronous Block Cipher Operation</title>
+ <programlisting>
+
+static int test_blkcipher(void)
+{
+ struct crypto_blkcipher *blkcipher = NULL;
+ char *cipher = "cbc(aes)";
+ // AES 128
+ charkey =
+"\x12\x34\x56\x78\x90\xab\xcd\xef\x12\x34\x56\x78\x90\xab\xcd\xef";
+ chariv =
+"\x12\x34\x56\x78\x90\xab\xcd\xef\x12\x34\x56\x78\x90\xab\xcd\xef";
+ unsigned int ivsize = 0;
+ char *scratchpad = NULL; // holds plaintext and ciphertext
+ struct scatterlist sg;
+ struct blkcipher_desc desc;
+ int ret = -EFAULT;
+
+ blkcipher = crypto_alloc_blkcipher(cipher, 0, 0);
+ if (IS_ERR(blkcipher)) {
+ printk("could not allocate blkcipher handle for %s\n", cipher);
+ return -PTR_ERR(blkcipher);
+ }
+
+ if (crypto_blkcipher_setkey(blkcipher, key, strlen(key))) {
+ printk("key could not be set\n");
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ ivsize = crypto_blkcipher_ivsize(blkcipher);
+ if (ivsize) {
+ if (ivsize != strlen(iv))
+ printk("IV length differs from expected length\n");
+ crypto_blkcipher_set_iv(blkcipher, iv, ivsize);
+ }
+
+ scratchpad = kmalloc(crypto_blkcipher_blocksize(blkcipher), GFP_KERNEL);
+ if (!scratchpad) {
+ printk("could not allocate scratchpad for %s\n", cipher);
+ goto out;
+ }
+ /* get some random data that we want to encrypt */
+ get_random_bytes(scratchpad, crypto_blkcipher_blocksize(blkcipher));
+
+ desc.flags = 0;
+ desc.tfm = blkcipher;
+ sg_init_one(&sg, scratchpad, crypto_blkcipher_blocksize(blkcipher));
+
+ /* encrypt data in place */
+ crypto_blkcipher_encrypt(&desc, &sg, &sg,
+ crypto_blkcipher_blocksize(blkcipher));
+
+ /* decrypt data in place
+ * crypto_blkcipher_decrypt(&desc, &sg, &sg,
+ */ crypto_blkcipher_blocksize(blkcipher));
+
+
+ printk("Cipher operation completed\n");
+ return 0;
+
+out:
+ if (blkcipher)
+ crypto_free_blkcipher(blkcipher);
+ if (scratchpad)
+ kzfree(scratchpad);
+ return ret;
+}
+ </programlisting>
+ </sect1>
+
+ <sect1><title>Code Example For Use of Operational State Memory With SHASH</title>
+ <programlisting>
+
+struct sdesc {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static struct sdescinit_sdesc(struct crypto_shash *alg)
+{
+ struct sdescsdesc;
+ int size;
+
+ size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
+ sdesc = kmalloc(size, GFP_KERNEL);
+ if (!sdesc)
+ return ERR_PTR(-ENOMEM);
+ sdesc->shash.tfm = alg;
+ sdesc->shash.flags = 0x0;
+ return sdesc;
+}
+
+static int calc_hash(struct crypto_shashalg,
+ const unsigned chardata, unsigned int datalen,
+ unsigned chardigest) {
+ struct sdescsdesc;
+ int ret;
+
+ sdesc = init_sdesc(alg);
+ if (IS_ERR(sdesc)) {
+ pr_info("trusted_key: can't alloc %s\n", hash_alg);
+ return PTR_ERR(sdesc);
+ }
+
+ ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
+ kfree(sdesc);
+ return ret;
+}
+ </programlisting>
+ </sect1>
+
+ <sect1><title>Code Example For Random Number Generator Usage</title>
+ <programlisting>
+
+static int get_random_numbers(u8 *buf, unsigned int len)
+{
+ struct crypto_rngrng = NULL;
+ chardrbg = "drbg_nopr_sha256"; /* Hash DRBG with SHA-256, no PR */
+ int ret;
+
+ if (!buf || !len) {
+ pr_debug("No output buffer provided\n");
+ return -EINVAL;
+ }
+
+ rng = crypto_alloc_rng(drbg, 0, 0);
+ if (IS_ERR(rng)) {
+ pr_debug("could not allocate RNG handle for %s\n", drbg);
+ return -PTR_ERR(rng);
+ }
+
+ ret = crypto_rng_get_bytes(rng, buf, len);
+ if (ret < 0)
+ pr_debug("generation of random numbers failed\n");
+ else if (ret == 0)
+ pr_debug("RNG returned no data");
+ else
+ pr_debug("RNG returned %d bytes of data\n", ret);
+
+out:
+ crypto_free_rng(rng);
+ return ret;
+}
+ </programlisting>
+ </sect1>
+ </chapter>
+ </book>
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 02/13] crypto: Documentation - compile crypto API spec
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 01/13] crypto: Documentation - crypto API high level spec Stephan Mueller
@ 2014-11-12 4:24 ` Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 03/13] crypto: Documentation - userspace interface spec Stephan Mueller
` (11 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:24 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
Add the crypto API documentation into the DocBook Makefile to allow it
being compiled
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
Documentation/DocBook/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index bec0665..9c7d92d 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -15,7 +15,7 @@ DOCBOOKS := z8530book.xml device-drivers.xml \
80211.xml debugobjects.xml sh.xml regulator.xml \
alsa-driver-api.xml writing-an-alsa-driver.xml \
tracepoint.xml drm.xml media_api.xml w1.xml \
- writing_musb_glue_layer.xml
+ writing_musb_glue_layer.xml crypto-API.xml
include Documentation/DocBook/media/Makefile
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 03/13] crypto: Documentation - userspace interface spec
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 01/13] crypto: Documentation - crypto API high level spec Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 02/13] crypto: Documentation - compile crypto API spec Stephan Mueller
@ 2014-11-12 4:24 ` Stephan Mueller
2014-11-12 4:25 ` [PATCH v3 04/13] crypto: Documentation - RNG API documentation Stephan Mueller
` (10 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:24 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The userspace interface of the kernel crypto API is documented with
* a general explanation
* a discussion of the memory in-place operation
* the description of the message digest API
* the description of the symmetric cipher API
The documentation refers to libkcapi as a working example on how to use
the kernel crypto API from user space.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
Documentation/crypto/crypto-API-userspace.txt | 205 ++++++++++++++++++++++++++
1 file changed, 205 insertions(+)
create mode 100644 Documentation/crypto/crypto-API-userspace.txt
diff --git a/Documentation/crypto/crypto-API-userspace.txt b/Documentation/crypto/crypto-API-userspace.txt
new file mode 100644
index 0000000..ac619cd
--- /dev/null
+++ b/Documentation/crypto/crypto-API-userspace.txt
@@ -0,0 +1,205 @@
+Introduction
+============
+
+The concepts of the kernel crypto API visible to kernel space is fully
+applicable to the user space interface as well. Therefore, the kernel crypto API
+high level discussion for the in-kernel use cases applies here as well.
+
+The major difference, however, is that user space can only act as a consumer
+and never as a provider of a transformation or cipher algorithm.
+
+The following covers the user space interface exported by the kernel crypto
+API. A working example of this description is libkcapi that can be obtained from
+[1]. That library can be used by user space applications that require
+cryptographic services from the kernel.
+
+Some details of the in-kernel kernel crypto API aspects do not
+apply to user space, however. This includes the difference between synchronous
+and asynchronous invocations. The user space API call is fully synchronous.
+In addition, only a subset of all cipher types are available as documented
+below.
+
+
+User space API general remarks
+==============================
+
+The kernel crypto API is accessible from user space. Currently, the following
+ciphers are accessible:
+
+ * Message digest including keyed message digest (HMAC, CMAC)
+
+ * Symmetric ciphers
+
+Note, AEAD ciphers are currently not supported via the symmetric cipher
+interface.
+
+The interface is provided via Netlink using the type AF_ALG. In addition, the
+setsockopt option type is SOL_ALG. In case the user space header files do not
+export these flags yet, use the following macros:
+
+#ifndef AF_ALG
+#define AF_ALG 38
+#endif
+#ifndef SOL_ALG
+#define SOL_ALG 279
+#endif
+
+A cipher is accessed with the same name as done for the in-kernel API calls.
+This includes the generic vs. unique naming schema for ciphers as well as the
+enforcement of priorities for generic names.
+
+To interact with the kernel crypto API, a Netlink socket must be created by
+the user space application. User space invokes the cipher operation with the
+send/write system call family. The result of the cipher operation is obtained
+with the read/recv system call family.
+
+The following API calls assume that the Netlink socket descriptor is already
+opened by the user space application and discusses only the kernel crypto API
+specific invocations.
+
+To initialize a Netlink interface, the following sequence has to be performed
+by the consumer:
+
+ 1. Create a socket of type AF_ALG with the struct sockaddr_alg parameter
+ specified below for the different cipher types.
+
+ 2. Invoke bind with the socket descriptor
+
+ 3. Invoke accept with the socket descriptor. The accept system call
+ returns a new file descriptor that is to be used to interact with
+ the particular cipher instance. When invoking send/write or recv/read
+ system calls to send data to the kernel or obtain data from the
+ kernel, the file descriptor returned by accept must be used.
+
+In-place cipher operation
+=========================
+
+Just like the in-kernel operation of the kernel crypto API, the user space
+interface allows the cipher operation in-place. That means that the input buffer
+used for the send/write system call and the output buffer used by the read/recv
+system call may be one and the same. This is of particular interest for
+symmetric cipher operations where a copying of the output data to its final
+destination can be avoided.
+
+If a consumer on the other hand wants to maintain the plaintext and the
+ciphertext in different memory locations, all a consumer needs to do is to
+provide different memory pointers for the encryption and decryption operation.
+
+Message digest API
+==================
+
+The message digest type to be used for the cipher operation is selected when
+invoking the bind syscall. bind requires the caller to provide a filled
+struct sockaddr data structure. This data structure must be filled as follows:
+
+struct sockaddr_alg sa = {
+ .salg_family = AF_ALG,
+ .salg_type = "hash", /* this selects the hash logic in the kernel */
+ .salg_name = "sha1" /* this is the cipher name */
+};
+
+The salg_type value "hash" applies to message digests and keyed message digests.
+Though, a keyed message digest is referenced by the appropriate salg_name.
+Please see below for the setsockopt interface that explains how the key can be
+set for a keyed message digest.
+
+Using the send() system call, the application provides the data that should be
+processed with the message digest. The send system call allows the following
+flags to be specified:
+
+ * MSG_MORE: If this flag is set, the send system call acts like a
+ message digest update function where the final hash is not
+ yet calculated. If the flag is not set, the send system call
+ calculates the final message digest immediately.
+
+With the recv() system call, the application can read the message digest from
+the kernel crypto API. If the buffer is too small for the message digest, the
+flag MSG_TRUNC is set by the kernel.
+
+In order to set a message digest key, the calling application must use the
+setsockopt() option of ALG_SET_KEY. If the key is not set the HMAC operation is
+performed without the initial HMAC state change caused by the key.
+
+
+Symmetric cipher API
+====================
+
+The operation is very similar to the message digest discussion. During
+initialization, the struct sockaddr data structure must be filled as follows:
+
+struct sockaddr_alg sa = {
+ .salg_family = AF_ALG,
+ .salg_type = "skcipher", /* this selects the symmetric cipher */
+ .salg_name = "cbc(aes)" /* this is the cipher name */
+};
+
+Before data can be sent to the kernel using the write/send system call family,
+the consumer must set the key. The key setting is described with the setsockopt
+invocation below.
+
+Using the sendmsg() system call, the application provides the data that should
+be processed for encryption or decryption. In addition, the IV is specified
+with the data structure provided by the sendmsg() system call.
+
+The sendmsg system call parameter of struct msghdr is embedded into the
+struct cmsghdr data structure. See recv(2) and cmsg(3) for more information
+on how the cmsghdr data structure is used together with the send/recv system
+call family. That cmsghdr data structure holds the following information
+specified with a separate header instances:
+
+ * specification of the cipher operation type with one of these flags:
+ ALG_OP_ENCRYPT - encryption of data
+ ALG_OP_DECRYPT - decryption of data
+
+ * specification of the IV information marked with the flag ALG_SET_IV
+
+The send system call family allows the following flag to be specified:
+
+ * MSG_MORE: If this flag is set, the send system call acts like a
+ cipher update function where more input data is expected
+ with a subsequent invocation of the send system call.
+
+Note: The kernel reports -EINVAL for any unexpected data. The caller must
+make sure that all data matches the constraints given in /proc/crypto for the
+selected cipher.
+
+With the recv() system call, the application can read the result of the
+cipher operation from the kernel crypto API. The output buffer must be at least
+as large as to hold all blocks of the encrypted or decrypted data. If the output
+data size is smaller, only as many blocks are returned that fit into that
+output buffer size.
+
+Setsockopt interface
+====================
+
+In addition to the read/recv and send/write system call handling to send and
+retrieve data subject to the cipher operation, a consumer also needs to set
+the additional information for the cipher operation. This additional information
+is set using the setsockopt system call that must be invoked with the file
+descriptor of the open cipher (i.e. the file descriptor returned by the
+accept system call).
+
+Each setsockopt invocation must use the level SOL_ALG.
+
+The setsockopt interface allows setting the following data using the mentioned
+optname:
+
+ * ALG_SET_KEY -- Setting the key. Key setting is applicable to:
+
+ - the skcipher cipher type (symmetric ciphers)
+
+ - the hash cipher type (keyed message digests)
+
+User space API example
+======================
+
+Please see [1] for libkcapi which provides an easy-to-use wrapper around the
+aforementioned Netlink kernel interface. [1] also contains a test application
+that invokes all libkcapi API calls.
+
+[1] http://www.chronox.de/libkcapi.html
+
+Author
+======
+
+Stephan Mueller <smueller@chronox.de>
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 04/13] crypto: Documentation - RNG API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (2 preceding siblings ...)
2014-11-12 4:24 ` [PATCH v3 03/13] crypto: Documentation - userspace interface spec Stephan Mueller
@ 2014-11-12 4:25 ` Stephan Mueller
2014-11-12 4:26 ` [PATCH v3 05/13] crypto: Documentation - hash data structures Stephan Mueller
` (9 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:25 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for RNGs to
be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/crypto/rng.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 80 insertions(+)
diff --git a/include/crypto/rng.h b/include/crypto/rng.h
index c93f9b9..a16fb10 100644
--- a/include/crypto/rng.h
+++ b/include/crypto/rng.h
@@ -20,11 +20,38 @@ extern struct crypto_rng *crypto_default_rng;
int crypto_get_default_rng(void);
void crypto_put_default_rng(void);
+/**
+ * DOC: Random number generator API
+ *
+ * The random number generator API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto)
+ */
+
static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
{
return (struct crypto_rng *)tfm;
}
+/**
+ * crypto_alloc_rng() -- allocate RNG handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * message digest cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a random number generator. The returned struct
+ * crypto_rng is the cipher handle that is required for any subsequent
+ * API invocation for that random number generator.
+ *
+ * For all random number generators, this call creates a new private copy of
+ * the random number generator that does not share a state with other
+ * instances. The only exception is the "krng" random number generator which
+ * is a kernel crypto API use case for the get_random_bytes() function of the
+ * /dev/random driver.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name,
u32 type, u32 mask)
{
@@ -40,6 +67,14 @@ static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
return &tfm->base;
}
+/**
+ * crypto_rng_alg - obtain name of RNG
+ * @tfm: cipher handle
+ *
+ * Return the generic name (cra_name) of the initialized random number generator
+ *
+ * Return: generic name string
+ */
static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
{
return &crypto_rng_tfm(tfm)->__crt_alg->cra_rng;
@@ -50,23 +85,68 @@ static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm)
return &crypto_rng_tfm(tfm)->crt_rng;
}
+/**
+ * crypto_free_rng() - zeroize and free RNG handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_rng(struct crypto_rng *tfm)
{
crypto_free_tfm(crypto_rng_tfm(tfm));
}
+/**
+ * crypto_rng_get_bytes() - get random number
+ * @tfm: cipher handle
+ * @rdata: output buffer holding the random numbers
+ * @dlen: length of the output buffer
+ *
+ * This function fills the caller-allocated buffer with random numbers using the
+ * random number generator referenced by the cipher handle.
+ *
+ * Return: > 0 function was successful and returns the number of generated
+ * bytes; < 0 if an error occurred
+ */
static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
u8 *rdata, unsigned int dlen)
{
return crypto_rng_crt(tfm)->rng_gen_random(tfm, rdata, dlen);
}
+/**
+ * crypto_rng_reset() - re-initialize the RNG
+ * @tfm: cipher handle
+ * @seed: seed input data
+ * @slen: length of the seed input data
+ *
+ * The reset function completely re-initializes the random number generator
+ * referenced by the cipher handle by clearing the current state. The new state
+ * is initialized with the caller provided seed or automatically, depending
+ * on the random number generator type (the ANSI X9.31 RNG requires
+ * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding).
+ * The seed is provided as a parameter to this function call. The provided seed
+ * should have the length of the seed size defined for the random number
+ * generator as defined by crypto_rng_seedsize.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_rng_reset(struct crypto_rng *tfm,
u8 *seed, unsigned int slen)
{
return crypto_rng_crt(tfm)->rng_reset(tfm, seed, slen);
}
+/**
+ * crypto_rng_seedsize() - obtain seed size of RNG
+ * @tfm: cipher handle
+ *
+ * The function returns the seed size for the random number generator
+ * referenced by the cipher handle. This value may be zero if the random
+ * number generator does not implement or require a reseeding. For example,
+ * the SP800-90A DRBGs implement an automated reseeding after reaching a
+ * pre-defined threshold.
+ *
+ * Return: seed size for the random number generator
+ */
static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
{
return crypto_rng_alg(tfm)->seedsize;
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 05/13] crypto: Documentation - hash data structures
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (3 preceding siblings ...)
2014-11-12 4:25 ` [PATCH v3 04/13] crypto: Documentation - RNG API documentation Stephan Mueller
@ 2014-11-12 4:26 ` Stephan Mueller
2014-11-12 4:26 ` [PATCH v3 06/13] crypto: Documentation - AHASH API documentation Stephan Mueller
` (8 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:26 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The hash data structures needed to be filled in by cipher developers are
documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/crypto/hash.h | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 95 insertions(+)
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 74b13ec..bf458fc 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -17,6 +17,28 @@
struct crypto_ahash;
+/**
+ * DOC: Message Digest Algorithm Definitions
+ *
+ * These data structures define modular message digest algorithm
+ * implementations, managed via crypto_register_ahash(),
+ * crypto_register_shash(), crypto_unregister_ahash() and
+ * crypto_unregister_shash().
+ */
+
+/**
+ * struct hash_alg_common - define properties of message digest
+ * @digestsize: Size of the result of the transformation. A buffer of this size
+ * must be available to the @final and @finup calls, so they can
+ * store the resulting hash into it. For various predefined sizes,
+ * search include/crypto/ using
+ * git grep _DIGEST_SIZE include/crypto.
+ * @statesize: Size of the block for partial state of the transformation. A
+ * buffer of this size must be passed to the @export function as it
+ * will save the partial state of the transformation into it. On the
+ * other side, the @import function will load the state from a
+ * buffer of this size as well.
+ */
struct hash_alg_common {
unsigned int digestsize;
unsigned int statesize;
@@ -37,6 +59,62 @@ struct ahash_request {
void *__ctx[] CRYPTO_MINALIGN_ATTR;
};
+/**
+ * struct ahash_alg - asynchronous message digest definition
+ * @init: Initialize the transformation context. Intended only to initialize the
+ * state of the HASH transformation at the begining. This shall fill in
+ * the internal structures used during the entire duration of the whole
+ * transformation. No data processing happens at this point.
+ * @update: Push a chunk of data into the driver for transformation. This
+ * function actually pushes blocks of data from upper layers into the
+ * driver, which then passes those to the hardware as seen fit. This
+ * function must not finalize the HASH transformation by calculating the
+ * final message digest as this only adds more data into the
+ * transformation. This function shall not modify the transformation
+ * context, as this function may be called in parallel with the same
+ * transformation object. Data processing can happen synchronously
+ * [SHASH] or asynchronously [AHASH] at this point.
+ * @final: Retrieve result from the driver. This function finalizes the
+ * transformation and retrieves the resulting hash from the driver and
+ * pushes it back to upper layers. No data processing happens at this
+ * point.
+ * @finup: Combination of @update and @final. This function is effectively a
+ * combination of @update and @final calls issued in sequence. As some
+ * hardware cannot do @update and @final separately, this callback was
+ * added to allow such hardware to be used at least by IPsec. Data
+ * processing can happen synchronously [SHASH] or asynchronously [AHASH]
+ * at this point.
+ * @digest: Combination of @init and @update and @final. This function
+ * effectively behaves as the entire chain of operations, @init,
+ * @update and @final issued in sequence. Just like @finup, this was
+ * added for hardware which cannot do even the @finup, but can only do
+ * the whole transformation in one run. Data processing can happen
+ * synchronously [SHASH] or asynchronously [AHASH] at this point.
+ * @setkey: Set optional key used by the hashing algorithm. Intended to push
+ * optional key used by the hashing algorithm from upper layers into
+ * the driver. This function can store the key in the transformation
+ * context or can outright program it into the hardware. In the former
+ * case, one must be careful to program the key into the hardware at
+ * appropriate time and one must be careful that .setkey() can be
+ * called multiple times during the existence of the transformation
+ * object. Not all hashing algorithms do implement this function as it
+ * is only needed for keyed message digests. SHAx/MDx/CRCx do NOT
+ * implement this function. HMAC(MDx)/HMAC(SHAx)/CMAC(AES) do implement
+ * this function. This function must be called before any other of the
+ * @init, @update, @final, @finup, @digest is called. No data
+ * processing happens at this point.
+ * @export: Export partial state of the transformation. This function dumps the
+ * entire state of the ongoing transformation into a provided block of
+ * data so it can be @import 'ed back later on. This is useful in case
+ * you want to save partial result of the transformation after
+ * processing certain amount of data and reload this partial result
+ * multiple times later on for multiple re-use. No data processing
+ * happens at this point.
+ * @import: Import partial state of the transformation. This function loads the
+ * entire state of the ongoing transformation from a provided block of
+ * data so the transformation can continue from this point onward. No
+ * data processing happens at this point.
+ */
struct ahash_alg {
int (*init)(struct ahash_request *req);
int (*update)(struct ahash_request *req);
@@ -63,6 +141,23 @@ struct shash_desc {
crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
struct shash_desc *shash = (struct shash_desc *)__##shash##_desc
+/**
+ * struct shash_alg - synchronous message digest definition
+ * @init: see struct ahash_alg
+ * @update: see struct ahash_alg
+ * @final: see struct ahash_alg
+ * @finup: see struct ahash_alg
+ * @digest: see struct ahash_alg
+ * @export: see struct ahash_alg
+ * @import: see struct ahash_alg
+ * @setkey: see struct ahash_alg
+ * @digestsize: see struct ahash_alg
+ * @statesize: see struct ahash_alg
+ * @dedcsize: Size of the operational state for the message digest. This state
+ * size is the memory size that needs to be allocated for
+ * shash_desc.__ctx
+ * @base: internally used
+ */
struct shash_alg {
int (*init)(struct shash_desc *desc);
int (*update)(struct shash_desc *desc, const u8 *data,
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 06/13] crypto: Documentation - AHASH API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (4 preceding siblings ...)
2014-11-12 4:26 ` [PATCH v3 05/13] crypto: Documentation - hash data structures Stephan Mueller
@ 2014-11-12 4:26 ` Stephan Mueller
2014-11-12 4:27 ` [PATCH v3 07/13] crypto: Documentation - SHASH " Stephan Mueller
` (7 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:26 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for AHASHes
to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/crypto/hash.h | 228 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 228 insertions(+)
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index bf458fc..b2c193a 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -202,11 +202,35 @@ struct crypto_shash {
struct crypto_tfm base;
};
+/**
+ * DOC: Asynchronous Message Digest API
+ *
+ * The asynchronous message digest API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_AHASH (listed as type "ahash" in /proc/crypto)
+ *
+ * The asynchronous cipher operation discussion provided for the
+ * CRYPTO_ALG_TYPE_ABLKCIPHER API applies here as well.
+ */
+
static inline struct crypto_ahash *__crypto_ahash_cast(struct crypto_tfm *tfm)
{
return container_of(tfm, struct crypto_ahash, base);
}
+/**
+ * crypto_alloc_ahash() - allocate ahash cipher handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * ahash cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for an ahash. The returned struct
+ * crypto_ahash is the cipher handle that is required for any subsequent
+ * API invocation for that ahash.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
u32 mask);
@@ -215,6 +239,10 @@ static inline struct crypto_tfm *crypto_ahash_tfm(struct crypto_ahash *tfm)
return &tfm->base;
}
+/**
+ * crypto_free_ahash() - zeroize and free the ahash handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_ahash(struct crypto_ahash *tfm)
{
crypto_destroy_tfm(tfm, crypto_ahash_tfm(tfm));
@@ -238,6 +266,16 @@ static inline struct hash_alg_common *crypto_hash_alg_common(
return __crypto_hash_alg_common(crypto_ahash_tfm(tfm)->__crt_alg);
}
+/**
+ * crypto_ahash_digestsize() - obtain message digest size
+ * @tfm: cipher handle
+ *
+ * The size for the message digest created by the message digest cipher
+ * referenced with the cipher handle is returned.
+ *
+ *
+ * Return: message digest size of cipher
+ */
static inline unsigned int crypto_ahash_digestsize(struct crypto_ahash *tfm)
{
return crypto_hash_alg_common(tfm)->digestsize;
@@ -263,12 +301,32 @@ static inline void crypto_ahash_clear_flags(struct crypto_ahash *tfm, u32 flags)
crypto_tfm_clear_flags(crypto_ahash_tfm(tfm), flags);
}
+/**
+ * crypto_ahash_reqtfm() - obtain cipher handle from request
+ * @req: asynchronous request handle that contains the reference to the ahash
+ * cipher handle
+ *
+ * Return the ahash cipher handle that is registered with the asynchronous
+ * request handle ahash_request.
+ *
+ * Return: ahash cipher handle
+ */
static inline struct crypto_ahash *crypto_ahash_reqtfm(
struct ahash_request *req)
{
return __crypto_ahash_cast(req->base.tfm);
}
+/**
+ * crypto_ahash_reqsize() - obtain size of the request data structure
+ * @tfm: cipher handle
+ *
+ * Return the size of the ahash state size. With the crypto_ahash_export
+ * function, the caller can export the state into a buffer whose size is
+ * defined with this function.
+ *
+ * Return: size of the ahash state
+ */
static inline unsigned int crypto_ahash_reqsize(struct crypto_ahash *tfm)
{
return tfm->reqsize;
@@ -279,38 +337,166 @@ static inline void *ahash_request_ctx(struct ahash_request *req)
return req->__ctx;
}
+/**
+ * crypto_ahash_setkey - set key for cipher handle
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the ahash cipher. The cipher
+ * handle must point to a keyed hash in order for this function to succeed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen);
+
+/**
+ * crypto_ahash_finup() - update and finalize message digest
+ * @req: reference to the ahash_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * This function is a "short-hand" for the function calls of
+ * crypto_ahash_update and crypto_shash_final. The parameters have the same
+ * meaning as discussed for those separate functions.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_ahash_finup(struct ahash_request *req);
+
+/**
+ * crypto_ahash_final() - calculate message digest
+ * @req: reference to the ahash_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * Finalize the message digest operation and create the message digest
+ * based on all data added to the cipher handle. The message digest is placed
+ * into the output buffer registered with the ahash_request handle.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_ahash_final(struct ahash_request *req);
+
+/**
+ * crypto_ahash_digest() - calculate message digest for a buffer
+ * @req: reference to the ahash_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * This function is a "short-hand" for the function calls of crypto_ahash_init,
+ * crypto_ahash_update and crypto_ahash_final. The parameters have the same
+ * meaning as discussed for those separate three functions.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_ahash_digest(struct ahash_request *req);
+/**
+ * crypto_ahash_export() - extract current message digest state
+ * @req: reference to the ahash_request handle whose state is exported
+ * @out: output buffer of sufficient size that can hold the hash state
+ *
+ * This function exports the hash state of the ahash_request handle into the
+ * caller-allocated output buffer out which must have sufficient size (e.g. by
+ * calling crypto_ahash_reqsize).
+ *
+ * Return: 0 if the export was successful; < 0 if an error occurred
+ */
static inline int crypto_ahash_export(struct ahash_request *req, void *out)
{
return crypto_ahash_reqtfm(req)->export(req, out);
}
+/**
+ * crypto_ahash_import() - import message digest state
+ * @req: reference to ahash_request handle the state is imported into
+ * @in: buffer holding the state
+ *
+ * This function imports the hash state into the ahash_request handle from the
+ * input buffer. That buffer should have been generated with the
+ * crypto_ahash_export function.
+ *
+ * Return: 0 if the import was successful; < 0 if an error occurred
+ */
static inline int crypto_ahash_import(struct ahash_request *req, const void *in)
{
return crypto_ahash_reqtfm(req)->import(req, in);
}
+/**
+ * crypto_ahash_init() - (re)initialize message digest handle
+ * @req: ahash_request handle that already is initialized with all necessary
+ * data using the ahash_request_* API functions
+ *
+ * The call (re-)initializes the message digest referenced by the ahash_request
+ * handle. Any potentially existing state created by previous operations is
+ * discarded.
+ *
+ * Return: 0 if the message digest initialization was successful; < 0 if an
+ * error occurred
+ */
static inline int crypto_ahash_init(struct ahash_request *req)
{
return crypto_ahash_reqtfm(req)->init(req);
}
+/**
+ * crypto_ahash_update() - add data to message digest for processing
+ * @req: ahash_request handle that was previously initialized with the
+ * crypto_ahash_init call.
+ *
+ * Updates the message digest state of the &ahash_request handle. The input data
+ * is pointed to by the scatter/gather list registered in the &ahash_request
+ * handle
+ *
+ * Return: 0 if the message digest update was successful; < 0 if an error
+ * occurred
+ */
static inline int crypto_ahash_update(struct ahash_request *req)
{
return crypto_ahash_reqtfm(req)->update(req);
}
+/**
+ * DOC: Asynchronous Hash Request Handle
+ *
+ * The &ahash_request data structure contains all pointers to data
+ * required for the asynchronous cipher operation. This includes the cipher
+ * handle (which can be used by multiple &ahash_request instances), pointer
+ * to plaintext and the message digest output buffer, asynchronous callback
+ * function, etc. It acts as a handle to the ahash_request_* API calls in a
+ * similar way as ahash handle to the crypto_ahash_* API calls.
+ */
+
+/**
+ * ahash_request_set_tfm() - update cipher handle reference in request
+ * @req: request handle to be modified
+ * @tfm: cipher handle that shall be added to the request handle
+ *
+ * Allow the caller to replace the existing ahash handle in the request
+ * data structure with a different one.
+ */
static inline void ahash_request_set_tfm(struct ahash_request *req,
struct crypto_ahash *tfm)
{
req->base.tfm = crypto_ahash_tfm(tfm);
}
+/**
+ * ahash_request_alloc() - allocate request data structure
+ * @tfm: cipher handle to be registered with the request
+ * @gfp: memory allocation flag that is handed to kmalloc by the API call.
+ *
+ * Allocate the request data structure that must be used with the ahash
+ * message digest API calls. During
+ * the allocation, the provided ahash handle
+ * is registered in the request data structure.
+ *
+ * Return: allocated request handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct ahash_request *ahash_request_alloc(
struct crypto_ahash *tfm, gfp_t gfp)
{
@@ -325,6 +511,10 @@ static inline struct ahash_request *ahash_request_alloc(
return req;
}
+/**
+ * ahash_request_free() - zeroize and free the request data structure
+ * @req: request data structure cipher handle to be freed
+ */
static inline void ahash_request_free(struct ahash_request *req)
{
kzfree(req);
@@ -336,6 +526,31 @@ static inline struct ahash_request *ahash_request_cast(
return container_of(req, struct ahash_request, base);
}
+/**
+ * ahash_request_set_callback() - set asynchronous callback function
+ * @req: request handle
+ * @flags: specify zero or an ORing of the flags
+ * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
+ * increase the wait queue beyond the initial maximum size;
+ * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
+ * @compl: callback function pointer to be registered with the request handle
+ * @data: The data pointer refers to memory that is not used by the kernel
+ * crypto API, but provided to the callback function for it to use. Here,
+ * the caller can provide a reference to memory the callback function can
+ * operate on. As the callback function is invoked asynchronously to the
+ * related functionality, it may need to access data structures of the
+ * related functionality which can be referenced using this pointer. The
+ * callback function can access the memory via the "data" field in the
+ * &crypto_async_request data structure provided to the callback function.
+ *
+ * This function allows setting the callback function that is triggered once
+ * the cipher operation completes.
+ *
+ * The callback function is registered with the &ahash_request handle and
+ * must comply with the following template
+ *
+ * void callback_function(struct crypto_async_request *req, int error)
+ */
static inline void ahash_request_set_callback(struct ahash_request *req,
u32 flags,
crypto_completion_t compl,
@@ -346,6 +561,19 @@ static inline void ahash_request_set_callback(struct ahash_request *req,
req->base.flags = flags;
}
+/**
+ * ahash_request_set_crypt() - set data buffers
+ * @req: ahash_request handle to be updated
+ * @src: source scatter/gather list
+ * @result: buffer that is filled with the message digest -- the caller must
+ * ensure that the buffer has sufficient space by, for example, calling
+ * crypto_ahash_digestsize()
+ * @nbytes: number of bytes to process from the source scatter/gather list
+ *
+ * By using this call, the caller references the source scatter/gather list.
+ * The source scatter/gather list points to the data the message digest is to
+ * be calculated for.
+ */
static inline void ahash_request_set_crypt(struct ahash_request *req,
struct scatterlist *src, u8 *result,
unsigned int nbytes)
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 07/13] crypto: Documentation - SHASH API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (5 preceding siblings ...)
2014-11-12 4:26 ` [PATCH v3 06/13] crypto: Documentation - AHASH API documentation Stephan Mueller
@ 2014-11-12 4:27 ` Stephan Mueller
2014-11-12 4:27 ` [PATCH v3 08/13] crypto: Documentation - cipher data structures Stephan Mueller
` (6 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:27 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for SHASHes
to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/crypto/hash.h | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 164 insertions(+)
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index b2c193a..3d66e8b 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -583,6 +583,33 @@ static inline void ahash_request_set_crypt(struct ahash_request *req,
req->result = result;
}
+/**
+ * DOC: Synchronous Message Digest API
+ *
+ * The synchronous message digest API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_SHASH (listed as type "shash" in /proc/crypto)
+ *
+ * The message digest API is able to maintain state information for the
+ * caller.
+ *
+ * The synchronous message digest API can store user-related context in in its
+ * shash_desc request data structure.
+ */
+
+/**
+ * crypto_alloc_shash() - allocate message digest handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * message digest cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a message digest. The returned &struct
+ * crypto_shash is the cipher handle that is required for any subsequent
+ * API invocation for that message digest.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
u32 mask);
@@ -591,6 +618,10 @@ static inline struct crypto_tfm *crypto_shash_tfm(struct crypto_shash *tfm)
return &tfm->base;
}
+/**
+ * crypto_free_shash() - zeroize and free the message digest handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_shash(struct crypto_shash *tfm)
{
crypto_destroy_tfm(tfm, crypto_shash_tfm(tfm));
@@ -602,6 +633,15 @@ static inline unsigned int crypto_shash_alignmask(
return crypto_tfm_alg_alignmask(crypto_shash_tfm(tfm));
}
+/**
+ * crypto_shash_blocksize() - obtain block size for cipher
+ * @tfm: cipher handle
+ *
+ * The block size for the message digest cipher referenced with the cipher
+ * handle is returned.
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_shash_blocksize(struct crypto_shash *tfm)
{
return crypto_tfm_alg_blocksize(crypto_shash_tfm(tfm));
@@ -617,6 +657,15 @@ static inline struct shash_alg *crypto_shash_alg(struct crypto_shash *tfm)
return __crypto_shash_alg(crypto_shash_tfm(tfm)->__crt_alg);
}
+/**
+ * crypto_shash_digestsize() - obtain message digest size
+ * @tfm: cipher handle
+ *
+ * The size for the message digest created by the message digest cipher
+ * referenced with the cipher handle is returned.
+ *
+ * Return: digest size of cipher
+ */
static inline unsigned int crypto_shash_digestsize(struct crypto_shash *tfm)
{
return crypto_shash_alg(tfm)->digestsize;
@@ -642,6 +691,21 @@ static inline void crypto_shash_clear_flags(struct crypto_shash *tfm, u32 flags)
crypto_tfm_clear_flags(crypto_shash_tfm(tfm), flags);
}
+/**
+ * crypto_shash_descsize() - obtain the operational state size
+ * @tfm: cipher handle
+ *
+ * The size of the operational state the cipher needs during operation is
+ * returned for the hash referenced with the cipher handle. This size is
+ * required to calculate the memory requirements to allow the caller allocating
+ * sufficient memory for operational state.
+ *
+ * The operational state is defined with struct shash_desc where the size of
+ * that data structure is to be calculated as
+ * sizeof(struct shash_desc) + crypto_shash_descsize(alg)
+ *
+ * Return: size of the operational state
+ */
static inline unsigned int crypto_shash_descsize(struct crypto_shash *tfm)
{
return tfm->descsize;
@@ -652,29 +716,129 @@ static inline void *shash_desc_ctx(struct shash_desc *desc)
return desc->__ctx;
}
+/**
+ * crypto_shash_setkey() - set key for message digest
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the keyed message digest cipher. The
+ * cipher handle must point to a keyed message digest cipher in order for this
+ * function to succeed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen);
+
+/**
+ * crypto_shash_digest() - calculate message digest for buffer
+ * @desc: see crypto_shash_final()
+ * @data: see crypto_shash_update()
+ * @len: see crypto_shash_update()
+ * @out: see crypto_shash_final()
+ *
+ * This function is a "short-hand" for the function calls of crypto_shash_init,
+ * crypto_shash_update and crypto_shash_final. The parameters have the same
+ * meaning as discussed for those separate three functions.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out);
+/**
+ * crypto_shash_export() - extract operational state for message digest
+ * @desc: reference to the operational state handle whose state is exported
+ * @out: output buffer of sufficient size that can hold the hash state
+ *
+ * This function exports the hash state of the operational state handle into the
+ * caller-allocated output buffer out which must have sufficient size (e.g. by
+ * calling crypto_shash_descsize).
+ *
+ * Return: 0 if the export creation was successful; < 0 if an error occurred
+ */
static inline int crypto_shash_export(struct shash_desc *desc, void *out)
{
return crypto_shash_alg(desc->tfm)->export(desc, out);
}
+/**
+ * crypto_shash_import() - import operational state
+ * @desc: reference to the operational state handle the state imported into
+ * @in: buffer holding the state
+ *
+ * This function imports the hash state into the operational state handle from
+ * the input buffer. That buffer should have been generated with the
+ * crypto_ahash_export function.
+ *
+ * Return: 0 if the import was successful; < 0 if an error occurred
+ */
static inline int crypto_shash_import(struct shash_desc *desc, const void *in)
{
return crypto_shash_alg(desc->tfm)->import(desc, in);
}
+/**
+ * crypto_shash_init() - (re)initialize message digest
+ * @desc: operational state handle that is already filled
+ *
+ * The call (re-)initializes the message digest referenced by the
+ * operational state handle. Any potentially existing state created by
+ * previous operations is discarded.
+ *
+ * Return: 0 if the message digest initialization was successful; < 0 if an
+ * error occurred
+ */
static inline int crypto_shash_init(struct shash_desc *desc)
{
return crypto_shash_alg(desc->tfm)->init(desc);
}
+/**
+ * crypto_shash_update() - add data to message digest for processing
+ * @desc: operational state handle that is already initialized
+ * @data: input data to be added to the message digest
+ * @len: length of the input data
+ *
+ * Updates the message digest state of the operational state handle.
+ *
+ * Return: 0 if the message digest update was successful; < 0 if an error
+ * occurred
+ */
int crypto_shash_update(struct shash_desc *desc, const u8 *data,
unsigned int len);
+
+/**
+ * crypto_shash_final() - calculate message digest
+ * @desc: operational state handle that is already filled with data
+ * @out: output buffer filled with the message digest
+ *
+ * Finalize the message digest operation and create the message digest
+ * based on all data added to the cipher handle. The message digest is placed
+ * into the output buffer. The caller must ensure that the output buffer is
+ * large enough by using crypto_shash_digestsize.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_shash_final(struct shash_desc *desc, u8 *out);
+
+/**
+ * crypto_shash_finup() - calculate message digest of buffer
+ * @desc: see crypto_shash_final()
+ * @data: see crypto_shash_update()
+ * @len: see crypto_shash_update()
+ * @out: see crypto_shash_final()
+ *
+ * This function is a "short-hand" for the function calls of
+ * crypto_shash_update and crypto_shash_final. The parameters have the same
+ * meaning as discussed for those separate functions.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out);
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 08/13] crypto: Documentation - cipher data structures
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (6 preceding siblings ...)
2014-11-12 4:27 ` [PATCH v3 07/13] crypto: Documentation - SHASH " Stephan Mueller
@ 2014-11-12 4:27 ` Stephan Mueller
2014-11-12 4:28 ` [PATCH v3 09/13] crypto: Documentation - ABLKCIPHER API documentation Stephan Mueller
` (5 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:27 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The data structure of struct crypto_alg together with various other
data structures needed by cipher developers is documented wit all
parameters that can be set by a developer of a transformation. All
parameters that are internal to the crypto API are marked as such.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 246 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 243 insertions(+), 3 deletions(-)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index d45e949..752360e 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -127,6 +127,13 @@ struct skcipher_givcrypt_request;
typedef void (*crypto_completion_t)(struct crypto_async_request *req, int err);
+/**
+ * DOC: Block Cipher Context Data Structures
+ *
+ * These data structures define the operating context for each block cipher
+ * type.
+ */
+
struct crypto_async_request {
struct list_head list;
crypto_completion_t complete;
@@ -194,9 +201,63 @@ struct hash_desc {
u32 flags;
};
-/*
- * Algorithms: modular crypto algorithm implementations, managed
- * via crypto_register_alg() and crypto_unregister_alg().
+/**
+ * DOC: Block Cipher Algorithm Definitions
+ *
+ * These data structures define modular crypto algorithm implementations,
+ * managed via crypto_register_alg() and crypto_unregister_alg().
+ */
+
+/**
+ * struct ablkcipher_alg - asynchronous block cipher definition
+ * @min_keysize: Minimum key size supported by the transformation. This is the
+ * smallest key length supported by this transformation algorithm.
+ * This must be set to one of the pre-defined values as this is
+ * not hardware specific. Possible values for this field can be
+ * found via git grep "_MIN_KEY_SIZE" include/crypto/
+ * @max_keysize: Maximum key size supported by the transformation. This is the
+ * largest key length supported by this transformation algorithm.
+ * This must be set to one of the pre-defined values as this is
+ * not hardware specific. Possible values for this field can be
+ * found via git grep "_MAX_KEY_SIZE" include/crypto/
+ * @setkey: Set key for the transformation. This function is used to either
+ * program a supplied key into the hardware or store the key in the
+ * transformation context for programming it later. Note that this
+ * function does modify the transformation context. This function can
+ * be called multiple times during the existence of the transformation
+ * object, so one must make sure the key is properly reprogrammed into
+ * the hardware. This function is also responsible for checking the key
+ * length for validity. In case a software fallback was put in place in
+ * the @cra_init call, this function might need to use the fallback if
+ * the algorithm doesn't support all of the key sizes.
+ * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
+ * the supplied scatterlist containing the blocks of data. The crypto
+ * API consumer is responsible for aligning the entries of the
+ * scatterlist properly and making sure the chunks are correctly
+ * sized. In case a software fallback was put in place in the
+ * @cra_init call, this function might need to use the fallback if
+ * the algorithm doesn't support all of the key sizes. In case the
+ * key was stored in transformation context, the key might need to be
+ * re-programmed into the hardware in this function. This function
+ * shall not modify the transformation context, as this function may
+ * be called in parallel with the same transformation object.
+ * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
+ * and the conditions are exactly the same.
+ * @givencrypt: Update the IV for encryption. With this function, a cipher
+ * implementation may provide the function on how to update the IV
+ * for encryption.
+ * @givdecrypt: Update the IV for decryption. This is the reverse of
+ * @givencrypt .
+ * @geniv: The transformation implementation may use an "IV generator" provided
+ * by the kernel crypto API. Several use cases have a predefined
+ * approach how IVs are to be updated. For such use cases, the kernel
+ * crypto API provides ready-to-use implementations that can be
+ * referenced with this variable.
+ * @ivsize: IV size applicable for transformation. The consumer must provide an
+ * IV of exactly that size to perform the encrypt or decrypt operation.
+ *
+ * All fields except @givencrypt , @givdecrypt , @geniv and @ivsize are
+ * mandatory and must be filled.
*/
struct ablkcipher_alg {
int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
@@ -213,6 +274,32 @@ struct ablkcipher_alg {
unsigned int ivsize;
};
+/**
+ * struct aead_alg - AEAD cipher definition
+ * @maxauthsize: Set the maximum authentication tag size supported by the
+ * transformation. A transformation may support smaller tag sizes.
+ * As the authentication tag is a message digest to ensure the
+ * integrity of the encrypted data, a consumer typically wants the
+ * largest authentication tag possible as defined by this
+ * variable.
+ * @setauthsize: Set authentication size for the AEAD transformation. This
+ * function is used to specify the consumer requested size of the
+ * authentication tag to be either generated by the transformation
+ * during encryption or the size of the authentication tag to be
+ * supplied during the decryption operation. This function is also
+ * responsible for checking the authentication tag size for
+ * validity.
+ * @setkey: see struct ablkcipher_alg
+ * @encrypt: see struct ablkcipher_alg
+ * @decrypt: see struct ablkcipher_alg
+ * @givencrypt: see struct ablkcipher_alg
+ * @givdecrypt: see struct ablkcipher_alg
+ * @geniv: see struct ablkcipher_alg
+ * @ivsize: see struct ablkcipher_alg
+ *
+ * All fields except @givencrypt , @givdecrypt , @geniv and @ivsize are
+ * mandatory and must be filled.
+ */
struct aead_alg {
int (*setkey)(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen);
@@ -228,6 +315,18 @@ struct aead_alg {
unsigned int maxauthsize;
};
+/**
+ * struct blkcipher_alg - synchronous block cipher definition
+ * @min_keysize: see struct ablkcipher_alg
+ * @max_keysize: see struct ablkcipher_alg
+ * @setkey: see struct ablkcipher_alg
+ * @encrypt: see struct ablkcipher_alg
+ * @decrypt: see struct ablkcipher_alg
+ * @geniv: see struct ablkcipher_alg
+ * @ivsize: see struct ablkcipher_alg
+ *
+ * All fields except @geniv and @ivsize are mandatory and must be filled.
+ */
struct blkcipher_alg {
int (*setkey)(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen);
@@ -245,6 +344,53 @@ struct blkcipher_alg {
unsigned int ivsize;
};
+/**
+ * struct cipher_alg - single-block symmetric ciphers definition
+ * @cia_min_keysize: Minimum key size supported by the transformation. This is
+ * the smallest key length supported by this transformation
+ * algorithm. This must be set to one of the pre-defined
+ * values as this is not hardware specific. Possible values
+ * for this field can be found via git grep "_MIN_KEY_SIZE"
+ * include/crypto/
+ * @cia_max_keysize: Maximum key size supported by the transformation. This is
+ * the largest key length supported by this transformation
+ * algorithm. This must be set to one of the pre-defined values
+ * as this is not hardware specific. Possible values for this
+ * field can be found via git grep "_MAX_KEY_SIZE"
+ * include/crypto/
+ * @cia_setkey: Set key for the transformation. This function is used to either
+ * program a supplied key into the hardware or store the key in the
+ * transformation context for programming it later. Note that this
+ * function does modify the transformation context. This function
+ * can be called multiple times during the existence of the
+ * transformation object, so one must make sure the key is properly
+ * reprogrammed into the hardware. This function is also
+ * responsible for checking the key length for validity.
+ * @cia_encrypt: Encrypt a single block. This function is used to encrypt a
+ * single block of data, which must be @cra_blocksize big. This
+ * always operates on a full @cra_blocksize and it is not possible
+ * to encrypt a block of smaller size. The supplied buffers must
+ * therefore also be at least of @cra_blocksize size. Both the
+ * input and output buffers are always aligned to @cra_alignmask.
+ * In case either of the input or output buffer supplied by user
+ * of the crypto API is not aligned to @cra_alignmask, the crypto
+ * API will re-align the buffers. The re-alignment means that a
+ * new buffer will be allocated, the data will be copied into the
+ * new buffer, then the processing will happen on the new buffer,
+ * then the data will be copied back into the original buffer and
+ * finally the new buffer will be freed. In case a software
+ * fallback was put in place in the @cra_init call, this function
+ * might need to use the fallback if the algorithm doesn't support
+ * all of the key sizes. In case the key was stored in
+ * transformation context, the key might need to be re-programmed
+ * into the hardware in this function. This function shall not
+ * modify the transformation context, as this function may be
+ * called in parallel with the same transformation object.
+ * @cia_decrypt: Decrypt a single block. This is a reverse counterpart to
+ * @cia_encrypt, and the conditions are exactly the same.
+ *
+ * All fields are mandatory and must be filled.
+ */
struct cipher_alg {
unsigned int cia_min_keysize;
unsigned int cia_max_keysize;
@@ -261,6 +407,25 @@ struct compress_alg {
unsigned int slen, u8 *dst, unsigned int *dlen);
};
+/**
+ * struct rng_alg - random number generator definition
+ * @rng_make_random: The function defined by this variable obtains a random
+ * number. The random number generator transform must generate
+ * the random number out of the context provided with this
+ * call.
+ * @rng_reset: Reset of the random number generator by clearing the entire state.
+ * With the invocation of this function call, the random number
+ * generator shall completely reinitialize its state. If the random
+ * number generator requires a seed for setting up a new state,
+ * the seed must be provided by the consumer while invoking this
+ * function. The required size of the seed is defined with
+ * @seedsize .
+ * @seedsize: The seed size required for a random number generator
+ * initialization defined with this variable. Some random number
+ * generators like the SP800-90A DRBG does not require a seed as the
+ * seeding is implemented internally without the need of support by
+ * the consumer. In this case, the seed size is set to zero.
+ */
struct rng_alg {
int (*rng_make_random)(struct crypto_rng *tfm, u8 *rdata,
unsigned int dlen);
@@ -277,6 +442,81 @@ struct rng_alg {
#define cra_compress cra_u.compress
#define cra_rng cra_u.rng
+/**
+ * struct crypto_alg - definition of a cryptograpic cipher algorithm
+ * @cra_flags: Flags describing this transformation. See include/linux/crypto.h
+ * CRYPTO_ALG_* flags for the flags which go in here. Those are
+ * used for fine-tuning the description of the transformation
+ * algorithm.
+ * @cra_blocksize: Minimum block size of this transformation. The size in bytes
+ * of the smallest possible unit which can be transformed with
+ * this algorithm. The users must respect this value.
+ * In case of HASH transformation, it is possible for a smaller
+ * block than @cra_blocksize to be passed to the crypto API for
+ * transformation, in case of any other transformation type, an
+ * error will be returned upon any attempt to transform smaller
+ * than @cra_blocksize chunks.
+ * @cra_ctxsize: Size of the operational context of the transformation. This
+ * value informs the kernel crypto API about the memory size
+ * needed to be allocated for the transformation context.
+ * @cra_alignmask: Alignment mask for the input and output data buffer. The data
+ * buffer containing the input data for the algorithm must be
+ * aligned to this alignment mask. The data buffer for the
+ * output data must be aligned to this alignment mask. Note that
+ * the Crypto API will do the re-alignment in software, but
+ * only under special conditions and there is a performance hit.
+ * The re-alignment happens at these occasions for different
+ * @cra_u types: cipher -- For both input data and output data
+ * buffer; ahash -- For output hash destination buf; shash --
+ * For output hash destination buf.
+ * This is needed on hardware which is flawed by design and
+ * cannot pick data from arbitrary addresses.
+ * @cra_priority: Priority of this transformation implementation. In case
+ * multiple transformations with same @cra_name are available to
+ * the Crypto API, the kernel will use the one with highest
+ * @cra_priority.
+ * @cra_name: Generic name (usable by multiple implementations) of the
+ * transformation algorithm. This is the name of the transformation
+ * itself. This field is used by the kernel when looking up the
+ * providers of particular transformation.
+ * @cra_driver_name: Unique name of the transformation provider. This is the
+ * name of the provider of the transformation. This can be any
+ * arbitrary value, but in the usual case, this contains the
+ * name of the chip or provider and the name of the
+ * transformation algorithm.
+ * @cra_type: Type of the cryptographic transformation. This is a pointer to
+ * struct crypto_type, which implements callbacks common for all
+ * trasnformation types. There are multiple options:
+ * &crypto_blkcipher_type, &crypto_ablkcipher_type,
+ * &crypto_ahash_type, &crypto_aead_type, &crypto_rng_type.
+ * This field might be empty. In that case, there are no common
+ * callbacks. This is the case for: cipher, compress, shash.
+ * @cra_u: Callbacks implementing the transformation. This is a union of
+ * multiple structures. Depending on the type of transformation selected
+ * by @cra_type and @cra_flags above, the associated structure must be
+ * filled with callbacks. This field might be empty. This is the case
+ * for ahash, shash.
+ * @cra_init: Initialize the cryptographic transformation object. This function
+ * is used to initialize the cryptographic transformation object.
+ * This function is called only once at the instantiation time, right
+ * after the transformation context was allocated. In case the
+ * cryptographic hardware has some special requirements which need to
+ * be handled by software, this function shall check for the precise
+ * requirement of the transformation and put any software fallbacks
+ * in place.
+ * @cra_exit: Deinitialize the cryptographic transformation object. This is a
+ * counterpart to @cra_init, used to remove various changes set in
+ * @cra_init.
+ * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
+ * @cra_list: internally used
+ * @cra_users: internally used
+ * @cra_refcnt: internally used
+ * @cra_destroy: internally used
+ *
+ * The struct crypto_alg describes a generic Crypto API algorithm and is common
+ * for all of the transformations. Any variable not documented here shall not
+ * be used by a cipher implementation as it is internal to the Crypto API.
+ */
struct crypto_alg {
struct list_head cra_list;
struct list_head cra_users;
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 09/13] crypto: Documentation - ABLKCIPHER API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (7 preceding siblings ...)
2014-11-12 4:27 ` [PATCH v3 08/13] crypto: Documentation - cipher data structures Stephan Mueller
@ 2014-11-12 4:28 ` Stephan Mueller
2014-11-12 4:29 ` [PATCH v3 10/13] crypto: Documentation - AEAD " Stephan Mueller
` (4 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:28 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for
asynchronous block ciphers to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 206 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 206 insertions(+)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 752360e..39c8fc6 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -821,6 +821,50 @@ static inline u32 crypto_skcipher_mask(u32 mask)
return mask;
}
+/**
+ * DOC: Asynchronous Block Cipher API
+ *
+ * Asynchronous block cipher API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_ABLKCIPHER (listed as type "ablkcipher" in /proc/crypto).
+ *
+ * Asynchronous cipher operations imply that the function invocation for a
+ * cipher request returns immediately before the completion of the operation.
+ * The cipher request is scheduled as a separate kernel thread and therefore
+ * load-balanced on the different CPUs via the process scheduler. To allow
+ * the kernel crypto API to inform the caller about the completion of a cipher
+ * request, the caller must provide a callback function. That function is
+ * invoked with the cipher handle when the request completes.
+ *
+ * To support the asynchronous operation, additional information than just the
+ * cipher handle must be supplied to the kernel crypto API. That additional
+ * information is given by filling in the ablkcipher_request data structure.
+ *
+ * For the asynchronous block cipher API, the state is maintained with the tfm
+ * cipher handle. A single tfm can be used across multiple calls and in
+ * parallel. For asynchronous block cipher calls, context data supplied and
+ * only used by the caller can be referenced the request data structure in
+ * addition to the IV used for the cipher request. The maintenance of such
+ * state information would be important for a crypto driver implementer to
+ * have, because when calling the callback function upon completion of the
+ * cipher operation, that callback function may need some information about
+ * which operation just finished if it invoked multiple in parallel. This
+ * state information is unused by the kernel crypto API.
+ */
+
+/**
+ * crypto_alloc_ablkcipher() - allocate asynchronous block cipher handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * ablkcipher cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for an ablkcipher. The returned struct
+ * crypto_ablkcipher is the cipher handle that is required for any subsequent
+ * API invocation for that ablkcipher.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
u32 type, u32 mask);
@@ -830,11 +874,25 @@ static inline struct crypto_tfm *crypto_ablkcipher_tfm(
return &tfm->base;
}
+/**
+ * crypto_free_ablkcipher() - zeroize and free cipher handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_ablkcipher(struct crypto_ablkcipher *tfm)
{
crypto_free_tfm(crypto_ablkcipher_tfm(tfm));
}
+/**
+ * crypto_has_ablkcipher() - Search for the availability of an ablkcipher.
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * ablkcipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Return: true when the ablkcipher is known to the kernel crypto API; false
+ * otherwise
+ */
static inline int crypto_has_ablkcipher(const char *alg_name, u32 type,
u32 mask)
{
@@ -848,12 +906,31 @@ static inline struct ablkcipher_tfm *crypto_ablkcipher_crt(
return &crypto_ablkcipher_tfm(tfm)->crt_ablkcipher;
}
+/**
+ * crypto_ablkcipher_ivsize() - obtain IV size
+ * @tfm: cipher handle
+ *
+ * The size of the IV for the ablkcipher referenced by the cipher handle is
+ * returned. This IV size may be zero if the cipher does not need an IV.
+ *
+ * Return: IV size in bytes
+ */
static inline unsigned int crypto_ablkcipher_ivsize(
struct crypto_ablkcipher *tfm)
{
return crypto_ablkcipher_crt(tfm)->ivsize;
}
+/**
+ * crypto_ablkcipher_blocksize() - obtain block size of cipher
+ * @tfm: cipher handle
+ *
+ * The block size for the ablkcipher referenced with the cipher handle is
+ * returned. The caller may use that information to allocate appropriate
+ * memory for the data returned by the encryption or decryption operation
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_ablkcipher_blocksize(
struct crypto_ablkcipher *tfm)
{
@@ -883,6 +960,22 @@ static inline void crypto_ablkcipher_clear_flags(struct crypto_ablkcipher *tfm,
crypto_tfm_clear_flags(crypto_ablkcipher_tfm(tfm), flags);
}
+/**
+ * crypto_ablkcipher_setkey() - set key for cipher
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the ablkcipher referenced by the cipher
+ * handle.
+ *
+ * Note, the key length determines the cipher type. Many block ciphers implement
+ * different cipher modes depending on the key size, such as AES-128 vs AES-192
+ * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
+ * is performed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_ablkcipher_setkey(struct crypto_ablkcipher *tfm,
const u8 *key, unsigned int keylen)
{
@@ -891,12 +984,32 @@ static inline int crypto_ablkcipher_setkey(struct crypto_ablkcipher *tfm,
return crt->setkey(crt->base, key, keylen);
}
+/**
+ * crypto_ablkcipher_reqtfm() - obtain cipher handle from request
+ * @req: ablkcipher_request out of which the cipher handle is to be obtained
+ *
+ * Return the crypto_ablkcipher handle when furnishing an ablkcipher_request
+ * data structure.
+ *
+ * Return: crypto_ablkcipher handle
+ */
static inline struct crypto_ablkcipher *crypto_ablkcipher_reqtfm(
struct ablkcipher_request *req)
{
return __crypto_ablkcipher_cast(req->base.tfm);
}
+/**
+ * crypto_ablkcipher_encrypt() - encrypt plaintext
+ * @req: reference to the ablkcipher_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * Encrypt plaintext data using the ablkcipher_request handle. That data
+ * structure and how it is filled with data is discussed with the
+ * ablkcipher_request_* functions.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
{
struct ablkcipher_tfm *crt =
@@ -904,6 +1017,17 @@ static inline int crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
return crt->encrypt(req);
}
+/**
+ * crypto_ablkcipher_decrypt() - decrypt ciphertext
+ * @req: reference to the ablkcipher_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * Decrypt ciphertext data using the ablkcipher_request handle. That data
+ * structure and how it is filled with data is discussed with the
+ * ablkcipher_request_* functions.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
{
struct ablkcipher_tfm *crt =
@@ -911,12 +1035,37 @@ static inline int crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
return crt->decrypt(req);
}
+/**
+ * DOC: Asynchronous Cipher Request Handle
+ *
+ * The ablkcipher_request data structure contains all pointers to data
+ * required for the asynchronous cipher operation. This includes the cipher
+ * handle (which can be used by multiple ablkcipher_request instances), pointer
+ * to plaintext and ciphertext, asynchronous callback function, etc. It acts
+ * as a handle to the ablkcipher_request_* API calls in a similar way as
+ * ablkcipher handle to the crypto_ablkcipher_* API calls.
+ */
+
+/**
+ * crypto_ablkcipher_reqsize() - obtain size of the request data structure
+ * @tfm: cipher handle
+ *
+ * Return: number of bytes
+ */
static inline unsigned int crypto_ablkcipher_reqsize(
struct crypto_ablkcipher *tfm)
{
return crypto_ablkcipher_crt(tfm)->reqsize;
}
+/**
+ * ablkcipher_request_set_tfm() - update cipher handle reference in request
+ * @req: request handle to be modified
+ * @tfm: cipher handle that shall be added to the request handle
+ *
+ * Allow the caller to replace the existing ablkcipher handle in the request
+ * data structure with a different one.
+ */
static inline void ablkcipher_request_set_tfm(
struct ablkcipher_request *req, struct crypto_ablkcipher *tfm)
{
@@ -929,6 +1078,18 @@ static inline struct ablkcipher_request *ablkcipher_request_cast(
return container_of(req, struct ablkcipher_request, base);
}
+/**
+ * ablkcipher_request_alloc() - allocate request data structure
+ * @tfm: cipher handle to be registered with the request
+ * @gfp: memory allocation flag that is handed to kmalloc by the API call.
+ *
+ * Allocate the request data structure that must be used with the ablkcipher
+ * encrypt and decrypt API calls. During the allocation, the provided ablkcipher
+ * handle is registered in the request data structure.
+ *
+ * Return: allocated request handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct ablkcipher_request *ablkcipher_request_alloc(
struct crypto_ablkcipher *tfm, gfp_t gfp)
{
@@ -943,11 +1104,40 @@ static inline struct ablkcipher_request *ablkcipher_request_alloc(
return req;
}
+/**
+ * ablkcipher_request_free() - zeroize and free request data structure
+ * @req: request data structure cipher handle to be freed
+ */
static inline void ablkcipher_request_free(struct ablkcipher_request *req)
{
kzfree(req);
}
+/**
+ * ablkcipher_request_set_callback() - set asynchronous callback function
+ * @req: request handle
+ * @flags: specify zero or an ORing of the flags
+ * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
+ * increase the wait queue beyond the initial maximum size;
+ * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
+ * @compl: callback function pointer to be registered with the request handle
+ * @data: The data pointer refers to memory that is not used by the kernel
+ * crypto API, but provided to the callback function for it to use. Here,
+ * the caller can provide a reference to memory the callback function can
+ * operate on. As the callback function is invoked asynchronously to the
+ * related functionality, it may need to access data structures of the
+ * related functionality which can be referenced using this pointer. The
+ * callback function can access the memory via the "data" field in the
+ * crypto_async_request data structure provided to the callback function.
+ *
+ * This function allows setting the callback function that is triggered once the
+ * cipher operation completes.
+ *
+ * The callback function is registered with the ablkcipher_request handle and
+ * must comply with the following template:
+ *
+ * void callback_function(struct crypto_async_request *req, int error)
+ */
static inline void ablkcipher_request_set_callback(
struct ablkcipher_request *req,
u32 flags, crypto_completion_t compl, void *data)
@@ -957,6 +1147,22 @@ static inline void ablkcipher_request_set_callback(
req->base.flags = flags;
}
+/**
+ * ablkcipher_request_set_crypt() - set data buffers
+ * @req: request handle
+ * @src: source scatter / gather list
+ * @dst: destination scatter / gather list
+ * @nbytes: number of bytes to process from @src
+ * @iv: IV for the cipher operation which must comply with the IV size defined
+ * by crypto_ablkcipher_ivsize
+ *
+ * This function allows setting of the source data and destination data
+ * scatter / gather lists.
+ *
+ * For encryption, the source is treated as the plaintext and the
+ * destination is the ciphertext. For a decryption operation, the use is
+ * reversed: the source is the ciphertext and the destination is the plaintext.
+ */
static inline void ablkcipher_request_set_crypt(
struct ablkcipher_request *req,
struct scatterlist *src, struct scatterlist *dst,
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 10/13] crypto: Documentation - AEAD API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (8 preceding siblings ...)
2014-11-12 4:28 ` [PATCH v3 09/13] crypto: Documentation - ABLKCIPHER API documentation Stephan Mueller
@ 2014-11-12 4:29 ` Stephan Mueller
2014-11-12 4:29 ` [PATCH v3 11/13] crypto: Documentation - BLKCIPHER " Stephan Mueller
` (3 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:29 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for AEAD
ciphers to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 251 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 251 insertions(+)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 39c8fc6..4704e71 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -1174,11 +1174,55 @@ static inline void ablkcipher_request_set_crypt(
req->info = iv;
}
+/**
+ * DOC: Authenticated Encryption With Associated Data (AEAD) Cipher API
+ *
+ * The AEAD cipher API is used with the ciphers of type CRYPTO_ALG_TYPE_AEAD
+ * (listed as type "aead" in /proc/crypto)
+ *
+ * The most prominent examples for this type of encryption is GCM and CCM.
+ * However, the kernel supports other types of AEAD ciphers which are defined
+ * with the following cipher string:
+ *
+ * authenc(keyed message digest, block cipher)
+ *
+ * For example: authenc(hmac(sha256), cbc(aes))
+ *
+ * The example code provided for the asynchronous block cipher operation
+ * applies here as well. Naturally all *ablkcipher* symbols must be exchanged
+ * the *aead* pendants discussed in the following. In addtion, for the AEAD
+ * operation, the aead_request_set_assoc function must be used to set the
+ * pointer to the associated data memory location before performing the
+ * encryption or decryption operation. In case of an encryption, the associated
+ * data memory is filled during the encryption operation. For decryption, the
+ * associated data memory must contain data that is used to verify the integrity
+ * of the decrypted data. Another deviation from the asynchronous block cipher
+ * operation is that the caller should explicitly check for -EBADMSG of the
+ * crypto_aead_decrypt. That error indicates an authentication error, i.e.
+ * a breach in the integrity of the message. In essence, that -EBADMSG error
+ * code is the key bonus an AEAD cipher has over "standard" block chaining
+ * modes.
+ */
+
static inline struct crypto_aead *__crypto_aead_cast(struct crypto_tfm *tfm)
{
return (struct crypto_aead *)tfm;
}
+/**
+ * crypto_alloc_aead() - allocate AEAD cipher handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * AEAD cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for an AEAD. The returned struct
+ * crypto_aead is the cipher handle that is required for any subsequent
+ * API invocation for that AEAD.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask);
static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm)
@@ -1186,6 +1230,10 @@ static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm)
return &tfm->base;
}
+/**
+ * crypto_free_aead() - zeroize and free aead handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_aead(struct crypto_aead *tfm)
{
crypto_free_tfm(crypto_aead_tfm(tfm));
@@ -1196,16 +1244,47 @@ static inline struct aead_tfm *crypto_aead_crt(struct crypto_aead *tfm)
return &crypto_aead_tfm(tfm)->crt_aead;
}
+/**
+ * crypto_aead_ivsize() - obtain IV size
+ * @tfm: cipher handle
+ *
+ * The size of the IV for the aead referenced by the cipher handle is
+ * returned. This IV size may be zero if the cipher does not need an IV.
+ *
+ * Return: IV size in bytes
+ */
static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm)
{
return crypto_aead_crt(tfm)->ivsize;
}
+/**
+ * crypto_aead_authsize() - obtain maximum authentication data size
+ * @tfm: cipher handle
+ *
+ * The maximum size of the authentication data for the AEAD cipher referenced
+ * by the AEAD cipher handle is returned. The authentication data size may be
+ * zero if the cipher implements a hard-coded maximum.
+ *
+ * The authentication data may also be known as "tag value".
+ *
+ * Return: authentication data size / tag size in bytes
+ */
static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm)
{
return crypto_aead_crt(tfm)->authsize;
}
+/**
+ * crypto_aead_blocksize() - obtain block size of cipher
+ * @tfm: cipher handle
+ *
+ * The block size for the AEAD referenced with the cipher handle is returned.
+ * The caller may use that information to allocate appropriate memory for the
+ * data returned by the encryption or decryption operation
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm)
{
return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm));
@@ -1231,6 +1310,22 @@ static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags)
crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags);
}
+/**
+ * crypto_aead_setkey() - set key for cipher
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the AEAD referenced by the cipher
+ * handle.
+ *
+ * Note, the key length determines the cipher type. Many block ciphers implement
+ * different cipher modes depending on the key size, such as AES-128 vs AES-192
+ * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
+ * is performed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_aead_setkey(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen)
{
@@ -1239,6 +1334,16 @@ static inline int crypto_aead_setkey(struct crypto_aead *tfm, const u8 *key,
return crt->setkey(crt->base, key, keylen);
}
+/**
+ * crypto_aead_setauthsize() - set authentication data size
+ * @tfm: cipher handle
+ * @authsize: size of the authentication data / tag in bytes
+ *
+ * Set the authentication data size / tag size. AEAD requires an authentication
+ * tag (or MAC) in addition to the associated data.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
@@ -1246,27 +1351,105 @@ static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
return __crypto_aead_cast(req->base.tfm);
}
+/**
+ * crypto_aead_encrypt() - encrypt plaintext
+ * @req: reference to the aead_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * Encrypt plaintext data using the aead_request handle. That data structure
+ * and how it is filled with data is discussed with the aead_request_*
+ * functions.
+ *
+ * IMPORTANT NOTE The encryption operation creates the authentication data /
+ * tag. That data is concatenated with the created ciphertext.
+ * The ciphertext memory size is therefore the given number of
+ * block cipher blocks + the size defined by the
+ * crypto_aead_setauthsize invocation. The caller must ensure
+ * that sufficient memory is available for the ciphertext and
+ * the authentication tag.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_aead_encrypt(struct aead_request *req)
{
return crypto_aead_crt(crypto_aead_reqtfm(req))->encrypt(req);
}
+/**
+ * crypto_aead_decrypt() - decrypt ciphertext
+ * @req: reference to the ablkcipher_request handle that holds all information
+ * needed to perform the cipher operation
+ *
+ * Decrypt ciphertext data using the aead_request handle. That data structure
+ * and how it is filled with data is discussed with the aead_request_*
+ * functions.
+ *
+ * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the
+ * authentication data / tag. That authentication data / tag
+ * must have the size defined by the crypto_aead_setauthsize
+ * invocation.
+ *
+ *
+ * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD
+ * cipher operation performs the authentication of the data during the
+ * decryption operation. Therefore, the function returns this error if
+ * the authentication of the ciphertext was unsuccessful (i.e. the
+ * integrity of the ciphertext or the associated data was violated);
+ * < 0 if an error occurred.
+ */
static inline int crypto_aead_decrypt(struct aead_request *req)
{
return crypto_aead_crt(crypto_aead_reqtfm(req))->decrypt(req);
}
+/**
+ * DOC: Asynchronous AEAD Request Handle
+ *
+ * The aead_request data structure contains all pointers to data required for
+ * the AEAD cipher operation. This includes the cipher handle (which can be
+ * used by multiple aead_request instances), pointer to plaintext and
+ * ciphertext, asynchronous callback function, etc. It acts as a handle to the
+ * aead_request_* API calls in a similar way as AEAD handle to the
+ * crypto_aead_* API calls.
+ */
+
+/**
+ * crypto_aead_reqsize() - obtain size of the request data structure
+ * @tfm: cipher handle
+ *
+ * Return: number of bytes
+ */
static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
{
return crypto_aead_crt(tfm)->reqsize;
}
+/**
+ * aead_request_set_tfm() - update cipher handle reference in request
+ * @req: request handle to be modified
+ * @tfm: cipher handle that shall be added to the request handle
+ *
+ * Allow the caller to replace the existing aead handle in the request
+ * data structure with a different one.
+ */
static inline void aead_request_set_tfm(struct aead_request *req,
struct crypto_aead *tfm)
{
req->base.tfm = crypto_aead_tfm(crypto_aead_crt(tfm)->base);
}
+/**
+ * aead_request_alloc() - allocate request data structure
+ * @tfm: cipher handle to be registered with the request
+ * @gfp: memory allocation flag that is handed to kmalloc by the API call.
+ *
+ * Allocate the request data structure that must be used with the AEAD
+ * encrypt and decrypt API calls. During the allocation, the provided aead
+ * handle is registered in the request data structure.
+ *
+ * Return: allocated request handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
gfp_t gfp)
{
@@ -1280,11 +1463,40 @@ static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
return req;
}
+/**
+ * aead_request_free() - zeroize and free request data structure
+ * @req: request data structure cipher handle to be freed
+ */
static inline void aead_request_free(struct aead_request *req)
{
kzfree(req);
}
+/**
+ * aead_request_set_callback() - set asynchronous callback function
+ * @req: request handle
+ * @flags: specify zero or an ORing of the flags
+ * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
+ * increase the wait queue beyond the initial maximum size;
+ * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
+ * @compl: callback function pointer to be registered with the request handle
+ * @data: The data pointer refers to memory that is not used by the kernel
+ * crypto API, but provided to the callback function for it to use. Here,
+ * the caller can provide a reference to memory the callback function can
+ * operate on. As the callback function is invoked asynchronously to the
+ * related functionality, it may need to access data structures of the
+ * related functionality which can be referenced using this pointer. The
+ * callback function can access the memory via the "data" field in the
+ * crypto_async_request data structure provided to the callback function.
+ *
+ * Setting the callback function that is triggered once the cipher operation
+ * completes
+ *
+ * The callback function is registered with the aead_request handle and
+ * must comply with the following template:
+ *
+ * void callback_function(struct crypto_async_request *req, int error)
+ */
static inline void aead_request_set_callback(struct aead_request *req,
u32 flags,
crypto_completion_t compl,
@@ -1295,6 +1507,36 @@ static inline void aead_request_set_callback(struct aead_request *req,
req->base.flags = flags;
}
+/**
+ * aead_request_set_crypt - set data buffers
+ * @req: request handle
+ * @src: source scatter / gather list
+ * @dst: destination scatter / gather list
+ * @cryptlen: number of bytes to process from @src
+ * @iv: IV for the cipher operation which must comply with the IV size defined
+ * by crypto_aead_ivsize()
+ *
+ * Setting the source data and destination data scatter / gather lists.
+ *
+ * For encryption, the source is treated as the plaintext and the
+ * destination is the ciphertext. For a decryption operation, the use is
+ * reversed: the source is the ciphertext and the destination is the plaintext.
+ *
+ * IMPORTANT NOTE AEAD requires an authentication tag (MAC). For decryption,
+ * the caller must concatenate the ciphertext followed by the
+ * authentication tag and provide the entire data stream to the
+ * decryption operation (i.e. the data length used for the
+ * initialization of the scatterlist and the data length for the
+ * decryption operation is identical). For encryption, however,
+ * the authentication tag is created while encrypting the data.
+ * The destination buffer must hold sufficient space for the
+ * ciphertext and the authentication tag while the encryption
+ * invocation must only point to the plaintext data size. The
+ * following code snippet illustrates the memory usage
+ * buffer = kmalloc(ptbuflen + (enc ? authsize : 0));
+ * sg_init_one(&sg, buffer, ptbuflen + (enc ? authsize : 0));
+ * aead_request_set_crypt(req, &sg, &sg, ptbuflen, iv);
+ */
static inline void aead_request_set_crypt(struct aead_request *req,
struct scatterlist *src,
struct scatterlist *dst,
@@ -1306,6 +1548,15 @@ static inline void aead_request_set_crypt(struct aead_request *req,
req->iv = iv;
}
+/**
+ * aead_request_set_assoc() - set the associated data scatter / gather list
+ * @req: request handle
+ * @assoc: associated data scatter / gather list
+ * @assoclen: number of bytes to process from @assoc
+ *
+ * For encryption, the memory is filled with the associated data. For
+ * decryption, the memory must point to the associated data.
+ */
static inline void aead_request_set_assoc(struct aead_request *req,
struct scatterlist *assoc,
unsigned int assoclen)
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 11/13] crypto: Documentation - BLKCIPHER API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (9 preceding siblings ...)
2014-11-12 4:29 ` [PATCH v3 10/13] crypto: Documentation - AEAD " Stephan Mueller
@ 2014-11-12 4:29 ` Stephan Mueller
2014-11-12 4:30 ` [PATCH v3 12/13] crypto: Documentation - CIPHER " Stephan Mueller
` (2 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:29 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for
synchronous block ciphers to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 188 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 188 insertions(+)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 4704e71..c9ebe45 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -1565,6 +1565,36 @@ static inline void aead_request_set_assoc(struct aead_request *req,
req->assoclen = assoclen;
}
+/**
+ * DOC: Synchronous Block Cipher API
+ *
+ * The synchronous block cipher API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_BLKCIPHER (listed as type "blkcipher" in /proc/crypto)
+ *
+ * Synchronous calls, have a context in the tfm. But since a single tfm can be
+ * used in multiple calls and in parallel, this info should not be changeable
+ * (unless a lock is used). This applies, for example, to the symmetric key.
+ * However, the IV is changeable, so there is an iv field in blkcipher_tfm
+ * structure for synchronous blkcipher api. So, its the only state info that can
+ * be kept for synchronous calls without using a big lock across a tfm.
+ *
+ * The block cipher API allows the use of a complete cipher, i.e. a cipher
+ * consisting of a template (a block chaining mode) and a single block cipher
+ * primitive (e.g. AES).
+ *
+ * The plaintext data buffer and the ciphertext data buffer are pointed to
+ * by using scatter/gather lists. The cipher operation is performed
+ * on all segments of the provided scatter/gather lists.
+ *
+ * The kernel crypto API supports a cipher operation "in-place" which means that
+ * the caller may provide the same scatter/gather list for the plaintext and
+ * cipher text. After the completion of the cipher operation, the plaintext
+ * data is replaced with the ciphertext data in case of an encryption and vice
+ * versa for a decryption. The caller must ensure that the scatter/gather lists
+ * for the output data point to sufficiently large buffers, i.e. multiples of
+ * the block size of the cipher.
+ */
+
static inline struct crypto_blkcipher *__crypto_blkcipher_cast(
struct crypto_tfm *tfm)
{
@@ -1578,6 +1608,20 @@ static inline struct crypto_blkcipher *crypto_blkcipher_cast(
return __crypto_blkcipher_cast(tfm);
}
+/**
+ * crypto_alloc_blkcipher() - allocate synchronous block cipher handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * blkcipher cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a block cipher. The returned struct
+ * crypto_blkcipher is the cipher handle that is required for any subsequent
+ * API invocation for that block cipher.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct crypto_blkcipher *crypto_alloc_blkcipher(
const char *alg_name, u32 type, u32 mask)
{
@@ -1594,11 +1638,25 @@ static inline struct crypto_tfm *crypto_blkcipher_tfm(
return &tfm->base;
}
+/**
+ * crypto_free_blkcipher() - zeroize and free the block cipher handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_blkcipher(struct crypto_blkcipher *tfm)
{
crypto_free_tfm(crypto_blkcipher_tfm(tfm));
}
+/**
+ * crypto_has_blkcipher() - Search for the availability of a block cipher
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * block cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Return: true when the block cipher is known to the kernel crypto API; false
+ * otherwise
+ */
static inline int crypto_has_blkcipher(const char *alg_name, u32 type, u32 mask)
{
type &= ~CRYPTO_ALG_TYPE_MASK;
@@ -1608,6 +1666,12 @@ static inline int crypto_has_blkcipher(const char *alg_name, u32 type, u32 mask)
return crypto_has_alg(alg_name, type, mask);
}
+/**
+ * crypto_blkcipher_name() - return the name / cra_name from the cipher handle
+ * @tfm: cipher handle
+ *
+ * Return: The character string holding the name of the cipher
+ */
static inline const char *crypto_blkcipher_name(struct crypto_blkcipher *tfm)
{
return crypto_tfm_alg_name(crypto_blkcipher_tfm(tfm));
@@ -1625,11 +1689,30 @@ static inline struct blkcipher_alg *crypto_blkcipher_alg(
return &crypto_blkcipher_tfm(tfm)->__crt_alg->cra_blkcipher;
}
+/**
+ * crypto_blkcipher_ivsize() - obtain IV size
+ * @tfm: cipher handle
+ *
+ * The size of the IV for the block cipher referenced by the cipher handle is
+ * returned. This IV size may be zero if the cipher does not need an IV.
+ *
+ * Return: IV size in bytes
+ */
static inline unsigned int crypto_blkcipher_ivsize(struct crypto_blkcipher *tfm)
{
return crypto_blkcipher_alg(tfm)->ivsize;
}
+/**
+ * crypto_blkcipher_blocksize() - obtain block size of cipher
+ * @tfm: cipher handle
+ *
+ * The block size for the block cipher referenced with the cipher handle is
+ * returned. The caller may use that information to allocate appropriate
+ * memory for the data returned by the encryption or decryption operation.
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_blkcipher_blocksize(
struct crypto_blkcipher *tfm)
{
@@ -1659,6 +1742,22 @@ static inline void crypto_blkcipher_clear_flags(struct crypto_blkcipher *tfm,
crypto_tfm_clear_flags(crypto_blkcipher_tfm(tfm), flags);
}
+/**
+ * crypto_blkcipher_setkey() - set key for cipher
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the block cipher referenced by the cipher
+ * handle.
+ *
+ * Note, the key length determines the cipher type. Many block ciphers implement
+ * different cipher modes depending on the key size, such as AES-128 vs AES-192
+ * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
+ * is performed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_blkcipher_setkey(struct crypto_blkcipher *tfm,
const u8 *key, unsigned int keylen)
{
@@ -1666,6 +1765,24 @@ static inline int crypto_blkcipher_setkey(struct crypto_blkcipher *tfm,
key, keylen);
}
+/**
+ * crypto_blkcipher_encrypt() - encrypt plaintext
+ * @desc: reference to the block cipher handle with meta data
+ * @dst: scatter/gather list that is filled by the cipher operation with the
+ * ciphertext
+ * @src: scatter/gather list that holds the plaintext
+ * @nbytes: number of bytes of the plaintext to encrypt.
+ *
+ * Encrypt plaintext data using the IV set by the caller with a preceding
+ * call of crypto_blkcipher_set_iv.
+ *
+ * The blkcipher_desc data structure must be filled by the caller and can
+ * reside on the stack. The caller must fill desc as follows: desc.tfm is filled
+ * with the block cipher handle; desc.flags is filled with either
+ * CRYPTO_TFM_REQ_MAY_SLEEP or 0.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_blkcipher_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
@@ -1675,6 +1792,25 @@ static inline int crypto_blkcipher_encrypt(struct blkcipher_desc *desc,
return crypto_blkcipher_crt(desc->tfm)->encrypt(desc, dst, src, nbytes);
}
+/**
+ * crypto_blkcipher_encrypt_iv() - encrypt plaintext with dedicated IV
+ * @desc: reference to the block cipher handle with meta data
+ * @dst: scatter/gather list that is filled by the cipher operation with the
+ * ciphertext
+ * @src: scatter/gather list that holds the plaintext
+ * @nbytes: number of bytes of the plaintext to encrypt.
+ *
+ * Encrypt plaintext data with the use of an IV that is solely used for this
+ * cipher operation. Any previously set IV is not used.
+ *
+ * The blkcipher_desc data structure must be filled by the caller and can
+ * reside on the stack. The caller must fill desc as follows: desc.tfm is filled
+ * with the block cipher handle; desc.info is filled with the IV to be used for
+ * the current operation; desc.flags is filled with either
+ * CRYPTO_TFM_REQ_MAY_SLEEP or 0.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_blkcipher_encrypt_iv(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
@@ -1683,6 +1819,23 @@ static inline int crypto_blkcipher_encrypt_iv(struct blkcipher_desc *desc,
return crypto_blkcipher_crt(desc->tfm)->encrypt(desc, dst, src, nbytes);
}
+/**
+ * crypto_blkcipher_decrypt() - decrypt ciphertext
+ * @desc: reference to the block cipher handle with meta data
+ * @dst: scatter/gather list that is filled by the cipher operation with the
+ * plaintext
+ * @src: scatter/gather list that holds the ciphertext
+ * @nbytes: number of bytes of the ciphertext to decrypt.
+ *
+ * Decrypt ciphertext data using the IV set by the caller with a preceding
+ * call of crypto_blkcipher_set_iv.
+ *
+ * The blkcipher_desc data structure must be filled by the caller as documented
+ * for the crypto_blkcipher_encrypt call above.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ *
+ */
static inline int crypto_blkcipher_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
@@ -1692,6 +1845,22 @@ static inline int crypto_blkcipher_decrypt(struct blkcipher_desc *desc,
return crypto_blkcipher_crt(desc->tfm)->decrypt(desc, dst, src, nbytes);
}
+/**
+ * crypto_blkcipher_decrypt_iv() - decrypt ciphertext with dedicated IV
+ * @desc: reference to the block cipher handle with meta data
+ * @dst: scatter/gather list that is filled by the cipher operation with the
+ * plaintext
+ * @src: scatter/gather list that holds the ciphertext
+ * @nbytes: number of bytes of the ciphertext to decrypt.
+ *
+ * Decrypt ciphertext data with the use of an IV that is solely used for this
+ * cipher operation. Any previously set IV is not used.
+ *
+ * The blkcipher_desc data structure must be filled by the caller as documented
+ * for the crypto_blkcipher_encrypt_iv call above.
+ *
+ * Return: 0 if the cipher operation was successful; < 0 if an error occurred
+ */
static inline int crypto_blkcipher_decrypt_iv(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
@@ -1700,12 +1869,31 @@ static inline int crypto_blkcipher_decrypt_iv(struct blkcipher_desc *desc,
return crypto_blkcipher_crt(desc->tfm)->decrypt(desc, dst, src, nbytes);
}
+/**
+ * crypto_blkcipher_set_iv() - set IV for cipher
+ * @tfm: cipher handle
+ * @src: buffer holding the IV
+ * @len: length of the IV in bytes
+ *
+ * The caller provided IV is set for the block cipher referenced by the cipher
+ * handle.
+ */
static inline void crypto_blkcipher_set_iv(struct crypto_blkcipher *tfm,
const u8 *src, unsigned int len)
{
memcpy(crypto_blkcipher_crt(tfm)->iv, src, len);
}
+/**
+ * crypto_blkcipher_get_iv() - obtain IV from cipher
+ * @tfm: cipher handle
+ * @dst: buffer filled with the IV
+ * @len: length of the buffer dst
+ *
+ * The caller can obtain the IV set for the block cipher referenced by the
+ * cipher handle and store it into the user-provided buffer. If the buffer
+ * has an insufficient space, the IV is truncated to fit the buffer.
+ */
static inline void crypto_blkcipher_get_iv(struct crypto_blkcipher *tfm,
u8 *dst, unsigned int len)
{
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 12/13] crypto: Documentation - CIPHER API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (10 preceding siblings ...)
2014-11-12 4:29 ` [PATCH v3 11/13] crypto: Documentation - BLKCIPHER " Stephan Mueller
@ 2014-11-12 4:30 ` Stephan Mueller
2014-11-12 4:30 ` [PATCH v3 13/13] crypto: Documentation - HASH " Stephan Mueller
2014-11-13 14:33 ` [PATCH v3 00/13] crypto: Documentation of kernel crypto API Herbert Xu
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:30 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for
signle block ciphers to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index c9ebe45..0f95a07 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -1900,6 +1900,23 @@ static inline void crypto_blkcipher_get_iv(struct crypto_blkcipher *tfm,
memcpy(dst, crypto_blkcipher_crt(tfm)->iv, len);
}
+/**
+ * DOC: Single Block Cipher API
+ *
+ * The single block cipher API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_CIPHER (listed as type "cipher" in /proc/crypto).
+ *
+ * Using the single block cipher API calls, operations with the basic cipher
+ * primitive can be implemented. These cipher primitives exclude any block
+ * chaining operations including IV handling.
+ *
+ * The purpose of this single block cipher API is to support the implementation
+ * of templates or other concepts that only need to perform the cipher operation
+ * on one block at a time. Templates invoke the underlying cipher primitive
+ * block-wise and process either the input or the output data of these cipher
+ * operations.
+ */
+
static inline struct crypto_cipher *__crypto_cipher_cast(struct crypto_tfm *tfm)
{
return (struct crypto_cipher *)tfm;
@@ -1911,6 +1928,20 @@ static inline struct crypto_cipher *crypto_cipher_cast(struct crypto_tfm *tfm)
return __crypto_cipher_cast(tfm);
}
+/**
+ * crypto_alloc_cipher() - allocate single block cipher handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * single block cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a single block cipher. The returned struct
+ * crypto_cipher is the cipher handle that is required for any subsequent API
+ * invocation for that single block cipher.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct crypto_cipher *crypto_alloc_cipher(const char *alg_name,
u32 type, u32 mask)
{
@@ -1926,11 +1957,25 @@ static inline struct crypto_tfm *crypto_cipher_tfm(struct crypto_cipher *tfm)
return &tfm->base;
}
+/**
+ * crypto_free_cipher() - zeroize and free the single block cipher handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_cipher(struct crypto_cipher *tfm)
{
crypto_free_tfm(crypto_cipher_tfm(tfm));
}
+/**
+ * crypto_has_cipher() - Search for the availability of a single block cipher
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * single block cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Return: true when the single block cipher is known to the kernel crypto API;
+ * false otherwise
+ */
static inline int crypto_has_cipher(const char *alg_name, u32 type, u32 mask)
{
type &= ~CRYPTO_ALG_TYPE_MASK;
@@ -1945,6 +1990,16 @@ static inline struct cipher_tfm *crypto_cipher_crt(struct crypto_cipher *tfm)
return &crypto_cipher_tfm(tfm)->crt_cipher;
}
+/**
+ * crypto_cipher_blocksize() - obtain block size for cipher
+ * @tfm: cipher handle
+ *
+ * The block size for the single block cipher referenced with the cipher handle
+ * tfm is returned. The caller may use that information to allocate appropriate
+ * memory for the data returned by the encryption or decryption operation
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_cipher_blocksize(struct crypto_cipher *tfm)
{
return crypto_tfm_alg_blocksize(crypto_cipher_tfm(tfm));
@@ -1972,6 +2027,22 @@ static inline void crypto_cipher_clear_flags(struct crypto_cipher *tfm,
crypto_tfm_clear_flags(crypto_cipher_tfm(tfm), flags);
}
+/**
+ * crypto_cipher_setkey() - set key for cipher
+ * @tfm: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the single block cipher referenced by the
+ * cipher handle.
+ *
+ * Note, the key length determines the cipher type. Many block ciphers implement
+ * different cipher modes depending on the key size, such as AES-128 vs AES-192
+ * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
+ * is performed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_cipher_setkey(struct crypto_cipher *tfm,
const u8 *key, unsigned int keylen)
{
@@ -1979,6 +2050,15 @@ static inline int crypto_cipher_setkey(struct crypto_cipher *tfm,
key, keylen);
}
+/**
+ * crypto_cipher_encrypt_one() - encrypt one block of plaintext
+ * @tfm: cipher handle
+ * @dst: points to the buffer that will be filled with the ciphertext
+ * @src: buffer holding the plaintext to be encrypted
+ *
+ * Invoke the encryption operation of one block. The caller must ensure that
+ * the plaintext and ciphertext buffers are at least one block in size.
+ */
static inline void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
u8 *dst, const u8 *src)
{
@@ -1986,6 +2066,15 @@ static inline void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
dst, src);
}
+/**
+ * crypto_cipher_decrypt_one() - decrypt one block of ciphertext
+ * @tfm: cipher handle
+ * @dst: points to the buffer that will be filled with the plaintext
+ * @src: buffer holding the ciphertext to be decrypted
+ *
+ * Invoke the decryption operation of one block. The caller must ensure that
+ * the plaintext and ciphertext buffers are at least one block in size.
+ */
static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
u8 *dst, const u8 *src)
{
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 13/13] crypto: Documentation - HASH API documentation
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (11 preceding siblings ...)
2014-11-12 4:30 ` [PATCH v3 12/13] crypto: Documentation - CIPHER " Stephan Mueller
@ 2014-11-12 4:30 ` Stephan Mueller
2014-11-13 14:33 ` [PATCH v3 00/13] crypto: Documentation of kernel crypto API Herbert Xu
13 siblings, 0 replies; 15+ messages in thread
From: Stephan Mueller @ 2014-11-12 4:30 UTC (permalink / raw)
To: Herbert Xu
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
The API function calls exported by the kernel crypto API for
message digests to be used by consumers are documented.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
include/linux/crypto.h | 119 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 0f95a07..208a632 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -2082,6 +2082,13 @@ static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
dst, src);
}
+/**
+ * DOC: Synchronous Message Digest API
+ *
+ * The synchronous message digest API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_HASH (listed as type "hash" in /proc/crypto)
+ */
+
static inline struct crypto_hash *__crypto_hash_cast(struct crypto_tfm *tfm)
{
return (struct crypto_hash *)tfm;
@@ -2094,6 +2101,20 @@ static inline struct crypto_hash *crypto_hash_cast(struct crypto_tfm *tfm)
return __crypto_hash_cast(tfm);
}
+/**
+ * crypto_alloc_hash() - allocate synchronous message digest handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * message digest cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a message digest. The returned struct
+ * crypto_hash is the cipher handle that is required for any subsequent
+ * API invocation for that message digest.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ * of an error, PTR_ERR() returns the error code.
+ */
static inline struct crypto_hash *crypto_alloc_hash(const char *alg_name,
u32 type, u32 mask)
{
@@ -2110,11 +2131,25 @@ static inline struct crypto_tfm *crypto_hash_tfm(struct crypto_hash *tfm)
return &tfm->base;
}
+/**
+ * crypto_free_hash() - zeroize and free message digest handle
+ * @tfm: cipher handle to be freed
+ */
static inline void crypto_free_hash(struct crypto_hash *tfm)
{
crypto_free_tfm(crypto_hash_tfm(tfm));
}
+/**
+ * crypto_has_hash() - Search for the availability of a message digest
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ * message digest cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Return: true when the message digest cipher is known to the kernel crypto
+ * API; false otherwise
+ */
static inline int crypto_has_hash(const char *alg_name, u32 type, u32 mask)
{
type &= ~CRYPTO_ALG_TYPE_MASK;
@@ -2130,6 +2165,15 @@ static inline struct hash_tfm *crypto_hash_crt(struct crypto_hash *tfm)
return &crypto_hash_tfm(tfm)->crt_hash;
}
+/**
+ * crypto_hash_blocksize() - obtain block size for message digest
+ * @tfm: cipher handle
+ *
+ * The block size for the message digest cipher referenced with the cipher
+ * handle is returned.
+ *
+ * Return: block size of cipher
+ */
static inline unsigned int crypto_hash_blocksize(struct crypto_hash *tfm)
{
return crypto_tfm_alg_blocksize(crypto_hash_tfm(tfm));
@@ -2140,6 +2184,15 @@ static inline unsigned int crypto_hash_alignmask(struct crypto_hash *tfm)
return crypto_tfm_alg_alignmask(crypto_hash_tfm(tfm));
}
+/**
+ * crypto_hash_digestsize() - obtain message digest size
+ * @tfm: cipher handle
+ *
+ * The size for the message digest created by the message digest cipher
+ * referenced with the cipher handle is returned.
+ *
+ * Return: message digest size
+ */
static inline unsigned int crypto_hash_digestsize(struct crypto_hash *tfm)
{
return crypto_hash_crt(tfm)->digestsize;
@@ -2160,11 +2213,38 @@ static inline void crypto_hash_clear_flags(struct crypto_hash *tfm, u32 flags)
crypto_tfm_clear_flags(crypto_hash_tfm(tfm), flags);
}
+/**
+ * crypto_hash_init() - (re)initialize message digest handle
+ * @desc: cipher request handle that to be filled by caller --
+ * desc.tfm is filled with the hash cipher handle;
+ * desc.flags is filled with either CRYPTO_TFM_REQ_MAY_SLEEP or 0.
+ *
+ * The call (re-)initializes the message digest referenced by the hash cipher
+ * request handle. Any potentially existing state created by previous
+ * operations is discarded.
+ *
+ * Return: 0 if the message digest initialization was successful; < 0 if an
+ * error occurred
+ */
static inline int crypto_hash_init(struct hash_desc *desc)
{
return crypto_hash_crt(desc->tfm)->init(desc);
}
+/**
+ * crypto_hash_update() - add data to message digest for processing
+ * @desc: cipher request handle
+ * @sg: scatter / gather list pointing to the data to be added to the message
+ * digest
+ * @nbytes: number of bytes to be processed from @sg
+ *
+ * Updates the message digest state of the cipher handle pointed to by the
+ * hash cipher request handle with the input data pointed to by the
+ * scatter/gather list.
+ *
+ * Return: 0 if the message digest update was successful; < 0 if an error
+ * occurred
+ */
static inline int crypto_hash_update(struct hash_desc *desc,
struct scatterlist *sg,
unsigned int nbytes)
@@ -2172,11 +2252,39 @@ static inline int crypto_hash_update(struct hash_desc *desc,
return crypto_hash_crt(desc->tfm)->update(desc, sg, nbytes);
}
+/**
+ * crypto_hash_final() - calculate message digest
+ * @desc: cipher request handle
+ * @out: message digest output buffer -- The caller must ensure that the out
+ * buffer has a sufficient size (e.g. by using the crypto_hash_digestsize
+ * function).
+ *
+ * Finalize the message digest operation and create the message digest
+ * based on all data added to the cipher handle. The message digest is placed
+ * into the output buffer.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
static inline int crypto_hash_final(struct hash_desc *desc, u8 *out)
{
return crypto_hash_crt(desc->tfm)->final(desc, out);
}
+/**
+ * crypto_hash_digest() - calculate message digest for a buffer
+ * @desc: see crypto_hash_final()
+ * @sg: see crypto_hash_update()
+ * @nbytes: see crypto_hash_update()
+ * @out: see crypto_hash_final()
+ *
+ * This function is a "short-hand" for the function calls of crypto_hash_init,
+ * crypto_hash_update and crypto_hash_final. The parameters have the same
+ * meaning as discussed for those separate three functions.
+ *
+ * Return: 0 if the message digest creation was successful; < 0 if an error
+ * occurred
+ */
static inline int crypto_hash_digest(struct hash_desc *desc,
struct scatterlist *sg,
unsigned int nbytes, u8 *out)
@@ -2184,6 +2292,17 @@ static inline int crypto_hash_digest(struct hash_desc *desc,
return crypto_hash_crt(desc->tfm)->digest(desc, sg, nbytes, out);
}
+/**
+ * crypto_hash_setkey() - set key for message digest
+ * @hash: cipher handle
+ * @key: buffer holding the key
+ * @keylen: length of the key in bytes
+ *
+ * The caller provided key is set for the message digest cipher. The cipher
+ * handle must point to a keyed hash in order for this function to succeed.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
static inline int crypto_hash_setkey(struct crypto_hash *hash,
const u8 *key, unsigned int keylen)
{
--
2.1.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v3 00/13] crypto: Documentation of kernel crypto API
2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
` (12 preceding siblings ...)
2014-11-12 4:30 ` [PATCH v3 13/13] crypto: Documentation - HASH " Stephan Mueller
@ 2014-11-13 14:33 ` Herbert Xu
13 siblings, 0 replies; 15+ messages in thread
From: Herbert Xu @ 2014-11-13 14:33 UTC (permalink / raw)
To: Stephan Mueller
Cc: Marek Vasut, David S. Miller, Jason Cooper, Grant Likely,
'Geert Uytterhoeven',
Joy M. Latten, Jonathan Corbet, LKML, linux-crypto
On Wed, Nov 12, 2014 at 05:22:00AM +0100, Stephan Mueller wrote:
> Hi,
>
> The following patch set adds documentation files under Documentation/crypto/
> covering the high-level description of the API. In addition, it contains
> source code comments added to the header files of the kernel crypto API
> documenting the API functions.
>
> The documentation is provided in a DocBook whose output can be reviewed at:
>
> http://www.chronox.de/crypto-API/index.html
>
> Changes v2:
All applied. Thanks everyone!
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2014-11-13 14:34 UTC | newest]
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2014-11-12 4:22 [PATCH v3 00/13] crypto: Documentation of kernel crypto API Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 01/13] crypto: Documentation - crypto API high level spec Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 02/13] crypto: Documentation - compile crypto API spec Stephan Mueller
2014-11-12 4:24 ` [PATCH v3 03/13] crypto: Documentation - userspace interface spec Stephan Mueller
2014-11-12 4:25 ` [PATCH v3 04/13] crypto: Documentation - RNG API documentation Stephan Mueller
2014-11-12 4:26 ` [PATCH v3 05/13] crypto: Documentation - hash data structures Stephan Mueller
2014-11-12 4:26 ` [PATCH v3 06/13] crypto: Documentation - AHASH API documentation Stephan Mueller
2014-11-12 4:27 ` [PATCH v3 07/13] crypto: Documentation - SHASH " Stephan Mueller
2014-11-12 4:27 ` [PATCH v3 08/13] crypto: Documentation - cipher data structures Stephan Mueller
2014-11-12 4:28 ` [PATCH v3 09/13] crypto: Documentation - ABLKCIPHER API documentation Stephan Mueller
2014-11-12 4:29 ` [PATCH v3 10/13] crypto: Documentation - AEAD " Stephan Mueller
2014-11-12 4:29 ` [PATCH v3 11/13] crypto: Documentation - BLKCIPHER " Stephan Mueller
2014-11-12 4:30 ` [PATCH v3 12/13] crypto: Documentation - CIPHER " Stephan Mueller
2014-11-12 4:30 ` [PATCH v3 13/13] crypto: Documentation - HASH " Stephan Mueller
2014-11-13 14:33 ` [PATCH v3 00/13] crypto: Documentation of kernel crypto API Herbert Xu
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