* [PATCH v6 3/4] crypto: AF_ALG: add random number generator support
2014-12-25 21:58 [PATCH v6 0/4] crypto: AF_ALG: add AEAD and RNG support Stephan Mueller
2014-12-25 21:59 ` [PATCH v6 2/4] crypto: AF_ALG: enable AEAD interface compilation Stephan Mueller
@ 2014-12-25 22:00 ` Stephan Mueller
2014-12-29 10:41 ` Herbert Xu
2014-12-25 22:00 ` [PATCH v6 4/4] crypto: AF_ALG: enable RNG interface compilation Stephan Mueller
` (2 subsequent siblings)
4 siblings, 1 reply; 14+ messages in thread
From: Stephan Mueller @ 2014-12-25 22:00 UTC (permalink / raw)
To: 'Herbert Xu'
Cc: Daniel Borkmann, 'Quentin Gouchet', 'LKML',
linux-crypto, linux-api
This patch adds the random number generator support for AF_ALG.
A random number generator's purpose is to generate data without
requiring the caller to provide any data. Therefore, the AF_ALG
interface handler for RNGs only implements a callback handler for
recvmsg.
The following parameters provided with a recvmsg are processed by the
RNG callback handler:
* sock - to resolve the RNG context data structure accessing the
RNG instance private to the socket
* len - this parameter allows userspace callers to specify how
many random bytes the RNG shall produce and return. As the
kernel context for the RNG allocates a buffer of 128 bytes to
store random numbers before copying them to userspace, the len
parameter is checked that it is not larger than 128. If a
caller wants more random numbers, a new request for recvmsg
shall be made.
The size of 128 bytes is chose because of the following considerations:
* to increase the memory footprint of the kernel too much (note,
that would be 128 bytes per open socket)
* 128 is divisible by any typical cryptographic block size an
RNG may have
* A request for random numbers typically only shall supply small
amount of data like for keys or IVs that should only require
one invocation of the recvmsg function.
Note, during instantiation of the RNG, the code checks whether the RNG
implementation requires seeding. If so, the RNG is seeded with output
from get_random_bytes.
A fully working example using all aspects of the RNG interface is
provided at http://www.chronox.de/libkcapi.html
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
crypto/algif_rng.c | 192 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 192 insertions(+)
create mode 100644 crypto/algif_rng.c
diff --git a/crypto/algif_rng.c b/crypto/algif_rng.c
new file mode 100644
index 0000000..91c06f5
--- /dev/null
+++ b/crypto/algif_rng.c
@@ -0,0 +1,192 @@
+/*
+ * algif_rng: User-space interface for random number generators
+ *
+ * This file provides the user-space API for random number generators.
+ *
+ * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, and the entire permission notice in its entirety,
+ * including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior
+ * written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU General Public License, in which case the provisions of the GPL2
+ * are required INSTEAD OF the above restrictions. (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
+ * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ */
+
+#include <linux/module.h>
+#include <crypto/rng.h>
+#include <linux/random.h>
+#include <crypto/if_alg.h>
+#include <linux/net.h>
+#include <net/sock.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("User-space interface for random number generators");
+
+struct rng_ctx {
+#define MAXSIZE 128
+ unsigned int len;
+ struct crypto_rng *drng;
+};
+
+static int rng_recvmsg(struct kiocb *unused, struct socket *sock,
+ struct msghdr *msg, size_t len, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct rng_ctx *ctx = ask->private;
+ int err = -EFAULT;
+ int genlen = 0;
+ u8 result[MAXSIZE];
+
+ if (len == 0)
+ return 0;
+ if (len > MAXSIZE)
+ len = MAXSIZE;
+
+ /*
+ * although not strictly needed, this is a precaution against coding
+ * errors
+ */
+ memset(result, 0, len);
+
+ /*
+ * The enforcement of a proper seeding of an RNG is done within an
+ * RNG implementation. Some RNGs (DRBG, krng) do not need specific
+ * seeding as they automatically seed. The X9.31 DRNG will return
+ * an error if it was not seeded properly.
+ */
+ genlen = crypto_rng_get_bytes(ctx->drng, result, len);
+ if (genlen < 0)
+ return genlen;
+
+ err = memcpy_to_msg(msg, result, len);
+ memzero_explicit(result, genlen);
+
+ return err ? err : len;
+}
+
+static struct proto_ops algif_rng_ops = {
+ .family = PF_ALG,
+
+ .connect = sock_no_connect,
+ .socketpair = sock_no_socketpair,
+ .getname = sock_no_getname,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .getsockopt = sock_no_getsockopt,
+ .mmap = sock_no_mmap,
+ .bind = sock_no_bind,
+ .accept = sock_no_accept,
+ .setsockopt = sock_no_setsockopt,
+ .poll = sock_no_poll,
+ .sendmsg = sock_no_sendmsg,
+ .sendpage = sock_no_sendpage,
+
+ .release = af_alg_release,
+ .recvmsg = rng_recvmsg,
+};
+
+static void *rng_bind(const char *name, u32 type, u32 mask)
+{
+ return crypto_alloc_rng(name, type, mask);
+}
+
+static void rng_release(void *private)
+{
+ crypto_free_rng(private);
+}
+
+static void rng_sock_destruct(struct sock *sk)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct rng_ctx *ctx = ask->private;
+
+ sock_kfree_s(sk, ctx, ctx->len);
+ af_alg_release_parent(sk);
+}
+
+static int rng_accept_parent(void *private, struct sock *sk)
+{
+ struct rng_ctx *ctx;
+ struct alg_sock *ask = alg_sk(sk);
+ unsigned int len = sizeof(*ctx);
+
+ ctx = sock_kmalloc(sk, len, GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->len = len;
+
+ /*
+ * No seeding done at that point -- if multiple accepts are
+ * done on one RNG instance, each resulting FD points to the same
+ * state of the RNG.
+ */
+
+ ctx->drng = private;
+ ask->private = ctx;
+ sk->sk_destruct = rng_sock_destruct;
+
+ return 0;
+}
+
+static int rng_setkey(void *private, const u8 *seed, unsigned int seedlen)
+{
+ /*
+ * Check whether seedlen is of sufficient size is done in RNG
+ * implementations.
+ */
+ return crypto_rng_reset(private, (u8 *)seed, seedlen);
+}
+
+static const struct af_alg_type algif_type_rng = {
+ .bind = rng_bind,
+ .release = rng_release,
+ .accept = rng_accept_parent,
+ .setkey = rng_setkey,
+ .ops = &algif_rng_ops,
+ .name = "rng",
+ .owner = THIS_MODULE
+};
+
+static int __init rng_init(void)
+{
+ return af_alg_register_type(&algif_type_rng);
+}
+
+void __exit rng_exit(void)
+{
+ int err = af_alg_unregister_type(&algif_type_rng);
+ BUG_ON(err);
+}
+
+module_init(rng_init);
+module_exit(rng_exit);
--
2.1.0
^ permalink raw reply [flat|nested] 14+ messages in thread* [PATCH v6 1/4] crypto: AF_ALG: add AEAD support
2014-12-25 21:58 [PATCH v6 0/4] crypto: AF_ALG: add AEAD and RNG support Stephan Mueller
` (2 preceding siblings ...)
2014-12-25 22:00 ` [PATCH v6 4/4] crypto: AF_ALG: enable RNG interface compilation Stephan Mueller
@ 2014-12-25 22:01 ` Stephan Mueller
2014-12-29 10:33 ` Herbert Xu
2014-12-29 10:20 ` [PATCH v6 0/4] crypto: AF_ALG: add AEAD and RNG support Herbert Xu
4 siblings, 1 reply; 14+ messages in thread
From: Stephan Mueller @ 2014-12-25 22:01 UTC (permalink / raw)
To: 'Herbert Xu'
Cc: Daniel Borkmann, 'Quentin Gouchet', 'LKML',
linux-crypto, linux-api
This patch adds the AEAD support for AF_ALG.
The implementation is based on algif_skcipher, but contains heavy
modifications to streamline the interface for AEAD uses.
To use AEAD, the user space consumer has to use the salg_type named
"aead".
The AEAD implementation includes some overhead to calculate the size of
the ciphertext, because the AEAD implementation of the kernel crypto API
makes implied assumption on the location of the authentication tag. When
performing an encryption, the tag will be added to the created
ciphertext (note, the tag is placed adjacent to the ciphertext). For
decryption, the caller must hand in the ciphertext with the tag appended
to the ciphertext. Therefore, the selection of the used memory
needs to add/subtract the tag size from the source/destination buffers
depending on the encryption type. The code is provided with comments
explaining when and how that operation is performed.
A fully working example using all aspects of AEAD is provided at
http://www.chronox.de/libkcapi.html
Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
crypto/algif_aead.c | 651 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 651 insertions(+)
create mode 100644 crypto/algif_aead.c
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
new file mode 100644
index 0000000..c5d7e26
--- /dev/null
+++ b/crypto/algif_aead.c
@@ -0,0 +1,651 @@
+/*
+ * algif_aeadr: User-space interface for AEAD algorithms
+ *
+ * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
+ *
+ * This file provides the user-space API for AEAD ciphers.
+ *
+ * This file is derived from algif_skcipher.c.
+ *
+ * This program 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.
+ *
+ */
+
+#include <crypto/scatterwalk.h>
+#include <crypto/if_alg.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <net/sock.h>
+
+struct aead_sg_list {
+ unsigned int cur;
+ struct scatterlist sg[ALG_MAX_PAGES];
+};
+
+struct aead_ctx {
+ struct aead_sg_list tsgl;
+ struct af_alg_sgl rsgl;
+
+ void *iv;
+
+ struct af_alg_completion completion;
+
+ unsigned long used;
+
+ unsigned int len;
+ bool more;
+ bool merge;
+ bool enc;
+
+ size_t aead_assoclen;
+ struct aead_request aead_req;
+};
+
+static inline int aead_sndbuf(struct sock *sk)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+
+ return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
+ ctx->used, 0);
+}
+
+static inline bool aead_writable(struct sock *sk)
+{
+ return PAGE_SIZE <= aead_sndbuf(sk);
+}
+
+static inline bool aead_sufficient_data(struct aead_ctx *ctx)
+{
+ unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
+
+ return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ?: as)));
+}
+static inline bool aead_readable(struct aead_ctx *ctx)
+{
+ /*
+ * Ensure that assoc data is present, the plaintext / ciphertext
+ * is non-zero and that the authentication tag is also present
+ * in case of a decryption operation.
+ *
+ * Also, wait until all data is received before processing.
+ */
+ return (aead_sufficient_data(ctx) && !ctx->more);
+}
+
+static void aead_put_sgl(struct sock *sk)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ struct aead_sg_list *sgl = &ctx->tsgl;
+ struct scatterlist *sg = sgl->sg;
+ unsigned int i;
+
+ for (i = 0; i < sgl->cur; i++) {
+ if (!sg_page(sg + i))
+ continue;
+
+ put_page(sg_page(sg + i));
+ sg_assign_page(sg + i, NULL);
+ }
+ sgl->cur = 0;
+ ctx->used = 0;
+ ctx->more = 0;
+ ctx->merge = 0;
+}
+
+static int aead_wait_for_wmem(struct sock *sk, unsigned flags)
+{
+ long timeout;
+ DEFINE_WAIT(wait);
+ int err = -ERESTARTSYS;
+
+ if (flags & MSG_DONTWAIT)
+ return -EAGAIN;
+
+ set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+
+ for (;;) {
+ if (signal_pending(current))
+ break;
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ timeout = MAX_SCHEDULE_TIMEOUT;
+ if (sk_wait_event(sk, &timeout, aead_writable(sk))) {
+ err = 0;
+ break;
+ }
+ }
+ finish_wait(sk_sleep(sk), &wait);
+
+ return err;
+}
+
+static void aead_wmem_wakeup(struct sock *sk)
+{
+ struct socket_wq *wq;
+
+ if (!aead_writable(sk))
+ return;
+
+ rcu_read_lock();
+ wq = rcu_dereference(sk->sk_wq);
+ if (wq_has_sleeper(wq))
+ wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
+ POLLRDNORM |
+ POLLRDBAND);
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ rcu_read_unlock();
+}
+
+static int aead_wait_for_data(struct sock *sk, unsigned flags)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ long timeout;
+ DEFINE_WAIT(wait);
+ int err = -ERESTARTSYS;
+
+ if (flags & MSG_DONTWAIT) {
+ return -EAGAIN;
+ }
+
+ set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+ for (;;) {
+ if (signal_pending(current))
+ break;
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ timeout = MAX_SCHEDULE_TIMEOUT;
+ if (sk_wait_event(sk, &timeout, aead_readable(ctx))) {
+ err = 0;
+ break;
+ }
+ }
+ finish_wait(sk_sleep(sk), &wait);
+
+ clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+ return err;
+}
+
+static void aead_data_wakeup(struct sock *sk)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ struct socket_wq *wq;
+
+ if (!aead_readable(ctx))
+ return;
+
+ rcu_read_lock();
+ wq = rcu_dereference(sk->sk_wq);
+ if (wq_has_sleeper(wq))
+ wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
+ POLLRDNORM |
+ POLLRDBAND);
+ sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
+ rcu_read_unlock();
+}
+
+static int aead_sendmsg(struct kiocb *unused, struct socket *sock,
+ struct msghdr *msg, size_t size)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ unsigned ivsize =
+ crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
+ struct aead_sg_list *sgl = &ctx->tsgl;
+ struct af_alg_control con = {};
+ long copied = 0;
+ bool enc = 0;
+ bool init = 0;
+ int err = -EINVAL;
+
+ if (msg->msg_controllen) {
+ err = af_alg_cmsg_send(msg, &con);
+ if (err)
+ return err;
+
+ init = 1;
+ switch (con.op) {
+ case ALG_OP_ENCRYPT:
+ enc = 1;
+ break;
+ case ALG_OP_DECRYPT:
+ enc = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (con.iv && con.iv->ivlen != ivsize)
+ return -EINVAL;
+
+ if (!con.aead_assoclen)
+ return -EINVAL;
+
+ /* aead_recvmsg limits the maximum AD size to one page */
+ if (con.aead_assoclen > PAGE_SIZE)
+ return -E2BIG;
+ }
+
+ lock_sock(sk);
+ if (!ctx->more && ctx->used)
+ goto unlock;
+
+ if (init) {
+ ctx->enc = enc;
+ if (con.iv)
+ memcpy(ctx->iv, con.iv->iv, ivsize);
+
+ ctx->aead_assoclen = con.aead_assoclen;
+ }
+
+ while (size) {
+ unsigned long len = size;
+ struct scatterlist *sg = NULL;
+
+ if (ctx->merge) {
+ sg = sgl->sg + sgl->cur - 1;
+ len = min_t(unsigned long, len,
+ PAGE_SIZE - sg->offset - sg->length);
+ err = memcpy_from_msg(page_address(sg_page(sg)) +
+ sg->offset + sg->length,
+ msg, len);
+ if (err)
+ goto unlock;
+
+ sg->length += len;
+ ctx->merge = (sg->offset + sg->length) &
+ (PAGE_SIZE - 1);
+
+ ctx->used += len;
+ copied += len;
+ size -= len;
+ }
+
+ if (!aead_writable(sk)) {
+ /*
+ * If there is more data to be expected, but we cannot
+ * write more data, forcefully define that we do not
+ * expect more data to invoke the AEAD operation. This
+ * prevents a deadlock in user space.
+ */
+ ctx->more = 0;
+ err = aead_wait_for_wmem(sk, msg->msg_flags);
+ if (err)
+ goto unlock;
+ }
+
+ len = min_t(unsigned long, size, aead_sndbuf(sk));
+ while (len && sgl->cur < ALG_MAX_PAGES) {
+ int plen = 0;
+
+ sg = sgl->sg + sgl->cur;
+ plen = min_t(int, len, PAGE_SIZE);
+
+ if (sgl->cur >= ALG_MAX_PAGES) {
+ err = -E2BIG;
+ goto unlock;
+ }
+
+ sg_assign_page(sg, alloc_page(GFP_KERNEL));
+ err = -ENOMEM;
+ if (!sg_page(sg))
+ goto unlock;
+
+ err = memcpy_from_msg(page_address(sg_page(sg)),
+ msg, plen);
+ if (err) {
+ __free_page(sg_page(sg));
+ sg_assign_page(sg, NULL);
+ goto unlock;
+ }
+
+ sg->length = plen;
+ len -= plen;
+ ctx->used += plen;
+ copied += plen;
+ sgl->cur++;
+ size -= plen;
+ ctx->merge = plen & (PAGE_SIZE - 1);
+ }
+ }
+
+ err = 0;
+
+ ctx->more = msg->msg_flags & MSG_MORE;
+
+unlock:
+ aead_data_wakeup(sk);
+ release_sock(sk);
+
+ return copied ?: err;
+}
+
+static ssize_t aead_sendpage(struct socket *sock, struct page *page,
+ int offset, size_t size, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ struct aead_sg_list *sgl = &ctx->tsgl;
+ int err = -EINVAL;
+
+ if (flags & MSG_SENDPAGE_NOTLAST)
+ flags |= MSG_MORE;
+
+ if (sgl->cur >= ALG_MAX_PAGES)
+ return -E2BIG;
+
+ lock_sock(sk);
+ if (!ctx->more && ctx->used)
+ goto unlock;
+
+ if (!size)
+ goto done;
+
+ if (!aead_writable(sk)) {
+ /* see aead_sendmsg why more is set to 0 */
+ ctx->more = 0;
+ err = aead_wait_for_wmem(sk, flags);
+ if (err)
+ goto unlock;
+ }
+
+ ctx->merge = 0;
+
+ get_page(page);
+ sg_set_page(sgl->sg + sgl->cur, page, size, offset);
+ sgl->cur++;
+ ctx->used += size;
+
+ err = 0;
+
+done:
+ ctx->more = flags & MSG_MORE;
+
+unlock:
+ aead_data_wakeup(sk);
+ release_sock(sk);
+
+ return err ?: size;
+}
+
+static int aead_recvmsg(struct kiocb *unused, struct socket *sock,
+ struct msghdr *msg, size_t ignored, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ unsigned bs = crypto_aead_blocksize(crypto_aead_reqtfm(&ctx->aead_req));
+ unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
+ struct aead_sg_list *sgl = &ctx->tsgl;
+ struct scatterlist *sg = sgl->sg;
+ struct scatterlist assoc;
+ size_t assoclen = 0;
+ unsigned int i = 0;
+ int err = -EAGAIN;
+ unsigned long used = 0;
+ unsigned long outlen = 0;
+
+ /*
+ * Require exactly one IOV block as the AEAD operation is a one shot
+ * due to the authentication tag.
+ */
+ if (msg->msg_iter.nr_segs != 1)
+ return -ENOMSG;
+
+ lock_sock(sk);
+ /*
+ * AEAD memory structure: For encryption, the tag is appended to the
+ * ciphertext which implies that the memory allocated for the ciphertext
+ * must be increased by the tag length. For decryption, the tag
+ * is expected to be concatenated to the ciphertext. The plaintext
+ * therefore has a memory size of the ciphertext minus the tag length.
+ *
+ * The memory structure for cipher operation has the following
+ * structure:
+ * AEAD encryption input: assoc data || plaintext
+ * AEAD encryption output: cipherntext || auth tag
+ * AEAD decryption input: assoc data || ciphertext || auth tag
+ * AEAD decryption output: plaintext
+ */
+
+ if (!aead_readable(ctx)) {
+ err = aead_wait_for_data(sk, flags);
+ if (err)
+ goto unlock;
+ }
+
+ used = ctx->used;
+
+ err = -ENOMEM;
+ if (!aead_sufficient_data(ctx))
+ goto unlock;
+ /*
+ * The cipher operation input data is reduced by the associated data
+ * length as this data is processed separately later on.
+ */
+ used -= ctx->aead_assoclen;
+
+ if (ctx->enc) {
+ /* round up output buffer to multiple of block size */
+ outlen = ((used + bs - 1) / bs * bs);
+ /* add the size needed for the auth tag to be created */
+ outlen += as;
+ } else {
+ /* output data size is input without the authentication tag */
+ outlen = used - as;
+ /* round up output buffer to multiple of block size */
+ outlen = ((outlen + bs - 1) / bs * bs);
+ }
+
+ /* ensure output buffer is sufficiently large */
+ if (msg->msg_iter.iov->iov_len < outlen)
+ goto unlock;
+
+ outlen = af_alg_make_sg(&ctx->rsgl, msg->msg_iter.iov->iov_base,
+ outlen, 1);
+ err = outlen;
+ if (err < 0)
+ goto unlock;
+
+ err = -EINVAL;
+ /*
+ * first chunk of input is AD -- one scatterlist entry is one page,
+ * and we process only one scatterlist, the maximum size of AD is
+ * one page
+ */
+ sg_init_table(&assoc, 1);
+ sg_set_page(&assoc, sg_page(sg), ctx->aead_assoclen, sg->offset);
+ aead_request_set_assoc(&ctx->aead_req, &assoc, ctx->aead_assoclen);
+
+ /* point sg to cipher/plaintext start */
+ assoclen = ctx->aead_assoclen;
+ for(i = 0; i < ctx->tsgl.cur; i++) {
+ sg = sgl->sg + i;
+ if (sg->length <= assoclen) {
+ assoclen -= sg->length;
+ if (i >= ctx->tsgl.cur)
+ goto unlock;
+ } else {
+ sg->length -= assoclen;
+ sg->offset += assoclen;
+ break;
+ }
+ }
+
+ aead_request_set_crypt(&ctx->aead_req, sg, ctx->rsgl.sg, used, ctx->iv);
+
+ err = af_alg_wait_for_completion(ctx->enc ?
+ crypto_aead_encrypt(&ctx->aead_req) :
+ crypto_aead_decrypt(&ctx->aead_req),
+ &ctx->completion);
+
+ af_alg_free_sg(&ctx->rsgl);
+
+ if (err)
+ goto unlock;
+
+ aead_put_sgl(sk);
+
+ err = 0;
+
+unlock:
+ aead_wmem_wakeup(sk);
+ release_sock(sk);
+
+ return err ? err : outlen;
+}
+
+static unsigned int aead_poll(struct file *file, struct socket *sock,
+ poll_table *wait)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ unsigned int mask;
+
+ sock_poll_wait(file, sk_sleep(sk), wait);
+ mask = 0;
+
+ if (aead_readable(ctx))
+ mask |= POLLIN | POLLRDNORM;
+
+ if (aead_writable(sk))
+ mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
+
+ return mask;
+}
+
+static struct proto_ops algif_aead_ops = {
+ .family = PF_ALG,
+
+ .connect = sock_no_connect,
+ .socketpair = sock_no_socketpair,
+ .getname = sock_no_getname,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .getsockopt = sock_no_getsockopt,
+ .mmap = sock_no_mmap,
+ .bind = sock_no_bind,
+ .accept = sock_no_accept,
+ .setsockopt = sock_no_setsockopt,
+
+ .release = af_alg_release,
+ .sendmsg = aead_sendmsg,
+ .sendpage = aead_sendpage,
+ .recvmsg = aead_recvmsg,
+ .poll = aead_poll,
+};
+
+static void *aead_bind(const char *name, u32 type, u32 mask)
+{
+ return crypto_alloc_aead(name, type, mask);
+}
+
+static void aead_release(void *private)
+{
+ crypto_free_aead(private);
+}
+
+static int aead_setauthsize(void *private, unsigned int authsize)
+{
+ return crypto_aead_setauthsize(private, authsize);
+}
+
+static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
+{
+ return crypto_aead_setkey(private, key, keylen);
+}
+
+static void aead_sock_destruct(struct sock *sk)
+{
+ struct alg_sock *ask = alg_sk(sk);
+ struct aead_ctx *ctx = ask->private;
+ unsigned int ivlen = crypto_aead_ivsize(
+ crypto_aead_reqtfm(&ctx->aead_req));
+
+ aead_put_sgl(sk);
+ sock_kzfree_s(sk, ctx->iv, ivlen);
+ sock_kfree_s(sk, ctx, ctx->len);
+ af_alg_release_parent(sk);
+}
+
+static int aead_accept_parent(void *private, struct sock *sk)
+{
+ struct aead_ctx *ctx;
+ struct alg_sock *ask = alg_sk(sk);
+ unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
+ unsigned int ivlen = crypto_aead_ivsize(private);
+
+ ctx = sock_kmalloc(sk, len, GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ memset(ctx, 0, len);
+
+ ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
+ if (!ctx->iv) {
+ sock_kfree_s(sk, ctx, len);
+ return -ENOMEM;
+ }
+ memset(ctx->iv, 0, ivlen);
+
+ ctx->len = len;
+ ctx->used = 0;
+ ctx->more = 0;
+ ctx->merge = 0;
+ ctx->enc = 0;
+ ctx->tsgl.cur = 0;
+ ctx->aead_assoclen = 0;
+ af_alg_init_completion(&ctx->completion);
+ sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
+
+ ask->private = ctx;
+
+ aead_request_set_tfm(&ctx->aead_req, private);
+ aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ af_alg_complete, &ctx->completion);
+
+ sk->sk_destruct = aead_sock_destruct;
+
+ return 0;
+}
+
+static const struct af_alg_type algif_type_aead = {
+ .bind = aead_bind,
+ .release = aead_release,
+ .setkey = aead_setkey,
+ .setauthsize = aead_setauthsize,
+ .accept = aead_accept_parent,
+ .ops = &algif_aead_ops,
+ .name = "aead",
+ .owner = THIS_MODULE
+};
+
+static int __init algif_aead_init(void)
+{
+ return af_alg_register_type(&algif_type_aead);
+}
+
+static void __exit algif_aead_exit(void)
+{
+ int err = af_alg_unregister_type(&algif_type_aead);
+ BUG_ON(err);
+}
+
+module_init(algif_aead_init);
+module_exit(algif_aead_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");
--
2.1.0
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