* [PATCH 1/3] Move certificate handling to its own directory
2015-08-14 15:56 [PATCH 0/3] Move cert handling to certs/ directory David Howells
@ 2015-08-14 15:57 ` David Howells
2015-08-14 15:57 ` [PATCH 2/3] modsign: Use if_changed rule for extracting cert from module signing key David Howells
2015-08-14 15:57 ` [PATCH 3/3] modsign: Handle signing key in source tree David Howells
2 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2015-08-14 15:57 UTC (permalink / raw)
To: keyrings
Cc: dhowells, linux-security-module, dwmw2, linux-kernel, linux-crypto
Move certificate handling out of the kernel/ directory and into a certs/
directory to get all the weird stuff in one place and move the generated
signing keys into this directory.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>
---
Documentation/module-signing.txt | 18 ++--
MAINTAINERS | 9 ++
Makefile | 4 -
certs/Kconfig | 42 ++++++++++
certs/Makefile | 147 ++++++++++++++++++++++++++++++++++++
certs/system_certificates.S | 23 ++++++
certs/system_keyring.c | 157 ++++++++++++++++++++++++++++++++++++++
crypto/Kconfig | 1
init/Kconfig | 39 ---------
kernel/Makefile | 143 -----------------------------------
kernel/system_certificates.S | 23 ------
kernel/system_keyring.c | 157 --------------------------------------
12 files changed, 390 insertions(+), 373 deletions(-)
create mode 100644 certs/Kconfig
create mode 100644 certs/Makefile
create mode 100644 certs/system_certificates.S
create mode 100644 certs/system_keyring.c
delete mode 100644 kernel/system_certificates.S
delete mode 100644 kernel/system_keyring.c
diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt
index 02a9baf1c72f..a78bf1ffa68c 100644
--- a/Documentation/module-signing.txt
+++ b/Documentation/module-signing.txt
@@ -92,13 +92,13 @@ This has a number of options available:
(4) "File name or PKCS#11 URI of module signing key" (CONFIG_MODULE_SIG_KEY)
Setting this option to something other than its default of
- "signing_key.pem" will disable the autogeneration of signing keys and
- allow the kernel modules to be signed with a key of your choosing.
- The string provided should identify a file containing both a private
- key and its corresponding X.509 certificate in PEM form, or — on
- systems where the OpenSSL ENGINE_pkcs11 is functional — a PKCS#11 URI
- as defined by RFC7512. In the latter case, the PKCS#11 URI should
- reference both a certificate and a private key.
+ "certs/signing_key.pem" will disable the autogeneration of signing keys
+ and allow the kernel modules to be signed with a key of your choosing.
+ The string provided should identify a file containing both a private key
+ and its corresponding X.509 certificate in PEM form, or — on systems where
+ the OpenSSL ENGINE_pkcs11 is functional — a PKCS#11 URI as defined by
+ RFC7512. In the latter case, the PKCS#11 URI should reference both a
+ certificate and a private key.
If the PEM file containing the private key is encrypted, or if the
PKCS#11 token requries a PIN, this can be provided at build time by
@@ -130,12 +130,12 @@ Under normal conditions, when CONFIG_MODULE_SIG_KEY is unchanged from its
default, the kernel build will automatically generate a new keypair using
openssl if one does not exist in the file:
- signing_key.pem
+ certs/signing_key.pem
during the building of vmlinux (the public part of the key needs to be built
into vmlinux) using parameters in the:
- x509.genkey
+ certs/x509.genkey
file (which is also generated if it does not already exist).
diff --git a/MAINTAINERS b/MAINTAINERS
index bde2e3f5a10b..294dc59ed5e1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2589,6 +2589,15 @@ S: Supported
F: Documentation/filesystems/ceph.txt
F: fs/ceph/
+CERTIFICATE HANDLING:
+M: David Howells <dhowells@redhat.com>
+M: David Woodhouse <dwmw2@infradead.org>
+L: keyrings@linux-nfs.org
+S: Maintained
+F: Documentation/module-signing.txt
+F: certs/
+F: scripts/extract-cert.c
+
CERTIFIED WIRELESS USB (WUSB) SUBSYSTEM:
L: linux-usb@vger.kernel.org
S: Orphan
diff --git a/Makefile b/Makefile
index 6ab99d8cc23c..2341942feb85 100644
--- a/Makefile
+++ b/Makefile
@@ -871,7 +871,7 @@ INITRD_COMPRESS-$(CONFIG_RD_LZ4) := lz4
ifdef CONFIG_MODULE_SIG_ALL
MODSECKEY = $(CONFIG_MODULE_SIG_KEY)
-MODPUBKEY = ./signing_key.x509
+MODPUBKEY = certs/signing_key.x509
export MODPUBKEY
mod_sign_cmd = scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODSECKEY) $(MODPUBKEY)
else
@@ -881,7 +881,7 @@ export mod_sign_cmd
ifeq ($(KBUILD_EXTMOD),)
-core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
+core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/
vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
$(core-y) $(core-m) $(drivers-y) $(drivers-m) \
diff --git a/certs/Kconfig b/certs/Kconfig
new file mode 100644
index 000000000000..b030b9c7ed34
--- /dev/null
+++ b/certs/Kconfig
@@ -0,0 +1,42 @@
+menu "Certificates for signature checking"
+
+config MODULE_SIG_KEY
+ string "File name or PKCS#11 URI of module signing key"
+ default "certs/signing_key.pem"
+ depends on MODULE_SIG
+ help
+ Provide the file name of a private key/certificate in PEM format,
+ or a PKCS#11 URI according to RFC7512. The file should contain, or
+ the URI should identify, both the certificate and its corresponding
+ private key.
+
+ If this option is unchanged from its default "certs/signing_key.pem",
+ then the kernel will automatically generate the private key and
+ certificate as described in Documentation/module-signing.txt
+
+config SYSTEM_TRUSTED_KEYRING
+ bool "Provide system-wide ring of trusted keys"
+ depends on KEYS
+ help
+ Provide a system keyring to which trusted keys can be added. Keys in
+ the keyring are considered to be trusted. Keys may be added at will
+ by the kernel from compiled-in data and from hardware key stores, but
+ userspace may only add extra keys if those keys can be verified by
+ keys already in the keyring.
+
+ Keys in this keyring are used by module signature checking.
+
+config SYSTEM_TRUSTED_KEYS
+ string "Additional X.509 keys for default system keyring"
+ depends on SYSTEM_TRUSTED_KEYRING
+ help
+ If set, this option should be the filename of a PEM-formatted file
+ containing trusted X.509 certificates to be included in the default
+ system keyring. Any certificate used for module signing is implicitly
+ also trusted.
+
+ NOTE: If you previously provided keys for the system keyring in the
+ form of DER-encoded *.x509 files in the top-level build directory,
+ those are no longer used. You will need to set this option instead.
+
+endmenu
diff --git a/certs/Makefile b/certs/Makefile
new file mode 100644
index 000000000000..5d33486d3b20
--- /dev/null
+++ b/certs/Makefile
@@ -0,0 +1,147 @@
+#
+# Makefile for the linux kernel signature checking certificates.
+#
+
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
+
+###############################################################################
+#
+# When a Kconfig string contains a filename, it is suitable for
+# passing to shell commands. It is surrounded by double-quotes, and
+# any double-quotes or backslashes within it are escaped by
+# backslashes.
+#
+# This is no use for dependencies or $(wildcard). We need to strip the
+# surrounding quotes and the escaping from quotes and backslashes, and
+# we *do* need to escape any spaces in the string. So, for example:
+#
+# Usage: $(eval $(call config_filename,FOO))
+#
+# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
+# transformed as described above to be suitable for use within the
+# makefile.
+#
+# Also, if the filename is a relative filename and exists in the source
+# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
+# be prefixed to *both* command invocation and dependencies.
+#
+# Note: We also print the filenames in the quiet_cmd_foo text, and
+# perhaps ought to have a version specially escaped for that purpose.
+# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
+# enough. It'll strip the quotes in the common case where there's no
+# space and it's a simple filename, and it'll retain the quotes when
+# there's a space. There are some esoteric cases in which it'll print
+# the wrong thing, but we don't really care. The actual dependencies
+# and commands *do* get it right, with various combinations of single
+# and double quotes, backslashes and spaces in the filenames.
+#
+###############################################################################
+#
+quote := $(firstword " ")
+space :=
+space +=
+space_escape := %%%SPACE%%%
+#
+define config_filename
+ifneq ($$(CONFIG_$(1)),"")
+$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
+ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
+else
+ifeq ($$(wildcard $$($(1)_FILENAME)),)
+ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
+$(1)_SRCPREFIX := $(srctree)/
+endif
+endif
+endif
+endif
+endef
+#
+###############################################################################
+
+ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
+
+$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
+
+# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
+$(obj)/system_certificates.o: $(obj)/x509_certificate_list
+
+# Cope with signing_key.x509 existing in $(srctree) not $(objtree)
+AFLAGS_system_certificates.o := -I$(srctree)
+
+quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
+ cmd_extract_certs = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
+
+targets += x509_certificate_list
+$(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
+ $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
+endif
+
+clean-files := x509_certificate_list .x509.list
+
+ifeq ($(CONFIG_MODULE_SIG),y)
+###############################################################################
+#
+# If module signing is requested, say by allyesconfig, but a key has not been
+# supplied, then one will need to be generated to make sure the build does not
+# fail and that the kernel may be used afterwards.
+#
+###############################################################################
+ifndef CONFIG_MODULE_SIG_HASH
+$(error Could not determine digest type to use from kernel config)
+endif
+
+# We do it this way rather than having a boolean option for enabling an
+# external private key, because 'make randconfig' might enable such a
+# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
+ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
+$(obj)/signing_key.pem: $(obj)/x509.genkey
+ @echo "###"
+ @echo "### Now generating an X.509 key pair to be used for signing modules."
+ @echo "###"
+ @echo "### If this takes a long time, you might wish to run rngd in the"
+ @echo "### background to keep the supply of entropy topped up. It"
+ @echo "### needs to be run as root, and uses a hardware random"
+ @echo "### number generator if one is available."
+ @echo "###"
+ openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
+ -batch -x509 -config $(obj)/x509.genkey \
+ -outform PEM -out $(obj)/signing_key.pem \
+ -keyout $(obj)/signing_key.pem 2>&1
+ @echo "###"
+ @echo "### Key pair generated."
+ @echo "###"
+
+$(obj)/x509.genkey:
+ @echo Generating X.509 key generation config
+ @echo >$@ "[ req ]"
+ @echo >>$@ "default_bits = 4096"
+ @echo >>$@ "distinguished_name = req_distinguished_name"
+ @echo >>$@ "prompt = no"
+ @echo >>$@ "string_mask = utf8only"
+ @echo >>$@ "x509_extensions = myexts"
+ @echo >>$@
+ @echo >>$@ "[ req_distinguished_name ]"
+ @echo >>$@ "#O = Unspecified company"
+ @echo >>$@ "CN = Build time autogenerated kernel key"
+ @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
+ @echo >>$@
+ @echo >>$@ "[ myexts ]"
+ @echo >>$@ "basicConstraints=critical,CA:FALSE"
+ @echo >>$@ "keyUsage=digitalSignature"
+ @echo >>$@ "subjectKeyIdentifier=hash"
+ @echo >>$@ "authorityKeyIdentifier=keyid"
+endif
+
+$(eval $(call config_filename,MODULE_SIG_KEY))
+
+# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
+ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
+X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
+endif
+
+# GCC PR#66871 again.
+$(obj)/system_certificates.o: $(obj)/signing_key.x509
+
+$(obj)/signing_key.x509: scripts/extract-cert include/config/module/sig/key.h $(X509_DEP)
+ $(call cmd,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
+endif
diff --git a/certs/system_certificates.S b/certs/system_certificates.S
new file mode 100644
index 000000000000..9216e8c81764
--- /dev/null
+++ b/certs/system_certificates.S
@@ -0,0 +1,23 @@
+#include <linux/export.h>
+#include <linux/init.h>
+
+ __INITRODATA
+
+ .align 8
+ .globl VMLINUX_SYMBOL(system_certificate_list)
+VMLINUX_SYMBOL(system_certificate_list):
+__cert_list_start:
+#ifdef CONFIG_MODULE_SIG
+ .incbin "certs/signing_key.x509"
+#endif
+ .incbin "certs/x509_certificate_list"
+__cert_list_end:
+
+ .align 8
+ .globl VMLINUX_SYMBOL(system_certificate_list_size)
+VMLINUX_SYMBOL(system_certificate_list_size):
+#ifdef CONFIG_64BIT
+ .quad __cert_list_end - __cert_list_start
+#else
+ .long __cert_list_end - __cert_list_start
+#endif
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
new file mode 100644
index 000000000000..2570598b784d
--- /dev/null
+++ b/certs/system_keyring.c
@@ -0,0 +1,157 @@
+/* System trusted keyring for trusted public keys
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include <crypto/pkcs7.h>
+
+struct key *system_trusted_keyring;
+EXPORT_SYMBOL_GPL(system_trusted_keyring);
+
+extern __initconst const u8 system_certificate_list[];
+extern __initconst const unsigned long system_certificate_list_size;
+
+/*
+ * Load the compiled-in keys
+ */
+static __init int system_trusted_keyring_init(void)
+{
+ pr_notice("Initialise system trusted keyring\n");
+
+ system_trusted_keyring =
+ keyring_alloc(".system_keyring",
+ KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
+ KEY_ALLOC_NOT_IN_QUOTA, NULL);
+ if (IS_ERR(system_trusted_keyring))
+ panic("Can't allocate system trusted keyring\n");
+
+ set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
+ return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(system_trusted_keyring_init);
+
+/*
+ * Load the compiled-in list of X.509 certificates.
+ */
+static __init int load_system_certificate_list(void)
+{
+ key_ref_t key;
+ const u8 *p, *end;
+ size_t plen;
+
+ pr_notice("Loading compiled-in X.509 certificates\n");
+
+ p = system_certificate_list;
+ end = p + system_certificate_list_size;
+ while (p < end) {
+ /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
+ * than 256 bytes in size.
+ */
+ if (end - p < 4)
+ goto dodgy_cert;
+ if (p[0] != 0x30 &&
+ p[1] != 0x82)
+ goto dodgy_cert;
+ plen = (p[2] << 8) | p[3];
+ plen += 4;
+ if (plen > end - p)
+ goto dodgy_cert;
+
+ key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ),
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_TRUSTED);
+ if (IS_ERR(key)) {
+ pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
+ PTR_ERR(key));
+ } else {
+ set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
+ pr_notice("Loaded X.509 cert '%s'\n",
+ key_ref_to_ptr(key)->description);
+ key_ref_put(key);
+ }
+ p += plen;
+ }
+
+ return 0;
+
+dodgy_cert:
+ pr_err("Problem parsing in-kernel X.509 certificate list\n");
+ return 0;
+}
+late_initcall(load_system_certificate_list);
+
+#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
+
+/**
+ * Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified.
+ * @len: Size of @data.
+ * @raw_pkcs7: The PKCS#7 message that is the signature.
+ * @pkcs7_len: The size of @raw_pkcs7.
+ * @usage: The use to which the key is being put.
+ */
+int system_verify_data(const void *data, unsigned long len,
+ const void *raw_pkcs7, size_t pkcs7_len,
+ enum key_being_used_for usage)
+{
+ struct pkcs7_message *pkcs7;
+ bool trusted;
+ int ret;
+
+ pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
+ if (IS_ERR(pkcs7))
+ return PTR_ERR(pkcs7);
+
+ /* The data should be detached - so we need to supply it. */
+ if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
+ pr_err("PKCS#7 signature with non-detached data\n");
+ ret = -EBADMSG;
+ goto error;
+ }
+
+ ret = pkcs7_verify(pkcs7, usage);
+ if (ret < 0)
+ goto error;
+
+ ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
+ if (ret < 0)
+ goto error;
+
+ if (!trusted) {
+ pr_err("PKCS#7 signature not signed with a trusted key\n");
+ ret = -ENOKEY;
+ }
+
+error:
+ pkcs7_free_message(pkcs7);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(system_verify_data);
+
+#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
diff --git a/crypto/Kconfig b/crypto/Kconfig
index b4cfc5754033..51b01de7c0ae 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1601,5 +1601,6 @@ config CRYPTO_HASH_INFO
source "drivers/crypto/Kconfig"
source crypto/asymmetric_keys/Kconfig
+source certs/Kconfig
endif # if CRYPTO
diff --git a/init/Kconfig b/init/Kconfig
index 5d1a703663ad..5526dfaac628 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1740,31 +1740,6 @@ config MMAP_ALLOW_UNINITIALIZED
See Documentation/nommu-mmap.txt for more information.
-config SYSTEM_TRUSTED_KEYRING
- bool "Provide system-wide ring of trusted keys"
- depends on KEYS
- help
- Provide a system keyring to which trusted keys can be added. Keys in
- the keyring are considered to be trusted. Keys may be added at will
- by the kernel from compiled-in data and from hardware key stores, but
- userspace may only add extra keys if those keys can be verified by
- keys already in the keyring.
-
- Keys in this keyring are used by module signature checking.
-
-config SYSTEM_TRUSTED_KEYS
- string "Additional X.509 keys for default system keyring"
- depends on SYSTEM_TRUSTED_KEYRING
- help
- If set, this option should be the filename of a PEM-formatted file
- containing trusted X.509 certificates to be included in the default
- system keyring. Any certificate used for module signing is implicitly
- also trusted.
-
- NOTE: If you previously provided keys for the system keyring in the
- form of DER-encoded *.x509 files in the top-level build directory,
- those are no longer used. You will need to set this option instead.
-
config SYSTEM_DATA_VERIFICATION
def_bool n
select SYSTEM_TRUSTED_KEYRING
@@ -1965,20 +1940,6 @@ config MODULE_SIG_HASH
default "sha384" if MODULE_SIG_SHA384
default "sha512" if MODULE_SIG_SHA512
-config MODULE_SIG_KEY
- string "File name or PKCS#11 URI of module signing key"
- default "signing_key.pem"
- depends on MODULE_SIG
- help
- Provide the file name of a private key/certificate in PEM format,
- or a PKCS#11 URI according to RFC7512. The file should contain, or
- the URI should identify, both the certificate and its corresponding
- private key.
-
- If this option is unchanged from its default "signing_key.pem",
- then the kernel will automatically generate the private key and
- certificate as described in Documentation/module-signing.txt
-
config MODULE_COMPRESS
bool "Compress modules on installation"
depends on MODULES
diff --git a/kernel/Makefile b/kernel/Makefile
index 65ef3846fbe8..1aa153a1be21 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -45,7 +45,6 @@ ifneq ($(CONFIG_SMP),y)
obj-y += up.o
endif
obj-$(CONFIG_UID16) += uid16.o
-obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_MODULE_SIG) += module_signing.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
@@ -111,145 +110,3 @@ $(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE
targets += config_data.h
$(obj)/config_data.h: $(obj)/config_data.gz FORCE
$(call filechk,ikconfiggz)
-
-###############################################################################
-#
-# When a Kconfig string contains a filename, it is suitable for
-# passing to shell commands. It is surrounded by double-quotes, and
-# any double-quotes or backslashes within it are escaped by
-# backslashes.
-#
-# This is no use for dependencies or $(wildcard). We need to strip the
-# surrounding quotes and the escaping from quotes and backslashes, and
-# we *do* need to escape any spaces in the string. So, for example:
-#
-# Usage: $(eval $(call config_filename,FOO))
-#
-# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
-# transformed as described above to be suitable for use within the
-# makefile.
-#
-# Also, if the filename is a relative filename and exists in the source
-# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
-# be prefixed to *both* command invocation and dependencies.
-#
-# Note: We also print the filenames in the quiet_cmd_foo text, and
-# perhaps ought to have a version specially escaped for that purpose.
-# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
-# enough. It'll strip the quotes in the common case where there's no
-# space and it's a simple filename, and it'll retain the quotes when
-# there's a space. There are some esoteric cases in which it'll print
-# the wrong thing, but we don't really care. The actual dependencies
-# and commands *do* get it right, with various combinations of single
-# and double quotes, backslashes and spaces in the filenames.
-#
-###############################################################################
-#
-quote := $(firstword " ")
-space :=
-space +=
-space_escape := %%%SPACE%%%
-#
-define config_filename
-ifneq ($$(CONFIG_$(1)),"")
-$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
-ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
-else
-ifeq ($$(wildcard $$($(1)_FILENAME)),)
-ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
-$(1)_SRCPREFIX := $(srctree)/
-endif
-endif
-endif
-endif
-endef
-#
-###############################################################################
-
-ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
-
-$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
-
-# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
-$(obj)/system_certificates.o: $(obj)/x509_certificate_list
-
-# Cope with signing_key.x509 existing in $(srctree) not $(objtree)
-AFLAGS_system_certificates.o := -I$(srctree)
-
-quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
- cmd_extract_certs = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
-
-targets += x509_certificate_list
-$(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
- $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
-endif
-
-clean-files := x509_certificate_list .x509.list
-
-ifeq ($(CONFIG_MODULE_SIG),y)
-###############################################################################
-#
-# If module signing is requested, say by allyesconfig, but a key has not been
-# supplied, then one will need to be generated to make sure the build does not
-# fail and that the kernel may be used afterwards.
-#
-###############################################################################
-ifndef CONFIG_MODULE_SIG_HASH
-$(error Could not determine digest type to use from kernel config)
-endif
-
-# We do it this way rather than having a boolean option for enabling an
-# external private key, because 'make randconfig' might enable such a
-# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
-ifeq ($(CONFIG_MODULE_SIG_KEY),"signing_key.pem")
-signing_key.pem: x509.genkey
- @echo "###"
- @echo "### Now generating an X.509 key pair to be used for signing modules."
- @echo "###"
- @echo "### If this takes a long time, you might wish to run rngd in the"
- @echo "### background to keep the supply of entropy topped up. It"
- @echo "### needs to be run as root, and uses a hardware random"
- @echo "### number generator if one is available."
- @echo "###"
- openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
- -batch -x509 -config x509.genkey \
- -outform PEM -out signing_key.pem \
- -keyout signing_key.pem 2>&1
- @echo "###"
- @echo "### Key pair generated."
- @echo "###"
-
-x509.genkey:
- @echo Generating X.509 key generation config
- @echo >x509.genkey "[ req ]"
- @echo >>x509.genkey "default_bits = 4096"
- @echo >>x509.genkey "distinguished_name = req_distinguished_name"
- @echo >>x509.genkey "prompt = no"
- @echo >>x509.genkey "string_mask = utf8only"
- @echo >>x509.genkey "x509_extensions = myexts"
- @echo >>x509.genkey
- @echo >>x509.genkey "[ req_distinguished_name ]"
- @echo >>x509.genkey "#O = Unspecified company"
- @echo >>x509.genkey "CN = Build time autogenerated kernel key"
- @echo >>x509.genkey "#emailAddress = unspecified.user@unspecified.company"
- @echo >>x509.genkey
- @echo >>x509.genkey "[ myexts ]"
- @echo >>x509.genkey "basicConstraints=critical,CA:FALSE"
- @echo >>x509.genkey "keyUsage=digitalSignature"
- @echo >>x509.genkey "subjectKeyIdentifier=hash"
- @echo >>x509.genkey "authorityKeyIdentifier=keyid"
-endif
-
-$(eval $(call config_filename,MODULE_SIG_KEY))
-
-# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
-ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
-X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
-endif
-
-# GCC PR#66871 again.
-$(obj)/system_certificates.o: signing_key.x509
-
-signing_key.x509: scripts/extract-cert include/config/module/sig/key.h $(X509_DEP)
- $(call cmd,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
-endif
diff --git a/kernel/system_certificates.S b/kernel/system_certificates.S
deleted file mode 100644
index 6ba2f75e7ba5..000000000000
--- a/kernel/system_certificates.S
+++ /dev/null
@@ -1,23 +0,0 @@
-#include <linux/export.h>
-#include <linux/init.h>
-
- __INITRODATA
-
- .align 8
- .globl VMLINUX_SYMBOL(system_certificate_list)
-VMLINUX_SYMBOL(system_certificate_list):
-__cert_list_start:
-#ifdef CONFIG_MODULE_SIG
- .incbin "signing_key.x509"
-#endif
- .incbin "kernel/x509_certificate_list"
-__cert_list_end:
-
- .align 8
- .globl VMLINUX_SYMBOL(system_certificate_list_size)
-VMLINUX_SYMBOL(system_certificate_list_size):
-#ifdef CONFIG_64BIT
- .quad __cert_list_end - __cert_list_start
-#else
- .long __cert_list_end - __cert_list_start
-#endif
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
deleted file mode 100644
index 2570598b784d..000000000000
--- a/kernel/system_keyring.c
+++ /dev/null
@@ -1,157 +0,0 @@
-/* System trusted keyring for trusted public keys
- *
- * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#include <linux/export.h>
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/cred.h>
-#include <linux/err.h>
-#include <keys/asymmetric-type.h>
-#include <keys/system_keyring.h>
-#include <crypto/pkcs7.h>
-
-struct key *system_trusted_keyring;
-EXPORT_SYMBOL_GPL(system_trusted_keyring);
-
-extern __initconst const u8 system_certificate_list[];
-extern __initconst const unsigned long system_certificate_list_size;
-
-/*
- * Load the compiled-in keys
- */
-static __init int system_trusted_keyring_init(void)
-{
- pr_notice("Initialise system trusted keyring\n");
-
- system_trusted_keyring =
- keyring_alloc(".system_keyring",
- KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
- ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
- KEY_ALLOC_NOT_IN_QUOTA, NULL);
- if (IS_ERR(system_trusted_keyring))
- panic("Can't allocate system trusted keyring\n");
-
- set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
- return 0;
-}
-
-/*
- * Must be initialised before we try and load the keys into the keyring.
- */
-device_initcall(system_trusted_keyring_init);
-
-/*
- * Load the compiled-in list of X.509 certificates.
- */
-static __init int load_system_certificate_list(void)
-{
- key_ref_t key;
- const u8 *p, *end;
- size_t plen;
-
- pr_notice("Loading compiled-in X.509 certificates\n");
-
- p = system_certificate_list;
- end = p + system_certificate_list_size;
- while (p < end) {
- /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
- * than 256 bytes in size.
- */
- if (end - p < 4)
- goto dodgy_cert;
- if (p[0] != 0x30 &&
- p[1] != 0x82)
- goto dodgy_cert;
- plen = (p[2] << 8) | p[3];
- plen += 4;
- if (plen > end - p)
- goto dodgy_cert;
-
- key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
- "asymmetric",
- NULL,
- p,
- plen,
- ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ),
- KEY_ALLOC_NOT_IN_QUOTA |
- KEY_ALLOC_TRUSTED);
- if (IS_ERR(key)) {
- pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
- PTR_ERR(key));
- } else {
- set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
- pr_notice("Loaded X.509 cert '%s'\n",
- key_ref_to_ptr(key)->description);
- key_ref_put(key);
- }
- p += plen;
- }
-
- return 0;
-
-dodgy_cert:
- pr_err("Problem parsing in-kernel X.509 certificate list\n");
- return 0;
-}
-late_initcall(load_system_certificate_list);
-
-#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
-
-/**
- * Verify a PKCS#7-based signature on system data.
- * @data: The data to be verified.
- * @len: Size of @data.
- * @raw_pkcs7: The PKCS#7 message that is the signature.
- * @pkcs7_len: The size of @raw_pkcs7.
- * @usage: The use to which the key is being put.
- */
-int system_verify_data(const void *data, unsigned long len,
- const void *raw_pkcs7, size_t pkcs7_len,
- enum key_being_used_for usage)
-{
- struct pkcs7_message *pkcs7;
- bool trusted;
- int ret;
-
- pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
- if (IS_ERR(pkcs7))
- return PTR_ERR(pkcs7);
-
- /* The data should be detached - so we need to supply it. */
- if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
- pr_err("PKCS#7 signature with non-detached data\n");
- ret = -EBADMSG;
- goto error;
- }
-
- ret = pkcs7_verify(pkcs7, usage);
- if (ret < 0)
- goto error;
-
- ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
- if (ret < 0)
- goto error;
-
- if (!trusted) {
- pr_err("PKCS#7 signature not signed with a trusted key\n");
- ret = -ENOKEY;
- }
-
-error:
- pkcs7_free_message(pkcs7);
- pr_devel("<==%s() = %d\n", __func__, ret);
- return ret;
-}
-EXPORT_SYMBOL_GPL(system_verify_data);
-
-#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 3/3] modsign: Handle signing key in source tree
2015-08-14 15:56 [PATCH 0/3] Move cert handling to certs/ directory David Howells
2015-08-14 15:57 ` [PATCH 1/3] Move certificate handling to its own directory David Howells
2015-08-14 15:57 ` [PATCH 2/3] modsign: Use if_changed rule for extracting cert from module signing key David Howells
@ 2015-08-14 15:57 ` David Howells
2 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2015-08-14 15:57 UTC (permalink / raw)
To: keyrings
Cc: dhowells, linux-security-module, dwmw2, linux-kernel, linux-crypto
From: David Woodhouse <David.Woodhouse@intel.com>
Since commit 1329e8cc69 ("modsign: Extract signing cert from
CONFIG_MODULE_SIG_KEY if needed"), the build system has carefully coped
with the signing key being specified as a relative path in either the
source or or the build trees.
However, the actual signing of modules has not worked if the filename
is relative to the source tree.
Fix that by moving the config_filename helper into scripts/Kbuild.include
so that it can be used from elsewhere, and then using it in the top-level
Makefile to find the signing key file.
Kill the intermediate $(MODPUBKEY) and $(MODSECKEY) variables too, while
we're at it. There's no need for them.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
Makefile | 7 +++---
certs/Makefile | 54 ------------------------------------------------
scripts/Kbuild.include | 51 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 54 insertions(+), 58 deletions(-)
diff --git a/Makefile b/Makefile
index 2341942feb85..7c90dda898f6 100644
--- a/Makefile
+++ b/Makefile
@@ -870,10 +870,9 @@ INITRD_COMPRESS-$(CONFIG_RD_LZ4) := lz4
# export INITRD_COMPRESS := $(INITRD_COMPRESS-y)
ifdef CONFIG_MODULE_SIG_ALL
-MODSECKEY = $(CONFIG_MODULE_SIG_KEY)
-MODPUBKEY = certs/signing_key.x509
-export MODPUBKEY
-mod_sign_cmd = scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODSECKEY) $(MODPUBKEY)
+$(eval $(call config_filename,MODULE_SIG_KEY))
+
+mod_sign_cmd = scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY) certs/signing_key.x509
else
mod_sign_cmd = true
endif
diff --git a/certs/Makefile b/certs/Makefile
index 3c782d025c36..28ac694dd11a 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -4,60 +4,6 @@
obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
-###############################################################################
-#
-# When a Kconfig string contains a filename, it is suitable for
-# passing to shell commands. It is surrounded by double-quotes, and
-# any double-quotes or backslashes within it are escaped by
-# backslashes.
-#
-# This is no use for dependencies or $(wildcard). We need to strip the
-# surrounding quotes and the escaping from quotes and backslashes, and
-# we *do* need to escape any spaces in the string. So, for example:
-#
-# Usage: $(eval $(call config_filename,FOO))
-#
-# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
-# transformed as described above to be suitable for use within the
-# makefile.
-#
-# Also, if the filename is a relative filename and exists in the source
-# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
-# be prefixed to *both* command invocation and dependencies.
-#
-# Note: We also print the filenames in the quiet_cmd_foo text, and
-# perhaps ought to have a version specially escaped for that purpose.
-# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
-# enough. It'll strip the quotes in the common case where there's no
-# space and it's a simple filename, and it'll retain the quotes when
-# there's a space. There are some esoteric cases in which it'll print
-# the wrong thing, but we don't really care. The actual dependencies
-# and commands *do* get it right, with various combinations of single
-# and double quotes, backslashes and spaces in the filenames.
-#
-###############################################################################
-#
-quote := $(firstword " ")
-space :=
-space +=
-space_escape := %%%SPACE%%%
-#
-define config_filename
-ifneq ($$(CONFIG_$(1)),"")
-$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
-ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
-else
-ifeq ($$(wildcard $$($(1)_FILENAME)),)
-ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
-$(1)_SRCPREFIX := $(srctree)/
-endif
-endif
-endif
-endif
-endef
-#
-###############################################################################
-
ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index d3437b82ac25..608ac65c61e3 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -303,3 +303,54 @@ why = \
echo-why = $(call escsq, $(strip $(why)))
endif
+
+###############################################################################
+#
+# When a Kconfig string contains a filename, it is suitable for
+# passing to shell commands. It is surrounded by double-quotes, and
+# any double-quotes or backslashes within it are escaped by
+# backslashes.
+#
+# This is no use for dependencies or $(wildcard). We need to strip the
+# surrounding quotes and the escaping from quotes and backslashes, and
+# we *do* need to escape any spaces in the string. So, for example:
+#
+# Usage: $(eval $(call config_filename,FOO))
+#
+# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
+# transformed as described above to be suitable for use within the
+# makefile.
+#
+# Also, if the filename is a relative filename and exists in the source
+# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
+# be prefixed to *both* command invocation and dependencies.
+#
+# Note: We also print the filenames in the quiet_cmd_foo text, and
+# perhaps ought to have a version specially escaped for that purpose.
+# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
+# enough. It'll strip the quotes in the common case where there's no
+# space and it's a simple filename, and it'll retain the quotes when
+# there's a space. There are some esoteric cases in which it'll print
+# the wrong thing, but we don't really care. The actual dependencies
+# and commands *do* get it right, with various combinations of single
+# and double quotes, backslashes and spaces in the filenames.
+#
+###############################################################################
+#
+space_escape := %%%SPACE%%%
+#
+define config_filename
+ifneq ($$(CONFIG_$(1)),"")
+$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
+ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
+else
+ifeq ($$(wildcard $$($(1)_FILENAME)),)
+ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
+$(1)_SRCPREFIX := $(srctree)/
+endif
+endif
+endif
+endif
+endef
+#
+###############################################################################
^ permalink raw reply [flat|nested] 4+ messages in thread