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authorDavid Howells <dhowells@redhat.com>2015-07-20 21:16:28 +0100
committerDavid Howells <dhowells@redhat.com>2015-08-07 16:26:13 +0100
commit091f6e26eb326adbd718f406e440c838bed8ebb6 (patch)
tree9562f51745eb81fdf44d1fb56d6e79090935d2e4
parent1c39449921fc6db1f942051f79868a19c92f4d47 (diff)
MODSIGN: Extract the blob PKCS#7 signature verifier from module signing
Extract the function that drives the PKCS#7 signature verification given a data blob and a PKCS#7 blob out from the module signing code and lump it with the system keyring code as it's generic. This makes it independent of module config options and opens it to use by the firmware loader. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ming Lei <ming.lei@canonical.com> Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Kyle McMartin <kyle@kernel.org>
-rw-r--r--include/keys/system_keyring.h5
-rw-r--r--init/Kconfig29
-rw-r--r--kernel/module_signing.c44
-rw-r--r--kernel/system_keyring.c50
4 files changed, 75 insertions, 53 deletions
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 72665eb80692..9791c907cdb7 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -28,4 +28,9 @@ static inline struct key *get_system_trusted_keyring(void)
}
#endif
+#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
+extern int system_verify_data(const void *data, unsigned long len,
+ const void *raw_pkcs7, size_t pkcs7_len);
+#endif
+
#endif /* _KEYS_SYSTEM_KEYRING_H */
diff --git a/init/Kconfig b/init/Kconfig
index e16d9e587cee..14b3d8422502 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1752,6 +1752,24 @@ config SYSTEM_TRUSTED_KEYRING
Keys in this keyring are used by module signature checking.
+config SYSTEM_DATA_VERIFICATION
+ def_bool n
+ select SYSTEM_TRUSTED_KEYRING
+ select KEYS
+ select CRYPTO
+ select ASYMMETRIC_KEY_TYPE
+ select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+ select PUBLIC_KEY_ALGO_RSA
+ select ASN1
+ select OID_REGISTRY
+ select X509_CERTIFICATE_PARSER
+ select PKCS7_MESSAGE_PARSER
+ help
+ Provide PKCS#7 message verification using the contents of the system
+ trusted keyring to provide public keys. This then can be used for
+ module verification, kexec image verification and firmware blob
+ verification.
+
config PROFILING
bool "Profiling support"
help
@@ -1860,16 +1878,7 @@ config MODULE_SRCVERSION_ALL
config MODULE_SIG
bool "Module signature verification"
depends on MODULES
- select SYSTEM_TRUSTED_KEYRING
- select KEYS
- select CRYPTO
- select ASYMMETRIC_KEY_TYPE
- select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
- select PUBLIC_KEY_ALGO_RSA
- select ASN1
- select OID_REGISTRY
- select X509_CERTIFICATE_PARSER
- select PKCS7_MESSAGE_PARSER
+ select SYSTEM_DATA_VERIFICATION
help
Check modules for valid signatures upon load: the signature
is simply appended to the module. For more information see
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 8eb20cc66b39..70ad463f6df0 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -10,10 +10,8 @@
*/
#include <linux/kernel.h>
-#include <linux/err.h>
#include <keys/system_keyring.h>
#include <crypto/public_key.h>
-#include <crypto/pkcs7.h>
#include "module-internal.h"
/*
@@ -37,46 +35,6 @@ struct module_signature {
};
/*
- * Verify a PKCS#7-based signature on a module.
- */
-static int mod_verify_pkcs7(const void *mod, unsigned long modlen,
- const void *raw_pkcs7, size_t pkcs7_len)
-{
- 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, mod, modlen) < 0) {
- pr_err("PKCS#7 signature with non-detached data\n");
- ret = -EBADMSG;
- goto error;
- }
-
- ret = pkcs7_verify(pkcs7);
- 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;
-}
-
-/*
* Verify the signature on a module.
*/
int mod_verify_sig(const void *mod, unsigned long *_modlen)
@@ -114,5 +72,5 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
return -EBADMSG;
}
- return mod_verify_pkcs7(mod, modlen, mod + modlen, sig_len);
+ return system_verify_data(mod, modlen, mod + modlen, sig_len);
}
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
index 4cda71ee51c7..95f2dcbc7616 100644
--- a/kernel/system_keyring.c
+++ b/kernel/system_keyring.c
@@ -16,6 +16,7 @@
#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);
@@ -103,3 +104,52 @@ dodgy_cert:
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.
+ */
+int system_verify_data(const void *data, unsigned long len,
+ const void *raw_pkcs7, size_t pkcs7_len)
+{
+ 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);
+ 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 */

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