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Message-ID: <20150717162016.2578.40159.stgit@warthog.procyon.org.uk>
Date: Fri, 17 Jul 2015 17:20:16 +0100
From: David Howells <dhowells@...hat.com>
To: mcgrof@...il.com
Cc: mjg59@...f.ucam.org, keyrings@...ux-nfs.org,
gregkh@...uxfoundation.org, kyle@...nel.org,
linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
seth.forshee@...onical.com, linux-security-module@...r.kernel.org,
zohar@...ux.vnet.ibm.com, dwmw2@...radead.org
Subject: [PATCH 27/27] KEYS: Restrict signature verification to keys
appropriate to the purpose
Restrict the verification of X.509 certificates such that a certificate can
only be verified if either:
(1) A certificate is signed with the key it holds.
(2) A certificate is signed with a key that has keyCertSign set in its
keyUsage extension and has no purpose restriction set.
Restrict the verification of PKCS#7 messages such that a signature can only
be verified by a matching key if the key does not have keyCertSign set and
either of the following is true:
(1) The key has no purpose restriction and the PKCS#7 is not a firmware
signature.
(2) The key has a recognised purpose restriction that matches the use to
which the PKCS#7 signature is being put.
In the event that a restriction mismatch occurs, EKEYREJECTED will be
returned and an error similar to one of the following will be logged to
dmesg:
PKEY: Firmware signed with non-firmware key (module sig)
PKEY: Restricted usage key (module sig) used for wrong purpose (kexec sig)
The PKCS#7 test key type is given the usage to specify in a module
parameter. For example:
echo 1 >/sys/module/pkcs7_test_key/parameters/usage
keyctl padd pkcs7_test foo @s </tmp/stuff.pkcs7
will attempt to check the signature on stuff.pkcs7 as if it contains a
firmware blob (1 being KEY_VERIFYING_FIRMWARE_SIGNATURE).
Signed-off-by: David Howells <dhowells@...hat.com>
---
arch/x86/kernel/kexec-bzimage64.c | 4 ++
crypto/asymmetric_keys/asymmetric_type.c | 11 ++++++
crypto/asymmetric_keys/pkcs7_key_type.c | 17 ++++++++-
crypto/asymmetric_keys/pkcs7_trust.c | 14 +++++---
crypto/asymmetric_keys/pkcs7_verify.c | 21 ++++++++---
crypto/asymmetric_keys/public_key.c | 56 ++++++++++++++++++++++++++++--
crypto/asymmetric_keys/public_key.h | 3 +-
crypto/asymmetric_keys/signature.c | 6 ++-
crypto/asymmetric_keys/verify_pefile.c | 9 +++--
crypto/asymmetric_keys/x509_parser.h | 3 +-
crypto/asymmetric_keys/x509_public_key.c | 15 +++++---
include/crypto/pkcs7.h | 6 +++
include/crypto/public_key.h | 16 ++++++++-
include/keys/asymmetric-subtype.h | 4 ++
include/keys/system_keyring.h | 2 +
include/linux/verify_pefile.h | 6 +++
kernel/module_signing.c | 3 +-
kernel/system_keyring.c | 7 +++-
security/integrity/digsig_asymmetric.c | 3 +-
19 files changed, 169 insertions(+), 37 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index ca83f7ac388b..3fcd04c48698 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -536,7 +536,9 @@ static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
int ret;
ret = verify_pefile_signature(kernel, kernel_len,
- system_trusted_keyring, &trusted);
+ system_trusted_keyring,
+ KEY_VERIFYING_KEXEC_SIGNATURE,
+ &trusted);
if (ret < 0)
return ret;
if (!trusted)
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index 411deb91ee70..3e4b493dae91 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -12,6 +12,7 @@
*/
#include <keys/asymmetric-subtype.h>
#include <keys/asymmetric-parser.h>
+#include <crypto/public_key.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/slab.h>
@@ -20,6 +21,16 @@
MODULE_LICENSE("GPL");
+const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
+ [KEY_VERIFYING_MODULE_SIGNATURE] = "mod sig",
+ [KEY_VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
+ [KEY_VERIFYING_KEXEC_SIGNATURE] = "kexec sig",
+ [KEY_VERIFYING_KEY_SIGNATURE] = "key sig",
+ [KEY_VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
+ [KEY_VERIFYING_INTEGRITY_SIGNATURE] = "ima sig",
+};
+EXPORT_SYMBOL_GPL(key_being_used_for);
+
static LIST_HEAD(asymmetric_key_parsers);
static DECLARE_RWSEM(asymmetric_key_parsers_sem);
diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c b/crypto/asymmetric_keys/pkcs7_key_type.c
index 3d13b042da73..d87d5b8983d7 100644
--- a/crypto/asymmetric_keys/pkcs7_key_type.c
+++ b/crypto/asymmetric_keys/pkcs7_key_type.c
@@ -14,16 +14,23 @@
#include <linux/err.h>
#include <linux/module.h>
#include <linux/key-type.h>
+#include <keys/asymmetric-type.h>
#include <crypto/pkcs7.h>
#include <keys/user-type.h>
#include <keys/system_keyring.h>
#include "pkcs7_parser.h"
+static unsigned pkcs7_usage;
+module_param_named(usage, pkcs7_usage, uint, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(pkcs7_usage,
+ "Usage to specify when verifying the PKCS#7 message");
+
/*
* Preparse a PKCS#7 wrapped and validated data blob.
*/
static int pkcs7_preparse(struct key_preparsed_payload *prep)
{
+ enum key_being_used_for usage = pkcs7_usage;
struct pkcs7_message *pkcs7;
const void *data, *saved_prep_data;
size_t datalen, saved_prep_datalen;
@@ -32,6 +39,11 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep)
kenter("");
+ if (usage >= NR__KEY_BEING_USED_FOR) {
+ pr_err("Invalid usage type %d\n", usage);
+ return -EINVAL;
+ }
+
saved_prep_data = prep->data;
saved_prep_datalen = prep->datalen;
pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen);
@@ -40,11 +52,12 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep)
goto error;
}
- ret = pkcs7_verify(pkcs7);
+ ret = pkcs7_verify(pkcs7, usage);
if (ret < 0)
goto error_free;
- ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
+ ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, usage,
+ &trusted);
if (ret < 0)
goto error_free;
if (!trusted)
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 90d6d47965b0..c5b1cd766902 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -25,7 +25,8 @@
*/
static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
struct pkcs7_signed_info *sinfo,
- struct key *trust_keyring)
+ struct key *trust_keyring,
+ enum key_being_used_for usage)
{
struct public_key_signature *sig = &sinfo->sig;
struct x509_certificate *x509, *last = NULL, *p;
@@ -65,6 +66,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
*/
pr_devel("sinfo %u: Cert %u as key %x\n",
sinfo->index, x509->index, key_serial(key));
+ usage = KEY_VERIFYING_KEY_SIGNATURE;
goto matched;
}
if (key == ERR_PTR(-ENOMEM))
@@ -95,6 +97,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
x509 = last;
pr_devel("sinfo %u: Root cert %u signer is key %x\n",
sinfo->index, x509->index, key_serial(key));
+ usage = KEY_VERIFYING_KEY_SIGNATURE;
goto matched;
}
if (PTR_ERR(key) != -ENOKEY)
@@ -121,7 +124,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
return -ENOKEY;
matched:
- ret = verify_signature(key, sig);
+ ret = verify_signature(key, sig, usage);
trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
key_put(key);
if (ret < 0) {
@@ -148,7 +151,8 @@ verified:
* pkcs7_validate_trust - Validate PKCS#7 trust chain
* @pkcs7: The PKCS#7 certificate to validate
* @trust_keyring: Signing certificates to use as starting points
- * @_trusted: Set to true if trustworth, false otherwise
+ * @usage: The use to which the key is being put.
+ * @_trusted: Set to true if trustworthy, false otherwise
*
* Validate that the certificate chain inside the PKCS#7 message intersects
* keys we already know and trust.
@@ -171,6 +175,7 @@ verified:
*/
int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
struct key *trust_keyring,
+ enum key_being_used_for usage,
bool *_trusted)
{
struct pkcs7_signed_info *sinfo;
@@ -182,7 +187,8 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
p->seen = false;
for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
- ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring);
+ ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring,
+ usage);
switch (ret) {
case -ENOKEY:
continue;
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 404f89a0f852..dabdc340d9eb 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -208,7 +208,8 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
x509->raw_issuer_size) != 0)
return 0;
- ret = x509_check_signature(x509->pub, x509);
+ ret = x509_check_signature(x509->pub, x509,
+ KEY_VERIFYING_KEY_SELF_SIGNATURE);
if (ret < 0)
goto maybe_missing_crypto_in_x509;
x509->signer = x509;
@@ -262,7 +263,8 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
sinfo->index);
return 0;
}
- ret = x509_check_signature(p->pub, x509);
+ ret = x509_check_signature(p->pub, x509,
+ KEY_VERIFYING_KEY_SIGNATURE);
if (ret < 0)
return ret;
x509->signer = p;
@@ -290,7 +292,8 @@ maybe_missing_crypto_in_x509:
* Verify one signed information block from a PKCS#7 message.
*/
static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
- struct pkcs7_signed_info *sinfo)
+ struct pkcs7_signed_info *sinfo,
+ enum key_being_used_for usage)
{
int ret;
@@ -315,7 +318,8 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
sinfo->signer->index, sinfo->index);
/* Verify the PKCS#7 binary against the key */
- ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);
+ ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig,
+ usage);
if (ret < 0)
return ret;
@@ -328,6 +332,7 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
/**
* pkcs7_verify - Verify a PKCS#7 message
* @pkcs7: The PKCS#7 message to be verified
+ * @usage: The use to which the key is being put
*
* Verify a PKCS#7 message is internally consistent - that is, the data digest
* matches the digest in the AuthAttrs and any signature in the message or one
@@ -339,6 +344,9 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
*
* Returns, in order of descending priority:
*
+ * (*) -EKEYREJECTED if a key was selected that had a usage restriction at
+ * odds with the specified usage, or:
+ *
* (*) -EKEYREJECTED if a signature failed to match for which we found an
* appropriate X.509 certificate, or:
*
@@ -350,7 +358,8 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
* (*) 0 if all the signature chains that don't incur -ENOPKG can be verified
* (note that a signature chain may be of zero length), or:
*/
-int pkcs7_verify(struct pkcs7_message *pkcs7)
+int pkcs7_verify(struct pkcs7_message *pkcs7,
+ enum key_being_used_for usage)
{
struct pkcs7_signed_info *sinfo;
struct x509_certificate *x509;
@@ -366,7 +375,7 @@ int pkcs7_verify(struct pkcs7_message *pkcs7)
}
for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
- ret = pkcs7_verify_one(pkcs7, sinfo);
+ ret = pkcs7_verify_one(pkcs7, sinfo, usage);
if (ret < 0) {
if (ret == -ENOPKG) {
sinfo->unsupported_crypto = true;
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index b627dc35f0aa..62ed623ac60a 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -39,6 +39,7 @@ EXPORT_SYMBOL_GPL(pkey_algo);
const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = {
[PKEY_ID_PGP] = "PGP",
[PKEY_ID_X509] = "X509",
+ [PKEY_ID_PKCS7] = "PKCS#7",
};
EXPORT_SYMBOL_GPL(pkey_id_type_name);
@@ -94,12 +95,56 @@ void public_key_destroy(void *payload)
EXPORT_SYMBOL_GPL(public_key_destroy);
/*
+ * Apply key usage policy.
+ */
+static int public_key_usage_policy(enum key_being_used_for usage,
+ enum key_usage_restriction restriction)
+{
+ switch (usage) {
+ case KEY_VERIFYING_MODULE_SIGNATURE:
+ if (restriction != KEY_RESTRICTED_TO_MODULE_SIGNING &&
+ restriction != KEY_USAGE_NOT_SPECIFIED)
+ goto wrong_purpose;
+ return 0;
+ case KEY_VERIFYING_FIRMWARE_SIGNATURE:
+ if (restriction != KEY_RESTRICTED_TO_FIRMWARE_SIGNING) {
+ pr_warn("Firmware signed with non-firmware key (%s)\n",
+ key_usage_restrictions[restriction]);
+ return -EKEYREJECTED;
+ }
+ return 0;
+ case KEY_VERIFYING_KEXEC_SIGNATURE:
+ if (restriction != KEY_RESTRICTED_TO_KEXEC_SIGNING &&
+ restriction != KEY_USAGE_NOT_SPECIFIED)
+ goto wrong_purpose;
+ return 0;
+ case KEY_VERIFYING_KEY_SIGNATURE:
+ if (restriction != KEY_RESTRICTED_TO_KEY_SIGNING &&
+ restriction != KEY_USAGE_NOT_SPECIFIED)
+ goto wrong_purpose;
+ return 0;
+ case KEY_VERIFYING_KEY_SELF_SIGNATURE:
+ return 0;
+ default:
+ BUG();
+ }
+
+wrong_purpose:
+ pr_warn("Restricted usage key (%s) used for wrong purpose (%s)\n",
+ key_usage_restrictions[restriction],
+ key_being_used_for[usage]);
+ return -EKEYREJECTED;
+}
+
+/*
* Verify a signature using a public key.
*/
int public_key_verify_signature(const struct public_key *pk,
- const struct public_key_signature *sig)
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage)
{
const struct public_key_algorithm *algo;
+ int ret;
BUG_ON(!pk);
BUG_ON(!pk->mpi[0]);
@@ -126,15 +171,20 @@ int public_key_verify_signature(const struct public_key *pk,
return -EINVAL;
}
+ ret = public_key_usage_policy(usage, pk->usage_restriction);
+ if (ret < 0)
+ return ret;
+
return algo->verify_signature(pk, sig);
}
EXPORT_SYMBOL_GPL(public_key_verify_signature);
static int public_key_verify_signature_2(const struct key *key,
- const struct public_key_signature *sig)
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage)
{
const struct public_key *pk = key->payload.data;
- return public_key_verify_signature(pk, sig);
+ return public_key_verify_signature(pk, sig, usage);
}
/*
diff --git a/crypto/asymmetric_keys/public_key.h b/crypto/asymmetric_keys/public_key.h
index 5c37a22a0637..c7b88df26d7b 100644
--- a/crypto/asymmetric_keys/public_key.h
+++ b/crypto/asymmetric_keys/public_key.h
@@ -33,4 +33,5 @@ extern const struct public_key_algorithm RSA_public_key_algorithm;
* public_key.c
*/
extern int public_key_verify_signature(const struct public_key *pk,
- const struct public_key_signature *sig);
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage);
diff --git a/crypto/asymmetric_keys/signature.c b/crypto/asymmetric_keys/signature.c
index 7525fd183574..3daadef69e75 100644
--- a/crypto/asymmetric_keys/signature.c
+++ b/crypto/asymmetric_keys/signature.c
@@ -22,11 +22,13 @@
* verify_signature - Initiate the use of an asymmetric key to verify a signature
* @key: The asymmetric key to verify against
* @sig: The signature to check
+ * @usage: The use to which the key is being put.
*
* Returns 0 if successful or else an error.
*/
int verify_signature(const struct key *key,
- const struct public_key_signature *sig)
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage)
{
const struct asymmetric_key_subtype *subtype;
int ret;
@@ -42,7 +44,7 @@ int verify_signature(const struct key *key,
if (!subtype->verify_signature)
return -ENOTSUPP;
- ret = subtype->verify_signature(key, sig);
+ ret = subtype->verify_signature(key, sig, usage);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index 2421f46184ce..6d8201035abd 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -393,6 +393,7 @@ error_no_desc:
* @pebuf: Buffer containing the PE binary image
* @pelen: Length of the binary image
* @trust_keyring: Signing certificates to use as starting points
+ * @usage: The use to which the key is being put.
* @_trusted: Set to true if trustworth, false otherwise
*
* Validate that the certificate chain inside the PKCS#7 message inside the PE
@@ -417,7 +418,9 @@ error_no_desc:
* May also return -ENOMEM.
*/
int verify_pefile_signature(const void *pebuf, unsigned pelen,
- struct key *trusted_keyring, bool *_trusted)
+ struct key *trusted_keyring,
+ enum key_being_used_for usage,
+ bool *_trusted)
{
struct pkcs7_message *pkcs7;
struct pefile_context ctx;
@@ -462,11 +465,11 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen,
if (ret < 0)
goto error;
- ret = pkcs7_verify(pkcs7);
+ ret = pkcs7_verify(pkcs7, usage);
if (ret < 0)
goto error;
- ret = pkcs7_validate_trust(pkcs7, trusted_keyring, _trusted);
+ ret = pkcs7_validate_trust(pkcs7, trusted_keyring, usage, _trusted);
error:
pkcs7_free_message(ctx.pkcs7);
diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index dcdb5c94f514..233d557e840a 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -55,4 +55,5 @@ extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen
*/
extern int x509_get_sig_params(struct x509_certificate *cert);
extern int x509_check_signature(const struct public_key *pub,
- struct x509_certificate *cert);
+ struct x509_certificate *cert,
+ enum key_being_used_for usage);
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 6b060b290e77..c7c8a2d42cb5 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -221,7 +221,8 @@ EXPORT_SYMBOL_GPL(x509_get_sig_params);
* Check the signature on a certificate using the provided public key
*/
int x509_check_signature(const struct public_key *pub,
- struct x509_certificate *cert)
+ struct x509_certificate *cert,
+ enum key_being_used_for usage)
{
int ret;
@@ -231,7 +232,7 @@ int x509_check_signature(const struct public_key *pub,
if (ret < 0)
return ret;
- ret = public_key_verify_signature(pub, &cert->sig);
+ ret = public_key_verify_signature(pub, &cert->sig, usage);
if (ret == -ENOPKG)
cert->unsupported_crypto = true;
pr_debug("Cert Verification: %d\n", ret);
@@ -264,9 +265,10 @@ static int x509_validate_trust(struct x509_certificate *cert,
cert->akid_id, cert->akid_skid,
false);
if (!IS_ERR(key)) {
- if (!use_builtin_keys
- || test_bit(KEY_FLAG_BUILTIN, &key->flags))
- ret = x509_check_signature(key->payload.data, cert);
+ if (!use_builtin_keys ||
+ test_bit(KEY_FLAG_BUILTIN, &key->flags))
+ ret = x509_check_signature(key->payload.data, cert,
+ KEY_VERIFYING_KEY_SIGNATURE);
key_put(key);
}
return ret;
@@ -321,7 +323,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
if ((!cert->akid_skid && !cert->akid_id) ||
asymmetric_key_id_same(cert->skid, cert->akid_skid) ||
asymmetric_key_id_same(cert->id, cert->akid_id)) {
- ret = x509_check_signature(cert->pub, cert); /* self-signed */
+ ret = x509_check_signature(cert->pub, cert,
+ KEY_VERIFYING_KEY_SELF_SIGNATURE);
if (ret < 0)
goto error_free_cert;
} else if (!prep->trusted) {
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 0999eac6313f..1a6fa53d07bc 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -9,6 +9,8 @@
* 2 of the Licence, or (at your option) any later version.
*/
+#include <crypto/public_key.h>
+
struct key;
struct pkcs7_message;
@@ -29,12 +31,14 @@ extern const char *pkcs7_get_firmware_name(const struct pkcs7_message *pkcs7);
*/
extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
struct key *trust_keyring,
+ enum key_being_used_for usage,
bool *_trusted);
/*
* pkcs7_verify.c
*/
-extern int pkcs7_verify(struct pkcs7_message *pkcs7);
+extern int pkcs7_verify(struct pkcs7_message *pkcs7,
+ enum key_being_used_for usage);
extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
const void *data, size_t datalen);
diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
index afcab5f40559..acf76c777aec 100644
--- a/include/crypto/public_key.h
+++ b/include/crypto/public_key.h
@@ -53,6 +53,19 @@ enum key_usage_restriction {
NR__KEY_USAGE_RESTRICTIONS
};
+/*
+ * The use to which an asymmetric key is being put when verifying a signature.
+ */
+enum key_being_used_for {
+ KEY_VERIFYING_MODULE_SIGNATURE,
+ KEY_VERIFYING_FIRMWARE_SIGNATURE,
+ KEY_VERIFYING_KEXEC_SIGNATURE,
+ KEY_VERIFYING_KEY_SIGNATURE,
+ KEY_VERIFYING_KEY_SELF_SIGNATURE,
+ KEY_VERIFYING_INTEGRITY_SIGNATURE,
+ NR__KEY_BEING_USED_FOR
+};
+extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR];
/*
* Cryptographic data for the public-key subtype of the asymmetric key type.
@@ -114,7 +127,8 @@ struct public_key_signature {
struct key;
extern int verify_signature(const struct key *key,
- const struct public_key_signature *sig);
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage);
struct asymmetric_key_id;
extern struct key *x509_request_asymmetric_key(struct key *keyring,
diff --git a/include/keys/asymmetric-subtype.h b/include/keys/asymmetric-subtype.h
index b6a47f09ef2b..81e5e18936be 100644
--- a/include/keys/asymmetric-subtype.h
+++ b/include/keys/asymmetric-subtype.h
@@ -18,6 +18,7 @@
#include <keys/asymmetric-type.h>
struct public_key_signature;
+enum key_being_used_for;
/*
* Keys of this type declare a subtype that indicates the handlers and
@@ -39,7 +40,8 @@ struct asymmetric_key_subtype {
/* Verify the signature on a key of this subtype (optional) */
int (*verify_signature)(const struct key *key,
- const struct public_key_signature *sig);
+ const struct public_key_signature *sig,
+ enum key_being_used_for usage);
};
/**
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 30303745f845..1cf609c692bd 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -15,6 +15,7 @@
#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
#include <linux/key.h>
+#include <crypto/public_key.h>
extern struct key *system_trusted_keyring;
static inline struct key *get_system_trusted_keyring(void)
@@ -31,6 +32,7 @@ static inline struct key *get_system_trusted_keyring(void)
#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
extern int system_verify_data(const void *data, unsigned long len,
const void *raw_pkcs7, size_t pkcs7_len,
+ enum key_being_used_for usage,
const char *firmware_name);
#endif
diff --git a/include/linux/verify_pefile.h b/include/linux/verify_pefile.h
index ac34819214f9..da2049b5161c 100644
--- a/include/linux/verify_pefile.h
+++ b/include/linux/verify_pefile.h
@@ -12,7 +12,11 @@
#ifndef _LINUX_VERIFY_PEFILE_H
#define _LINUX_VERIFY_PEFILE_H
+#include <crypto/public_key.h>
+
extern int verify_pefile_signature(const void *pebuf, unsigned pelen,
- struct key *trusted_keyring, bool *_trusted);
+ struct key *trusted_keyring,
+ enum key_being_used_for usage,
+ bool *_trusted);
#endif /* _LINUX_VERIFY_PEFILE_H */
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 9361711897ce..2ac070a89496 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -72,5 +72,6 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
return -EBADMSG;
}
- return system_verify_data(mod, modlen, mod + modlen, sig_len, NULL);
+ return system_verify_data(mod, modlen, mod + modlen, sig_len,
+ KEY_VERIFYING_MODULE_SIGNATURE, NULL);
}
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
index ccb2814f89c1..943c30e4f71d 100644
--- a/kernel/system_keyring.c
+++ b/kernel/system_keyring.c
@@ -113,10 +113,12 @@ late_initcall(load_system_certificate_list);
* @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.
* @firmware_name: The required firmware name or NULL.
*/
int system_verify_data(const void *data, unsigned long len,
const void *raw_pkcs7, size_t pkcs7_len,
+ enum key_being_used_for usage,
const char *firmware_name)
{
struct pkcs7_message *pkcs7;
@@ -156,11 +158,12 @@ int system_verify_data(const void *data, unsigned long len,
goto error;
}
- ret = pkcs7_verify(pkcs7);
+ ret = pkcs7_verify(pkcs7, usage);
if (ret < 0)
goto error;
- ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
+ ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, usage,
+ &trusted);
if (ret < 0)
goto error;
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index 4fec1816a2b3..7d6424c602fe 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -96,7 +96,8 @@ int asymmetric_verify(struct key *keyring, const char *sig,
pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen);
if (pks.rsa.s)
- ret = verify_signature(key, &pks);
+ ret = verify_signature(key, &pks,
+ KEY_VERIFYING_INTEGRITY_SIGNATURE);
mpi_free(pks.rsa.s);
key_put(key);
--
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