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authorEric Biggers <ebiggers@google.com>2018-02-22 14:38:34 +0000
committerDavid Howells <dhowells@redhat.com>2018-02-22 14:38:34 +0000
commit4b34968e77ad09628cfb3c4a7daf2adc2cefc6e8 (patch)
treec10c13fc4f09f9a6705d969f6b268b060e885b3b
parent437499eea4291ae9621e8763a41df027c110a1ef (diff)
X.509: fix NULL dereference when restricting key with unsupported_sig
The asymmetric key type allows an X.509 certificate to be added even if its signature's hash algorithm is not available in the crypto API. In that case 'payload.data[asym_auth]' will be NULL. But the key restriction code failed to check for this case before trying to use the signature, resulting in a NULL pointer dereference in key_or_keyring_common() or in restrict_link_by_signature(). Fix this by returning -ENOPKG when the signature is unsupported. Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled and keyctl has support for the 'restrict_keyring' command: keyctl new_session keyctl restrict_keyring @s asymmetric builtin_trusted openssl req -new -sha512 -x509 -batch -nodes -outform der \ | keyctl padd asymmetric desc @s Fixes: a511e1af8b12 ("KEYS: Move the point of trust determination to __key_link()") Cc: <stable@vger.kernel.org> # v4.7+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r--crypto/asymmetric_keys/restrict.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index 86fb68508952..7c93c7728454 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -67,8 +67,9 @@ __setup("ca_keys=", ca_keys_setup);
*
* Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
* matching parent certificate in the trusted list, -EKEYREJECTED if the
- * signature check fails or the key is blacklisted and some other error if
- * there is a matching certificate but the signature check cannot be performed.
+ * signature check fails or the key is blacklisted, -ENOPKG if the signature
+ * uses unsupported crypto, or some other error if there is a matching
+ * certificate but the signature check cannot be performed.
*/
int restrict_link_by_signature(struct key *dest_keyring,
const struct key_type *type,
@@ -88,6 +89,8 @@ int restrict_link_by_signature(struct key *dest_keyring,
return -EOPNOTSUPP;
sig = payload->data[asym_auth];
+ if (!sig)
+ return -ENOPKG;
if (!sig->auth_ids[0] && !sig->auth_ids[1])
return -ENOKEY;
@@ -139,6 +142,8 @@ static int key_or_keyring_common(struct key *dest_keyring,
return -EOPNOTSUPP;
sig = payload->data[asym_auth];
+ if (!sig)
+ return -ENOPKG;
if (!sig->auth_ids[0] && !sig->auth_ids[1])
return -ENOKEY;
@@ -222,9 +227,9 @@ static int key_or_keyring_common(struct key *dest_keyring,
*
* Returns 0 if the new certificate was accepted, -ENOKEY if we
* couldn't find a matching parent certificate in the trusted list,
- * -EKEYREJECTED if the signature check fails, and some other error if
- * there is a matching certificate but the signature check cannot be
- * performed.
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
*/
int restrict_link_by_key_or_keyring(struct key *dest_keyring,
const struct key_type *type,
@@ -249,9 +254,9 @@ int restrict_link_by_key_or_keyring(struct key *dest_keyring,
*
* Returns 0 if the new certificate was accepted, -ENOKEY if we
* couldn't find a matching parent certificate in the trusted list,
- * -EKEYREJECTED if the signature check fails, and some other error if
- * there is a matching certificate but the signature check cannot be
- * performed.
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
*/
int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
const struct key_type *type,