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authorEric Biggers <ebiggers@google.com>2018-02-22 14:38:34 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-28 10:19:39 +0100
commit99b2095ac71e316ed366f027913646d40640d0be (patch)
tree01c5752496f5c073f4826c0cb02e41d8221a389d
parentdcb04cc794835964c1efeea24b392e5e35e88ab8 (diff)
X.509: fix NULL dereference when restricting key with unsupported_sig
commit 4b34968e77ad09628cfb3c4a7daf2adc2cefc6e8 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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,