KEYS: Add identifier pointers to public_key_signature struct

Add key identifier pointers to public_key_signature struct so that they can
be used to retain the identifier of the key to be used to verify the
signature in both PKCS#7 and X.509.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

crypto/asymmetric_keys/signature.c

@@ -24,7 +24,11 @@
  */
 void public_key_signature_free(struct public_key_signature *sig)
 {
+	int i;
+
 	if (sig) {
+		for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
+			kfree(sig->auth_ids[i]);
 		kfree(sig->s);
 		kfree(sig->digest);
 		kfree(sig);

include/crypto/public_key.h

@@ -47,6 +47,7 @@ extern void public_key_free(struct public_key *key);
  * Public key cryptography signature data
  */
 struct public_key_signature {
+	struct asymmetric_key_id *auth_ids[2];
 	u8 *s;			/* Signature */
 	u32 s_size;		/* Number of bytes in signature */
 	u8 *digest;