KEYS: Allow authentication data to be stored in an asymmetric key

Allow authentication data to be stored in an asymmetric key in the 4th
element of the key payload and provide a way for it to be destroyed.

For the public key subtype, this will be a public_key_signature struct.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/crypto/asymmetric_keys/signature.c b/crypto/asymmetric_keys/signature.c
index 004d5fc8e56b..3beee3976ed5 100644
--- a/crypto/asymmetric_keys/signature.c
+++ b/crypto/asymmetric_keys/signature.c
@@ -15,9 +15,23 @@
 #include <keys/asymmetric-subtype.h>
 #include <linux/export.h>
 #include <linux/err.h>
+#include <linux/slab.h>
 #include <crypto/public_key.h>
 #include "asymmetric_keys.h"
 
+/*
+ * Destroy a public key signature.
+ */
+void public_key_signature_free(struct public_key_signature *sig)
+{
+	if (sig) {
+		kfree(sig->s);
+		kfree(sig->digest);
+		kfree(sig);
+	}
+}
+EXPORT_SYMBOL_GPL(public_key_signature_free);
+
 /**
  * verify_signature - Initiate the use of an asymmetric key to verify a signature
  * @key: The asymmetric key to verify against