ima: Support EC keys for signature verification

Add support for IMA signature verification for EC keys. Since SHA type
of hashes can be used by RSA and ECDSA signature schemes we need to
look at the key and derive from the key which signature scheme to use.
Since this can be applied to all types of keys, we change the selection
of the encoding type to be driven by the key's signature scheme rather
than by the hash type.

Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: linux-integrity@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Vitaly Chikunov <vt@altlinux.org>
Reviewed-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index a29d3ff2e7e8..c432fdb8547f 100644
--- a/include/keys/asymmetric-type.h
+++ b/include/keys/asymmetric-type.h
@@ -72,6 +72,12 @@ const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
 	return key->payload.data[asym_key_ids];
 }
 
+static inline
+const struct public_key *asymmetric_key_public_key(const struct key *key)
+{
+	return key->payload.data[asym_crypto];
+}
+
 extern struct key *find_asymmetric_key(struct key *keyring,
 				       const struct asymmetric_key_id *id_0,
 				       const struct asymmetric_key_id *id_1,