[PATCH 4/5] crypto: ecdsa ima support

[Hongbo Li <herbert.tencent@gmail.com>]

From: Hongbo Li <herberthbli@tencent.com>

This patch is borrowed from Stefan Berger's ecdsa patch series,
will be removed when ecdsa is merged into kernel.

Signed-off-by: Hongbo Li <herberthbli@tencent.com>
---
 include/keys/asymmetric-type.h         |  6 ++++++
 security/integrity/digsig_asymmetric.c | 29 ++++++++++++++---------------
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index a29d3ff..c432fdb8 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,
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index a662024..183f452 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -84,6 +84,7 @@ int asymmetric_verify(struct key *keyring, const char *sig,
 {
 	struct public_key_signature pks;
 	struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
+	const struct public_key *pk;
 	struct key *key;
 	int ret;
 
@@ -105,23 +106,21 @@ int asymmetric_verify(struct key *keyring, const char *sig,
 	memset(&pks, 0, sizeof(pks));
 
 	pks.hash_algo = hash_algo_name[hdr->hash_algo];
-	switch (hdr->hash_algo) {
-	case HASH_ALGO_STREEBOG_256:
-	case HASH_ALGO_STREEBOG_512:
-		/* EC-RDSA and Streebog should go together. */
-		pks.pkey_algo = "ecrdsa";
-		pks.encoding = "raw";
-		break;
-	case HASH_ALGO_SM3_256:
-		/* SM2 and SM3 should go together. */
-		pks.pkey_algo = "sm2";
-		pks.encoding = "raw";
-		break;
-	default:
-		pks.pkey_algo = "rsa";
+
+	pk = asymmetric_key_public_key(key);
+	pks.pkey_algo = pk->pkey_algo;
+	if (!strcmp(pk->pkey_algo, "rsa")) {
 		pks.encoding = "pkcs1";
-		break;
+	} else if (!strncmp(pk->pkey_algo, "ecdsa-", 6)) {
+		/* edcsa-nist-p192 etc. */
+		pks.encoding = "x962";
+	} else if (!strcmp(pk->pkey_algo, "ecrdsa") ||
+		   !strcmp(pk->pkey_algo, "sm2")) {
+		pks.encoding = "raw";
+	} else {
+		return -ENOPKG;
 	}
+
 	pks.digest = (u8 *)data;
 	pks.digest_size = datalen;
 	pks.s = hdr->sig;
-- 
1.8.3.1