[PATCH v3 4/4] ima: add support for rsa pss verification

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

This patch adds support for ima verification for rsa with
pss encoding.

And a patch for ima-evm-utils will be sent later.

Signed-off-by: Hongbo Li <herbert.tencent@gmail.com>
---
 security/integrity/digsig_asymmetric.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index 23240d7..ef7a51a 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -85,6 +85,7 @@ 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 public_key_signature *cert_sig;
 	struct key *key;
 	int ret;
 
@@ -109,16 +110,21 @@ int asymmetric_verify(struct key *keyring, const char *sig,
 
 	pk = asymmetric_key_public_key(key);
 	pks.pkey_algo = pk->pkey_algo;
-	if (!strcmp(pk->pkey_algo, "rsa"))
-		pks.encoding = "pkcs1";
-	else if (!strncmp(pk->pkey_algo, "ecdsa-", 6))
+	if (!strcmp(pk->pkey_algo, "rsa")) {
+		cert_sig = key->payload.data[asym_auth];
+		if (cert_sig)
+			pks.encoding = cert_sig->encoding;
+		else
+			pks.encoding = "pkcs1";
+	} 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"))
+	} else if (!strcmp(pk->pkey_algo, "ecrdsa") ||
+		   !strcmp(pk->pkey_algo, "sm2")) {
 		pks.encoding = "raw";
-	else
+	} else {
 		return -ENOPKG;
+	}
 
 	pks.digest = (u8 *)data;
 	pks.digest_size = datalen;
-- 
1.8.3.1