[PATCH v2 13/18] crypto: rsa-psspad: Get signature parameters from a given signature

[Varad Gautam]

Implement akcipher_alg->set_sig_params for rsassa-psspad to receive the
salt length and MGF hash function for the signature being verified.

Signed-off-by: Varad Gautam <varad.gautam@xxxxxxxx>
---
v2: Set mgf_hash_algo in psspad_set_sig_params. v1 assumed this to be the same
  as the digest hash.

 crypto/rsa-psspad.c                  | 21 ++++++++++++++++++++-
 include/crypto/internal/rsa-common.h |  2 ++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/crypto/rsa-psspad.c b/crypto/rsa-psspad.c
index 855e82ca071a7..eec303bb55b2d 100644
--- a/crypto/rsa-psspad.c
+++ b/crypto/rsa-psspad.c
@@ -9,6 +9,7 @@
 #include <crypto/hash.h>
 #include <crypto/internal/akcipher.h>
 #include <crypto/internal/rsa-common.h>
+#include <crypto/public_key.h>
 
 static int psspad_setup_shash(struct crypto_shash **hash_tfm, struct shash_desc **desc,
 			      const char *hash_algo)
@@ -33,6 +34,23 @@ static void psspad_free_shash(struct crypto_shash *hash_tfm, struct shash_desc *
 	crypto_free_shash(hash_tfm);
 }
 
+static int psspad_set_sig_params(struct crypto_akcipher *tfm,
+				 const void *sig,
+				 unsigned int siglen)
+{
+	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
+	struct rsapad_inst_ctx *ictx = akcipher_instance_ctx(inst);
+	const struct public_key_signature *s = sig;
+
+	if (!sig)
+		return -EINVAL;
+
+	ictx->salt_len = s->salt_length;
+	ictx->mgf_hash_algo = s->mgf_hash_algo;
+
+	return 0;
+}
+
 static int psspad_s_v_e_d(struct akcipher_request *req)
 {
 	return -EOPNOTSUPP;
@@ -48,7 +66,8 @@ static struct akcipher_alg psspad_alg = {
 	.verify = psspad_s_v_e_d,
 	.set_pub_key = rsapad_set_pub_key,
 	.set_priv_key = rsapad_set_priv_key,
-	.max_size = rsapad_get_max_size
+	.max_size = rsapad_get_max_size,
+	.set_sig_params = psspad_set_sig_params
 };
 
 static int psspad_create(struct crypto_template *tmpl, struct rtattr **tb)
diff --git a/include/crypto/internal/rsa-common.h b/include/crypto/internal/rsa-common.h
index 4fa3cf5a989cc..8b7ba0174d5bf 100644
--- a/include/crypto/internal/rsa-common.h
+++ b/include/crypto/internal/rsa-common.h
@@ -26,6 +26,8 @@ struct rsapad_tfm_ctx {
 struct rsapad_inst_ctx {
 	struct crypto_akcipher_spawn spawn;
 	const struct rsa_asn1_template *digest_info;
+	u16 salt_len;
+	const char *mgf_hash_algo;
 };
 
 struct rsapad_akciper_req_ctx {
-- 
2.30.2