Extract private key and group order in s computation

This pushes a few variables no longer needed in ossl_ecdsa_sign_sig() into
ecdsa_compute_s() separating API logic and pure computation a bit more.

ok beck

1 files changed, 18 insertions, 19 deletions

diff --git a/src/lib/libcrypto/ecdsa/ecs_ossl.c b/src/lib/libcrypto/ecdsa/ecs_ossl.c
index dcc823bbaa..4bc77a4920 100644
--- a/src/lib/libcrypto/ecdsa/ecs_ossl.c
+++ b/src/lib/libcrypto/ecdsa/ecs_ossl.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ecs_ossl.c,v 1.67 2023/07/04 10:31:57 tb Exp $ */
+/* $OpenBSD: ecs_ossl.c,v 1.68 2023/07/04 10:53:42 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project
  */
@@ -269,8 +269,10 @@ ossl_ecdsa_sign_setup(EC_KEY *key, BN_CTX *in_ctx, BIGNUM **out_kinv,
 
 static int
 ecdsa_compute_s(BIGNUM **out_s, const BIGNUM *e, const BIGNUM *kinv,
-    const BIGNUM *r, const BIGNUM *priv_key, const BIGNUM *order, BN_CTX *ctx)
+    const BIGNUM *r, const EC_KEY *key, BN_CTX *ctx)
 {
+        const EC_GROUP *group;
+        const BIGNUM *order, *priv_key;
         BIGNUM *b, *binv, *be, *bxr;
         BIGNUM *s = NULL;
         int ret = 0;
@@ -279,6 +281,19 @@ ecdsa_compute_s(BIGNUM **out_s, const BIGNUM *e, const BIGNUM *kinv,
 
         BN_CTX_start(ctx);
 
+        if ((group = EC_KEY_get0_group(key)) == NULL) {
+                ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
+                goto err;
+        }
+        if ((order = EC_GROUP_get0_order(group)) == NULL) {
+                ECDSAerror(ERR_R_EC_LIB);
+                goto err;
+        }
+        if ((priv_key = EC_KEY_get0_private_key(key)) == NULL) {
+                ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
+                goto err;
+        }
+
         if ((b = BN_CTX_get(ctx)) == NULL)
                 goto err;
         if ((binv = BN_CTX_get(ctx)) == NULL)
@@ -353,24 +368,13 @@ ECDSA_SIG *
 ossl_ecdsa_sign_sig(const unsigned char *digest, int digest_len,
     const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *key)
 {
-        const EC_GROUP *group;
         BN_CTX *ctx = NULL;
         BIGNUM *kinv = NULL, *r = NULL, *s = NULL;
         BIGNUM *e;
-        const BIGNUM *order, *priv_key;
         int caller_supplied_values = 0;
         int attempts = 0;
         ECDSA_SIG *sig = NULL;
 
-        if ((group = EC_KEY_get0_group(key)) == NULL) {
-                ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
-                goto err;
-        }
-        if ((priv_key = EC_KEY_get0_private_key(key)) == NULL) {
-                ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
-                goto err;
-        }
-
         if ((ctx = BN_CTX_new()) == NULL) {
                 ECDSAerror(ERR_R_MALLOC_FAILURE);
                 goto err;
@@ -381,11 +385,6 @@ ossl_ecdsa_sign_sig(const unsigned char *digest, int digest_len,
         if ((e = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
-        if ((order = EC_GROUP_get0_order(group)) == NULL) {
-                ECDSAerror(ERR_R_EC_LIB);
-                goto err;
-        }
-
         if (!ecdsa_prepare_digest(digest, digest_len, key, e))
                 goto err;
 
@@ -416,7 +415,7 @@ ossl_ecdsa_sign_sig(const unsigned char *digest, int digest_len,
                 }
 
                 /* If s is non-NULL, we have a valid signature. */
-                if (!ecdsa_compute_s(&s, e, kinv, r, priv_key, order, ctx))
+                if (!ecdsa_compute_s(&s, e, kinv, r, key, ctx))
                         goto err;
                 if (s != NULL)
                         break;