Rework eckey_priv_decode()

Factor out the pubkey computation and bring it into more sensible form.
This removes lots of pointless setting of errors (twice) and makes the
code a bit easier on the eyes. Other than that perform some stylistic
cleanup like single exit and add an error check for EVP_PKEY_assign().

ok jsing

diff --git a/lib/libcrypto/ec/ec_ameth.c b/lib/libcrypto/ec/ec_ameth.c
index 245001e..2b3b3db 100644 (file)
--- a/lib/libcrypto/ec/ec_ameth.c
+++ b/lib/libcrypto/ec/ec_ameth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_ameth.c,v 1.46 2023/12/29 18:45:39 tb Exp $ */
+/* $OpenBSD: ec_ameth.c,v 1.47 2023/12/29 18:46:24 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -301,69 +301,73 @@ eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
        return -2;
 }
 
+static int
+eckey_compute_pubkey(EC_KEY *eckey)
+{
+       const BIGNUM *priv_key;
+       const EC_GROUP *group;
+       EC_POINT *pub_key = NULL;
+       int ret = 0;
+
+       if ((priv_key = EC_KEY_get0_private_key(eckey)) == NULL)
+               goto err;
+       if ((group = EC_KEY_get0_group(eckey)) == NULL)
+               goto err;
+       if ((pub_key = EC_POINT_new(group)) == NULL)
+               goto err;
+       if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, NULL))
+               goto err;
+       if (!EC_KEY_set_public_key(eckey, pub_key))
+               goto err;
+       pub_key = NULL;
+
+       ret = 1;
+
+ err:
+       EC_POINT_free(pub_key);
+
+       return ret;
+}
+
 static int
 eckey_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
 {
-       const unsigned char *p = NULL;
+       const unsigned char *priv = NULL;
+       int priv_len;
        const void *pval;
-       int ptype, pklen;
+       int ptype;
        EC_KEY *eckey = NULL;
        const X509_ALGOR *palg;
+       int ret = 0;
 
-       if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
-               return 0;
-       X509_ALGOR_get0(NULL, &ptype, &pval, palg);
+       if (!PKCS8_pkey_get0(NULL, &priv, &priv_len, &palg, p8))
+               goto err;
 
+       X509_ALGOR_get0(NULL, &ptype, &pval, palg);
        if (!eckey_from_params(ptype, pval, &eckey))
-               goto ecliberr;
+               goto err;
 
-       /* We have parameters now set private key */
-       if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
+       /* Decode private key into eckey. */
+       if (d2i_ECPrivateKey(&eckey, &priv, priv_len) == NULL) {
                ECerror(EC_R_DECODE_ERROR);
-               goto ecerr;
+               goto err;
        }
-       /* calculate public key (if necessary) */
+       /* If public key was missing from SEC1 key, compute it. */
        if (EC_KEY_get0_public_key(eckey) == NULL) {
-               const BIGNUM *priv_key;
-               const EC_GROUP *group;
-               EC_POINT *pub_key;
-               /*
-                * the public key was not included in the SEC1 private key =>
-                * calculate the public key
-                */
-               group = EC_KEY_get0_group(eckey);
-               pub_key = EC_POINT_new(group);
-               if (pub_key == NULL) {
-                       ECerror(ERR_R_EC_LIB);
-                       goto ecliberr;
-               }
-               if (!EC_POINT_copy(pub_key, EC_GROUP_get0_generator(group))) {
-                       EC_POINT_free(pub_key);
-                       ECerror(ERR_R_EC_LIB);
-                       goto ecliberr;
-               }
-               priv_key = EC_KEY_get0_private_key(eckey);
-               if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, NULL)) {
-                       EC_POINT_free(pub_key);
-                       ECerror(ERR_R_EC_LIB);
-                       goto ecliberr;
-               }
-               if (EC_KEY_set_public_key(eckey, pub_key) == 0) {
-                       EC_POINT_free(pub_key);
-                       ECerror(ERR_R_EC_LIB);
-                       goto ecliberr;
-               }
-               EC_POINT_free(pub_key);
+               if (!eckey_compute_pubkey(eckey))
+                       goto err;
        }
-       EVP_PKEY_assign_EC_KEY(pkey, eckey);
-       return 1;
 
- ecliberr:
-       ECerror(ERR_R_EC_LIB);
- ecerr:
-       if (eckey)
-               EC_KEY_free(eckey);
-       return 0;
+       if (!EVP_PKEY_assign_EC_KEY(pkey, eckey))
+               goto err;
+       eckey = NULL;
+
+       ret = 1;
+
+ err:
+       EC_KEY_free(eckey);
+
+       return ret;
 }
 
 static int