EC_GROUP_cmp should return zero if the groups match.

(I got this wrong when reading the OpenSSL code.)

Change-Id: Ib289ef41d0ab5a3157ad8b9454d2de96d1f86c22
Reviewed-on: https://boringssl-review.googlesource.com/3620
Reviewed-by: Adam Langley <agl@google.com>

2 files changed, 8 insertions, 5 deletions

diff --git a/crypto/ec/ec.c b/crypto/ec/ec.c
index 21a39405..ad47bb55 100644
--- a/crypto/ec/ec.c
+++ b/crypto/ec/ec.c
@@ -500,10 +500,9 @@ err:
 }
 
 int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ignored) {
-  if (a->curve_name == NID_undef || b->curve_name == NID_undef) {
-    return 0;
-  }
-  return a->curve_name == b->curve_name;
+  return a->curve_name == NID_undef ||
+         b->curve_name == NID_undef ||
+         a->curve_name != b->curve_name;
 }
 
 const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group) {
diff --git a/crypto/evp/p_ec_asn1.c b/crypto/evp/p_ec_asn1.c
index 8967b502..670ee744 100644
--- a/crypto/evp/p_ec_asn1.c
+++ b/crypto/evp/p_ec_asn1.c
@@ -382,7 +382,11 @@ static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from) {
 static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b) {
   const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
                  *group_b = EC_KEY_get0_group(b->pkey.ec);
-  return EC_GROUP_cmp(group_a, group_b, NULL);
+  if (EC_GROUP_cmp(group_a, group_b, NULL) != 0) {
+    /* mismatch */
+    return 0;
+  }
+  return 1;
 }
 
 static void int_ec_free(EVP_PKEY *pkey) { EC_KEY_free(pkey->pkey.ec); }