Fix BN_to_ASN1_INTEGER() misuse

You can either let this API reuse an existing ASN1_INTEGER or you can let
it allocate a new one. If you try to do both at the same time, you'll leak.

ok jsing

1 files changed, 6 insertions, 7 deletions

diff --git a/src/lib/libcrypto/ec/ec_asn1.c b/src/lib/libcrypto/ec/ec_asn1.c
index 2ce7d785c4..504948b237 100644
--- a/src/lib/libcrypto/ec/ec_asn1.c
+++ b/src/lib/libcrypto/ec/ec_asn1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_asn1.c,v 1.53 2024/04/17 23:24:18 tb Exp $ */
+/* $OpenBSD: ec_asn1.c,v 1.54 2024/10/03 04:15:52 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -760,20 +760,19 @@ ec_asn1_group2parameters(const EC_GROUP *group, ECPARAMETERS *param)
                 ECerror(ERR_R_ASN1_LIB);
                 goto err;
         }
-        /* set the order */
         if (!EC_GROUP_get_order(group, tmp, NULL)) {
                 ECerror(ERR_R_EC_LIB);
                 goto err;
         }
-        ret->order = BN_to_ASN1_INTEGER(tmp, ret->order);
-        if (ret->order == NULL) {
+        ASN1_INTEGER_free(ret->order);
+        if ((ret->order = BN_to_ASN1_INTEGER(tmp, NULL)) == NULL) {
                 ECerror(ERR_R_ASN1_LIB);
                 goto err;
         }
-        /* set the cofactor (optional) */
+        ASN1_INTEGER_free(ret->cofactor);
+        ret->cofactor = NULL;
         if (EC_GROUP_get_cofactor(group, tmp, NULL)) {
-                ret->cofactor = BN_to_ASN1_INTEGER(tmp, ret->cofactor);
-                if (ret->cofactor == NULL) {
+                if ((ret->cofactor = BN_to_ASN1_INTEGER(tmp, NULL)) == NULL) {
                         ECerror(ERR_R_ASN1_LIB);
                         goto err;
                 }