1 files changed, 3 insertions, 5 deletions

diff --git a/src/lib/libcrypto/ecdh/ech_key.c b/src/lib/libcrypto/ecdh/ech_key.c
index 1dfb3c0fa9..b364b31c88 100644
--- a/src/lib/libcrypto/ecdh/ech_key.c
+++ b/src/lib/libcrypto/ecdh/ech_key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ech_key.c,v 1.20 2023/07/01 14:39:34 tb Exp $ */
+/* $OpenBSD: ech_key.c,v 1.21 2023/07/01 14:48:01 tb Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -98,8 +98,8 @@ ossl_ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
         const BIGNUM *priv_key;
         const EC_GROUP* group;
         int ret = -1;
-        size_t buflen, len;
         unsigned char *buf = NULL;
+        int buflen, len;
 
         if (outlen > INT_MAX) {
                 /* Sort of, anyway. */
@@ -156,9 +156,7 @@ ossl_ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
                 ECDHerror(ERR_R_MALLOC_FAILURE);
                 goto err;
         }
-
-        memset(buf, 0, buflen - len);
-        if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
+        if (BN_bn2binpad(x, buf, buflen) != buflen) {
                 ECDHerror(ERR_R_BN_LIB);
                 goto err;
         }