i2d_ECDSA_SIG() may return a negative value in case of error.

Do no use this as length in iked(8) _dsa_verify_prepare().
OK tobhe@ tb@

diff --git a/sbin/iked/crypto.c b/sbin/iked/crypto.c
index 50ee275..f1a6614 100644 (file)
--- a/sbin/iked/crypto.c
+++ b/sbin/iked/crypto.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: crypto.c,v 1.41 2022/11/30 12:42:24 tb Exp $  */
+/*     $OpenBSD: crypto.c,v 1.42 2023/03/30 17:20:53 bluhm Exp $       */
 
 /*
  * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
@@ -1120,7 +1120,8 @@ _dsa_verify_prepare(struct iked_dsa *dsa, uint8_t **sigp, size_t *lenp,
 {
        ECDSA_SIG       *obj = NULL;
        uint8_t         *ptr = NULL;
-       size_t           bnlen, len, off;
+       size_t           bnlen, off;
+       ssize_t          len;
        int              ret = -1;
        BIGNUM          *r = NULL, *s = NULL;
 
@@ -1156,7 +1157,7 @@ _dsa_verify_prepare(struct iked_dsa *dsa, uint8_t **sigp, size_t *lenp,
                    (r = BN_bin2bn(*sigp, bnlen, NULL)) == NULL ||
                    (s = BN_bin2bn(*sigp+bnlen, bnlen, NULL)) == NULL ||
                    ECDSA_SIG_set0(obj, r, s) == 0 ||
-                   (len = i2d_ECDSA_SIG(obj, &ptr)) == 0)
+                   (len = i2d_ECDSA_SIG(obj, &ptr)) <= 0)
                        goto done;
                r = s = NULL;
                *lenp = len;