1 files changed, 4 insertions, 3 deletions

diff --git a/src/lib/libtls/tls_verify.c b/src/lib/libtls/tls_verify.c
index e1073e863a..23e58ebef7 100644
--- a/src/lib/libtls/tls_verify.c
+++ b/src/lib/libtls/tls_verify.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_verify.c,v 1.17 2016/09/04 12:26:43 bcook Exp $ */
+/* $OpenBSD: tls_verify.c,v 1.18 2016/11/04 15:32:40 jsing Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  *
@@ -127,7 +127,7 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name)
                                 data = ASN1_STRING_data(altname->d.dNSName);
                                 len = ASN1_STRING_length(altname->d.dNSName);
 
-                                if (len < 0 || len != strlen(data)) {
+                                if (len < 0 || (size_t)len != strlen(data)) {
                                         tls_set_errorx(ctx,
                                             "error verifying name '%s': "
                                             "NUL byte in subjectAltName, "
@@ -220,7 +220,8 @@ tls_check_common_name(struct tls *ctx, X509 *cert, const char *name)
             common_name_len + 1);
 
         /* NUL bytes in CN? */
-        if (common_name_len != strlen(common_name)) {
+        if (common_name_len < 0 ||
+            (size_t)common_name_len != strlen(common_name)) {
                 tls_set_errorx(ctx, "error verifying name '%s': "
                     "NUL byte in Common Name field, "
                     "probably a malicious certificate", name);