Empty SNI names are not valid

[openssl.git] / ssl / s3_lib.c

diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 64793d6af34f848d142c067ad9cd23a1e04a55d9..5970e617f0052de44d26f91773cbf307f25c9446 100644 (file)
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3263,6 +3263,8 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
 #ifndef OPENSSL_NO_TLSEXT
     case SSL_CTRL_SET_TLSEXT_HOSTNAME:
         if (larg == TLSEXT_NAMETYPE_host_name) {
+            size_t len;
+
             if (s->tlsext_hostname != NULL)
                 OPENSSL_free(s->tlsext_hostname);
             s->tlsext_hostname = NULL;
@@ -3270,7 +3272,8 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
             ret = 1;
             if (parg == NULL)
                 break;
-            if (strlen((char *)parg) > TLSEXT_MAXLEN_host_name) {
+            len = strlen((char *)parg);
+            if (len == 0 || len > TLSEXT_MAXLEN_host_name) {
                 SSLerr(SSL_F_SSL3_CTRL, SSL_R_SSL3_EXT_INVALID_SERVERNAME);
                 return 0;
             }