[nginx] SSL: server name callback changed to return fatal errors.

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/d430babbe643
branches:  
changeset: 7472:d430babbe643
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Sun Mar 03 16:48:06 2019 +0300
description:
SSL: server name callback changed to return fatal errors.

Notably this affects various allocation errors, and should generally
improve things if an allocation error actually happens during a callback.

Depending on the OpenSSL version, returning an error can result in
either SSL_R_CALLBACK_FAILED or SSL_R_CLIENTHELLO_TLSEXT error from
SSL_do_handshake(), so both errors were switched to the "info" level.

diffstat:

 src/event/ngx_event_openssl.c |   6 ++++++
 src/http/ngx_http_request.c   |  29 ++++++++++++++++++++++-------
 2 files changed, 28 insertions(+), 7 deletions(-)

diffs (82 lines):

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -2855,9 +2855,15 @@ ngx_ssl_connection_error(ngx_connection_
             || n == SSL_R_NO_COMPRESSION_SPECIFIED                   /*  187 */
             || n == SSL_R_NO_SHARED_CIPHER                           /*  193 */
             || n == SSL_R_RECORD_LENGTH_MISMATCH                     /*  213 */
+#ifdef SSL_R_CLIENTHELLO_TLSEXT
+            || n == SSL_R_CLIENTHELLO_TLSEXT                         /*  226 */
+#endif
 #ifdef SSL_R_PARSE_TLSEXT
             || n == SSL_R_PARSE_TLSEXT                               /*  227 */
 #endif
+#ifdef SSL_R_CALLBACK_FAILED
+            || n == SSL_R_CALLBACK_FAILED                            /*  234 */
+#endif
             || n == SSL_R_UNEXPECTED_MESSAGE                         /*  244 */
             || n == SSL_R_UNEXPECTED_RECORD                          /*  245 */
             || n == SSL_R_UNKNOWN_ALERT_TYPE                         /*  246 */
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -855,6 +855,7 @@ ngx_http_ssl_handshake_handler(ngx_conne
 int
 ngx_http_ssl_servername(ngx_ssl_conn_t *ssl_conn, int *ad, void *arg)
 {
+    ngx_int_t                  rc;
     ngx_str_t                  host;
     const char                *servername;
     ngx_connection_t          *c;
@@ -872,7 +873,8 @@ ngx_http_ssl_servername(ngx_ssl_conn_t *
     c = ngx_ssl_get_connection(ssl_conn);
 
     if (c->ssl->handshaked) {
-        return SSL_TLSEXT_ERR_OK;
+        *ad = SSL_AD_NO_RENEGOTIATION;
+        return SSL_TLSEXT_ERR_ALERT_FATAL;
     }
 
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
@@ -886,22 +888,35 @@ ngx_http_ssl_servername(ngx_ssl_conn_t *
 
     host.data = (u_char *) servername;
 
-    if (ngx_http_validate_host(&host, c->pool, 1) != NGX_OK) {
+    rc = ngx_http_validate_host(&host, c->pool, 1);
+
+    if (rc == NGX_ERROR) {
+        *ad = SSL_AD_INTERNAL_ERROR;
+        return SSL_TLSEXT_ERR_ALERT_FATAL;
+    }
+
+    if (rc == NGX_DECLINED) {
         return SSL_TLSEXT_ERR_OK;
     }
 
     hc = c->data;
 
-    if (ngx_http_find_virtual_server(c, hc->addr_conf->virtual_names, &host,
-                                     NULL, &cscf)
-        != NGX_OK)
-    {
+    rc = ngx_http_find_virtual_server(c, hc->addr_conf->virtual_names, &host,
+                                      NULL, &cscf);
+
+    if (rc == NGX_ERROR) {
+        *ad = SSL_AD_INTERNAL_ERROR;
+        return SSL_TLSEXT_ERR_ALERT_FATAL;
+    }
+
+    if (rc == NGX_DECLINED) {
         return SSL_TLSEXT_ERR_OK;
     }
 
     hc->ssl_servername = ngx_palloc(c->pool, sizeof(ngx_str_t));
     if (hc->ssl_servername == NULL) {
-        return SSL_TLSEXT_ERR_OK;
+        *ad = SSL_AD_INTERNAL_ERROR;
+        return SSL_TLSEXT_ERR_ALERT_FATAL;
     }
 
     *hc->ssl_servername = host;