[nginx] SSL: only select SPDY using NPN if "spdy" is enabled.

[Maxim Dounin]

details:   http://hg.nginx.org/nginx/rev/5ae5142d39a3
branches:  stable-1.8
changeset: 6345:5ae5142d39a3
user:      Valentin Bartenev <vbart at nginx.com>
date:      Thu Nov 05 15:01:09 2015 +0300
description:
SSL: only select SPDY using NPN if "spdy" is enabled.

OpenSSL doesn't check if the negotiated protocol has been announced.
As a result, the client might force using SPDY even if it wasn't
enabled in configuration.

diffstat:

 src/http/ngx_http_request.c |  28 ++++++++++++++++++----------
 1 files changed, 18 insertions(+), 10 deletions(-)

diffs (46 lines):

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
@@ -770,24 +770,32 @@ ngx_http_ssl_handshake_handler(ngx_conne
         {
         unsigned int             len;
         const unsigned char     *data;
+        ngx_http_connection_t   *hc;
         static const ngx_str_t   spdy = ngx_string(NGX_SPDY_NPN_NEGOTIATED);
 
+        hc = c->data;
+
+        if (hc->addr_conf->spdy) {
+
 #ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
-        SSL_get0_alpn_selected(c->ssl->connection, &data, &len);
+            SSL_get0_alpn_selected(c->ssl->connection, &data, &len);
 
 #ifdef TLSEXT_TYPE_next_proto_neg
-        if (len == 0) {
+            if (len == 0) {
+                SSL_get0_next_proto_negotiated(c->ssl->connection, &data, &len);
+            }
+#endif
+
+#else /* TLSEXT_TYPE_next_proto_neg */
             SSL_get0_next_proto_negotiated(c->ssl->connection, &data, &len);
-        }
 #endif
 
-#else /* TLSEXT_TYPE_next_proto_neg */
-        SSL_get0_next_proto_negotiated(c->ssl->connection, &data, &len);
-#endif
-
-        if (len == spdy.len && ngx_strncmp(data, spdy.data, spdy.len) == 0) {
-            ngx_http_spdy_init(c->read);
-            return;
+            if (len == spdy.len
+                && ngx_strncmp(data, spdy.data, spdy.len) == 0)
+            {
+                ngx_http_spdy_init(c->read);
+                return;
+            }
         }
         }
 #endif