[nginx] SPDY: stop emitting multiple empty header values.

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/87ada3ba1392
branches:  
changeset: 5891:87ada3ba1392
user:      Piotr Sikora <piotr at cloudflare.com>
date:      Mon Oct 27 14:25:56 2014 -0700
description:
SPDY: stop emitting multiple empty header values.

Previously, nginx would emit empty values in a header with multiple,
NULL-separated values.

This is forbidden by the SPDY specification, which requires headers to
have either a single (possibly empty) value or multiple, NULL-separated
non-empty values.

Signed-off-by: Piotr Sikora <piotr at cloudflare.com>

diffstat:

 src/http/ngx_http_spdy_filter_module.c |  8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diffs (19 lines):

diff -r 049c3ea24480 -r 87ada3ba1392 src/http/ngx_http_spdy_filter_module.c
--- a/src/http/ngx_http_spdy_filter_module.c	Tue Oct 28 21:58:49 2014 +0300
+++ b/src/http/ngx_http_spdy_filter_module.c	Mon Oct 27 14:25:56 2014 -0700
@@ -493,9 +493,13 @@ ngx_http_spdy_header_filter(ngx_http_req
                 continue;
             }
 
-            *last++ = '\0';
+            if (h[j].value.len) {
+                if (last != p) {
+                    *last++ = '\0';
+                }
 
-            last = ngx_cpymem(last, h[j].value.data, h[j].value.len);
+                last = ngx_cpymem(last, h[j].value.data, h[j].value.len);
+            }
 
             h[j].hash = 2;
         }