[nginx] SPDY: fixed the DATA frame length handling in case of so...

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/d74889fbf06d
branches:  
changeset: 5627:d74889fbf06d
user:      Valentin Bartenev <vbart at nginx.com>
date:      Fri Mar 28 20:05:07 2014 +0400
description:
SPDY: fixed the DATA frame length handling in case of some errors.

There are a few cases in ngx_http_spdy_state_read_data() related to error
handling when ngx_http_spdy_state_skip() might be called with an inconsistent
state between *pos and sc->length, that leads to violation of frame layout
parsing and resuted in corruption of spdy connection.

Based on a patch by Xiaochen Wang.

diffstat:

 src/http/ngx_http_spdy.c |  3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diffs (20 lines):

diff -r 2411d4b5be2c -r d74889fbf06d src/http/ngx_http_spdy.c
--- a/src/http/ngx_http_spdy.c	Wed Mar 26 18:01:11 2014 +0400
+++ b/src/http/ngx_http_spdy.c	Fri Mar 28 20:05:07 2014 +0400
@@ -1528,7 +1528,6 @@ ngx_http_spdy_state_read_data(ngx_http_s
         complete = 1;
 
     } else {
-        sc->length -= size;
         complete = 0;
     }
 
@@ -1571,6 +1570,8 @@ ngx_http_spdy_state_read_data(ngx_http_s
             }
         }
 
+        sc->length -= size;
+
         if (tf) {
             buf->start = pos;
             buf->pos = pos;