[nginx] Fixed buffer over-read while logging invalid request headers.

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/71edd9192f24
branches:  
changeset: 6409:71edd9192f24
user:      Valentin Bartenev <vbart at nginx.com>
date:      Wed Feb 24 16:01:23 2016 +0300
description:
Fixed buffer over-read while logging invalid request headers.

Since 667aaf61a778 (1.1.17) the ngx_http_parse_header_line() function can return
NGX_HTTP_PARSE_INVALID_HEADER when a header contains NUL character.  In this
case the r->header_end pointer isn't properly initialized, but the log message
in ngx_http_process_request_headers() hasn't been adjusted.  It used the pointer
in size calculation, which might result in up to 2k buffer over-read.

Found with afl-fuzz.

diffstat:

 src/http/ngx_http_request.c |  7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diffs (19 lines):

diff -r cfc3cfa434ec -r 71edd9192f24 src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c	Fri Feb 19 18:13:54 2016 +0300
+++ b/src/http/ngx_http_request.c	Wed Feb 24 16:01:23 2016 +0300
@@ -1351,12 +1351,11 @@ ngx_http_process_request_headers(ngx_eve
             continue;
         }
 
-        /* rc == NGX_HTTP_PARSE_INVALID_HEADER: "\r" is not followed by "\n" */
+        /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
 
         ngx_log_error(NGX_LOG_INFO, c->log, 0,
-                      "client sent invalid header line: \"%*s\\r...\"",
-                      r->header_end - r->header_name_start,
-                      r->header_name_start);
+                      "client sent invalid header line");
+
         ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
         return;
     }