[nginx] Core: allow strings without null-termination in ngx_parse_url().

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/5df5d7d771f6
branches:  
changeset: 6463:5df5d7d771f6
user:      Piotr Sikora <piotrsikora at google.com>
date:      Fri Feb 26 17:30:27 2016 -0800
description:
Core: allow strings without null-termination in ngx_parse_url().

This fixes buffer over-read while using variables in the "proxy_pass",
"fastcgi_pass", "scgi_pass", and "uwsgi_pass" directives, where result
of string evaluation isn't null-terminated.

Found with MemorySanitizer.

Signed-off-by: Piotr Sikora <piotrsikora at google.com>

diffstat:

 src/core/ngx_inet.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (22 lines):

diff -r fd4b52e74f96 -r 5df5d7d771f6 src/core/ngx_inet.c
--- a/src/core/ngx_inet.c	Fri Mar 25 14:10:38 2016 +0300
+++ b/src/core/ngx_inet.c	Fri Feb 26 17:30:27 2016 -0800
@@ -529,14 +529,16 @@ ngx_int_t
 ngx_parse_url(ngx_pool_t *pool, ngx_url_t *u)
 {
     u_char  *p;
+    size_t   len;
 
     p = u->url.data;
+    len = u->url.len;
 
-    if (ngx_strncasecmp(p, (u_char *) "unix:", 5) == 0) {
+    if (len >= 5 && ngx_strncasecmp(p, (u_char *) "unix:", 5) == 0) {
         return ngx_parse_unix_domain_url(pool, u);
     }
 
-    if (p[0] == '[') {
+    if (len && p[0] == '[') {
         return ngx_parse_inet6_url(pool, u);
     }