[nginx] Variables: fixed buffer over-read when evaluating "$arg_".

[Sergey Kandaurov]

details:   https://hg.nginx.org/nginx/rev/028b16e2798f
branches:  
changeset: 7648:028b16e2798f
user:      Sergey Kandaurov <pluknet at nginx.com>
date:      Fri May 08 19:19:16 2020 +0300
description:
Variables: fixed buffer over-read when evaluating "$arg_".

diffstat:

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

diffs (12 lines):

diff -r 716eddd74bc2 -r 028b16e2798f src/http/ngx_http_variables.c
--- a/src/http/ngx_http_variables.c	Thu Apr 23 15:10:26 2020 +0300
+++ b/src/http/ngx_http_variables.c	Fri May 08 19:19:16 2020 +0300
@@ -1075,7 +1075,7 @@ ngx_http_variable_argument(ngx_http_requ
     len = name->len - (sizeof("arg_") - 1);
     arg = name->data + sizeof("arg_") - 1;
 
-    if (ngx_http_arg(r, arg, len, &value) != NGX_OK) {
+    if (len == 0 || ngx_http_arg(r, arg, len, &value) != NGX_OK) {
         v->not_found = 1;
         return NGX_OK;
     }