uhttpd/file: fix string out of buffer range on uh_defer_script

if a url path length is multiple of 8, tailing zero will be trimed out on uh_defer_script, cause a strangle error.
it's simple to reproduce.

1. create a luci controller, register a entry with path length multiple of 8 (including '/cgi-bin/'), for example, '/cgi-bin/luci/admin/system/admin'.
2. set uhttpd max_requests to 1, and restart uhttpd
3. request '/cgi-bin/luci/admin/system/admin' with at least 2 process
4. some responses will produce a error:
```
Unable to launch the requested CGI program:
  /www/cgi-bin/luci: No such file or directory
```

Signed-off-by: Liangbin Lian <jjm2473@gmail.com>

diff --git a/file.c b/file.c
index ac781c1acce43b60ff9f54363bc3ce5c5a8d32f1..d117387878d99611a6a29ef471ad2b3a379fb801 100644 (file)
--- a/file.c
+++ b/file.c
@@ -797,7 +797,7 @@ uh_defer_script(struct client *cl, struct dispatch_handler *d, char *url, struct
                /* allocate enough memory to duplicate all path_info strings in one block */
 #undef _field
 #define _field(_name) &_##_name, field_len(pi->_name),
-               dr = calloc_a(sizeof(*dr), &_url, strlen(url), path_info_fields NULL);
+               dr = calloc_a(sizeof(*dr), &_url, strlen(url) + 1, path_info_fields NULL);
 
                memcpy(&dr->pi, pi, sizeof(*pi));
                dr->path = true;
@@ -807,7 +807,7 @@ uh_defer_script(struct client *cl, struct dispatch_handler *d, char *url, struct
 #define _field(_name) if (pi->_name) dr->pi._name = strcpy(_##_name, pi->_name);
                path_info_fields
        } else {
-               dr = calloc_a(sizeof(*dr), &_url, strlen(url), NULL);
+               dr = calloc_a(sizeof(*dr), &_url, strlen(url) + 1, NULL);
        }
 
        cl->dispatch.req_data = dr;