[nginx] Fixed handling of very long locations (ticket #2435).

[Sergey Kandaurov]

details:   https://hg.nginx.org/nginx/rev/4eb1383f6432
branches:  
changeset: 8121:4eb1383f6432
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Thu Jan 26 03:34:44 2023 +0300
description:
Fixed handling of very long locations (ticket #2435).

Previously, location prefix length in ngx_http_location_tree_node_t was
stored as "u_char", and therefore location prefixes longer than 255 bytes
were handled incorrectly.

Fix is to use "u_short" instead.  With "u_short", prefixes up to 65535 bytes
can be safely used, and this isn't reachable due to NGX_CONF_BUFFER, which
is 4096 bytes.

diffstat:

 src/http/ngx_http.c             |  2 +-
 src/http/ngx_http_core_module.h |  2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diffs (25 lines):

diff -r c7e103acb409 -r 4eb1383f6432 src/http/ngx_http.c
--- a/src/http/ngx_http.c	Tue Jan 24 03:01:51 2023 +0300
+++ b/src/http/ngx_http.c	Thu Jan 26 03:34:44 2023 +0300
@@ -1130,7 +1130,7 @@ ngx_http_create_locations_tree(ngx_conf_
     node->auto_redirect = (u_char) ((lq->exact && lq->exact->auto_redirect)
                            || (lq->inclusive && lq->inclusive->auto_redirect));
 
-    node->len = (u_char) len;
+    node->len = (u_short) len;
     ngx_memcpy(node->name, &lq->name->data[prefix], len);
 
     ngx_queue_split(locations, q, &tail);
diff -r c7e103acb409 -r 4eb1383f6432 src/http/ngx_http_core_module.h
--- a/src/http/ngx_http_core_module.h	Tue Jan 24 03:01:51 2023 +0300
+++ b/src/http/ngx_http_core_module.h	Thu Jan 26 03:34:44 2023 +0300
@@ -463,8 +463,8 @@ struct ngx_http_location_tree_node_s {
     ngx_http_core_loc_conf_t        *exact;
     ngx_http_core_loc_conf_t        *inclusive;
 
+    u_short                          len;
     u_char                           auto_redirect;
-    u_char                           len;
     u_char                           name[1];
 };