Proxy: fixed segfault in URI change.

If request URI was shorter than location prefix, as after replacement
with try_files, location length was used to copy the remaining URI part
leading to buffer overread.

The fix is to replace full request URI in this case.  In the following
configuration, request "/123" is changed to "/" when sent to backend.

    location /1234 {
        try_files /123 =404;
        proxy_pass http://127.0.0.1:8080/;
    }

Closes #983 on GitHub.

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 8d5385c1de3cec42b0703affde11a45f01ceb504..d3836602e14e04f05a8c98fd5b6f5ed635dcc478 100644 (file)
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1206,7 +1206,8 @@ ngx_http_proxy_create_key(ngx_http_request_t *r)
         return NGX_OK;
     }
 
-    loc_len = (r->valid_location && ctx->vars.uri.len) ? plcf->location.len : 0;
+    loc_len = (r->valid_location && ctx->vars.uri.len)
+              ? ngx_min(plcf->location.len, r->uri.len) : 0;
 
     if (r->quoted_uri || r->internal) {
         escape = 2 * ngx_escape_uri(NULL, r->uri.data + loc_len,
@@ -1318,8 +1319,8 @@ ngx_http_proxy_create_request(ngx_http_request_t *r)
         uri_len = r->unparsed_uri.len;
 
     } else {
-        loc_len = (r->valid_location && ctx->vars.uri.len) ?
-                      plcf->location.len : 0;
+        loc_len = (r->valid_location && ctx->vars.uri.len)
+                  ? ngx_min(plcf->location.len, r->uri.len) : 0;
 
         if (r->quoted_uri || r->internal) {
             escape = 2 * ngx_escape_uri(NULL, r->uri.data + loc_len,