# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1315324516 -14400
# Node ID 1c8c48040004bee990fc2dd984d27e49ca80b017
# Parent e854e5abda69f3bdee0f87425f9167dc8cd6adca
Core: protection from cycles with named locations and post_action.

Now redirects to named locations are counted against normal uri changes
limit, and post_action respect this limit as well. As a result at least the
following (bad) configurations no longer trigger infinite cycles:

1. Post action which recursively triggers post action:

location / {
post_action /index.html;
}

2. Post action pointing to nonexistent named location:

location / {
post_action @nonexistent;
}

3. Recursive error page for 500 (Internal Server Error) pointing to
a nonexistent named location:

location / {
recursive_error_pages on;
error_page 500 @nonexistent;
return 500;
}

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2525,6 +2525,16 @@ ngx_http_named_location(ngx_http_request
ngx_http_core_main_conf_t *cmcf;

r->main->count++;
+ r->uri_changes--;
+
+ if (r->uri_changes == 0) {
+ ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+ "rewrite or internal redirection cycle "
+ "while redirect to named location \"%V\"", name);
+
+ ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
+ return NGX_DONE;
+ }

cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2896,6 +2896,10 @@ ngx_http_post_action(ngx_http_request_t
return NGX_DECLINED;
}

+ if (r->post_action && r->uri_changes == 0) {
+ return NGX_DECLINED;
+ }
+
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"post action: \"%V\"", &clcf->post_action);


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