commit 81be60376f48ec95bf1a74654f10d5bb3f803344
author Ruslan Ermilov <ru@nginx.com> Mon Dec 16 15:19:01 2019 +0300
committer Ruslan Ermilov <ru@nginx.com> Mon Dec 16 15:19:01 2019 +0300
tree 4fe3659398eb0ab9cac080ba15e644631c4abb35
parent 47464469bb952985ff0bae5a360d33846d1ca106

Rewrite: disallow empty replacements.

While empty replacements were caught at run-time, parsing code
of the "rewrite" directive expects that a minimum length of the
"replacement" argument is 1.

src/http/modules/ngx_http_rewrite_module.c

diff --git a/src/http/modules/ngx_http_rewrite_module.c b/src/http/modules/ngx_http_rewrite_module.c
index 3b49c45..0e6d4df 100644
--- a/src/http/modules/ngx_http_rewrite_module.c
+++ b/src/http/modules/ngx_http_rewrite_module.c
@@ -318,6 +318,11 @@
 
     value = cf->args->elts;
 
+    if (value[2].len == 0) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty replacement");
+        return NGX_CONF_ERROR;
+    }
+
     ngx_memzero(&rc, sizeof(ngx_regex_compile_t));
 
     rc.pattern = value[1];