bugfix: nginx rewrite directive may initiate internal redirects without clearing any module ctx and rewrite_by_lua* handlers might think it was re-entered and thus it might lead to request hang. thanks twistedfall for the report in #1235.

Author: agentzh

src/ngx_http_lua_rewriteby.c

@@ -126,6 +126,11 @@ ngx_http_lua_rewrite_handler(ngx_http_request_t *r)
 
                 return NGX_HTTP_OK;
             }
+
+            r->write_event_handler = ngx_http_core_run_phases;
+            ctx->entered_rewrite_phase = 0;
+
+            return NGX_DECLINED;
         }
 
         return rc;
@@ -363,6 +368,9 @@ ngx_http_lua_rewrite_by_chunk(lua_State *L, ngx_http_request_t *r)
             return NGX_HTTP_OK;
         }
 
+        r->write_event_handler = ngx_http_core_run_phases;
+        ctx->entered_rewrite_phase = 0;
+
         return NGX_DECLINED;
     }
 

t/023-rewrite/redirect.t

@@ -122,3 +122,43 @@ GET /read
 --- raw_response_headers_like: Location: /foo\r\n
 --- response_body_like: 302 Found
 --- error_code: 302
+
+
+
+=== TEST 7: internal redirects that do not clear module ctx
+--- http_config
+    rewrite_by_lua_no_postpone on;
+--- config
+	rewrite_by_lua_block {
+        -- this is empty by intention
+	}
+
+	location /url1 {
+		rewrite ^ /url2;
+	}
+--- request
+GET /url1
+--- response_body_like: 404 Not Found
+--- error_log eval
+qr{\[error\] .*?/html/url2".*?No such file or directory}
+--- error_code: 404
+
+
+
+=== TEST 8: internal redirects that do not clear module ctx (yield in rewrite handler)
+--- http_config
+    rewrite_by_lua_no_postpone on;
+--- config
+	rewrite_by_lua_block {
+        ngx.sleep(0.001)
+	}
+
+	location /url1 {
+		rewrite ^ /url2;
+	}
+--- request
+GET /url1
+--- response_body_like: 404 Not Found
+--- error_log eval
+qr{\[error\] .*?/html/url2".*?No such file or directory}
+--- error_code: 404