From: 최대우 (Daewoo Choi) <daewoo.choi@hanwha.com>
Date: Mon, 2 Nov 2026 04:07:30 +0000 (+0900)
Subject: Control API: fixed handling of oversized requests
X-Git-Url: https://git.kaiwu.me/?a=commitdiff_plain;h=050076e2b4a5cd7cb701a97b6b85c51b99382910;p=nginx.git

Control API: fixed handling of oversized requests

A request line larger than the receive buffer was answered with no
response at all, while every other malformed request gets a status
code.  The buffer-full check also ran at the start of the next read
event, which may never arrive, since SIGIO is raised by new data.
The check is now made after parsing, so 400 is returned right away.
---

diff --git a/src/os/unix/ngx_control.c b/src/os/unix/ngx_control.c
index 2877b6a65..bfe508948 100644
--- a/src/os/unix/ngx_control.c
+++ b/src/os/unix/ngx_control.c
@@ -567,12 +567,6 @@ ngx_control_handle_read(ngx_control_request_t *r)
 
     b = r->in;
 
-    if (b->last == b->end) {
-        ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0,
-                      "control: request too large");
-        return NGX_ERROR;
-    }
-
     n = recv(r->fd, b->last, b->end - b->last, 0);
 
     if (n < 0) {
@@ -594,6 +588,13 @@ ngx_control_handle_read(ngx_control_request_t *r)
     switch (ngx_control_parse_request_line(r)) {
 
     case NGX_AGAIN:
+        if (b->last == b->end) {
+            ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0,
+                          "control: request too large");
+            ngx_control_pollfd[r->index].events &= ~POLLIN;
+            return ngx_control_send_response(r, NGX_CTRL_BAD_REQUEST, NULL);
+        }
+
         return NGX_AGAIN;
 
     case NGX_DECLINED: