[nginx] HTTP/3: fixed handling of :authority and Host with port.

[noreply at nginx.com]

details:   https://github.com/nginx/nginx/commit/4da771108282cd233ddc37f83ba8bd01981beeb7
branches:  master
commit:    4da771108282cd233ddc37f83ba8bd01981beeb7
user:      Roman Arutyunyan <arut at nginx.com>
date:      Thu, 26 Jun 2025 20:19:59 +0400
description:
HTTP/3: fixed handling of :authority and Host with port.

RFC 9114, Section 4.3.1. specifies a restriction for :authority and Host
coexistence in an HTTP/3 request:

: If both fields are present, they MUST contain the same value.

Previously, this restriction was correctly enforced only for portless
values.  When Host contained a port, the request failed as if :authority
and Host were different, regardless of :authority presence.

This happens because the value of r->headers_in.server used for :authority
has port stripped.  The fix is to use r->host_start / r->host_end instead.

---
 src/http/v3/ngx_http_v3_request.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/http/v3/ngx_http_v3_request.c b/src/http/v3/ngx_http_v3_request.c
index e41ad50a8..32b11b598 100644
--- a/src/http/v3/ngx_http_v3_request.c
+++ b/src/http/v3/ngx_http_v3_request.c
@@ -1003,6 +1003,7 @@ ngx_http_v3_process_request_header(ngx_http_request_t *r)
 {
     ssize_t                  n;
     ngx_buf_t               *b;
+    ngx_str_t                host;
     ngx_connection_t        *c;
     ngx_http_v3_session_t   *h3c;
     ngx_http_v3_srv_conf_t  *h3scf;
@@ -1034,11 +1035,13 @@ ngx_http_v3_process_request_header(ngx_http_request_t *r)
         goto failed;
     }
 
-    if (r->headers_in.host) {
-        if (r->headers_in.host->value.len != r->headers_in.server.len
-            || ngx_memcmp(r->headers_in.host->value.data,
-                          r->headers_in.server.data,
-                          r->headers_in.server.len)
+    if (r->headers_in.host && r->host_end) {
+
+        host.len = r->host_end - r->host_start;
+        host.data = r->host_start;
+
+        if (r->headers_in.host->value.len != host.len
+            || ngx_memcmp(r->headers_in.host->value.data, host.data, host.len)
                != 0)
         {
             ngx_log_error(NGX_LOG_INFO, c->log, 0,