[nginx] Disabled requests with both Content-Length and Transfer-Encoding.

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/bea0f9e5c309
branches:  
changeset: 7878:bea0f9e5c309
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Mon Jun 28 18:01:06 2021 +0300
description:
Disabled requests with both Content-Length and Transfer-Encoding.

HTTP clients are not allowed to generate such requests since Transfer-Encoding
introduction in RFC 2068, and they are not expected to appear in practice
except in attempts to perform a request smuggling attack.  While handling of
such requests is strictly defined, the most secure approach seems to reject
them.

diffstat:

 src/http/ngx_http_request.c |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (21 lines):

diff -r 63c66b7cc07c -r bea0f9e5c309 src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c	Mon Jun 28 18:01:04 2021 +0300
+++ b/src/http/ngx_http_request.c	Mon Jun 28 18:01:06 2021 +0300
@@ -1985,8 +1985,15 @@ ngx_http_process_request_header(ngx_http
             && ngx_strncasecmp(r->headers_in.transfer_encoding->value.data,
                                (u_char *) "chunked", 7) == 0)
         {
-            r->headers_in.content_length = NULL;
-            r->headers_in.content_length_n = -1;
+            if (r->headers_in.content_length) {
+                ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+                              "client sent \"Content-Length\" and "
+                              "\"Transfer-Encoding\" headers "
+                              "at the same time");
+                ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
+                return NGX_ERROR;
+            }
+
             r->headers_in.chunked = 1;
 
         } else {