[nginx] Proxy: detection of data after final chunk.

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/d225b70d38b6
branches:  
changeset: 7676:d225b70d38b6
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Mon Jul 06 18:36:20 2020 +0300
description:
Proxy: detection of data after final chunk.

Previously, additional data after final chunk was either ignored
(in the same buffer, or during unbuffered proxying) or sent to the
client (in the next buffer already if it was already read from the
socket).  Now additional data are properly detected and ignored
in all cases.  Additionally, a warning is now logged and keepalive
is disabled in the connection.

diffstat:

 src/http/modules/ngx_http_proxy_module.c |  31 ++++++++++++++++++++++++++++++-
 1 files changed, 30 insertions(+), 1 deletions(-)

diffs (57 lines):

diff -r 9afa45068b8f -r d225b70d38b6 src/http/modules/ngx_http_proxy_module.c
--- a/src/http/modules/ngx_http_proxy_module.c	Mon Jul 06 18:36:19 2020 +0300
+++ b/src/http/modules/ngx_http_proxy_module.c	Mon Jul 06 18:36:20 2020 +0300
@@ -2104,6 +2104,23 @@ ngx_http_proxy_chunked_filter(ngx_event_
         return NGX_ERROR;
     }
 
+    if (p->upstream_done) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, p->log, 0,
+                       "http proxy data after close");
+        return NGX_OK;
+    }
+
+    if (p->length == 0) {
+
+        ngx_log_error(NGX_LOG_WARN, p->log, 0,
+                      "upstream sent data after final chunk");
+
+        r->upstream->keepalive = 0;
+        p->upstream_done = 1;
+
+        return NGX_OK;
+    }
+
     b = NULL;
     prev = &buf->shadow;
 
@@ -2166,9 +2183,15 @@ ngx_http_proxy_chunked_filter(ngx_event_
 
             /* a whole response has been parsed successfully */
 
-            p->upstream_done = 1;
+            p->length = 0;
             r->upstream->keepalive = !r->upstream->headers_in.connection_close;
 
+            if (buf->pos != buf->last) {
+                ngx_log_error(NGX_LOG_WARN, p->log, 0,
+                              "upstream sent data after final chunk");
+                r->upstream->keepalive = 0;
+            }
+
             break;
         }
 
@@ -2347,6 +2370,12 @@ ngx_http_proxy_non_buffered_chunked_filt
             u->keepalive = !u->headers_in.connection_close;
             u->length = 0;
 
+            if (buf->pos != buf->last) {
+                ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
+                              "upstream sent data after final chunk");
+                u->keepalive = 0;
+            }
+
             break;
         }