From: Willy Tarreau <w@1wt.eu>
Date: Tue, 28 Sep 2010 12:16:41 +0000 (+0200)
Subject: [BUG] stream_sock: try to flush any extra pending request data after a POST
X-Git-Tag: v1.5-dev8~459
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=58bd8fd46dae559694452a79370d7ebd5c10dce5;p=thirdparty%2Fhaproxy.git

[BUG] stream_sock: try to flush any extra pending request data after a POST

Some broken browsers still happen to send a CRLF after a POST. Those which
send a CRLF in a second packet have it queued into the system's buffers,
which causes an RST to be emitted by some systems upon close of the response
(eg: Linux). The client may then receive the RST without the last response
segments, resulting in a truncated response.

This change leaves request polling enabled on a POST so that we can flush
any late data from the request buffers.

A more complete workaround would consist in reading from the request for a
long time, until we get confirmation that the close has been ACKed. This
is much more complex and should only be studied for newer versions.
(cherry picked from commit 12e316af4f0245fde12dbc224ebe33c8fea806b2)
---

diff --git a/src/proto_http.c b/src/proto_http.c
index 6875f0aad8..20cd8d1da4 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -3834,9 +3834,14 @@ int http_sync_req_state(struct session *s)
 
 	if (txn->req.msg_state == HTTP_MSG_DONE) {
 		/* No need to read anymore, the request was completely parsed.
-		 * We can shut the read side unless we want to abort_on_close.
+		 * We can shut the read side unless we want to abort_on_close,
+		 * or we have a POST request. The issue with POST requests is
+		 * that some browsers still send a CRLF after the request, and
+		 * this CRLF must be read so that it does not remain in the kernel
+		 * buffers, otherwise a close could cause an RST on some systems
+		 * (eg: Linux).
 		 */
-		if (buf->cons->state == SI_ST_EST || !(s->be->options & PR_O_ABRT_CLOSE))
+		if (!(s->be->options & PR_O_ABRT_CLOSE) && txn->meth != HTTP_METH_POST)
 			buffer_dont_read(buf);
 
 		if (txn->rsp.msg_state == HTTP_MSG_ERROR)
@@ -4272,6 +4277,14 @@ int http_request_forward_body(struct session *s, struct buffer *req, int an_bit)
 				buffer_auto_read(req);
 				buffer_auto_close(req);
 			}
+			else if (s->txn.meth == HTTP_METH_POST) {
+				/* POST requests may require to read extra CRLF
+				 * sent by broken browsers and which could cause
+				 * an RST to be sent upon close on some systems
+				 * (eg: Linux).
+				 */
+				buffer_auto_read(req);
+			}
 
 			return 0;
 		}