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- From 294e4676a3b775a7accb50eb8428f293c218b5e2 Mon Sep 17 00:00:00 2001
- From: Willy Tarreau <w@1wt.eu>
- Date: Mon, 11 May 2015 18:30:33 +0200
- Subject: [PATCH 2/2] BUG/MEDIUM: http: don't forward client shutdown without
- NOLINGER except for tunnels
-
- There's an issue related with shutting down POST transfers or closing the
- connection after the end of the upload : the shutdown is forwarded to the
- server regardless of the abortonclose option. The problem it causes is that
- during a scan, brute force or whatever, it becomes possible that all source
- ports are exhausted with all sockets in TIME_WAIT state.
-
- There are multiple issues at once in fact :
- - no action is done for the close, it automatically happens at the lower
- layers thanks for channel_auto_close(), so we cannot act on NOLINGER ;
-
- - we *do* want to continue to send a clean shutdown in tunnel mode because
- some protocols transported over HTTP may need this, regardless of option
- abortonclose, thus we can't set the option inconditionally
-
- - for all other modes, we do want to close the dirty way because we're
- certain whether we've sent everything or not, and we don't want to eat
- all source ports.
-
- The solution is a bit complex and applies to DONE/TUNNEL states :
-
- 1) disable automatic close for everything not a tunnel and not just
- keep-alive / server-close. Force-close is now covered, as is HTTP/1.0
- which implicitly works in force-close mode ;
-
- 2) when processing option abortonclose, we know we can disable lingering
- if the client has closed and the connection is not in tunnel mode.
-
- Since the last case above leads to a situation where the client side reports
- an error, we know the connection will not be reused, so leaving the flag on
- the stream-interface is safe. A client closing in the middle of the data
- transmission already aborts the transaction so this case is not a problem.
-
- This fix must be backported to 1.5 where the problem was detected.
- (cherry picked from commit bbfb6c40854925367ae5f9e8b22c5c9a18dc69d5)
- ---
- src/proto_http.c | 14 ++++++++++----
- 1 file changed, 10 insertions(+), 4 deletions(-)
-
- diff --git a/src/proto_http.c b/src/proto_http.c
- index 0ac3a47..5db64b5 100644
- --- a/src/proto_http.c
- +++ b/src/proto_http.c
- @@ -5452,9 +5452,10 @@ int http_request_forward_body(struct session *s, struct channel *req, int an_bit
- msg->sov -= msg->next;
- msg->next = 0;
-
- - /* for keep-alive we don't want to forward closes on DONE */
- - if ((txn->flags & TX_CON_WANT_MSK) == TX_CON_WANT_KAL ||
- - (txn->flags & TX_CON_WANT_MSK) == TX_CON_WANT_SCL)
- + /* we don't want to forward closes on DONE except in
- + * tunnel mode.
- + */
- + if ((txn->flags & TX_CON_WANT_MSK) != TX_CON_WANT_TUN)
- channel_dont_close(req);
- if (http_resync_states(s)) {
- /* some state changes occurred, maybe the analyser
- @@ -5478,10 +5479,15 @@ int http_request_forward_body(struct session *s, struct channel *req, int an_bit
- * want to monitor the client's connection and forward
- * any shutdown notification to the server, which will
- * decide whether to close or to go on processing the
- - * request.
- + * request. We only do that in tunnel mode, and not in
- + * other modes since it can be abused to exhaust source
- + * ports.
- */
- if (s->be->options & PR_O_ABRT_CLOSE) {
- channel_auto_read(req);
- + if ((req->flags & (CF_SHUTR|CF_READ_NULL)) &&
- + ((txn->flags & TX_CON_WANT_MSK) != TX_CON_WANT_TUN))
- + s->si[1].flags |= SI_FL_NOLINGER;
- channel_auto_close(req);
- }
- else if (s->txn.meth == HTTP_METH_POST) {
- --
- 2.0.5
-
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