Amaury Denoyelle 74b95922ef BUG/MEDIUM: quic: do not release BE quic-conn prior to upper conn
For frontend side, quic_conn is only released if MUX wasn't allocated,
either due to handshake abort, in which case upper layer is never
allocated, or after transfer completion when full conn + MUX layers are
already released.

On the backend side, initialization is not performed in the same order.
Indeed, in this case, connection is first instantiated, the nthe
quic_conn is created to execute the handshake, while MUX is still only
allocated on handshake completion. As such, it is not possible anymore
to free immediately quic_conn on handshake failure. Else, this can cause
crash if the connection try to reaccess to its transport layer after
quic_conn release.

Such crash can easily be reproduced in case of connection error to the
QUIC server. Here is an example of an experienced backtrace.

Thread 1 "haproxy" received signal SIGSEGV, Segmentation fault.
  0x0000555555739733 in quic_close (conn=0x55555734c0d0, xprt_ctx=0x5555573a6e50) at src/xprt_quic.c:28
  28              qc->conn = NULL;
  [ ## gdb ## ] bt
  #0  0x0000555555739733 in quic_close (conn=0x55555734c0d0, xprt_ctx=0x5555573a6e50) at src/xprt_quic.c:28
  #1  0x00005555559c9708 in conn_xprt_close (conn=0x55555734c0d0) at include/haproxy/connection.h:162
  #2  0x00005555559c97d2 in conn_full_close (conn=0x55555734c0d0) at include/haproxy/connection.h:206
  #3  0x00005555559d01a9 in sc_detach_endp (scp=0x7fffffffd648) at src/stconn.c:451
  #4  0x00005555559d05b9 in sc_reset_endp (sc=0x55555734bf00) at src/stconn.c:533
  #5  0x000055555598281d in back_handle_st_cer (s=0x55555734adb0) at src/backend.c:2754
  #6  0x000055555588158a in process_stream (t=0x55555734be10, context=0x55555734adb0, state=516) at src/stream.c:1907
  #7  0x0000555555dc31d9 in run_tasks_from_lists (budgets=0x7fffffffdb30) at src/task.c:655
  #8  0x0000555555dc3dd3 in process_runnable_tasks () at src/task.c:889
  #9  0x0000555555a1daae in run_poll_loop () at src/haproxy.c:2865
  #10 0x0000555555a1e20c in run_thread_poll_loop (data=0x5555569d1c00 <ha_thread_info>) at src/haproxy.c:3081
  #11 0x0000555555a1f66b in main (argc=5, argv=0x7fffffffde18) at src/haproxy.c:3671

To fix this, change the condition prior to calling quic_conn release. If
<conn> member is not NULL, delay the release, similarly to the case when
MUX is allocated. This allows connection to be freed first, and detach
from quic_conn layer through close xprt operation.

No need to backport.
2025-06-20 17:46:10 +02:00
2025-04-03 15:59:41 +02:00
2021-09-16 09:14:14 +02:00
2025-06-11 14:31:33 +02:00
2025-06-11 14:31:33 +02:00
2025-06-11 14:31:33 +02:00

HAProxy

alpine/musl AWS-LC openssl no-deprecated Illumos NetBSD FreeBSD VTest

HAProxy logo

HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.

Installation

The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.

Getting help

The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.

The issue tracker is only for bug reports or feature requests.

Documentation

The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.

Please refer to the following files depending on what you're looking for:

  • INSTALL for instructions on how to build and install HAProxy
  • BRANCHES to understand the project's life cycle and what version to use
  • LICENSE for the project's license
  • CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory:

License

HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.

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