HAProxy - Load balancer
Find a file
Willy Tarreau 4de03e42cd BUG/MAJOR: mux-h2: force a hard error upon short read with pending error
A risk of truncated packet was addressed in 2.9 by commit 19fb19976f
("BUG/MEDIUM: mux-h2: Only Report H2C error on read error if demux
buffer is empty") by ignoring CO_FL_ERROR after a recv() call as long
as some data remained present in the buffer. However it has a side
effect due to the fact that some frame processors only deal with full
frames, for example, HEADERS. The side effect is that an incomplete
frame will not be processed and will remain in the buffer, preventing
the error from being taken into account, so the I/O handler wakes up
the H2 parser to handle the error, and that one just subscribes for
more data, and this loops forever wasting CPU cycles.

Note that this only happens with errors at the SSL layer exclusively,
otherwise we'd have a read0 pending that would properly be detected:

  conn->flags = CO_FL_XPRT_TRACKED | CO_FL_ERROR | CO_FL_XPRT_READY | CO_FL_CTRL_READY
  conn->err_code = CO_ERR_SSL_FATAL
  h2c->flags  = H2_CF_ERR_PENDING | H2_CF_WINDOW_OPENED | H2_CF_MBUF_HAS_DATA | H2_CF_DEM_IN_PROGRESS | H2_CF_DEM_SHORT_READ

The condition to report the error in h2_recv() needs to be refined, so
that connection errors are taken into account either when the buffer is
empty, or when there's an incomplete frame, since we're certain it will
never be completed. We're certain to enter that function because
H2_CF_DEM_SHORT_READ implies too short a frame, and earlier there's a
protocol check to validate that no frame size is larger than bufsize,
hence a H2_CF_DEM_SHORT_READ implies there's some room left in the
buffer and we're allowed to try to receive.

The condition to reproduce the bug seems super hard to meet but was
observed once by Patrick Hemmer who had the reflex to capture lots of
information that allowed to explain the problem. In order to reproduce
it, the SSL code had to be significantly modified to alter received
contents at very empiric places, but that was sufficient to reproduce
it and confirm that the current patch works as expected.

The bug was tagged MAJOR because when it triggers there's no other
solution to get rid of it but to restart the process. However given how
hard it is to trigger on a lab, it does not seem very likely to occur
in field.

This needs to be backported to 2.9.
2024-07-17 15:07:47 +02:00
.github CI: weekly QUIC Interop: try to fix private image 2024-07-10 09:43:02 +02:00
addons BUG/MINOR: promex: Remove Help prefix repeated twice for each metric 2024-07-01 10:50:27 +02:00
admin ADMIN: acme.sh: remove the old acme.sh code 2024-05-31 13:37:47 +02:00
dev MEDIUM: mux-spop: Introduce the SPOP multiplexer 2024-07-12 15:27:04 +02:00
doc DOC: spoe: Update SPOE documentation to reflect recent refactoring 2024-07-12 16:38:49 +02:00
examples CLEANUP: assorted typo fixes in the code and comments 2023-11-23 16:23:14 +01:00
include MINOR: debug: use LIM2A to show limits 2024-07-16 14:04:41 +02:00
reg-tests MEDIUM: check/spoe: Use SPOP multiplexer to perform SPOP health-checks 2024-07-12 15:27:04 +02:00
scripts SCRIPTS: create-release: no more need to skip architecture.txt 2024-07-10 15:38:45 +02:00
src BUG/MAJOR: mux-h2: force a hard error upon short read with pending error 2024-07-17 15:07:47 +02:00
tests MAJOR: import: update mt_list to support exponential back-off (try #2) 2024-07-09 16:46:38 +02:00
.cirrus.yml CI: FreeBSD: upgrade image, packages 2024-06-04 11:19:00 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore CONTRIB: Add vi file extensions to .gitignore 2023-06-02 18:14:34 +02:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml CI: travis-ci: temporarily disable arm64 builds 2021-08-07 07:28:15 +02:00
BRANCHES DOC: fix some spelling issues over multiple files 2021-01-08 14:53:47 +01:00
BSDmakefile BUILD: makefile: commit the tiny FreeBSD makefile stub 2023-05-24 17:17:36 +02:00
CHANGELOG [RELEASE] Released version 3.1-dev3 2024-07-10 15:39:36 +02:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2021-08-16 12:37:59 +02:00
INSTALL DOC: install: don't reference removed CPU arg 2024-07-16 20:06:06 +02:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS MAJOR: spoe: Let the SPOE back into the game 2024-05-22 09:04:38 +02:00
Makefile MEDIUM: mux-spop: Introduce the SPOP multiplexer 2024-07-12 15:27:04 +02:00
README.md DOC: change the link to the FreeBSD CI in README.md 2024-06-03 15:21:29 +02:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 3.1-dev3 2024-07-10 15:39:36 +02:00
VERSION [RELEASE] Released version 3.1-dev3 2024-07-10 15:39:36 +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.