HAProxy - Load balancer
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Willy Tarreau 3e3b9eebf8 BUG/MEDIUM: sample: fix risk of overflow when replacing multiple regex back-refs
Aleandro Prudenzano of Doyensec and Edoardo Geraci of Codean Labs
reported a bug in sample_conv_regsub(), which can cause replacements
of multiple back-references to overflow the temporary trash buffer.

The problem happens when doing "regsub(match,replacement,g)": we're
replacing every occurrence of "match" with "replacement" in the input
sample, which requires a length check. For this, a max is applied, so
that a replacement may not use more than the remaining length in the
buffer. However, the length check is made on the replaced pattern and
not on the temporary buffer used to carry the new string. This results
in the remaining size to be usable for each input match, which can go
beyond the temporary buffer size if more than one occurrence has to be
replaced with something that's larger than the remaining room.

The fix proposed by Aleandro and Edoardo is the correct one (check on
"trash" not "output"), and is the one implemented in this patch.

While it is very unlikely that a config will replace multiple short
patterns each with a larger one in a request, this possibility cannot
be entirely ruled out (e.g. mask a known, short IP address using
"XXX.XXX.XXX.XXX").  However when this happens, the replacement pattern
will be static, and not be user-controlled, which is why this patch is
marked as medium.

The bug was introduced in 2.2 with commit 07e1e3c93e ("MINOR: sample:
regsub now supports backreferences"), so it must be backported to all
versions.

Special thanks go to Aleandro and Edoardo for reporting this bug with
a simple reproducer and a fix.
2025-04-07 15:57:28 +02:00
.github CI: codespell: add "pres" to spellcheck whitelist 2025-04-03 11:37:25 +02:00
addons CLEANUP: assorted typo fixes in the code, commits and doc 2025-04-03 11:37:25 +02:00
admin CLEANUP: assorted typo fixes in the code and comments 2024-09-03 17:49:21 +02:00
dev CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
doc MINOR: hlua_fcn: add Queue:alarm() 2025-04-03 17:52:44 +02:00
examples EXAMPLES: add "games.cfg" and an example game in Lua 2025-04-01 09:10:00 +02:00
include BUILD: atomics: fix build issue on non-x86/non-arm systems 2025-04-07 09:38:22 +02:00
reg-tests REGTESTS: extend conn reuse test with transparent proxy 2025-04-02 14:57:40 +02:00
scripts TESTS: unit-tests: store sh -x in a result file 2025-03-06 21:22:38 +01:00
src BUG/MEDIUM: sample: fix risk of overflow when replacing multiple regex back-refs 2025-04-07 15:57:28 +02:00
tests TESTS: Fix build for filltab25.c 2025-04-03 15:59:41 +02:00
.cirrus.yml CI: cirrus-ci: bump FreeBSD image to 14-2 2025-02-12 13:18:55 +01:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore MINOR: tevt/dev: Add term_events tool 2025-01-31 10:41:50 +01:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml MEDIUM: mworker: remove USE_SYSTEMD requirement for -Ws 2024-11-20 12:07:38 +01:00
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 3.2-dev9 2025-04-02 18:12:34 +02:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
INSTALL DOC: update INSTALL to reflect the minimum compiler version 2025-04-02 18:09:47 +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 MINOR: cpu-topo: allocate and initialize the ha_cpu_topo array. 2025-03-14 18:30:30 +01:00
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 3.2-dev9 2025-04-02 18:12:34 +02:00
VERSION [RELEASE] Released version 3.2-dev9 2025-04-02 18:12:34 +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.