d2a9149f09
Stephen Farrell reported in issue #2942 that recent haproxy versions crash if there's no resolv.conf. A quick bisect with his reproducer showed that it started with commit 4194f75 ("MEDIUM: tree-wide: avoid manually initializing proxies") which reorders the proxies initialization sequence a bit. The crash shows a corrupted tree, typically indicating a use-after-free. With the help of ASAN it was possible to find that a resolver proxy had been destroyed and freed before the name insertion that causes the crash, very likely caused by the absence of the needed resolv.conf: #0 0x7ffff72a82f7 in free (/usr/local/lib64/libasan.so.5+0x1062f7) #1 0x94c1fd in free_proxy src/proxy.c:436 #2 0x9355d1 in resolvers_destroy src/resolvers.c:2604 #3 0x93e899 in resolvers_create_default src/resolvers.c:3892 #4 0xc6ed29 in httpclient_resolve_init src/http_client.c:1170 #5 0xc6fbcf in httpclient_create_proxy src/http_client.c:1310 #6 0x4ae9da in ssl_ocsp_update_precheck src/ssl_ocsp.c:1452 #7 0xa1b03f in step_init_2 src/haproxy.c:2050 But free_proxy() doesn't delete the ebpt_node that carries the name, which perfectly explains the situation. This patch simply deletes the name node and Stephen confirmed that it fixed the problem for him as well. Let's also free it since the key points to p->id which is never freed either in this function! No backport is needed since the patch above was first merged into 3.2-dev10.
HAProxy
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:
- doc/intro.txt for a quick introduction on HAProxy
- doc/configuration.txt for the configuration's reference manual
- doc/lua.txt for the Lua's reference manual
- doc/SPOE.txt for how to use the SPOE engine
- doc/network-namespaces.txt for how to use network namespaces under Linux
- doc/management.txt for the management guide
- doc/regression-testing.txt for how to use the regression testing suite
- doc/peers.txt for the peers protocol reference
- doc/coding-style.txt for how to adopt HAProxy's coding style
- doc/internals for developer-specific documentation (not all up to date)
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.