Michael Tuexen 1ed2bf1e00 tcp: cleanup resource handling in SYN handling
Handle cred, ipopts, and maclabel using the same pattern:
allocate at the beginning and set to NULL when the object is
transferred to a struct syncache. When exiting the function, free
these objects if not transferred or when transferred to the on-stack
struct syncache. This makes use of a new function syncache_release().

This fixes a use after free problem: ipopts should only be freed,
if the on-stack struct syncache is used and the pointer in this
structure still points to the allocated ipopts. If the ipopts
are moved from the struct syncache to the struct inpcb in
syncache_socket(), which is called by syncache_tfo_expand(),
the pointer in the struct syncache is set to NULL.

In a FreeBSD default setup this problem is mitigated by
1. TCP fast open support on the server side not being enabled
   (the sysctl-variable net.inet.tcp.fastopen.server_enable is 0).
2. Incoming IP packet with source routing options are not being
    processed by the host stack
    (the sysctl-variable net.inet.ip.accept_sourceroute is 0).

Only if these two sysctl-variables are changed, a FreeBSD system
is affected, if a server actually using TCP fast open is running.

Reported by:		Yuxiang Yang, Yizhou Zhao, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM5.1 from Z.ai
Reviewed by:		markj, rscheff
MFC after:		3 days
Sponsored by:		Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D57374
2026-06-17 15:46:56 +02:00
2026-06-16 22:23:18 +02:00
2026-06-06 22:48:32 +02:00
2026-06-11 22:50:52 -07:00
2026-06-04 16:45:13 -07:00
2026-02-21 20:53:19 -05:00
2026-02-21 20:53:19 -05:00
2017-12-19 03:38:06 +00:00
2026-03-07 00:51:15 -07:00
2026-01-01 00:29:23 +00:00
2023-12-26 10:28:25 -07:00
2026-05-06 15:46:29 +01:00

FreeBSD Source:

This is the top level of the FreeBSD source directory.

FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.

For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.

The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), FreeBSD handbook on building userland, and Handbook for kernels for more information, including setting make(1) variables.

For information on the CPU architectures and platforms supported by FreeBSD, see the FreeBSD website's Platforms page.

For official FreeBSD bootable images, see the release page.

Source Roadmap:

Directory Description
bin System/user commands.
cddl Source code for third-party software under the Common Development and Distribution License.
contrib Source code for third-party software.
crypto Source code for cryptographic libraries and commands (see crypto/README).
etc Template files for /etc.
gnu Source code for third-party software under the GNU General Public License (GPL) or Lesser General Public License (LGPL). Please see gnu/COPYING and gnu/COPYING.LIB for more information.
include System include files.
kerberos5 Build system for Kerberos 5 (Heimdal).
krb5 Build system for Kerberos 5 (MIT).
lib System libraries.
libexec System commands intended to be executed by other commands or daemons.
packages Base system packages.
release Makefiles and scripts used for building releases and VM images.
rescue Build system for statically linked /rescue commands.
sbin System commands.
secure Build system for cryptographic libraries and commands (excluding Kerberos).
share Shared resources.
stand Boot loader sources.
sys Kernel sources (see sys/README.md).
targets Support for experimental DIRDEPS_BUILD
tests Tests which can be run by Kyua. See tests/README for additional information.
tools Ancillary utilities and tests (not included in the build).
usr.bin User commands.
usr.sbin System administration commands.

For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see FreeBSD Handbook.

S
Description
The FreeBSD src tree publish-only repository. Experimenting with 'simple' pull requests....
Readme
3.8 GiB
0 Stars 1 Watchers 0 Forks
Languages
C 59.9%
C++ 26.8%
Roff 4.5%
Shell 2.8%
Assembly 1.7%
Other 3.7%