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
FreeBSD Source:
This is the top level of the FreeBSD source directory.
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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.
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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.