FreeBSD Security Advisory FreeBSD-SA-22:04.netmap


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============================================================================= FreeBSD-SA-22:04.netmap Security Advisory The FreeBSD Project
Topic: Potential jail escape vulnerabilities in netmap
Category: core Module: netmap Announced: 2022-04-06 Credits: Reno Robert and Lucas Leong (@_wmliang_) Trend Micro Zero Day Initiative Affects: All supported versions of FreeBSD. Corrected: 2022-03-19 17:53:35 UTC (stable/13, 13.1-STABLE) 2022-04-06 03:26:07 UTC (releng/13.1, 13.1-RC1-p1) 2022-04-06 03:04:13 UTC (releng/13.0, 13.0-RELEASE-p11) 2022-03-20 09:08:23 UTC (stable/12, 12.3-STABLE) 2022-04-06 03:06:25 UTC (releng/12.3, 12.3-RELEASE-p5) CVE Name: CVE-2022-23084, CVE-2022-23085
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I. Background
netmap is a framework for extremely fast and efficient packet I/O for userspace and kernel clients, and for Virtual Machines.
II. Problem Description
The total size of the user-provided nmreq to nmreq_copyin() was first computed and then trusted during the copyin. This time-of-check to time-of-use bug could lead to kernel memory corruption. [CVE-2022-23084]
A user-provided integer option was passed to nmreq_copyin() without checking if it would overflow. This insufficient bounds checking could lead to kernel memory corruption. [CVE-2022-23085]
III. Impact
On systems configured to include netmap in their devfs_ruleset, a privileged process running in a jail can affect the host environment.
IV. Workaround
No workaround is available. Systems that do not include netmap in their devfs_ruleset are unaffected. A default installation of FreeBSD does not include netmap in its devfs_ruleset.
V. Solution
Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot.
Perform one of the following:
1) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the amd64, i386, or (on FreeBSD 13 and later) arm64 platforms can be updated via the freebsd-update(8) utility:
# freebsd-update fetch # freebsd-update install # shutdown -r +10min “Rebooting for a security update”
2) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to the applicable FreeBSD release branches.
a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility.
# fetch security.FreeBSD.org/patches/SA-22:04/netmap.patch # fetch security.FreeBSD.org/patches/SA-22:04/netmap.patch.asc # gpg –verify netmap.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in and reboot the system.
VI. Correction details
This issue is corrected by the corresponding Git commit hash or Subversion revision number in the following stable and release branches:
Branch/path Hash Revision – ————————————————————————- stable/13/ 9f600a260a73 stable/13-n250049 releng/13.1/ 7c55c52696d2 releng/13.1-n250081 releng/13.0/ 4996f46e03a4 releng/13.0-n244794 stable/12/ r371757 releng/12.3/ r371870 – ————————————————————————-
For FreeBSD 13 and later:
Run the following command to see which files were modified by a particular commit:
# git show –stat
Or visit the following URL, replacing NNNNNN with the hash:

To determine the commit count in a working tree (for comparison against nNNNNNN in the table above), run:
# git rev-list –count –first-parent HEAD
For FreeBSD 12 and earlier:
Run the following command to see which files were modified by a particular revision, replacing NNNNNN with the revision number:
# svn diff -cNNNNNN –summarize svn://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:

VII. References

The latest revision of this advisory is available at —–BEGIN PGP SIGNATURE—–
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