-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

============================================================================= FreeBSD-SA-23:13.capsicum Security Advisory
The FreeBSD Project

Topic: copy_file_range insufficient capability rights check

Category: core
Module: capsicum
Announced: 2023-10-03
Credits: David Chisnall
Affects: FreeBSD 13.2
Corrected: 2023-10-02 16:00:27 UTC (stable/13, 13.2-STABLE)
2023-10-03 21:24:41 UTC (releng/13.2, 13.2-RELEASE-p4)
CVE Name: CVE-2023-5369

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>.

I. Background

Capsicum is a lightweight OS capability and sandbox framework. It provides
two kernel primatives, capability mode and capabilities. Capabilities limit operations that can be performed on file descriptors.

copy_file_range is a system call that performs a kernel copy of a byte range from one file to another or within one file. copy_file_range accepts
optional pointers to offsets for the input and output file descriptors.

II. Problem Description

The syscall checked only for the CAP_READ and CAP_WRITE capabilities on the input and output file descriptors, respectively. Using an offset is
logically equivalent to seeking, and the syscall must additionally require
the CAP_SEEK capability.

III. Impact

A sandboxed process with only read or write but no seek capability on a file descriptor may be able to read data from or write data to an arbitrary
location within the file corresponding to that file descriptor.

IV. Workaround

No workaround is available.

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 https://security.FreeBSD.org/patches/SA-23:13/capsicum.patch
# fetch https://security.FreeBSD.org/patches/SA-23:13/capsicum.patch.asc
# gpg --verify capsicum.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 <URL:https://www.FreeBSD.org/handbook/kernelconfig.html> 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/ 3f0ce63828dc stable/13-n256458 releng/13.2/ 2d23f6c33431 releng/13.2-n254636
- -------------------------------------------------------------------------

Run the following command to see which files were modified by a
particular commit:

# git show --stat <commit hash>

Or visit the following URL, replacing NNNNNN with the hash:

<URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>

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

VII. References

<URL:https://reviews.freebsd.org/D41967>

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-5369>

The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-23:13.capsicum.asc> -----BEGIN PGP SIGNATURE-----

iQIzBAEBCgAdFiEEthUnfoEIffdcgYM7bljekB8AGu8FAmUclU0ACgkQbljekB8A Gu/a3Q//aXO1+HdImFnqAzKEto8E97DEv6vB2HUZAoxrmwSX9VNjkrIo9Z9+LRyL q7WXMcok1OPQCCE3ad+g05eqXwnmJ55CpToP/jEXrOOZRDInK0Z5owZbwVpmyAmW zF/+xoEjcw90H7ReIQQ3+TNGDf025tCoXlTQKdzWtNN6BcY3px4zuDYHPUKgMwSv XJDrjYWBzBede00CnlolwmsBorjvZvRMfllTIpiVTlmtD73s+sRDI7rc768MY0RZ gCplCL9S9EkIGL8XJhDWB2+TsG7nvwrUII5M2u0Db252IK7nmgty4l03PtYotx4p jH/a3oXWKeqExGHJaqNcaUwS6xdu+pvMRuJgY4mH6rd+uvOMbC5jvac3FopSlmXq aVIctA2LCRomyYmVDsWXIGLcBT5cAOhsqkrw+JE0kA/k2Pl6NDNK7HNgo6Fj01TR lVf91A1mTsDJxfymU4SWB/KGgImAnR9e7gHUo4gLZCNyYXvcnFa/ntHoswNZ+12L e/b4+PnHts2X4/+I4K6qdF522yzF/vpyF6UjfwAGtT6qmbmGyW9VbDcn6TIL9I3p IDKJCWeHPBfyspWua2hCUIi3/EwpSFvIECPad3hFT6cej1pZ6hfJt8XT0ma82QGp ocbh3tb3E1phSGvgZitk8J0oyWDehuck3YfZ+6nHMwzPBgmr6Lo=
=lS69
-----END PGP SIGNATURE-----

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)