FreeBSD Errata Notice FreeBSD-EN-25:16.vfs
16 September, 2025 by errata-notices@freebsd.org | freebsd
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FreeBSD-EN-25:16.vfs Errata Notice
The FreeBSD Project
Topic: copy_file_range(2) fails to set output parameters
Category: core
Module: vfs
Announced: 2025-09-16
Affects: FreeBSD 14.3
Corrected: 2025-08-23 21:25:20 UTC (stable/14, 14.3-STABLE)
2025-09-16 16:31:07 UTC (releng/14.3, 14.3-RELEASE-p3)
For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit
<URL:https://security.FreeBSD.org/>.
I. Background
copy_file_range(2) is a system call which takes two file descriptors as input
and copies data from one file to the other.
II. Problem Description
The copy_file_range(2) system call accepts two optional pointer arguments,
inoffp and outoffp. When non-NULL, the kernel is to use their values to
determine the starting offsets for the input and output files, respectively.
In this case, the seek offset corresponding to the file descriptor is not
used or updated.
When finishing the copy, the kernel is supposed to write updated offsets to
the pointed-to values. However, it does not do so.
III. Impact
Applications which rely on this behaviour may behave incorrectly. No such
applications exist in the base system.
IV. Workaround
No workaround is available.
V. Solution
Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date.
Perform one of the following:
1) To update your system via a binary patch:
Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms,
or the i386 platform on FreeBSD 13, can be updated via the freebsd-update(8)
utility:
# freebsd-update fetch
# freebsd-update install
# shutdown -r now
2) To update your 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/EN-25:16/vfs.patch
# fetch https://security.FreeBSD.org/patches/EN-25:16/vfs.patch.asc
# gpg --verify vfs.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 as of the corresponding Git commit hash in the
following stable and release branches:
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/14/ 2fd0083fcc23 stable/14-n272229
releng/14.3/ d1e981cbf3bd releng/14.3-n271441
- -------------------------------------------------------------------------
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://bugs.freebsd.org/bugzilla/show_bug.cgi?id(8985>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-25:16.vfs.asc>
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