FreeBSD Errata Notice FreeBSD-EN-25:10.zfs
2 July, 2025 by errata-notices@freebsd.org | freebsd
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FreeBSD-EN-25:10.zfs Errata Notice
The FreeBSD Project
Topic: Corruption in ZFS replication streams from encrypted datasets
Category: contrib
Module: zfs
Announced: 2025-07-02
Credits: Klara, Inc.
Affects: All supported versions of FreeBSD.
Corrected: 2025-06-21 22:05:40 UTC (stable/14, 14.3-STABLE)
2025-07-02 18:27:44 UTC (releng/14.3, 14.3-RELEASE-p1)
2025-07-02 18:28:09 UTC (releng/14.2, 14.2-RELEASE-p4)
2025-06-27 20:07:48 UTC (stable/13, 13.5-STABLE)
2025-07-02 18:28:29 UTC (releng/13.5, 13.5-RELEASE-p2)
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
ZFS is an advanced and scalable file system originally developed by Sun
Microsystems for its Solaris operating system. ZFS was integrated as part of
the FreeBSD starting with FreeBSD 7.0, and it has since become a prominent
and preferred choice for storage management.
II. Problem Description
ZFS has built-in replication and backup functionality, which serializes a
filesystem for transport to another system, known as "ZFS send". ZFS send
also supports incremental updates between a pair of snapshots. When sending
an encrypted dataset, the dataset can either be left encrypted for
transit/receipt (raw mode), or decrypted. During a decrypting (normal) send,
a bug in the code caused some metadata (key mappings) in the snapshots to be
decrypted in memory, but not properly released. As a result, the key mappings
used for decryption were not freed from the in-memory table.
III. Impact
The leaked mappings can cause two problems. The first is that they can result
in spurious checksum errors when they are incorrectly used to access data
later. In the second case, in order to export a pool, ZFS requires that all
the mappings be freed. These leaked mappings were never cleaned up, resulting
in any attempt to export the pool causing the command to hang.
IV. Workaround
No workaround is available. Systems not using ZFS, or not using ZFS native
encryption are unaffected.
V. Solution
Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date. A reboot is required following the
upgrade.
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
# reboot
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-25:10/zfs.patch
# fetch https://security.FreeBSD.org/patches/EN-25:10/zfs.patch.asc
# gpg --verify zfs.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/ 6abe6a8a0d54 stable/14-n271756
releng/14.3/ cb24a62cd75b releng/14.3-n271433
releng/14.2/ c5feebf38389 releng/14.2-n269526
stable/13/ eae830109571 stable/13-n259318
releng/13.5/ 4d9c4ecf6a48 releng/13.5-n259168
- -------------------------------------------------------------------------
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://github.com/openzfs/zfs/pull/17340>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-25:10.zfs.asc>
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