From security-advisories at freebsd.org Tue Apr 6 20:22:58 2021
From: security-advisories at freebsd.org (FreeBSD Security Advisories)
Date: Tue, 6 Apr 2021 20:22:58 +0000 (UTC)
Subject: FreeBSD Security Advisory FreeBSD-SA-21:08.vm
Message-ID: <20210406202258.1A67E15C4C@freefall.freebsd.org>
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=============================================================================
FreeBSD-SA-21:08.vm Security Advisory
The FreeBSD Project
Topic: Memory disclosure by stale virtual memory mapping
Category: core
Module: vm
Announced: 2021-04-06
Credits: Ryan Libby, Dell Inc.
Affects: All supported versions of FreeBSD.
Corrected: 2021-04-06 18:50:46 UTC (stable/13, 13.0-STABLE)
2021-04-06 19:18:49 UTC (releng/13.0, 13.0-RC5-p1)
2021-04-06 19:20:46 UTC (stable/12, 12.2-STABLE)
2021-04-06 19:21:30 UTC (releng/12.2, 12.2-RELEASE-p6)
2021-04-06 19:22:31 UTC (stable/11, 11.4-STABLE)
2021-04-06 19:22:56 UTC (releng/11.4, 11.4-RELEASE-p9)
CVE Name: CVE-2021-29626
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit .
I. Background
Memory mappings shared between processes are a feature of the FreeBSD
virtual memory system. They may be established by unprivileged
processes with the mmap(2), fork(2), and other system calls.
II. Problem Description
A particular case of memory sharing is mishandled in the virtual memory
system. It is possible and legal to establish a relationship where
multiple descendant processes share a mapping which shadows memory of an
ancestor process. In this scenario, when one process modifies memory
through such a mapping, the copy-on-write logic fails to invalidate
other mappings of the source page. These stale mappings may remain even
after the mapped pages have been reused for another purpose.
III. Impact
An unprivileged local user process can maintain a mapping of a page
after it is freed, allowing that process to read private data belonging
to other processes or the kernel.
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.
[FreeBSD 13.0]
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.13.patch
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.13.patch.asc
# gpg --verify vm_fault.13.patch.asc
[FreeBSD 12.2]
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.12.patch
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.12.patch.asc
# gpg --verify vm_fault.12.patch.asc
[FreeBSD 11.4]
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.11.patch
# fetch https://security.FreeBSD.org/patches/SA-21:08/vm_fault.11.patch.asc
# gpg --verify vm_fault.11.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
The following list contains the correction revision numbers for each
affected branch.
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/13/ 2e08308d62f3 stable/13-n245117
releng/13.0/ 724bc23da1a9 releng/13.0-n244728
stable/12/ r369551
releng/12.2/ r369556
stable/11/ r369559
releng/11.4/ r369561
- -------------------------------------------------------------------------
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 HHHHHH 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
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From security-advisories at freebsd.org Tue Apr 6 20:23:04 2021
From: security-advisories at freebsd.org (FreeBSD Security Advisories)
Date: Tue, 6 Apr 2021 20:23:03 +0000 (UTC)
Subject: FreeBSD Security Advisory FreeBSD-SA-21:09.accept_filter
Message-ID: <20210406202303.4129115C4E@freefall.freebsd.org>
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Hash: SHA512
=============================================================================
FreeBSD-SA-21:09.accept_filter Security Advisory
The FreeBSD Project
Topic: double free in accept_filter(9) socket configuration interface
Category: core
Module: accept_filter
Announced: 2021-04-06
Credits: Alexey Kulaev
Affects: FreeBSD 12.2 and later.
Corrected: 2021-03-28 00:24:15 UTC (stable/13, 13.0-STABLE)
2021-03-28 15:03:37 UTC (releng/13.0, 13.0-RC4)
2021-03-28 00:26:49 UTC (stable/12, 12.2-STABLE)
2021-04-06 19:21:21 UTC (releng/12.2, 12.2-RELEASE-p6)
CVE Name: CVE-2021-29627
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit .
I. Background
FreeBSD features an accept_filter(9) mechanism which allows an
application to request that the kernel pre-process incoming connections.
For example, the accf_http(9) accept filter prevents accept(2) from
returning until a full HTTP request has been buffered.
No accept filters are enabled by default. A system administrator must
either compile the FreeBSD kernel with a particular accept filter option
(such as ACCEPT_FILTER_HTTP) or load the filter using kldload(8) in
order to utilize accept filters.
II. Problem Description
An unprivileged process can configure an accept filter on a listening
socket. This is done using the setsockopt(2) system call. The process
supplies the name of the accept filter which is to be attached to the
socket, as well as a string containing filter-specific information.
If the filter implements the accf_create callback, the socket option
handler attempts to preserve the process-supplied argument string. A
bug in the socket option handler caused this string to be freed
prematurely, leaving a dangling pointer. Additional operations on the
socket can turn this into a double free or a use-after-free.
III. Impact
The bug may be exploited to trigger local privilege escalation or kernel
memory disclosure.
IV. Workaround
Systems not using accept filters, or using only the accept filters
included with the FreeBSD base system (accf_data(9), accf_dns(9), and
accf_http(9)) are unaffected. Note that no accept filters are loaded
in the kernel by default.
Systems using a third-party accept filter module are affected if the
module defines an accf_create callback. In this case, the only
workaround is to ensure that the module is not loaded into the kernel.
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-21:09/accept_filter.patch
# fetch https://security.FreeBSD.org/patches/SA-21:09/accept_filter.patch.asc
# gpg --verify accept_filter.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
The following list contains the correction revision numbers for each
affected branch.
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/13/ c7d10e7ec872 stable/13-n245050
releng/13.0/ af6611e5adc6 releng/13.0-n244711
stable/12/ r369525
releng/12.2/ r369553
- -------------------------------------------------------------------------
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 HHHHHH 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
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From security-advisories at freebsd.org Tue Apr 6 20:23:11 2021
From: security-advisories at freebsd.org (FreeBSD Security Advisories)
Date: Tue, 6 Apr 2021 20:23:09 +0000 (UTC)
Subject: FreeBSD Security Advisory FreeBSD-SA-21:10.jail_mount
Message-ID: <20210406202310.00FF315EA9@freefall.freebsd.org>
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Hash: SHA512
=============================================================================
FreeBSD-SA-21:10.jail_mount Security Advisory
The FreeBSD Project
Topic: jail escape possible by mounting over jail root
Category: core
Module: jail
Announced: 2021-04-06
Credits: Mateusz Guzik
Affects: All supported versions of FreeBSD.
Corrected: 2021-04-06 18:50:48 UTC (stable/13, 13.0-STABLE)
2021-04-06 19:18:59 UTC (releng/13.0, 13.0-RC5-p1)
2021-04-06 19:20:50 UTC (stable/12, 12.2-STABLE)
2021-04-06 19:21:33 UTC (releng/12.2, 12.2-RELEASE-p6)
2021-04-06 19:22:31 UTC (stable/11, 11.4-STABLE)
2021-04-06 19:22:59 UTC (releng/11.4, 11.4-RELEASE-p9)
CVE Name: CVE-2020-25584
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit .
I. Background
The jail(2) system call allows a system administrator to lock a process
and all of its descendants inside an environment with a very limited
ability to affect the system outside that environment, even for
processes with superuser privileges. It is an extension of, but
far more powerful than, the traditional UNIX chroot(2) system call.
II. Problem Description
Due to a race condition between lookup of ".." and remounting a filesystem,
a process running inside a jail might access filesystem hierarchy outside
of jail.
III. Impact
A process with superuser privileges running inside a jail configured
with the allow.mount permission (not enabled by default) could change the root
directory outside of the jail, and thus gain full read and write access
to all files and directories in the system.
IV. Workaround
As a workaround, disable allow.mount permission for all jails with untrusted
root users; see jail(1) and jail.conf(5) manual pages for details.
Note that this permission is not enabled by default.
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.
[FreeBSD 13.0]
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.13.patch
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.13.patch.asc
# gpg --verify jail_mount.13.patch.asc
[FreeBSD 12.2]
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.12.patch
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.12.patch.asc
# gpg --verify jail_mount.12.patch.asc
[FreeBSD 11.4]
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.11.patch
# fetch https://security.FreeBSD.org/patches/SA-21:10/jail_mount.11.patch.asc
# gpg --verify jail_mount.11.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
The following list contains the correction revision numbers for each
affected branch.
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/13/ 3ae17faa3704 stable/13-n245118
releng/13.0/ 4710439ec594 releng/13.0-n244729
stable/12/ r369552
releng/12.2/ r369557
stable/11/ r369560
releng/11.4/ r369562
- -------------------------------------------------------------------------
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 HHHHHH 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
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