| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20190822192610.EF893500D@freefall.freebsd.org>
Date: Thu, 22 Aug 2019 19:26:10 +0000 (UTC)
From: FreeBSD Security Advisories <security-advisories@...ebsd.org>
To: Bugtraq <bugtraq@...urityfocus.com>
Subject: FreeBSD Security Advisory FreeBSD-SA-19:23.midi [REVISED]
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
=============================================================================
FreeBSD-SA-19:23.midi Security Advisory
The FreeBSD Project
Topic: kernel memory disclosure from /dev/midistat
Category: core
Module: sound
Announced: 2019-08-20
Credits: Peter Holm, Mark Johnston
Affects: All supported versions of FreeBSD.
Corrected: 2019-08-20 17:53:16 UTC (stable/12, 12.0-STABLE)
2019-08-20 17:50:33 UTC (releng/12.0, 12.0-RELEASE-p10)
2019-08-20 17:54:18 UTC (stable/11, 11.3-STABLE)
2019-08-20 17:50:33 UTC (releng/11.3, 11.3-RELEASE-p3)
2019-08-20 17:50:33 UTC (releng/11.2, 11.2-RELEASE-p14)
CVE Name: CVE-2019-5612
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/>.
0. Revision history
v1.0 2019-08-20 Initial release.
v1.1 2019-08-21 Updated workaround.
I. Background
/dev/midistat is a device file which can be read to obtain a
human-readable list of the available MIDI-capable devices in the system.
II. Problem Description
The kernel driver for /dev/midistat implements a handler for read(2).
This handler is not thread-safe, and a multi-threaded program can
exploit races in the handler to cause it to copy out kernel memory
outside the boundaries of midistat's data buffer.
III. Impact
The races allow a program to read kernel memory within a 4GB window
centered at midistat's data buffer. The buffer is allocated each
time the device is opened, so an attacker is not limited to a static
4GB region of memory.
On 32-bit platforms, an attempt to trigger the race may cause a page
fault in kernel mode, leading to a panic.
IV. Workaround
Restrict permissions on /dev/midistat by adding an entry to
/etc/devfs.conf and restarting the service:
# echo "perm midistat 0600" >> /etc/devfs.conf
# service devfs restart
Custom kernels without "device sound" are not vulnerable.
V. Solution
Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date,
and reboot.
1) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
# shutdown -r +10min "Rebooting for 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-19:23/midi.patch
# fetch https://security.FreeBSD.org/patches/SA-19:23/midi.patch.asc
# gpg --verify midi.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
The following list contains the correction revision numbers for each
affected branch.
Branch/path Revision
- -------------------------------------------------------------------------
stable/12/ r351264
releng/12.0/ r351260
stable/11/ r351265
releng/11.3/ r351260
releng/11.2/ r351260
- -------------------------------------------------------------------------
To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:
# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:
<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
VII. References
<other info on vulnerability>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5612>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:23.midi.asc>
-----BEGIN PGP SIGNATURE-----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=AI8Q
-----END PGP SIGNATURE-----
Powered by blists - more mailing lists