139 lines
5.2 KiB
Text
139 lines
5.2 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
|
|
Hash: SHA512
|
|
|
|
=============================================================================
|
|
FreeBSD-EN-18:12.mem Errata Notice
|
|
The FreeBSD Project
|
|
|
|
Topic: Small kernel memory disclosures in two system calls
|
|
|
|
Category: core
|
|
Module: kernel
|
|
Announced: 2018-09-27
|
|
Credits: Thomas Barabosch, Fraunhofer FKIE
|
|
Affects: All supported versions of FreeBSD.
|
|
Corrected: 2018-09-27 18:42:40 UTC (stable/11, 11.2-STABLE)
|
|
2018-09-27 18:36:30 UTC (releng/11.2, 11.2-RELEASE-p4)
|
|
2018-09-27 18:36:30 UTC (releng/11.1, 11.1-RELEASE-p15)
|
|
2018-09-27 18:44:40 UTC (stable/10, 10.4-STABLE)
|
|
2018-09-27 18:36:30 UTC (releng/10.4, 10.4-RELEASE-p13)
|
|
CVE Name: CVE-2018-17155
|
|
|
|
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
|
|
|
|
The kernel provides an interface for userland programs via system calls. Two
|
|
of these system calls are named getcontext and swapcontext.
|
|
|
|
II. Problem Description
|
|
|
|
Due to insufficient initialization of memory copied to userland in the
|
|
getcontext and swapcontext system calls, small amounts of kernel memory may
|
|
be disclosed to userland processes.
|
|
|
|
III. Impact
|
|
|
|
An unprivileged local user may be able to create a specific program to read
|
|
the contents of small portions of kernel memory.
|
|
|
|
Such memory might contain sensitive information, such as portions of the file
|
|
cache or terminal buffers. This information might be directly useful, or it
|
|
might be leveraged to obtain elevated privileges in some way; for example,
|
|
a terminal buffer might include a user-entered password.
|
|
|
|
IV. Workaround
|
|
|
|
No workaround is available.
|
|
|
|
V. Solution
|
|
|
|
Perform one of the following:
|
|
|
|
1) Upgrade your system to a supported FreeBSD stable or release / security
|
|
branch (releng) dated after the correction date.
|
|
|
|
Afterward, reboot the system.
|
|
|
|
2) To update your 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
|
|
|
|
Afterward, reboot the system.
|
|
|
|
3) 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-18:12/mem.patch
|
|
# fetch https://security.FreeBSD.org/patches/EN-18:12/mem.patch.asc
|
|
# gpg --verify mem.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/10/ r339984
|
|
releng/10.4/ r338981
|
|
stable/11/ r339983
|
|
releng/11.1/ r338981
|
|
releng/11.2/ r338981
|
|
- -------------------------------------------------------------------------
|
|
|
|
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
|
|
|
|
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-17155>
|
|
|
|
The latest revision of this advisory is available at
|
|
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-18:12.mem.asc>
|
|
-----BEGIN PGP SIGNATURE-----
|
|
|
|
iQKSBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAlutKU5fFIAAAAAALgAo
|
|
aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD
|
|
MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n
|
|
5cJfGA/3XLR2dunxnQZYQvdpA8k9HA1zHfKFUMbTJqESIZPofvLnFJiw7gwDl0mF
|
|
pMC5LCi+k+LIIsXPLzRk/7BUmoCt/hCbD7BOVuiYXhIZy0VgKhaOggSvOXYOsjNl
|
|
JTJa5zGsKm4BUNhAkxcJtCO9i+gOShZ2fxiJ9SU7bO/gVl5HoMh56KWTLUBXX2jD
|
|
vZfEvxJvllbvk6ST68jb7C0Ix47+idRO2hdfxVLyZfD1PsILIy6JThqKqsbGgqbA
|
|
+ma7OnCigxwI0bds4nusi7vNu3IiFuzjBLfV9exW8kcRgyotOsmCfCjSOlOcEJvR
|
|
gKcmqZccf1SMGFR336YwGB66xL56QwpgN+UZ/QhmBX15mqI/oAekd0W3fb3OmfvW
|
|
bMiDo0MHmtZqiSnQyUOcCPRW5s0l8EHeWCVbjKX1ViqY6e4NdQajrjRUyXnOqcM5
|
|
vtTWAJ+BCc3Acg1V4nkjF7HNCUyGObKZcbDqK7M7p5+i/CFxJkCdKu0x8dsZRHL8
|
|
7V4SL1sb9OkPWjBxyzHuiQNGJfTgknDsIxvBYcdPVukTtGzrWH1skhdWL2O0CNvQ
|
|
Quk2YQePQ/X4ICPIB3s+Yao5N8t0FoEM4Hus6nSCpNRyP5XpCaBISHbhG8Ay7yJr
|
|
1p0YkV22eQ5KXiNY6Qmof7S0S1p8IZlomO8J8I/yGuwqh2mkkQ==
|
|
=uZtl
|
|
-----END PGP SIGNATURE-----
|