Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2019.0345
System call kernel data register leak
6 February 2019
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: FreeBSD kernel
Publisher: FreeBSD
Operating System: FreeBSD
Impact/Access: Access Privileged Data -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2019-5595
Original Bulletin:
https://security.freebsd.org/advisories/FreeBSD-SA-19:01.syscall.asc
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
=============================================================================
FreeBSD-SA-19:01.syscall Security Advisory
The FreeBSD Project
Topic: System call kernel data register leak
Category: core
Module: kernel
Announced: 2019-02-05
Credits: Konstantin Belousov
Affects: All supported versions of FreeBSD.
Corrected: 2019-02-05 17:52:06 UTC (stable/12, 12.0-STABLE)
2019-02-05 18:05:05 UTC (releng/12.0, 12.0-RELEASE-p3)
2019-02-05 17:54:02 UTC (stable/11, 11.2-STABLE)
2019-02-05 18:07:45 UTC (releng/11.2, 11.2-RELEASE-p9)
CVE Name: CVE-2019-5595
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/>.
I. Background
The FreeBSD/amd64 architecture defines the SYSCALL instruction for syscalls,
and uses registers calling conventions for passing syscalls arguments and
return values in addition to the registers usage imposed by the SYSCALL and
SYSRET instructions in long mode. In particular, the arguments are passed in
registers specified by the C ABI, and the content of the registers specified
as caller-save, is undefined after the return from syscall.
II. Problem Description
The callee-save registers are used by kernel and for some of them (%r8, %r10,
and for non-PTI configurations, %r9) the content is not sanitized before
return from syscalls, potentially leaking sensitive information.
III. Impact
Typically an address of some kernel data structure used in the syscall
implementation, is exposed.
IV. Workaround
No workaround is available.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date,
and reboot.
2) 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 +10m "Rebooting for security update"
3) 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 12.0]
# fetch https://security.FreeBSD.org/patches/SA-19:01/syscall.patch
# fetch https://security.FreeBSD.org/patches/SA-19:01/syscall.patch.asc
# gpg --verify syscall.patch.asc
[FreeBSD 11.2]
# fetch https://security.FreeBSD.org/patches/SA-19:01/syscall.11.2.patch
# fetch https://security.FreeBSD.org/patches/SA-19:01/syscall.11.2.patch.asc
# gpg --verify syscall.patch.11.2.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/ r343781
releng/12.0/ r343788
stable/11/ r343782
releng/11.2/ r343789
- - -------------------------------------------------------------------------
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-2019-5595>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:01.syscall.asc>
- -----BEGIN PGP SIGNATURE-----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=Aktj
- -----END PGP SIGNATURE-----
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
https://www.auscert.org.au/bulletins/
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967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=rsmm
-----END PGP SIGNATURE-----