FreeBSD Security Advisories
2012-Jun-12 13:26 UTC
FreeBSD Security Advisory FreeBSD-SA-12:04.sysret
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============================================================================FreeBSD-SA-12:04.sysret
Security Advisory
The FreeBSD Project
Topic: Privilege escalation when returning from kernel
Category: core
Module: sys_amd64
Announced: 2012-06-12
Credits: Rafal Wojtczuk, John Baldwin
Affects: All supported versions of FreeBSD
Corrected: 2012-06-12 12:10:10 UTC (RELENG_7, 7.4-STABLE)
2012-06-12 12:10:10 UTC (RELENG_7_4, 7.4-RELEASE-p9)
2012-06-12 12:10:10 UTC (RELENG_8, 8.3-STABLE)
2012-06-12 12:10:10 UTC (RELENG_8_3, 8.3-RELEASE-p3)
2012-06-12 12:10:10 UTC (RELENG_8_2, 8.2-RELEASE-p9)
2012-06-12 12:10:10 UTC (RELENG_8_1, 8.1-RELEASE-p11)
2012-06-12 12:10:10 UTC (RELENG_9, 9.0-STABLE)
2012-06-12 12:10:10 UTC (RELENG_9_0, 9.0-RELEASE-p3)
CVE Name: CVE-2012-0217
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.
I. Background
The FreeBSD operating system implements a rings model of security, where
privileged operations are done in the kernel, and most applications
request access to these operations by making a system call, which puts
the CPU into the required privilege level and passes control to the
kernel.
II. Problem Description
FreeBSD/amd64 runs on CPUs from different vendors. Due to varying
behaviour of CPUs in 64 bit mode a sanity check of the kernel may be
insufficient when returning from a system call.
III. Impact
Successful exploitation of the problem can lead to local kernel privilege
escalation, kernel data corruption and/or crash.
To exploit this vulnerability, an attacker must be able to run code with user
privileges on the target system.
IV. Workaround
No workaround is available.
However FreeBSD/amd64 running on AMD CPUs is not vulnerable to this
particular problem.
Systems with 64 bit capable CPUs, but running the 32 bit FreeBSD/i386
kernel are not vulnerable, nor are systems running on different
processor architectures.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 7-STABLE, 8-STABLE, or 9-STABLE,
or to the RELENG_7_4, RELENG_8_3, RELENG_8_2, RELENG_8_1, or RELENG_9_0
security branch dated after the correction date.
2) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to FreeBSD 7.4,
8.3, 8.2, 8.1 and 9.0 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch http://security.FreeBSD.org/patches/SA-12:04/sysret.patch
# fetch http://security.FreeBSD.org/patches/SA-12:04/sysret.patch.asc
b) Apply the patch.
# cd /usr/src
# patch < /path/to/patch
c) Recompile your kernel as described in
<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
system.
3) To update your vulnerable system via a binary patch:
Systems running 7.4-RELEASE, 8.3-RELEASE, 8.2-RELEASE, 8.1-RELEASE,
or 9.0-RELEASE on the i386 or amd64 platforms can be updated via the
freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
CVS:
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_7
src/sys/amd64/amd64/trap.c 1.319.2.14
RELENG_7_4
src/UPDATING 1.507.2.36.2.11
src/sys/conf/newvers.sh 1.72.2.18.2.14
src/sys/amd64/amd64/trap.c 1.319.2.12.2.2
RELENG_8
src/sys/amd64/amd64/trap.c 1.332.2.24
RELENG_8_3
src/UPDATING 1.632.2.26.2.5
src/sys/conf/newvers.sh 1.83.2.15.2.7
src/sys/amd64/amd64/trap.c 1.332.2.21.2.2
RELENG_8_2
src/UPDATING 1.632.2.19.2.11
src/sys/conf/newvers.sh 1.83.2.12.2.14
src/sys/amd64/amd64/trap.c 1.332.2.14.2.2
RELENG_8_1
src/UPDATING 1.632.2.14.2.14
src/sys/conf/newvers.sh 1.83.2.10.2.15
src/sys/amd64/amd64/trap.c 1.332.2.10.2.2
RELENG_9
src/sys/amd64/amd64/trap.c 1.357.2.9
RELENG_9_0
src/UPDATING 1.702.2.4.2.5
src/sys/conf/newvers.sh 1.95.2.4.2.7
src/sys/amd64/amd64/trap.c 1.357.2.2.2.3
- -------------------------------------------------------------------------
Subversion:
Branch/path Revision
- -------------------------------------------------------------------------
stable/7/ r236953
releng/7.4/ r236953
stable/8/ r236953
releng/8.3/ r236953
releng/8.2/ r236953
releng/8.1/ r236953
stable/9/ r236953
releng/9.0/ r236953
- -------------------------------------------------------------------------
VII. References
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0217
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-12:04.sysret.asc
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On Tue, Jun 12, 2012 at 01:26:33PM +0000, FreeBSD Security Advisories wrote:> IV. Workaround > > No workaround is available. > > However FreeBSD/amd64 running on AMD CPUs is not vulnerable to this > particular problem. > > Systems with 64 bit capable CPUs, but running the 32 bit FreeBSD/i386 > kernel are not vulnerable, nor are systems running on different > processor architectures.I found these last two paragraphs a little confusing. Is the correct interpretation that FreeBSD/amd64 running on Intel CPUs is the vulnerable combination? -- Greg Lewis Email : glewis@eyesbeyond.com Eyes Beyond Web : http://www.eyesbeyond.com Information Technology FreeBSD : glewis@FreeBSD.org
On 6/14/12, Greg Lewis <glewis@eyesbeyond.com> wrote:> On Tue, Jun 12, 2012 at 01:26:33PM +0000, FreeBSD Security Advisories > wrote: >> IV. Workaround >> >> No workaround is available. >> >> However FreeBSD/amd64 running on AMD CPUs is not vulnerable to this >> particular problem. >> >> Systems with 64 bit capable CPUs, but running the 32 bit FreeBSD/i386 >> kernel are not vulnerable, nor are systems running on different >> processor architectures. > > I found these last two paragraphs a little confusing. Is the correct > interpretation that FreeBSD/amd64 running on Intel CPUs is the vulnerable > combination? > > -- > Greg Lewis Email : glewis@eyesbeyond.com > Eyes Beyond Web : http://www.eyesbeyond.com > Information Technology FreeBSD : glewis@FreeBSD.org > _______________________________________________ > freebsd-security@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-security > To unsubscribe, send any mail to "freebsd-security-unsubscribe@freebsd.org" >http://www.kb.cert.org/vuls/byvendor?searchview&Query=FIELD+Reference=649219&SearchOrder=4
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 06/13/12 15:37, Greg Lewis wrote:> On Tue, Jun 12, 2012 at 01:26:33PM +0000, FreeBSD Security > Advisories wrote: >> IV. Workaround >> >> No workaround is available. >> >> However FreeBSD/amd64 running on AMD CPUs is not vulnerable to >> this particular problem. >> >> Systems with 64 bit capable CPUs, but running the 32 bit >> FreeBSD/i386 kernel are not vulnerable, nor are systems running >> on different processor architectures. > > I found these last two paragraphs a little confusing. Is the > correct interpretation that FreeBSD/amd64 running on Intel CPUs is > the vulnerable combination?Correct. Cheers, - -- Xin LI <delphij@delphij.net> https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iQEcBAEBCAAGBQJP2S/WAAoJEG80Jeu8UPuz9JMIALQwTqb6SDKAUwLkxupOgyEa 7dSHYAxwbNWKNvjbK0brS05kx5RdEmxdkoRqdKOlPcY8JnbqpbROWIbUHA8XIfCW igHIISTgQhiw5nx8XqMMoEfzztPR7UKr9rE+CToWLT8GbHWEpiYlE1RpIQgoZ0TK ldlQSOOMZ32zushxbM1ZncSM0/Rm9ie+ISezGfCV/lXqQUycVxnxjV/Euf6OKzxC xQC2nI21UIu1nZi8sfT0Qnlz8o/ehEYMmHDJgkphxLxMqtWW6l/WqdPMtEGWwBVB rBGRVQvkCrqu8aKBUsOFmX9+vZ4riDtggrXjSadAUGVQNMtBlHBPJ83vmyiQ5LA=Qpu0 -----END PGP SIGNATURE-----
On Thu, Jun 14, 2012 at 02:23:02AM +0200, Oliver Pinter wrote:> On 6/14/12, Greg Lewis <glewis@eyesbeyond.com> wrote: > > On Tue, Jun 12, 2012 at 01:26:33PM +0000, FreeBSD Security Advisories > > wrote: > >> IV. Workaround > >> > >> No workaround is available. > >> > >> However FreeBSD/amd64 running on AMD CPUs is not vulnerable to this > >> particular problem. > >> > >> Systems with 64 bit capable CPUs, but running the 32 bit FreeBSD/i386 > >> kernel are not vulnerable, nor are systems running on different > >> processor architectures. > > > > I found these last two paragraphs a little confusing. Is the correct > > interpretation that FreeBSD/amd64 running on Intel CPUs is the vulnerable > > combination? > > http://www.kb.cert.org/vuls/byvendor?searchview&Query=FIELD+Reference=649219&SearchOrder=4Thanks :). That was much clearer. -- Greg Lewis Email : glewis@eyesbeyond.com Eyes Beyond Web : http://www.eyesbeyond.com Information Technology FreeBSD : glewis@FreeBSD.org
On Wednesday, June 13, 2012 6:37:58 pm Greg Lewis wrote:> On Tue, Jun 12, 2012 at 01:26:33PM +0000, FreeBSD Security Advisories wrote: > > IV. Workaround > > > > No workaround is available. > > > > However FreeBSD/amd64 running on AMD CPUs is not vulnerable to this > > particular problem. > > > > Systems with 64 bit capable CPUs, but running the 32 bit FreeBSD/i386 > > kernel are not vulnerable, nor are systems running on different > > processor architectures. > > I found these last two paragraphs a little confusing. Is the correct > interpretation that FreeBSD/amd64 running on Intel CPUs is the vulnerable > combination?It is only know that AMD CPUs are safe. It is not known if non-AMD, non-Intel CPUs (e.g. the 64-bit capable VIA CPUs) are vulnerable. -- John Baldwin