Date: 07 January 2010
Click here for printable version
Click here for PGP verifiable version
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2010.0009
ZFS ZIL playback with insecure permissions
7 January 2010
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: zfs
Publisher: FreeBSD
Operating System: FreeBSD
Impact/Access: Increased Privileges -- Existing Account
Modify Permissions -- Existing Account
Access Confidential Data -- Existing Account
Resolution: Patch/Upgrade
Original Bulletin:
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-10:03.zfs.asc
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
=============================================================================
FreeBSD-SA-10:03.zfs Security Advisory
The FreeBSD Project
Topic: ZFS ZIL playback with insecure permissions
Category: contrib
Module: zfs
Announced: 2010-01-06
Credits: Pawel Jakub Dawidek
Affects: FreeBSD 7.0 and later.
Corrected: 2009-11-14 11:59:59 UTC (RELENG_8, 8.0-STABLE)
2010-01-06 21:45:30 UTC (RELENG_8_0, 8.0-RELEASE-p2)
2010-01-06 21:45:30 UTC (RELENG_7, 7.2-STABLE)
2010-01-06 21:45:30 UTC (RELENG_7_2, 7.2-RELEASE-p6)
2010-01-06 21:45:30 UTC (RELENG_7_1, 7.1-RELEASE-p10)
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
ZFS is a file-system originally developed by Sun Microsystems.
The ZFS Intent Log ("ZIL") is a mechanism that gathers together in memory
transactions of writes, and is flushed onto disk when synchronous
semantics is necessary. In the event of crash or power failure, the
log is examined and the uncommitted transaction would be replayed to
maintain the synchronous semantics.
II. Problem Description
When replaying setattr transaction, the replay code would set the
attributes with certain insecure defaults, when the logged
transaction did not touch these attributes.
III. Impact
A system crash or power fail would leave some file with mode set
to 07777. This could leak sensitive information or cause privilege
escalation.
IV. Workaround
No workaround is available, but systems not using ZFS are not
vulnerable.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 7-STABLE or 8-STABLE, or to the
RELENG_8_0, RELENG_7_2, or RELENG_7_1 security branch dated after the
correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 7.1, 7.2,
and 8.0 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 7.x]
# fetch http://security.FreeBSD.org/patches/SA-10:03/zfs712.patch
# fetch http://security.FreeBSD.org/patches/SA-10:03/zfs712.patch.asc
[FreeBSD 8.0]
# fetch http://security.FreeBSD.org/patches/SA-10:03/zfs.patch
# fetch http://security.FreeBSD.org/patches/SA-10:03/zfs.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) Examine the system and look for affected files.
These files can be identified with the following command:
# find / -perm -7777 -print0 | xargs -0 ls -ld
The system administrator will have to correct these problems if there
is any files with such permission modes. For example:
# find / -perm -7777 -print0 | xargs -0 chmod u=rwx,go=
Will reset access mode bits to be readable, writable and executable
by the owner only. The system administrator should determine the
appropriate mode bits wisely.
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/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_replay.c 1.6.2.3
RELENG_7_2
src/UPDATING 1.507.2.23.2.9
src/sys/conf/newvers.sh 1.72.2.11.2.10
src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_replay.c
1.6.2.1.4.1
RELENG_7_1
src/UPDATING 1.507.2.13.2.13
src/sys/conf/newvers.sh 1.72.2.9.2.14
src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_replay.c
1.6.2.1.2.1
RELENG_8
src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_replay.c 1.8.2.2
RELENG_8_0
src/UPDATING 1.632.2.7.2.5
src/sys/conf/newvers.sh 1.83.2.6.2.5
src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_replay.c 1.8.4.1
- - -------------------------------------------------------------------------
Subversion:
Branch/path Revision
- - -------------------------------------------------------------------------
stable/7/ r201679
releng/7.2/ r201679
releng/7.1/ r201679
stable/8/ r199266
releng/8.0/ r201679
head/ r199157
- - -------------------------------------------------------------------------
VII. References
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-10:03.zfs.asc
- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (FreeBSD)
iD8DBQFLRRILFdaIBMps37IRAnI3AJ9ioK1Bbg++DpPYW/RX9wnujAeJxACff+Ph
oEIfaiJ5y/DoGhklcAJdXTU=
=JPje
- -----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:
http://www.auscert.org.au/render.html?cid=1980
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
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
iD8DBQFLRTWKNVH5XJJInbgRAkXoAJ9+lZNCHvvLz+rfP+/u9q+9Hiq5dwCbB2CW
5kQBCbdhpHJzTAQsc9TrsG4=
=YiOl
-----END PGP SIGNATURE-----
|