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-----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. 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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-----