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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0273 -- FreeBSD-SA-05:02.sendfile sendfile kernel memory disclosure 5 April 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: sendfile Publisher: FreeBSD Operating System: FreeBSD Impact: Read-only Data Access Access Privileged Data Access: Existing Account CVE Names: CAN-2005-0708 Original Bulletin: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:02.sendfile.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-05:02.sendfile Security Advisory The FreeBSD Project Topic: sendfile kernel memory disclosure Category: core Module: sys_kern Announced: 2005-04-04 Credits: Sven Berkvens <sven@berkvens.net> Marc Olzheim <zlo@zlo.nu> Affects: All FreeBSD 4.x releases All FreeBSD 5.x releases prior to 5.4-RELEASE Corrected: 2005-04-04 23:52:02 UTC (RELENG_5, 5.4-STABLE) 2005-04-04 23:52:35 UTC (RELENG_5_4, 5.4-RELEASE) 2005-04-04 23:53:24 UTC (RELENG_5_3, 5.3-RELEASE-p7) 2005-04-04 23:53:36 UTC (RELENG_4, 4.11-STABLE) 2005-04-04 23:53:56 UTC (RELENG_4_11, 4.11-RELEASE-p2) 2005-04-04 23:54:13 UTC (RELENG_4_10, 4.10-RELEASE-p7) 2005-04-04 23:54:33 UTC (RELENG_4_8, 4.8-RELEASE-p29) CVE Name: CAN-2005-0708 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://www.freebsd.org/security/>. I. Background The sendfile(2) system call allows a server application (such as an HTTP or FTP server) to transmit the contents of a file over a network connection without first copying it to application memory. High performance servers such as Apache and ftpd use sendfile. II. Problem Description If the file being transmitted is truncated after the transfer has started but before it completes, sendfile(2) will transfer the contents of more or less random portions of kernel memory in lieu of the missing part of the file. III. Impact A local user could create a large file and truncate it while transferring it to himself, thus obtaining a copy of portions of system memory to which he would normally not have access. 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 known workaround. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 4-STABLE or 5-STABLE, or to the RELENG_5_3, RELENG_4_11, RELENG_4_10, or RELENG_4_8 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 4.8, 4.10, 4.11, and 5.3 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. [FreeBSD 4.x] # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:02/sendfile_4.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:02/sendfile_4.patch.asc [FreeBSD 5.3] # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:02/sendfile_5.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:02/sendfile_5.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. VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - ------------------------------------------------------------------------- RELENG_4 src/sys/ufs/ffs/ffs_inode.c 1.56.2.6 RELENG_4_11 src/UPDATING 1.73.2.91.2.3 src/sys/conf/newvers.sh 1.44.2.39.2.6 src/sys/ufs/ffs/ffs_inode.c 1.56.2.5.12.1 RELENG_4_10 src/UPDATING 1.73.2.90.2.8 src/sys/conf/newvers.sh 1.44.2.34.2.8 src/sys/ufs/ffs/ffs_inode.c 1.56.2.5.10.1 RELENG_4_8 src/UPDATING 1.73.2.80.2.33 src/sys/conf/newvers.sh 1.44.2.29.2.29 src/sys/ufs/ffs/ffs_inode.c 1.56.2.5.6.1 RELENG_5 src/sys/ufs/ffs/ffs_inode.c 1.93.2.2 RELENG_5_4 src/UPDATING 1.342.2.24.2.1 src/sys/ufs/ffs/ffs_inode.c 1.93.2.1.2.1 RELENG_5_3 src/UPDATING 1.342.2.13.2.10 src/sys/conf/newvers.sh 1.62.2.15.2.12 src/sys/ufs/ffs/ffs_inode.c 1.93.4.1 - - ------------------------------------------------------------------------- The latest revision of this advisory is available at ftp://ftp.freebsd.org/pub/CERT/advisories/FreeBSD-SA-05:02.sendfile.asc - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFCUdSBFdaIBMps37IRAkJQAJ9jiw22zHygE8ui8ksl3T5jo12L6gCgkq5i CYhVGcVxiWOU9Yu1Muwi1Xw= =83NE - -----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 iQCVAwUBQlHuqCh9+71yA2DNAQKU/gP/dvG7lpPICwiNvXDitIG+xwHidxFeuvyH jQuA3oqlLyD9fp+rgp2M8Dw8s29eLPTed2PnDs31t13MgYA4ZxZ9Aq2VMXrEKi/d zFqBXXsnDfPvp3XcG6HjSyNIiBmE3dby5V5iEivYchlIUe4KnUgLuCgmD87dR5Ln 5JI4rRxFyIw= =s5XI -----END PGP SIGNATURE-----