-----BEGIN PGP SIGNED MESSAGE----- NetBSD Security Advisory 2001-016 ================================= Topic: unsafe chdir usage in fts(3) Version: All NetBSD releases prior to July 9, 2001. Severity: Local users can trick processes that walk file system trees to perform their actions in the wrong location. Fixed: NetBSD-current: July 9, 2001 NetBSD-1.5 branch: August 22, 2001 (1.5.2 includes the fix) Abstract ======== The fts(3) functions can be tricked by a rogue user into performing actions on incorrect file system hierarchies. Technical Details ================= The macro for chdir used in libc/gen/fts (__fts13.c after NetBSD 1.3) did not perform sufficient safety checks. If any directory (or symlink to a directory) above the current directory fts was processing was moved, the fts-using application could be made to descend the wrong directory sub-tree, and/or ascend above the original starting directory. Once it has ascended above the starting directory, the process could descend into an unintended file system hierarchy. This is particularly dangerous when combined with automated scripts which run programs such as 'rm -r'. Solutions and Workarounds ========================= The following instructions describe how to upgrade your C library and affected statically linked system binaries by updating your source tree and rebuilding and installing a new version of the C library and affected binaries. * NetBSD-current: Systems running NetBSD-current dated from before 2001-06-09 should be upgraded to NetBSD-current dated 2001-06-10 or later. The following directory needs to be updated from the netbsd-current CVS branch (aka HEAD): src/lib/libc To update from CVS, re-build, and re-install libc: # cd /usr/src/lib/libc # cvs update -d -P # make cleandir dependall install Alternatively, apply the following patch (with potential offset differences) and rebuild & re-install libc: ftp://ftp.netbsd.org/pub/NetBSD/security/patches/SA2001-016-fts.patch To patch, re-build and re-install libc: # cd /usr/src # patch < /path/to/SA2001-016-fts.patch # make cleandir dependall install The following static binaries must also be rebuilt for the fix to be complete: /bin/chmod /bin/cp /bin/ksh /bin/ls /bin/pax /bin/rm /sbin/dump /sbin/dump_lfs * NetBSD 1.5, 1.5.1: Systems running NetBSD releases up to and including 1.5.1 should apply the following patch (with potential offset differences): ftp://ftp.netbsd.org/pub/NetBSD/security/patches/SA2001-016-fts-1.5.patch To patch, re-build and re-install libc # cd /usr/src # patch < /path/to/SA2001-016-fts.patch # make cleandir dependall install The following static binaries must also be rebuilt for the fix to be complete: /bin/chmod /bin/cp /bin/ksh /bin/ls /bin/pax /bin/rm /sbin/dump /sbin/dump_lfs Systems running releases older than NetBSD 1.5 should be upgraded to NetBSD 1.5.1 before applying the fixes described here. Thanks To ========= Kris Kennaway for initial notification of the issue. Christos Zoulas for patches, inspired by Todd C. Miller, and for clarification of the descriptions in this advisory. Revision History ================ 2001-09-06 Initial release More Information ================ An up-to-date PGP signed copy of this release will be maintained at ftp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2001-016.txt.asc Information about NetBSD and NetBSD security can be found at http://www.NetBSD.ORG/ and http://www.NetBSD.ORG/Security/. Copyright 2001, The NetBSD Foundation, Inc. All Rights Reserved. $NetBSD: NetBSD-SA2001-016.txt,v 1.11 2001/09/06 15:40:50 lukem Exp $ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (NetBSD) Comment: For info see http://www.gnupg.org iQCVAwUBO5eZIj5Ru2/4N2IFAQG7WAP+MDviy39gwuXdaUdYtPvpPULDsD/Euh6e OUbJIZDykDAwS/w8NSa+vlS3+PJmaWPl1FW0uYTnjWAyfS6A3HGozS45QrXCRhj+ f7yrqp24SaIYOG6/eNRg0J9Ekm53DzN6BsBWveFCS/P/oaji7JT7UC7A3mtzn9et 5zg8cBYPLxs= =RvHM -----END PGP SIGNATURE-----
This archive was generated by hypermail 2b30 : Thu Sep 06 2001 - 11:10:37 PDT