FreeBSD Security Advisories
2009-Oct-02 20:12 UTC
FreeBSD Security Advisory FreeBSD-SA-09:14.devfs
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============================================================================FreeBSD-SA-09:14.devfs
Security Advisory
The FreeBSD Project
Topic: Devfs / VFS NULL pointer race condition
Category: core
Module: kern
Announced: 2009-10-02
Credits: Przemyslaw Frasunek
Affects: FreeBSD 6.x and 7.x
Corrected: 2009-05-18 10:41:59 UTC (RELENG_7, 7.2-STABLE)
2009-10-02 18:09:56 UTC (RELENG_7_2, 7.2-RELEASE-p4)
2009-10-02 18:09:56 UTC (RELENG_7_1, 7.1-RELEASE-p8)
2009-10-02 18:09:56 UTC (RELENG_6, 6.4-STABLE)
2009-10-02 18:09:56 UTC (RELENG_6_4, 6.4-RELEASE-p7)
2009-10-02 18:09:56 UTC (RELENG_6_3, 6.3-RELEASE-p13)
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 device file system (devfs) provides access to system devices, such as
storage devices and serial ports, via the file system namespace.
VFS is the Virtual File System, which abstracts file system operations in
the kernel from the actual underlying file system.
II. Problem Description
Due to the interaction between devfs and VFS, a race condition exists
where the kernel might dereference a NULL pointer.
III. Impact
Successful exploitation of the race condition 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
An errata note, FreeBSD-EN-09:05.null has been released simultaneously to
this advisory, and contains a kernel patch implementing a workaround for a
more broad class of vulnerabilities. However, prior to those changes, no
workaround is available.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 6-STABLE, or 7-STABLE, or to the
RELENG_7_2, RELENG_7_1, RELENG_6_4, or RELENG_6_3 security branch
dated after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 6.3, 6.4,
7.1, and 7.2 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 6.x]
# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch
# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch.asc
[FreeBSD 7.x]
# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.patch
# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.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.
CVS:
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_6
src/sys/fs/devfs/devfs_vnops.c 1.114.2.17
RELENG_6_4
src/UPDATING 1.416.2.40.2.11
src/sys/conf/newvers.sh 1.69.2.18.2.13
src/sys/fs/devfs/devfs_vnops.c 1.114.2.16.2.2
RELENG_6_3
src/UPDATING 1.416.2.37.2.18
src/sys/conf/newvers.sh 1.69.2.15.2.17
src/sys/fs/devfs/devfs_vnops.c 1.114.2.15.2.1
RELENG_7
src/sys/fs/devfs/devfs_vnops.c 1.149.2.9
RELENG_7_2
src/UPDATING 1.507.2.23.2.7
src/sys/conf/newvers.sh 1.72.2.11.2.8
src/sys/fs/devfs/devfs_vnops.c 1.149.2.8.2.2
RELENG_7_1
src/UPDATING 1.507.2.13.2.11
src/sys/conf/newvers.sh 1.72.2.9.2.12
src/sys/fs/devfs/devfs_vnops.c 1.149.2.4.2.2
- -------------------------------------------------------------------------
Subversion:
Branch/path Revision
- -------------------------------------------------------------------------
stable/6/ r197715
releng/6.4/ r197715
releng/6.3/ r197715
stable/7/ r192301
releng/7.2/ r197715
releng/7.1/ r197715
- -------------------------------------------------------------------------
VII. References
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-09:14.devfs.asc
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On Sat, Oct 3, 2009 at 3:12 AM, FreeBSD Security Advisories <security-advisories@freebsd.org> wrote:> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > ============================================================================> FreeBSD-SA-09:14.devfs ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Security Advisory > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?The FreeBSD Project > > Topic: ? ? ? ? ?Devfs / VFS NULL pointer race condition > > Category: ? ? ? core > Module: ? ? ? ? kern > Announced: ? ? ?2009-10-02 > Credits: ? ? ? ?Przemyslaw Frasunek > Affects: ? ? ? ?FreeBSD 6.x and 7.x > Corrected: ? ? ?2009-05-18 10:41:59 UTC (RELENG_7, 7.2-STABLE) > ? ? ? ? ? ? ? ?2009-10-02 18:09:56 UTC (RELENG_7_2, 7.2-RELEASE-p4) > ? ? ? ? ? ? ? ?2009-10-02 18:09:56 UTC (RELENG_7_1, 7.1-RELEASE-p8) > ? ? ? ? ? ? ? ?2009-10-02 18:09:56 UTC (RELENG_6, 6.4-STABLE) > ? ? ? ? ? ? ? ?2009-10-02 18:09:56 UTC (RELENG_6_4, 6.4-RELEASE-p7) > ? ? ? ? ? ? ? ?2009-10-02 18:09:56 UTC (RELENG_6_3, 6.3-RELEASE-p13) > > 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 device file system (devfs) provides access to system devices, such as > storage devices and serial ports, via the file system namespace. > > VFS is the Virtual File System, which abstracts file system operations in > the kernel from the actual underlying file system. > > II. ?Problem Description > > Due to the interaction between devfs and VFS, a race condition exists > where the kernel might dereference a NULL pointer. > > III. Impact > > Successful exploitation of the race condition 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 > > An errata note, FreeBSD-EN-09:05.null has been released simultaneously to > this advisory, and contains a kernel patch implementing a workaround for a > more broad class of vulnerabilities. ?However, prior to those changes, no > workaround is available. > > V. ? Solution > > Perform one of the following: > > 1) Upgrade your vulnerable system to 6-STABLE, or 7-STABLE, or to the > RELENG_7_2, RELENG_7_1, RELENG_6_4, or RELENG_6_3 security branch > dated after the correction date. > > 2) To patch your present system: > > The following patches have been verified to apply to FreeBSD 6.3, 6.4, > 7.1, and 7.2 systems. > > a) Download the relevant patch from the location below, and verify the > detached PGP signature using your PGP utility. > > [FreeBSD 6.x] > # fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch > # fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch.asc > > [FreeBSD 7.x] > # fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.patch > # fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.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. > > CVS: > > Branch ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Revision > ?Path > - ------------------------------------------------------------------------- > RELENG_6 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.114.2.17 > RELENG_6_4 > ?src/UPDATING ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.416.2.40.2.11 > ?src/sys/conf/newvers.sh ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.69.2.18.2.13 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? 1.114.2.16.2.2 > RELENG_6_3 > ?src/UPDATING ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.416.2.37.2.18 > ?src/sys/conf/newvers.sh ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.69.2.15.2.17 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? 1.114.2.15.2.1 > RELENG_7 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.149.2.9 > RELENG_7_2 > ?src/UPDATING ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.507.2.23.2.7 > ?src/sys/conf/newvers.sh ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.72.2.11.2.8 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.149.2.8.2.2 > RELENG_7_1 > ?src/UPDATING ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.507.2.13.2.11 > ?src/sys/conf/newvers.sh ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.72.2.9.2.12 > ?src/sys/fs/devfs/devfs_vnops.c ? ? ? ? ? ? ? ? ? ? ? ? ? ?1.149.2.4.2.2 > - ------------------------------------------------------------------------- > > Subversion: > > Branch/path ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Revision > - ------------------------------------------------------------------------- > stable/6/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r197715 > releng/6.4/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r197715 > releng/6.3/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r197715 > stable/7/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r192301 > releng/7.2/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r197715 > releng/7.1/ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? r197715 > - ------------------------------------------------------------------------- > > VII. References > > The latest revision of this advisory is available at > http://security.FreeBSD.org/advisories/FreeBSD-SA-09:14.devfs.asc > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (FreeBSD) > > iD8DBQFKxltlFdaIBMps37IRAp4zAJwJEwIySGqxH4EXwc0wjkDXlcTb1wCfTltO > Syds53GSM0YbsMNUVMGsLaU> =exPZ > -----END PGP SIGNATURE----- > _______________________________________________ > 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" >Hi folks, I just got some problem when compling my kerne. Here we go: rm -f hack.c MAKE=make sh /usr/src/sys/conf/newvers.sh WILLSZPROXY cc -c -O -pipe -std=c99 -g -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual -Wundef -Wno-pointer-sign -fformat-extensions -nostdinc -I. -I/usr/src/sys -I/usr/src/sys/contrib/altq -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -fno-common -finline-limit=8000 --param inline-unit-growth=100 --param large-function-growth=1000 -mno-align-long-strings -mpreferred-stack-boundary=2 -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -ffreestanding -Werror vers.c linking kernel.debug kern_fork.o(.text+0x1d18): In function `fork1': /usr/src/sys/kern/kern_fork.c:737: undefined reference to `knote_fork' *** Error code 1 Stop in /usr/obj/usr/src/sys/WILLSZPROXY. *** Error code 1 Stop in /usr/src. *** Error code 1 Stop in /usr/src. My box running FreeBSD 7.2-STABLE. Thanks in advance. -- budsz