SecurityTracker.com
Keep Track of the Latest Vulnerabilities
with SecurityTracker!
    Home    |    View Topics    |    Search    |    Contact Us    |   

SecurityTracker
Archives


 
Sign Up
Sign Up for Your FREE Weekly SecurityTracker E-mail Alert Summary
Instant Alerts
Buy our Premium Vulnerability Notification Service to receive customized, instant alerts
Affiliates
Put SecurityTracker Vulnerability Alerts on Your Web Site -- It's Free!
Partners
Become a Partner and License Our Database or Notification Service
Report a Bug
Report a vulnerability that you have found to SecurityTracker
bugs
@
securitytracker.com






Category:   OS (UNIX)  >   FreeBSD Kernel Vendors:   FreeBSD
FreeBSD Kernel Integer Overflow in Pipe Implementation Lets Local Users Read System Memory
SecurityTracker Alert ID:  1022365
SecurityTracker URL:  http://securitytracker.com/id/1022365
CVE Reference:   CVE-2009-1935   (Links to External Site)
Updated:  Jun 23 2009
Original Entry Date:  Jun 10 2009
Impact:   Disclosure of system information, Disclosure of user information
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): 6.3, 6.4, 7.1, 7.2
Description:   A vulnerability was reported in FreeBSD. A local user can view portions of system memory.

A local user can trigger an integer overflow in the pipe implementation to read pages of memory of other processes or of the kernel.

Pieter de Boer reported this vulnerability.

Impact:   A local user can obtain potentially sensitive information from system memory.
Solution:   The vendor has issued a fix and has provided the following solution instructions [quoted]:

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.

# fetch http://security.FreeBSD.org/patches/SA-09:09/pipe.patch
# fetch http://security.FreeBSD.org/patches/SA-09:09/pipe.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.

The vendor's advisory is available at:

http://security.FreeBSD.org/advisories/FreeBSD-SA-09:09.pipe.asc

Vendor URL:  security.FreeBSD.org/advisories/FreeBSD-SA-09:09.pipe.asc (Links to External Site)
Cause:   Boundary error
Underlying OS:  

Message History:   None.


 Source Message Contents

Date:  Wed, 10 Jun 2009 10:41:54 GMT
Subject:  FreeBSD Security Advisory FreeBSD-SA-09:09.pipe

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

=============================================================================
FreeBSD-SA-09:09.pipe                                       Security Advisory
                                                          The FreeBSD Project

Topic:          Local information disclosure via direct pipe writes

Category:       core
Module:         kern
Announced:      2009-06-10
Credits:        Pieter de Boer
Affects:        All supported versions of FreeBSD.
Corrected:      2009-06-10 10:31:11 UTC (RELENG_7, 7.2-STABLE)
                2009-06-10 10:31:11 UTC (RELENG_7_2, 7.2-RELEASE-p1)
                2009-06-10 10:31:11 UTC (RELENG_7_1, 7.1-RELEASE-p6)
                2009-06-10 10:31:11 UTC (RELENG_6, 6.4-STABLE)
                2009-06-10 10:31:11 UTC (RELENG_6_4, 6.4-RELEASE-p5)
                2009-06-10 10:31:11 UTC (RELENG_6_3, 6.3-RELEASE-p11)

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

One of the most commonly used forms of interprocess communication on
FreeBSD and other UNIX-like systems is the (anonymous) pipe.  In this
mechanism, a pair of file descriptors is created, and data written to
one descriptor can be read from the other.

FreeBSD's pipe implementation contains an optimization known as "direct
writes".  In this optimization, rather than copying data into kernel
memory when the write(2) system call is invoked and then copying the
data again when the read(2) system call is invoked, the FreeBSD kernel
takes advantage of virtual memory mapping to allow the data to be copied
directly between processes.

II.  Problem Description

An integer overflow in computing the set of pages containing data to be
copied can result in virtual-to-physical address lookups not being
performed.

III. Impact

An unprivileged process can read pages of memory which belong to other
processes or to the kernel.  These may contain information which is
sensitive in itself; or may contain passwords or cryptographic keys
which can be indirectly exploited to gain sensitive information or
access.

IV.  Workaround

No workaround is available, but systems without untrusted local users
are not vulnerable.  System administrators are reminded that even if a
system is not intended to have untrusted local users, it may be possible
for an attacker to exploit some other vulnerability to obtain local user
access to a system.

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.

# fetch http://security.FreeBSD.org/patches/SA-09:09/pipe.patch
# fetch http://security.FreeBSD.org/patches/SA-09:09/pipe.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/kern/sys_pipe.c                                       1.184.2.5
RELENG_6_4
  src/UPDATING                                             1.416.2.40.2.9
  src/sys/conf/newvers.sh                                  1.69.2.18.2.11
  src/sys/kern/sys_pipe.c                                   1.184.2.4.2.2
RELENG_6_3
  src/UPDATING                                            1.416.2.37.2.16
  src/sys/conf/newvers.sh                                  1.69.2.15.2.15
  src/sys/kern/sys_pipe.c                                   1.184.2.2.6.2
RELENG_7
  src/sys/kern/sys_pipe.c                                       1.191.2.5
RELENG_7_2
  src/UPDATING                                             1.507.2.23.2.4
  src/sys/conf/newvers.sh                                   1.72.2.11.2.5
  src/sys/kern/sys_pipe.c                                   1.191.2.3.4.2
RELENG_7_1
  src/UPDATING                                             1.507.2.13.2.9
  src/sys/conf/newvers.sh                                   1.72.2.9.2.10
  src/sys/kern/sys_pipe.c                                   1.191.2.3.2.2
- -------------------------------------------------------------------------

Subversion:

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/6/                                                         r193893
releng/6.4/                                                       r193893
releng/6.3/                                                       r193893
stable/7/                                                         r193893
releng/7.2/                                                       r193893
releng/7.1/                                                       r193893
- -------------------------------------------------------------------------

VII. References

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-09:09.pipe.asc
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (FreeBSD)

iEYEARECAAYFAkovjN0ACgkQFdaIBMps37JkXwCgmLcEMOMAEIXRoJ220zwZhMKn
f+gAn1bZyLMhfZU7TI0xxhizwetDwMVI
=J37B
-----END PGP SIGNATURE-----

 
 


Go to the Top of This SecurityTracker Archive Page





Home   |    View Topics   |    Search   |    Contact Us

Copyright 2014, SecurityGlobal.net LLC