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Gentoo Linux Security Advisory GLSA 200408-24

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                                         http://security.gentoo.org/

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Severity: Normal
Title: Linux Kernel: Multiple information leaks
Date: August 25, 2004
Bugs: #59378, #59905, #59769
ID: 200408-24

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Synopsis

Multiple information leaks have been found in the Linux kernel,
allowing an attacker to obtain sensitive data which may be used for
further exploitation of the system.

Background

The Linux kernel is responsible for managing the core aspects of a
GNU/Linux system, providing an interface for core system applications
as well as providing the essential structure and capability to access
hardware that is needed for a running system.

Affected packages

 -------------------------------------------------------------------
  Kernel                 /      Unaffected      /           Remerge
 -------------------------------------------------------------------

1 aa-sources … *>= 2.4.23-r2 … YES
… >= 2.6.5-r5 … YES
2 alpha-sources … >= 2.4.21-r12 …
3 ck-sources … *>= 2.4.26-r1 … YES
… >= 2.6.7-r5 … YES
4 development-sources … >= 2.6.8 …
5 gentoo-dev-sources … >= 2.6.7-r12 …
6 gentoo-sources … *>= 2.4.19-r22 …
… *>= 2.4.20-r25 …
… *>= 2.4.22-r16 …
… *>= 2.4.25-r9 …
… >= 2.4.26-r9 …
7 grsec-sources … >= 2.4.27.2.0.1-r1 …
8 gs-sources … >= 2.4.25_pre7-r11 …
9 hardened-dev-sources … >= 2.6.7-r7 …
10 hardened-sources … >= 2.4.27-r1 …
11 hppa-dev-sources … >= 2.6.7_p14-r1 …
12 hppa-sources … >= 2.4.26_p7-r1 … YES
13 ia64-sources … >= 2.4.24-r10 …
14 mips-sources … *>= 2.4.25-r8 …
… *>= 2.4.26-r8 …
… *>= 2.6.4-r8 …
… *>= 2.6.6-r8 …
… >= 2.6.7-r5 …
15 mm-sources … >= 2.6.8_rc4-r1 …
16 openmosix-sources … >= 2.4.24-r4 …
17 pac-sources … >= 2.4.23-r12 …
18 pegasos-dev-sources … >= 2.6.8 …
19 rsbac-sources … >= 2.4.26-r5 …
20 rsbac-dev-sources … >= 2.6.7-r5 …
21 selinux-sources … >= 2.4.26-r3 …
22 sparc-sources … >= 2.4.27-r1 …
23 uclinux-sources … *>= 2.4.26_p0-r6 …
… >= 2.6.7_p0-r5 …
24 usermode-sources … *>= 2.4.24-r9 …
… *>= 2.4.26-r6 …
… >= 2.6.6-r6 …
25 vanilla-sources … >= 2.4.27 …
26 vserver-sources … >= 2.4.26.1.28-r4 …
27 win4lin-sources … *>= 2.4.26-r6 …
… >= 2.6.7-r2 …
28 wolk-sources … *>= 4.9-r14 …
… *>= 4.11-r10 …
… >= 4.14-r7 …
29 xbox-sources … *>= 2.4.27-r1 …
… >= 2.6.7-r5 …
-------------------------------------------------------------------
NOTE: Packages marked with "Remerge" as "YES" require a re-merge
even though Portage does not indicate a newer version!
-------------------------------------------------------------------
29 affected packages on all of their supported architectures.
-------------------------------------------------------------------

Description

The Linux kernel allows a local attacker to obtain sensitive kernel
information by gaining access to kernel memory via several leaks in the
/proc interfaces. These vulnerabilities exist in various drivers which
make up a working Linux kernel, some of which are present across all
architectures and configurations.

CAN-2004-0415 deals with addressing invalid 32 to 64 bit conversions in
the kernel, as well as insecure direct access to file offset pointers
in kernel code which can be modified by the open(…), lseek(…) and
other core system I/O functions by an attacker.

CAN-2004-0685 deals with certain USB drivers using uninitialized
structures and then using the copy_to_user(…) kernel call to copy
these structures. This may leak uninitialized kernel memory, which can
contain sensitive information from user applications.

Finally, a race condition with the /proc/…/cmdline node was found,
allowing environment variables to be read while the process was still
spawning. If the race is won, environment variables of the process,
which might not be owned by the attacker, can be read.

Impact

These vulnerabilities allow a local unprivileged attacker to access
segments of kernel memory or environment variables which may contain
sensitive information. Kernel memory may contain passwords, data
transferred between processes, any memory which applications did not
clear upon exiting as well as the kernel cache and kernel buffers.

This information may be used to read sensitive data, open other attack
vectors for further exploitation or cause a Denial of Service if the
attacker can gain superuser access via the leaked information.

Workaround

There is no temporary workaround for any of these information leaks
other than totally disabling /proc support - otherwise, a kernel
upgrade is required. A list of unaffected kernels is provided along
with this announcement.

Resolution

Users are encouraged to upgrade to the latest available sources for
their system:

 # emerge sync
 # emerge -pv your-favorite-sources
 # emerge your-favorite-sources

 # # Follow usual procedure for compiling and installing a kernel.
 # # If you use genkernel, run genkernel as you would normally.

References

[ 1 ] CAN-2004-0415
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0415
[ 2 ] CAN-2004-0685
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0685

Availability

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

http://security.gentoo.org/glsa/glsa-200408-24.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
[email protected] or alternatively, you may file a bug at
http://bugs.gentoo.org.

License

Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/1.0