Bug 499548 - kernel: proc: avoid information leaks to non-privileged processes [rhel-4.9]
Summary: kernel: proc: avoid information leaks to non-privileged processes [rhel-4.9]
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel
Version: 4.9
Hardware: All
OS: Linux
high
high
Target Milestone: rc
: ---
Assignee: Cong Wang
QA Contact: Evan McNabb
URL:
Whiteboard:
Depends On: 499541
Blocks:
TreeView+ depends on / blocked
 
Reported: 2009-05-07 06:19 UTC by Eugene Teo (Security Response)
Modified: 2013-09-30 02:08 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of: 499541
Environment:
Last Closed: 2011-02-16 15:48:11 UTC
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0263 0 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 4.9 kernel security and bug fix update 2011-02-16 15:14:55 UTC

Description Eugene Teo (Security Response) 2009-05-07 06:19:00 UTC
+++ This bug was initially created as a clone of Bug #499541 +++

Description of problem:
By using the same test as is used for /proc/pid/maps and /proc/pid/smaps, only allow processes that can ptrace() a given process to see information that might be used to bypass address space layout randomization (ASLR). These include eip, esp, wchan, and start_stack in /proc/pid/stat as well as the non-symbolic output from /proc/pid/wchan.

ASLR can be bypassed by sampling eip as shown by the proof-of-concept code at http://code.google.com/p/fuzzyaslr/ As part of a presentation (http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were also noted as possibly usable information leaks as well.  The start_stack address also leaks potentially useful information.

Upstream commit: http://git.kernel.org/linus/f83ce3e6b02d5e48b3a43b001390e2b58820389d

--- Additional comment from eteo on 2009-05-07 02:09:48 EDT ---

Created an attachment (id=342773)
Upstream patch

Comment 1 Eugene Teo (Security Response) 2009-05-13 09:23:51 UTC
Wang Cong, remember to change the status after posting the patch to rhkl. Thanks.

Comment 2 Vivek Goyal 2009-06-03 13:57:22 UTC
Committed in 89.2.EL

Comment 5 errata-xmlrpc 2011-02-16 15:48:11 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0263.html


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