Bug 499549 - kernel: proc: avoid information leaks to non-privileged processes [rhel-4.8.z]
kernel: proc: avoid information leaks to non-privileged processes [rhel-4.8.z]
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
high Severity high
: rc
: ---
Assigned To: Vitaly Mayatskikh
Red Hat Kernel QE team
: ZStream
Depends On: 499541
  Show dependency treegraph
Reported: 2009-05-07 02:23 EDT by Eugene Teo (Security Response)
Modified: 2009-06-30 04:06 EDT (History)
7 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 499541
Last Closed: 2009-06-30 04:06:52 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

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Description Eugene Teo (Security Response) 2009-05-07 02:23:52 EDT
+++ 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@redhat.com on 2009-05-07 02:09:48 EDT ---

Created an attachment (id=342773)
Upstream patch
Comment 2 Jiri Olsa 2009-06-15 04:08:09 EDT
Committed in 89.0.3
Comment 6 errata-xmlrpc 2009-06-30 04:06:52 EDT
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.


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