Bug 499541 - kernel: proc: avoid information leaks to non-privileged processes [rhel-5.4]
kernel: proc: avoid information leaks to non-privileged processes [rhel-5.4]
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
urgent Severity high
: rc
: ---
Assigned To: Cong Wang
Red Hat Kernel QE team
: ZStream
Depends On:
Blocks: 499546 499548 499549 499550
  Show dependency treegraph
Reported: 2009-05-07 02:04 EDT by Eugene Teo (Security Response)
Modified: 2013-09-29 22:08 EDT (History)
11 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 499546 499548 499549 499550 (view as bug list)
Last Closed: 2009-09-02 04:02:33 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
Upstream patch (3.30 KB, patch)
2009-05-07 02:09 EDT, Eugene Teo (Security Response)
no flags Details | Diff

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2009:1243 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 5.4 kernel security and bug fix update 2009-09-01 04:53:34 EDT

  None (edit)
Description Eugene Teo (Security Response) 2009-05-07 02:04:16 EDT
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
Comment 1 Eugene Teo (Security Response) 2009-05-07 02:09:48 EDT
Created attachment 342773 [details]
Upstream patch
Comment 3 RHEL Product and Program Management 2009-05-11 16:59:36 EDT
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
Comment 5 Don Zickus 2009-06-04 12:07:28 EDT
in kernel-2.6.18-152.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.
Comment 9 errata-xmlrpc 2009-09-02 04:02:33 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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