Bug 795913 - (CVE-2012-0875) CVE-2012-0875 systemtap: kernel panic when processing malformed DWARF unwind data
CVE-2012-0875 systemtap: kernel panic when processing malformed DWARF unwind ...
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Red Hat Product Security
: Security
Depends On: 796325 796326 796327 796328 796329
Blocks: 795947
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Reported: 2012-02-21 14:36 EST by Vincent Danen
Modified: 2016-11-08 11:15 EST (History)
4 users (show)

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Doc Type: Bug Fix
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Last Closed: 2013-02-28 11:21:22 EST
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Description Vincent Danen 2012-02-21 14:36:26 EST
A flaw was discovered [1] in how systemtap handled DWARF expressions when unwinding the stack.  This could result in an invalid pointer read, leading to reading kernel memory, or a kernel panic (and if the kernel reboot on panic flag was set (panic_on_oops), it would cause the system to reboot).

In order to trigger this flaw, an admin would have to enable unprivileged mode (giving users membership in the 'stapusr' group and configuring the local machine with 'signer,all-users' stap-server trust). If an admin has enabled unprivileged mode, a user with such access could use this to crash the local machine.

A workaround is to disable unprivileged mode.

This will be corrected in a forthcoming upstream release of systemtap, and is currently fixed in git [2].  It is believed that this flaw was introduced via git commit 16d59279f [3], so would affect systemtap >= 1.4.

[1] http://sourceware.org/bugzilla/show_bug.cgi?id=13714
[2] http://sourceware.org/git/?p=systemtap.git;a=commit;h=64b0cff3b
[3] http://sourceware.org/git/?p=systemtap.git;a=commit;h=16d59279f
Comment 2 Vincent Danen 2012-02-22 12:18:08 EST
Created systemtap tracking bugs for this issue

Affects: fedora-all [bug 796329]
Comment 5 errata-xmlrpc 2012-03-08 16:13:58 EST
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5
  Red Hat Enterprise Linux 6

Via RHSA-2012:0376 https://rhn.redhat.com/errata/RHSA-2012-0376.html

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