Bug 1312852 - (CVE-2016-2779) CVE-2016-2779 util-linux: runuser tty hijack via TIOCSTI ioctl
CVE-2016-2779 util-linux: runuser tty hijack via TIOCSTI ioctl
Status: POST
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
medium Severity medium
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Assigned To: Red Hat Product Security
impact=moderate,public=20160226,repor...
: Security
Depends On: 1312855
Blocks: 1312867
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Reported: 2016-02-29 06:57 EST by Adam Mariš
Modified: 2017-03-09 20:35 EST (History)
5 users (show)

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Description Adam Mariš 2016-02-29 06:57:29 EST
It was found that when executing a program via "runuser -u nonpriv program" the nonpriv session can escape to the parent session by using the TIOCSTI ioctl to push characters into the terminal's input buffer, allowing privilege escalation. This issue has been fixed in "su" by calling setsid() and in "sudo" by using the "use_pty" flag.

CVE request (contains reproducer):

http://seclists.org/oss-sec/2016/q1/447
Comment 1 Adam Mariš 2016-02-29 06:59:37 EST
Created util-linux tracking bugs for this issue:

Affects: fedora-all [bug 1312855]
Comment 5 Karel Zak 2016-09-29 10:41:23 EDT
Upstream libseccomp based workaround: 

https://github.com/karelzak/util-linux/commit/8e4925016875c6a4f2ab4f833ba66f0fc57396a2

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