Bug 1267844 - (CVE-2015-1335) CVE-2015-1335 lxc: Directory traversal flaw when lxc-start is initially setting up the mounts for a container
CVE-2015-1335 lxc: Directory traversal flaw when lxc-start is initially setti...
Status: NEW
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=20150929,repor...
: Security
Depends On: 1267845 1267846 1267847
Blocks:
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Reported: 2015-10-01 04:40 EDT by Adam Mariš
Modified: 2015-11-11 19:48 EST (History)
5 users (show)

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Description Adam Mariš 2015-10-01 04:40:09 EDT
Directory traversal flaw was found in lxc.
As reported in http://seclists.org/oss-sec/2015/q3/648 :

"If an attacker constructs a malicious symlink in the target path of a container mount point, the symlink could be mishandled the next time the container is started and the mount operation may be performed at an undesired target location.

Additionally, if the source path of the mount is a malicious symlink relative to the container, the symlink could be mishandled to bind mount an undesired file or directory into the container.

Direct modification of the host's mount table is not possible since a slave copy of the mount table is used.

An example of an attack that is made possible by this flaw is a user inside of the container could leave behind a malicious symlink, at a mount point target under their control, that would cause /proc/self/attr to be mounted over. lxc-start would then unknowingly write to a "fake" /proc/self/attr/current file, prior to launching the container init, to perform an AppArmor profile transition. The profile transition would not occur and the container init would run under incorrect confinement."

Upstream patch:

https://github.com/lxc/lxc/commit/592fd47a6245508b79fe6ac819fe6d3b2c1289be
Comment 1 Adam Mariš 2015-10-01 04:40:53 EDT
Created lxc tracking bugs for this issue:

Affects: fedora-all [bug 1267845]
Affects: epel-6 [bug 1267846]
Affects: epel-7 [bug 1267847]
Comment 2 Fedora Update System 2015-10-31 22:30:47 EDT
lxc-1.1.4-2.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
Comment 3 Fedora Update System 2015-11-11 13:22:30 EST
lxc-1.0.7-4.el7 has been pushed to the Fedora EPEL 7 stable repository. If problems still persist, please make note of it in this bug report.
Comment 4 Fedora Update System 2015-11-11 13:55:03 EST
lxc-1.0.7-4.el6 has been pushed to the Fedora EPEL 6 stable repository. If problems still persist, please make note of it in this bug report.
Comment 5 Fedora Update System 2015-11-11 19:21:01 EST
lxc-1.1.4-2.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
Comment 6 Fedora Update System 2015-11-11 19:48:46 EST
lxc-1.0.7-4.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.

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