CVE-2022-47952

lxc-user-nic in lxc through 5.0.1 is installed setuid root, and may allow
local users to infer whether any file exists, even within a protected
directory tree, because “Failed to open” often indicates that a file does
not exist, whereas “does not refer to a network namespace path” often
indicates that a file exists. NOTE: this is different from CVE-2018-6556
because the CVE-2018-6556 fix design was based on the premise that “we will
report back to the user that the open() failed but the user has no way of
knowing why it failed”; however, in many realistic cases, there are no
plausible reasons for failing except that the file does not exist.

Bugs

• <https://bugzilla.redhat.com/show_bug.cgi?id=2157281&gt;
• <https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1783591/comments/45&gt;