CVE-2019-13272

In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c
mishandles the recording of the credentials of a process that wants to
create a ptrace relationship, which allows local users to obtain root
access by leveraging certain scenarios with a parent-child process
relationship, where a parent drops privileges and calls execve (potentially
allowing control by an attacker). One contributing factor is an object
lifetime issue (which can also cause a panic). Another contributing factor
is incorrect marking of a ptrace relationship as privileged, which is
exploitable through (for example) Polkit’s pkexec helper with
PTRACE_TRACEME. NOTE: SELinux deny_ptrace might be a usable workaround in
some environments.

Bugs

• <https://bugs.chromium.org/p/project-zero/issues/detail?id=1903&gt;
• <https://bugzilla.redhat.com/show_bug.cgi?id=1730895&gt;
• <https://bugzilla.suse.com/show_bug.cgi?id=1140671&gt;