[PATCH] Forbid invocation of kexec_load() outside initial PID namespace

richard -rw- weinberger richard.weinberger at gmail.com
Fri Aug 3 11:25:02 UTC 2012

On Fri, Aug 3, 2012 at 12:53 PM, Daniel P. Berrange <berrange at redhat.com> wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
> The following commit
>     commit cf3f89214ef6a33fad60856bc5ffd7bb2fc4709b
>     Author: Daniel Lezcano <daniel.lezcano at free.fr>
>     Date:   Wed Mar 28 14:42:51 2012 -0700
>     pidns: add reboot_pid_ns() to handle the reboot syscall
> introduced custom handling of the reboot() syscall when invoked
> from a non-initial PID namespace. The intent was that a process
> in a container can be allowed to keep CAP_SYS_BOOT and execute
> reboot() to shutdown/reboot just their private container, rather
> than the host.
> Unfortunately the kexec_load() syscall also relies on the
> CAP_SYS_BOOT capability. So by allowing a container to keep
> this capability to safely invoke reboot(), they mistakenly
> also gain the ability to use kexec_load(). The solution is
> to make kexec_load() return -EPERM if invoked from a PID
> namespace that is not the initial namespace
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> Cc: Serge Hallyn <serge.hallyn at canonical.com>
> Cc: Daniel Lezcano <daniel.lezcano at free.fr>
> Cc: Michael Kerrisk <mtk.manpages at gmail.com>
> Cc: "Eric W. Biederman" <ebiederm at xmission.com>
> Cc: Tejun Heo <tj at kernel.org>
> Cc: Oleg Nesterov <oleg at redhat.com>

Why is this commit not marked for -stable?


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