diff options
| author | Daniel P. Berrange <berrange@redhat.com> | 2012-08-03 11:53:04 +0100 |
|---|---|---|
| committer | John Rigby <john.rigby@linaro.org> | 2012-08-15 23:46:27 -0600 |
| commit | eb219cfe47a1cf60f1f31a55f7ddff0e9b94dd3e (patch) | |
| tree | c9906e3dbbd715e26eda34382dbea1506c26974b | |
| parent | 95dcb28bfe9bff9e970a4d0ab2a72546df51e8c6 (diff) | |
UBUNTU: SAUCE: (drop after 3.6) Forbid invocation of kexec_load() outside initial PID namespace
BugLink: http://bugs.launchpad.net/bugs/1034125
The following commit
commit cf3f89214ef6a33fad60856bc5ffd7bb2fc4709b
Author: Daniel Lezcano <daniel.lezcano@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@redhat.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
| -rw-r--r-- | kernel/kexec.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c index 0668d58d641..b152bdefcb8 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -947,6 +947,11 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, if (!capable(CAP_SYS_BOOT)) return -EPERM; + /* Processes in containers must not be allowed to load a new + * kernel, even if they have CAP_SYS_BOOT */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EPERM; + /* * Verify we have a legal set of flags * This leaves us room for future extensions. |