linux-kernel - Re: [PATCH] kernel: allow reboots from user

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <511CD3C4.4030805@free.fr>
Date:	Thu, 14 Feb 2013 13:08:36 +0100
From:	Daniel Lezcano <daniel.lezcano@...e.fr>
To:	Glauber Costa <glommer@...allels.com>
CC:	linux-kernel@...r.kernel.org,
	containers@...ts.linux-foundation.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] kernel: allow reboots from user_ns

On 02/14/2013 12:56 PM, Glauber Costa wrote:
> Reboot support for pid namespaces is already implemented and it works
> well. However, in most containers the tasks will join all namespaces,
> including the now supported user namespace. In that situation, we will
> fail the "capable" test and won't be able to reboot.
>
> The proposed solution is to allow reboots for CAP_SYS_BOOT processes
> in the user namespace that owns the pid namespace.
>
> Signed-off-by: Glauber Costa <glommer@...allels.com>
> Cc: Eric W. Biederman <ebiederm@...ssion.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> ---
Acked-by: Daniel Lezcano <daniel.lezcano@...e.fr>

>  kernel/sys.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sys.c b/kernel/sys.c
> index 265b376..3b0958e 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -435,9 +435,10 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
>  {
>  	char buffer[256];
>  	int ret = 0;
> +	struct pid_namespace *curr_pidns = task_active_pid_ns(current);
>  
>  	/* We only trust the superuser with rebooting the system. */
> -	if (!capable(CAP_SYS_BOOT))
> +	if (!ns_capable(curr_pidns->user_ns, CAP_SYS_BOOT))
>  		return -EPERM;
>  
>  	/* For safety, we require "magic" arguments. */
> @@ -453,7 +454,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
>  	 * pid_namespace, the command is handled by reboot_pid_ns() which will
>  	 * call do_exit().
>  	 */
> -	ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
> +	ret = reboot_pid_ns(curr_pidns, cmd);
>  	if (ret)
>  		return ret;
>  

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/