From: Gao feng <gaofeng@cn.fujitsu.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Linux Containers <containers@lists.linux-foundation.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH review 6/6] userns: Allow the userns root to mount tmpfs.
Date: Mon, 28 Jan 2013 09:28:03 +0800 [thread overview]
Message-ID: <5105D423.9080909@cn.fujitsu.com> (raw)
In-Reply-To: <87d2wshe6v.fsf@xmission.com>
On 2013/01/26 10:26, Eric W. Biederman wrote:
>
> There is no backing store to tmpfs and file creation rules are the
> same as for any other filesystem so it is semantically safe to allow
> unprivileged users to mount it. ramfs is safe for the same reasons so
> allow either flavor of tmpfs to be mounted by a user namespace root
> user.
>
> The memory control group successfully limits how much memory tmpfs can
> consume on any system that cares about a user namespace root using
> tmpfs to exhaust memory the memory control group can be deployed.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
useful to me,thanks Eric & Serge.
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
> mm/shmem.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 5c90d84..197ca5e 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2766,6 +2766,7 @@ static struct file_system_type shmem_fs_type = {
> .name = "tmpfs",
> .mount = shmem_mount,
> .kill_sb = kill_litter_super,
> + .fs_flags = FS_USERNS_MOUNT,
> };
>
> int __init shmem_init(void)
> @@ -2823,6 +2824,7 @@ static struct file_system_type shmem_fs_type = {
> .name = "tmpfs",
> .mount = ramfs_mount,
> .kill_sb = kill_litter_super,
> + .fs_flags = FS_USERNS_MOUNT,
> };
>
> int __init shmem_init(void)
>
prev parent reply other threads:[~2013-01-28 1:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-26 2:15 [PATCH review 0/6] miscelaneous user namespace patches Eric W. Biederman
2013-01-26 2:19 ` [PATCH review 1/6] userns: Avoid recursion in put_user_ns Eric W. Biederman
2013-01-26 20:58 ` Serge E. Hallyn
2013-01-28 14:51 ` Vasily Kulikov
2013-01-28 16:34 ` Eric W. Biederman
2013-01-26 2:21 ` [PATCH review 2/6] userns: Allow any uid or gid mappings that don't overlap Eric W. Biederman
2013-01-26 21:08 ` Serge E. Hallyn
2013-01-28 14:28 ` Aristeu Rozanski
2013-01-28 14:41 ` Lord Glauber Costa of Sealand
2013-01-28 15:12 ` Aristeu Rozanski
2013-01-26 2:22 ` [PATCH review 3/6] userns: Recommend use of memory control groups Eric W. Biederman
2013-01-26 21:13 ` Serge E. Hallyn
2013-01-27 6:19 ` Eric W. Biederman
2013-01-28 7:37 ` Lord Glauber Costa of Sealand
2013-01-28 7:50 ` Lord Glauber Costa of Sealand
2013-01-28 8:14 ` Eric W. Biederman
2013-01-28 8:22 ` Lord Glauber Costa of Sealand
2013-01-28 16:19 ` Eric W. Biederman
2013-01-28 16:37 ` Lord Glauber Costa of Sealand
2013-01-28 17:18 ` Eric W. Biederman
2013-01-28 8:05 ` Eric W. Biederman
2013-01-26 2:23 ` [PATCH review 4/6] userns: Allow the userns root to mount of devpts Eric W. Biederman
2013-01-26 21:22 ` Serge E. Hallyn
2013-01-26 2:26 ` [PATCH review 5/6] userns: Allow the userns root to mount ramfs Eric W. Biederman
2013-01-26 21:29 ` Serge E. Hallyn
2013-01-27 6:09 ` Eric W. Biederman
2013-01-27 18:23 ` Serge E. Hallyn
2013-01-27 18:23 ` Serge E. Hallyn
2013-01-26 2:26 ` [PATCH review 6/6] userns: Allow the userns root to mount tmpfs Eric W. Biederman
2013-01-27 18:23 ` Serge E. Hallyn
2013-01-28 1:28 ` Gao feng [this message]
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