[Devel] [PATCH rh7] fs: Allow to mount ext4 and binfmt_misc under non-root user ns

[Andrey Wagin]

2015-10-02 20:26 GMT+03:00 Kirill Tkhai <ktkhai at odin.com>:
> https://jira.sw.ru/browse/PSBM-40100

We can allow to mount these file systems only if we are in the ve's userns.
A non-root user in a container can create a new userns, but he should
not be able to mount ext4, doesn't he?

>
> Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
> ---
>  fs/binfmt_misc.c |    2 +-
>  fs/ext4/super.c  |    3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
> index 90c306e..2be9b62 100644
> --- a/fs/binfmt_misc.c
> +++ b/fs/binfmt_misc.c
> @@ -748,7 +748,7 @@ static struct file_system_type bm_fs_type = {
>         .name           = "binfmt_misc",
>         .mount          = bm_mount,
>         .kill_sb        = kill_litter_super,
> -       .fs_flags       = FS_VIRTUALIZED,
> +       .fs_flags       = FS_VIRTUALIZED | FS_USERNS_MOUNT,
>  };
>  MODULE_ALIAS_FS("binfmt_misc");
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 5209777..2193000 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5727,7 +5727,8 @@ static struct file_system_type ext4_fs_type = {
>         .mount          = ext4_mount,
>         .kill_sb        = ext4_kill_sb,
>         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_INVALIDATE_RANGE |
> -                         FS_VIRTUALIZED | FS_HAS_MMAP_PREP,
> +                         FS_VIRTUALIZED | FS_HAS_MMAP_PREP | FS_USERNS_MOUNT |
> +                         FS_USERNS_DEV_MOUNT,
>  };
>  MODULE_ALIAS_FS("ext4");
>
>
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