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| author | Eric W. Biederman <ebiederm@xmission.com> | 2015-05-08 23:22:29 -0500 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-07-12 09:49:24 -0400 |
| commit | 78ee73651f6e3f0b53ca6e00615c2ca43a57174e (patch) | |
| tree | 70b5f457655866b2bf20d5152e777985c02f790a /fs/sysfs | |
| parent | 866cebe251f4fb2b435f4ecfe6d3bb4025938533 (diff) | |
| download | lwn-78ee73651f6e3f0b53ca6e00615c2ca43a57174e.tar.gz lwn-78ee73651f6e3f0b53ca6e00615c2ca43a57174e.zip | |
mnt: Refactor the logic for mounting sysfs and proc in a user namespace
[ Upstream commit 1b852bceb0d111e510d1a15826ecc4a19358d512 ]
Fresh mounts of proc and sysfs are a very special case that works very
much like a bind mount. Unfortunately the current structure can not
preserve the MNT_LOCK... mount flags. Therefore refactor the logic
into a form that can be modified to preserve those lock bits.
Add a new filesystem flag FS_USERNS_VISIBLE that requires some mount
of the filesystem be fully visible in the current mount namespace,
before the filesystem may be mounted.
Move the logic for calling fs_fully_visible from proc and sysfs into
fs/namespace.c where it has greater access to mount namespace state.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/mount.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 8a49486bf30c..1c6ac6fcee9f 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -31,9 +31,6 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, bool new_sb; if (!(flags & MS_KERNMOUNT)) { - if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type)) - return ERR_PTR(-EPERM); - if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) return ERR_PTR(-EPERM); } @@ -58,7 +55,7 @@ static struct file_system_type sysfs_fs_type = { .name = "sysfs", .mount = sysfs_mount, .kill_sb = sysfs_kill_sb, - .fs_flags = FS_USERNS_MOUNT, + .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT, }; int __init sysfs_init(void) |