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authorEric W. Biederman <ebiederm@xmission.com>2015-05-08 23:22:29 -0500
committerEric W. Biederman <ebiederm@xmission.com>2015-05-13 21:44:11 -0500
commit1b852bceb0d111e510d1a15826ecc4a19358d512 (patch)
treeb7a6b015d68f3ad25f79d7197690a29e08f0e21c /fs/sysfs
parent7e96c1b0e0f495c5a7450dc4aa7c9a24ba4305bd (diff)
downloadlwn-1b852bceb0d111e510d1a15826ecc4a19358d512.tar.gz
lwn-1b852bceb0d111e510d1a15826ecc4a19358d512.zip
mnt: Refactor the logic for mounting sysfs and proc in a user namespace
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>
Diffstat (limited to 'fs/sysfs')
-rw-r--r--fs/sysfs/mount.c5
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)