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authorEric W. Biederman <ebiederm@xmission.com>2015-05-09 07:22:29 +0300
committerEric W. Biederman <ebiederm@xmission.com>2015-05-14 05:44:11 +0300
commit1b852bceb0d111e510d1a15826ecc4a19358d512 (patch)
treeb7a6b015d68f3ad25f79d7197690a29e08f0e21c /fs/proc/root.c
parent7e96c1b0e0f495c5a7450dc4aa7c9a24ba4305bd (diff)
downloadlinux-1b852bceb0d111e510d1a15826ecc4a19358d512.tar.xz
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/proc/root.c')
-rw-r--r--fs/proc/root.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/fs/proc/root.c b/fs/proc/root.c
index b7fa4bfe896a..64e1ab64bde6 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -112,9 +112,6 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
ns = task_active_pid_ns(current);
options = data;
- if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
- return ERR_PTR(-EPERM);
-
/* Does the mounter have privilege over the pid namespace? */
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
@@ -159,7 +156,7 @@ static struct file_system_type proc_fs_type = {
.name = "proc",
.mount = proc_mount,
.kill_sb = proc_kill_sb,
- .fs_flags = FS_USERNS_MOUNT,
+ .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT,
};
void __init proc_root_init(void)