@@ -2141,6 +2141,8 @@ unlock:
return err;
}
+static bool fs_fully_visible(struct file_system_type *fs_type);
+
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
@@ -2172,6 +2174,10 @@ static int do_new_mount(struct path *path, const char *fstype, int flags,
flags |= MS_NODEV;
mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV;
}
+ if (type->fs_flags & FS_USERNS_VISIBLE) {
+ if (!fs_fully_visible(type))
+ return -EPERM;
+ }
}
mnt = vfs_kern_mount(type, flags, name, data);
@@ -2990,7 +2996,7 @@ bool current_chrooted(void)
return chrooted;
}
-bool fs_fully_visible(struct file_system_type *type)
+static bool fs_fully_visible(struct file_system_type *type)
{
struct mnt_namespace *ns = current->nsproxy->mnt_ns;
struct mount *mnt;
@@ -110,9 +110,6 @@ 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);
@@ -155,7 +152,7 @@ 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)
@@ -113,9 +113,6 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
int error;
if (!(flags & MS_KERNMOUNT)) {
- if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
- return ERR_PTR(-EPERM);
-
for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) {
if (!kobj_ns_current_may_mount(type))
return ERR_PTR(-EPERM);
@@ -160,7 +157,7 @@ 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)
@@ -1815,6 +1815,7 @@ struct file_system_type {
#define FS_HAS_SUBTYPE 4
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
#define FS_USERNS_DEV_MOUNT 16 /* A userns mount does not imply MNT_NODEV */
+#define FS_USERNS_VISIBLE 32 /* FS must already be visible */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);
@@ -1901,7 +1902,6 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
extern int freeze_super(struct super_block *super);
extern int thaw_super(struct super_block *super);
extern bool our_mnt(struct vfsmount *mnt);
-extern bool fs_fully_visible(struct file_system_type *);
extern int current_umask(void);