Merge branch 'timecounter-next'

[cascardo/linux.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 5b66b2b..cd1e968 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -963,7 +963,8 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
        }
 
        /* Don't allow unprivileged users to reveal what is under a mount */
-       if ((flag & CL_UNPRIVILEGED) && list_empty(&old->mnt_expire))
+       if ((flag & CL_UNPRIVILEGED) &&
+           (!(flag & CL_EXPIRE) || list_empty(&old->mnt_expire)))
                mnt->mnt.mnt_flags |= MNT_LOCKED;
 
        atomic_inc(&sb->s_active);
@@ -1369,6 +1370,8 @@ void umount_tree(struct mount *mnt, int how)
        }
        if (last) {
                last->mnt_hash.next = unmounted.first;
+               if (unmounted.first)
+                       unmounted.first->pprev = &last->mnt_hash.next;
                unmounted.first = tmp_list.first;
                unmounted.first->pprev = &unmounted.first;
        }
@@ -1544,6 +1547,9 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
                goto dput_and_out;
        if (mnt->mnt.mnt_flags & MNT_LOCKED)
                goto dput_and_out;
+       retval = -EPERM;
+       if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
+               goto dput_and_out;
 
        retval = do_umount(mnt, flags);
 dput_and_out:
@@ -1569,17 +1575,13 @@ SYSCALL_DEFINE1(oldumount, char __user *, name)
 static bool is_mnt_ns_file(struct dentry *dentry)
 {
        /* Is this a proxy for a mount namespace? */
-       struct inode *inode = dentry->d_inode;
-       struct proc_ns *ei;
-
-       if (!proc_ns_inode(inode))
-               return false;
-
-       ei = get_proc_ns(inode);
-       if (ei->ns_ops != &mntns_operations)
-               return false;
+       return dentry->d_op == &ns_dentry_operations &&
+              dentry->d_fsdata == &mntns_operations;
+}
 
-       return true;
+struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
+{
+       return container_of(ns, struct mnt_namespace, ns);
 }
 
 static bool mnt_ns_loop(struct dentry *dentry)
@@ -1591,7 +1593,7 @@ static bool mnt_ns_loop(struct dentry *dentry)
        if (!is_mnt_ns_file(dentry))
                return false;
 
-       mnt_ns = get_proc_ns(dentry->d_inode)->ns;
+       mnt_ns = to_mnt_ns(get_proc_ns(dentry->d_inode));
        return current->nsproxy->mnt_ns->seq >= mnt_ns->seq;
 }
 
@@ -1610,7 +1612,6 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
        if (IS_ERR(q))
                return q;
 
-       q->mnt.mnt_flags &= ~MNT_LOCKED;
        q->mnt_mountpoint = mnt->mnt_mountpoint;
 
        p = mnt;
@@ -2020,7 +2021,10 @@ static int do_loopback(struct path *path, const char *old_name,
        if (IS_MNT_UNBINDABLE(old))
                goto out2;
 
-       if (!check_mnt(parent) || !check_mnt(old))
+       if (!check_mnt(parent))
+               goto out2;
+
+       if (!check_mnt(old) && old_path.dentry->d_op != &ns_dentry_operations)
                goto out2;
 
        if (!recurse && has_locked_children(old, old_path.dentry))
@@ -2098,7 +2102,13 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
        }
        if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
            !(mnt_flags & MNT_NODEV)) {
-               return -EPERM;
+               /* Was the nodev implicitly added in mount? */
+               if ((mnt->mnt_ns->user_ns != &init_user_ns) &&
+                   !(sb->s_type->fs_flags & FS_USERNS_DEV_MOUNT)) {
+                       mnt_flags |= MNT_NODEV;
+               } else {
+                       return -EPERM;
+               }
        }
        if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) &&
            !(mnt_flags & MNT_NOSUID)) {
@@ -2640,7 +2650,7 @@ dput_out:
 
 static void free_mnt_ns(struct mnt_namespace *ns)
 {
-       proc_free_inum(ns->proc_inum);
+       ns_free_inum(&ns->ns);
        put_user_ns(ns->user_ns);
        kfree(ns);
 }
@@ -2662,11 +2672,12 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
        new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
        if (!new_ns)
                return ERR_PTR(-ENOMEM);
-       ret = proc_alloc_inum(&new_ns->proc_inum);
+       ret = ns_alloc_inum(&new_ns->ns);
        if (ret) {
                kfree(new_ns);
                return ERR_PTR(ret);
        }
+       new_ns->ns.ops = &mntns_operations;
        new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
        atomic_set(&new_ns->count, 1);
        new_ns->root = NULL;
@@ -2958,6 +2969,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
        /* mount new_root on / */
        attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp);
        touch_mnt_namespace(current->nsproxy->mnt_ns);
+       /* A moved mount should not expire automatically */
+       list_del_init(&new_mnt->mnt_expire);
        unlock_mount_hash();
        chroot_fs_refs(&root, &new);
        put_mountpoint(root_mp);
@@ -3002,6 +3015,7 @@ static void __init init_mount_tree(void)
 
        root.mnt = mnt;
        root.dentry = mnt->mnt_root;
+       mnt->mnt_flags |= MNT_LOCKED;
 
        set_fs_pwd(current->fs, &root);
        set_fs_root(current->fs, &root);
@@ -3144,31 +3158,31 @@ found:
        return visible;
 }
 
-static void *mntns_get(struct task_struct *task)
+static struct ns_common *mntns_get(struct task_struct *task)
 {
-       struct mnt_namespace *ns = NULL;
+       struct ns_common *ns = NULL;
        struct nsproxy *nsproxy;
 
        task_lock(task);
        nsproxy = task->nsproxy;
        if (nsproxy) {
-               ns = nsproxy->mnt_ns;
-               get_mnt_ns(ns);
+               ns = &nsproxy->mnt_ns->ns;
+               get_mnt_ns(to_mnt_ns(ns));
        }
        task_unlock(task);
 
        return ns;
 }
 
-static void mntns_put(void *ns)
+static void mntns_put(struct ns_common *ns)
 {
-       put_mnt_ns(ns);
+       put_mnt_ns(to_mnt_ns(ns));
 }
 
-static int mntns_install(struct nsproxy *nsproxy, void *ns)
+static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 {
        struct fs_struct *fs = current->fs;
-       struct mnt_namespace *mnt_ns = ns;
+       struct mnt_namespace *mnt_ns = to_mnt_ns(ns);
        struct path root;
 
        if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
@@ -3198,17 +3212,10 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns)
        return 0;
 }
 
-static unsigned int mntns_inum(void *ns)
-{
-       struct mnt_namespace *mnt_ns = ns;
-       return mnt_ns->proc_inum;
-}
-
 const struct proc_ns_operations mntns_operations = {
        .name           = "mnt",
        .type           = CLONE_NEWNS,
        .get            = mntns_get,
        .put            = mntns_put,
        .install        = mntns_install,
-       .inum           = mntns_inum,
 };