MLK-9769-10 Add Blob command bitdefs.

[karo-tx-linux.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 9954f6032546ccceba8d9c47ba2bbc34417dcff6..039f3802d70efed3d5e2b5efea811dde3d41e69d 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -777,6 +777,20 @@ static void attach_mnt(struct mount *mnt,
        list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
 }
 
+static void attach_shadowed(struct mount *mnt,
+                       struct mount *parent,
+                       struct mount *shadows)
+{
+       if (shadows) {
+               hlist_add_after_rcu(&shadows->mnt_hash, &mnt->mnt_hash);
+               list_add(&mnt->mnt_child, &shadows->mnt_child);
+       } else {
+               hlist_add_head_rcu(&mnt->mnt_hash,
+                               m_hash(&parent->mnt, mnt->mnt_mountpoint));
+               list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+       }
+}
+
 /*
  * vfsmount lock must be held for write
  */
@@ -795,12 +809,7 @@ static void commit_tree(struct mount *mnt, struct mount *shadows)
 
        list_splice(&head, n->list.prev);
 
-       if (shadows)
-               hlist_add_after_rcu(&shadows->mnt_hash, &mnt->mnt_hash);
-       else
-               hlist_add_head_rcu(&mnt->mnt_hash,
-                               m_hash(&parent->mnt, mnt->mnt_mountpoint));
-       list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
+       attach_shadowed(mnt, parent, shadows);
        touch_mnt_namespace(n);
 }
 
@@ -1217,6 +1226,11 @@ static void namespace_unlock(void)
        head.first->pprev = &head.first;
        INIT_HLIST_HEAD(&unmounted);
 
+       /* undo decrements we'd done in umount_tree() */
+       hlist_for_each_entry(mnt, &head, mnt_hash)
+               if (mnt->mnt_ex_mountpoint.mnt)
+                       mntget(mnt->mnt_ex_mountpoint.mnt);
+
        up_write(&namespace_sem);
 
        synchronize_rcu();
@@ -1253,6 +1267,9 @@ void umount_tree(struct mount *mnt, int how)
                hlist_add_head(&p->mnt_hash, &tmp_list);
        }
 
+       hlist_for_each_entry(p, &tmp_list, mnt_hash)
+               list_del_init(&p->mnt_child);
+
        if (how)
                propagate_umount(&tmp_list);
 
@@ -1263,9 +1280,9 @@ void umount_tree(struct mount *mnt, int how)
                p->mnt_ns = NULL;
                if (how < 2)
                        p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
-               list_del_init(&p->mnt_child);
                if (mnt_has_parent(p)) {
                        put_mountpoint(p->mnt_mp);
+                       mnt_add_count(p->mnt_parent, -1);
                        /* move the reference to mountpoint into ->mnt_ex_mountpoint */
                        p->mnt_ex_mountpoint.dentry = p->mnt_mountpoint;
                        p->mnt_ex_mountpoint.mnt = &p->mnt_parent->mnt;
@@ -1278,6 +1295,8 @@ 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;
        }
@@ -1348,6 +1367,8 @@ static int do_umount(struct mount *mnt, int flags)
                 * Special case for "unmounting" root ...
                 * we just try to remount it readonly.
                 */
+               if (!capable(CAP_SYS_ADMIN))
+                       return -EPERM;
                down_write(&sb->s_umount);
                if (!(sb->s_flags & MS_RDONLY))
                        retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
@@ -1420,6 +1441,9 @@ 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:
@@ -1496,6 +1520,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                        continue;
 
                for (s = r; s; s = next_mnt(s, r)) {
+                       struct mount *t = NULL;
                        if (!(flag & CL_COPY_UNBINDABLE) &&
                            IS_MNT_UNBINDABLE(s)) {
                                s = skip_mnt_tree(s);
@@ -1517,7 +1542,14 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                                goto out;
                        lock_mount_hash();
                        list_add_tail(&q->mnt_list, &res->mnt_list);
-                       attach_mnt(q, parent, p->mnt_mp);
+                       mnt_set_mountpoint(parent, p->mnt_mp, q);
+                       if (!list_empty(&parent->mnt_mounts)) {
+                               t = list_last_entry(&parent->mnt_mounts,
+                                       struct mount, mnt_child);
+                               if (t->mnt_mp != p->mnt_mp)
+                                       t = NULL;
+                       }
+                       attach_shadowed(q, parent, t);
                        unlock_mount_hash();
                }
        }
@@ -1937,7 +1969,13 @@ 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)) {
@@ -2804,6 +2842,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
        /* make sure we can reach put_old from new_root */
        if (!is_path_reachable(old_mnt, old.dentry, &new))
                goto out4;
+       /* make certain new is below the root */
+       if (!is_path_reachable(new_mnt, new.dentry, &root))
+               goto out4;
        root_mp->m_count++; /* pin it so it won't go away */
        lock_mount_hash();
        detach_mnt(new_mnt, &parent_path);