Btrfs: Fix BTRFS_IOC_SUBVOL_SETFLAGS ioctl

- Check user-specified flags correctly
- Check the inode owership
- Search root item in root tree but not fs tree

Reported-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index be2d4f6aaa5e..5fdb2abc4fa7 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1071,12 +1071,15 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
         if (copy_from_user(&flags, arg, sizeof(flags)))
                 return -EFAULT;
 
-        if (flags & ~BTRFS_SUBVOL_CREATE_ASYNC)
+        if (flags & BTRFS_SUBVOL_CREATE_ASYNC)
                 return -EINVAL;
 
         if (flags & ~BTRFS_SUBVOL_RDONLY)
                 return -EOPNOTSUPP;
 
+        if (!is_owner_or_cap(inode))
+                return -EACCES;
+
         down_write(&root->fs_info->subvol_sem);
 
         /* nothing to do */
@@ -1097,7 +1100,7 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
                 goto out_reset;
         }
 
-        ret = btrfs_update_root(trans, root,
+        ret = btrfs_update_root(trans, root->fs_info->tree_root,
                                 &root->root_key, &root->root_item);
 
         btrfs_commit_transaction(trans, root);