Merge tag 'vfs-fix-ioctl-checking-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull common SETFLAGS/FSSETXATTR parameter checking from Darrick Wong:
 "Here's a patch series that sets up common parameter checking functions
  for the FS_IOC_SETFLAGS and FS_IOC_FSSETXATTR ioctl implementations.

  The goal here is to reduce the amount of behaviorial variance between
  the filesystems where those ioctls originated (ext2 and XFS,
  respectively) and everybody else.

   - Standardize parameter checking for the SETFLAGS and FSSETXATTR
     ioctls (which were the file attribute setters for ext4 and xfs and
     have now been hoisted to the vfs)

   - Only allow the DAX flag to be set on files and directories"

* tag 'vfs-fix-ioctl-checking-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: only allow FSSETXATTR to set DAX flag on files and dirs
  vfs: teach vfs_ioc_fssetxattr_check to check extent size hints
  vfs: teach vfs_ioc_fssetxattr_check to check project id info
  vfs: create a generic checking function for FS_IOC_FSSETXATTR
  vfs: create a generic checking and prep function for FS_IOC_SETFLAGS

1 files changed, 11 insertions, 19 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 56ae2f659b6d..cfeff1b8dce0 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -187,7 +187,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	struct btrfs_inode *binode = BTRFS_I(inode);
 	struct btrfs_root *root = binode->root;
 	struct btrfs_trans_handle *trans;
-	unsigned int fsflags;
+	unsigned int fsflags, old_fsflags;
 	int ret;
 	const char *comp = NULL;
 	u32 binode_flags = binode->flags;
@@ -212,13 +212,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	inode_lock(inode);
 
 	fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
-	if ((fsflags ^ btrfs_inode_flags_to_fsflags(binode->flags)) &
-	    (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
-		if (!capable(CAP_LINUX_IMMUTABLE)) {
-			ret = -EPERM;
-			goto out_unlock;
-		}
-	}
+	old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
+	ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
+	if (ret)
+		goto out_unlock;
 
 	if (fsflags & FS_SYNC_FL)
 		binode_flags |= BTRFS_INODE_SYNC;
@@ -376,9 +373,7 @@ static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
 	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
 	struct fsxattr fa;
 
-	memset(&fa, 0, sizeof(fa));
-	fa.fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
-
+	simple_fill_fsxattr(&fa, btrfs_inode_flags_to_xflags(binode->flags));
 	if (copy_to_user(arg, &fa, sizeof(fa)))
 		return -EFAULT;
 
@@ -391,7 +386,7 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	struct btrfs_inode *binode = BTRFS_I(inode);
 	struct btrfs_root *root = binode->root;
 	struct btrfs_trans_handle *trans;
-	struct fsxattr fa;
+	struct fsxattr fa, old_fa;
 	unsigned old_flags;
 	unsigned old_i_flags;
 	int ret = 0;
@@ -402,7 +397,6 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	memset(&fa, 0, sizeof(fa));
 	if (copy_from_user(&fa, arg, sizeof(fa)))
 		return -EFAULT;
 
@@ -422,13 +416,11 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	old_flags = binode->flags;
 	old_i_flags = inode->i_flags;
 
-	/* We need the capabilities to change append-only or immutable inode */
-	if (((old_flags & (BTRFS_INODE_APPEND | BTRFS_INODE_IMMUTABLE)) ||
-	     (fa.fsx_xflags & (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE))) &&
-	    !capable(CAP_LINUX_IMMUTABLE)) {
-		ret = -EPERM;
+	simple_fill_fsxattr(&old_fa,
+			    btrfs_inode_flags_to_xflags(binode->flags));
+	ret = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
+	if (ret)
 		goto out_unlock;
-	}
 
 	if (fa.fsx_xflags & FS_XFLAG_SYNC)
 		binode->flags |= BTRFS_INODE_SYNC;