xfs: lift common checks into xfs_ioc_attr_list

Lift the flags and bufsize checks from both callers into the common code
in xfs_ioc_attr_list.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_ioctl.c

@@ -361,6 +361,18 @@ xfs_ioc_attr_list(
 	struct xfs_attrlist		*alist;
 	int				error;
 
+	if (bufsize < sizeof(struct xfs_attrlist) ||
+	    bufsize > XFS_XATTR_LIST_MAX)
+		return -EINVAL;
+
+	/*
+	 * Reject flags, only allow namespaces.
+	 */
+	if (flags & ~(ATTR_ROOT | ATTR_SECURE))
+		return -EINVAL;
+	if (flags == (ATTR_ROOT | ATTR_SECURE))
+		return -EINVAL;
+
 	/*
 	 * Validate the cursor.
 	 */
@@ -415,17 +427,6 @@ xfs_attrlist_by_handle(
 		return -EPERM;
 	if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t)))
 		return -EFAULT;
-	if (al_hreq.buflen < sizeof(struct xfs_attrlist) ||
-	    al_hreq.buflen > XFS_XATTR_LIST_MAX)
-		return -EINVAL;
-
-	/*
-	 * Reject flags, only allow namespaces.
-	 */
-	if (al_hreq.flags & ~(ATTR_ROOT | ATTR_SECURE))
-		return -EINVAL;
-	if (al_hreq.flags == (ATTR_ROOT | ATTR_SECURE))
-		return -EINVAL;
 
 	dentry = xfs_handlereq_to_dentry(parfilp, &al_hreq.hreq);
 	if (IS_ERR(dentry))

fs/xfs/xfs_ioctl32.c

@@ -366,17 +366,6 @@ xfs_compat_attrlist_by_handle(
 	if (copy_from_user(&al_hreq, arg,
 			   sizeof(compat_xfs_fsop_attrlist_handlereq_t)))
 		return -EFAULT;
-	if (al_hreq.buflen < sizeof(struct xfs_attrlist) ||
-	    al_hreq.buflen > XFS_XATTR_LIST_MAX)
-		return -EINVAL;
-
-	/*
-	 * Reject flags, only allow namespaces.
-	 */
-	if (al_hreq.flags & ~(ATTR_ROOT | ATTR_SECURE))
-		return -EINVAL;
-	if (al_hreq.flags == (ATTR_ROOT | ATTR_SECURE))
-		return -EINVAL;
 
 	dentry = xfs_compat_handlereq_to_dentry(parfilp, &al_hreq.hreq);
 	if (IS_ERR(dentry))