[PATCH 4.14 039/173] ubifs: Reject unsupported ioctl flags explicitly

From: Greg Kroah-Hartman
Date: Thu Feb 13 2020 - 10:26:31 EST


From: Hou Tao <houtao1@xxxxxxxxxx>

commit 2fe8b2d5578d7d142982e3bf62e4c0caf8b8fe02 upstream.

Reject unsupported ioctl flags explicitly, so the following command
on a regular ubifs file will fail:
chattr +d ubifs_file

And xfstests generic/424 will pass.

Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/ubifs/ioctl.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -28,6 +28,11 @@
#include <linux/mount.h>
#include "ubifs.h"

+/* Need to be kept consistent with checked flags in ioctl2ubifs() */
+#define UBIFS_SUPPORTED_IOCTL_FLAGS \
+ (FS_COMPR_FL | FS_SYNC_FL | FS_APPEND_FL | \
+ FS_IMMUTABLE_FL | FS_DIRSYNC_FL)
+
/**
* ubifs_set_inode_flags - set VFS inode flags.
* @inode: VFS inode to set flags for
@@ -166,6 +171,9 @@ long ubifs_ioctl(struct file *file, unsi
if (get_user(flags, (int __user *) arg))
return -EFAULT;

+ if (flags & ~UBIFS_SUPPORTED_IOCTL_FLAGS)
+ return -EOPNOTSUPP;
+
if (!S_ISDIR(inode->i_mode))
flags &= ~FS_DIRSYNC_FL;