[lvc-project] [PATCH] ocfs2: add extra flags check in ocfs2_ioctl_move_extents()

[Dmitry Antipov]

In 'ocfs2_ioctl_move_extents()', add extra check whether only actually
supported flags are passed via 'ioctl(..., OCFS2_IOC_MOVE_EXT, ...)',
and reject anything beyond OCFS2_MOVE_EXT_FL_AUTO_DEFRAG and
OCFS2_MOVE_EXT_FL_PART_DEFRAG with -EINVAL. In particular,
OCFS2_MOVE_EXT_FL_COMPLETE may be set by the kernel only and
should never be passed from userspace.

Reported-by: syzbot+727d161855d11d81e411 at syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=727d161855d11d81e411
Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
 fs/ocfs2/move_extents.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index 86f2631e6360..e038c009cdef 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -1031,6 +1031,12 @@ int ocfs2_ioctl_move_extents(struct file *filp, void __user *argp)
 	if (range.me_threshold > i_size_read(inode))
 		range.me_threshold = i_size_read(inode);
 
+	if (range.me_flags & ~(OCFS2_MOVE_EXT_FL_AUTO_DEFRAG |
+			       OCFS2_MOVE_EXT_FL_PART_DEFRAG)) {
+		status = -EINVAL;
+		goto out_free;
+	}
+
 	if (range.me_flags & OCFS2_MOVE_EXT_FL_AUTO_DEFRAG) {
 		context->auto_defrag = 1;
 
-- 
2.51.0