ceph: avoid divide by zero in __validate_layout()
If "l->stripe_unit" is zero the the mod on the next line will cause a
divide by zero bug. This comes from the copy_from_user() in
ceph_ioctl_set_layout_policy(). Passing 0 is valid, though (it means
"do not change") so avoid the % check in that case.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index 8e3fb69..1396ceb 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -42,7 +42,8 @@
/* validate striping parameters */
if ((l->object_size & ~PAGE_MASK) ||
(l->stripe_unit & ~PAGE_MASK) ||
- ((unsigned)l->object_size % (unsigned)l->stripe_unit))
+ (l->stripe_unit != 0 &&
+ ((unsigned)l->object_size % (unsigned)l->stripe_unit)))
return -EINVAL;
/* make sure it's a valid data pool */
