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 <[email protected]> Signed-off-by: Sage Weil <[email protected]> Reviewed-by: Alex Elder <[email protected]>
niw · Aug 21, 2012 · 45f2e08 · 45f2e08
1 parent 6d4221b
commit 45f2e08
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
@@ -42,7 +42,8 @@ static long __validate_layout(struct ceph_mds_client *mdsc,
 	/* 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 */