ceph: fix overflow check in build_snap_context()

The overflow check for a + n * b should be (n > (ULONG_MAX - a) / b),
rather than (n > ULONG_MAX / b - a).

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Xi Wang 2012-02-16 11:56:29 -05:00 committed by Alex Elder
parent 6448669777
commit 80834312a4
1 changed files with 1 additions and 1 deletions

View File

@ -331,7 +331,7 @@ static int build_snap_context(struct ceph_snap_realm *realm)
/* alloc new snap context */
err = -ENOMEM;
if (num > ULONG_MAX / sizeof(u64) - sizeof(*snapc))
if (num > (ULONG_MAX - sizeof(*snapc)) / sizeof(u64))
goto fail;
snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS);
if (!snapc)