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* [PATCH] ceph: fix overflow check in build_snap_context()
@ 2012-02-29  4:56 Alex Elder
  0 siblings, 0 replies; 2+ messages in thread
From: Alex Elder @ 2012-02-29  4:56 UTC (permalink / raw)
  To: ceph-devel

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>
---
  fs/ceph/snap.c |    2 +-
  1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index a559c80..f04c096 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -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)
-- 
1.7.5.4


^ permalink raw reply related	[flat|nested] 2+ messages in thread
* [PATCH] ceph: fix overflow check in build_snap_context()
@ 2012-02-16 16:56 Xi Wang
  0 siblings, 0 replies; 2+ messages in thread
From: Xi Wang @ 2012-02-16 16:56 UTC (permalink / raw)
  To: Sage Weil; +Cc: ceph-devel, linux-kernel, Xi Wang

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>
---
 fs/ceph/snap.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index a559c80..f04c096 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -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)
-- 
1.7.5.4


^ permalink raw reply related	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2012-02-29  4:56 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
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2012-02-29  4:56 [PATCH] ceph: fix overflow check in build_snap_context() Alex Elder
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2012-02-16 16:56 Xi Wang

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