Fix a bug where an unsigned calculation goes negative and causes very large memcpy() call.

Fix a bug where an unsigned calculation goes negative and causes very large memcpy() call.

Potentially fixes the crash listed in the bug.

BUG=589616
Committed: https://crrev.com/fdfdd80259808aa3329001efd9ca1fab00091ffb
Cr-Commit-Position: refs/heads/master@{#377709}

[hubbe, 2016-02-24 22:33:51]

hubbe@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[DaleCurtis, 2016-02-24 23:14:11]

How can this happen? It seems like something a test should be added for too.

[hubbe, 2016-02-25 01:28:09]

On 2016/02/24 23:14:11, DaleCurtis wrote:
> How can this happen? It seems like something a test should be added for too.

It happens when you seek past the end of the file. (but not too far past the end
of the file)
Test added (it triggers the bug without the fix)

[DaleCurtis, 2016-02-25 01:30:21]

lgtm

[hubbe, 2016-02-25 01:30:49]

The CQ bit was checked by hubbe@chromium.org

[commit-bot: I haz the power, 2016-02-25 01:32:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729223003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729223003/20001

[DaleCurtis, 2016-02-25 01:35:17]

The CQ bit was checked by dalecurtis@chromium.org

[commit-bot: I haz the power, 2016-02-25 01:39:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729223003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729223003/20001

[commit-bot: I haz the power, 2016-02-25 01:49:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-02-25 01:49:50]

Try jobs failed on following builders:
  mac_chromium_gn_rel on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_gn_r...)

[hubbe, 2016-02-25 21:29:25]

The CQ bit was checked by hubbe@chromium.org

[hubbe, 2016-02-25 21:29:25]

The patchset sent to the CQ was uploaded after l-g-t-m from
dalecurtis@chromium.org
Link to the patchset: https://codereview.chromium.org/1729223003/#ps40001
(title: "compile fix")

[commit-bot: I haz the power, 2016-02-25 21:33:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729223003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729223003/40001

[commit-bot: I haz the power, 2016-02-25 23:43:32]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-02-25 23:44:36]

Description was changed from

==========
Fix a bug where an unsigned calculation goes negative and causes very large
memcpy() call.

Potentially fixes the crash listed in the bug.

BUG=589616
==========

to

==========
Fix a bug where an unsigned calculation goes negative and causes very large
memcpy() call.

Potentially fixes the crash listed in the bug.

BUG=589616

Committed: https://crrev.com/fdfdd80259808aa3329001efd9ca1fab00091ffb
Cr-Commit-Position: refs/heads/master@{#377709}
==========

[commit-bot: I haz the power, 2016-02-25 23:44:37]

Patchset 3 (id:??) landed as
https://crrev.com/fdfdd80259808aa3329001efd9ca1fab00091ffb
Cr-Commit-Position: refs/heads/master@{#377709}