This is a serious security regression. If you are not able to fix this quickly, please revert the change that introduced it.

If this doesn't affect a release branch, or has not been properly classified for severity, please update the Security_Impact or Security_Severity labels, and remove the ReleaseBlock label. To disable this altogether, apply ReleaseBlock-NA.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Nice!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3749e7b625216973a65a6cbef1cea950097021a2

commit 3749e7b625216973a65a6cbef1cea950097021a2
Author: Robert Sesek <rsesek@chromium.org>
Date: Thu Oct 19 17:36:57 2017

Fix heap-buffer-overflow in safe_browsing::dmg::HFSBTreeIterator::Next.

The BTree leaf structure contains a length and embedded string. Check
that the length of the embedded string is not larger than node
containing the leaf.

Bug:  776307 
Test: Covered by fuzzer.
Change-Id: I2c39c55b42da34bcc8cb26c481e269b66b19811d
Reviewed-on: https://chromium-review.googlesource.com/728084
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510119}
[modify] https://crrev.com/3749e7b625216973a65a6cbef1cea950097021a2/chrome/utility/safe_browsing/mac/hfs.cc

ClusterFuzz has detected this issue as fixed in range 510085:510141.

Detailed report: https://clusterfuzz.com/testcase?key=4750298378928128

Fuzzer: libFuzzer_safe_browsing_hfs_fuzzer
Job Type: mac_libfuzzer_chrome_asan
Platform Id: mac

Crash Type: Heap-buffer-overflow READ 2
Crash Address: 0x621000008900
Crash State:
  safe_browsing::dmg::HFSBTreeIterator::Next
  safe_browsing::dmg::HFSIterator::Next
  start
  
Sanitizer: address (ASAN)

Recommended Security Severity: Medium

Regressed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=509376:509426
Fixed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=510085:510141

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=4750298378928128

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.md for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase 4750298378928128 is verified as fixed, so closing issue as verified.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot