The following revision refers to this bug:
  https://chromium.googlesource.com/external/webrtc.git/+/89f237cedcb8204f2c5553673669f55a41a9e2d9

commit 89f237cedcb8204f2c5553673669f55a41a9e2d9
Author: kwiberg <kwiberg@webrtc.org>
Date: Wed May 18 09:20:28 2016

Fix UBSan errors (left shift of negative value, left shift overflows int)

BUG= chromium:603498 

Review-Url: https://codereview.webrtc.org/1979973003
Cr-Commit-Position: refs/heads/master@{#12787}

[modify] https://crrev.com/89f237cedcb8204f2c5553673669f55a41a9e2d9/webrtc/modules/audio_coding/codecs/isac/main/source/arith_routines_hist.c
[modify] https://crrev.com/89f237cedcb8204f2c5553673669f55a41a9e2d9/webrtc/modules/audio_coding/codecs/isac/main/source/entropy_coding.c

My manual testing says that the cl in comment #3 fixes the bug.

ClusterFuzz has detected this issue as fixed in range 394410:394495.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5745058254422016

Fuzzer: libfuzzer_audio_decoder_isac_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  WebRtcIsac_DecHistOneStepMulti
  WebRtcIsac_DecodeFrameLen
  WebRtcIsac_DecodeLb
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=386932:386961
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=394410:394495

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv95O_bcIWC0MoSK_uWCRgsbFMpKDrpKBrW1DY3yv4tM1qpzK0V-qA59dFOZ7Y6L3uxleAcq0o2lYEzScBr-jLXUxnjRVIuBA61f9I2Vq_MQMGjgnyY-XdznsxC0j3SMk1_qsO2_YZsPzXIiy1u0W0LRBnynzuQ

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.

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