1465440 - Disable CRC checks in FlacDemuxer for FUZZING

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, enhancement, P3)

Description

[Christian Holler (:decoder)]

The FlacDemuxer has some CRC8/CRC16 header checks that we should probably disable in FUZZING builds.

Comment 1

[Jean-Yves Avenard [:jya]]

can't the fuzzer simply set the CRC value?

it's not that much required. Especially if you know the existing CRC and are only changing a byte at the time. The new CRC can be easily calculated from there

Comment 2

[Christian Holler (:decoder)]

No, the fuzzer cannot do that. In order to do so, the fuzzer (in this case libfuzzer) would have to know the file structure and it doesn't know that.

Comment 3

[Jean-Yves Avenard [:jya]]

let's fix libfuzzer then :D

Comment 4

[Christian Holler (:decoder)]

(In reply to Jean-Yves Avenard [:jya] from comment #3)
> let's fix libfuzzer then :D

It is the whole point of libFuzzer not being required to know the target file format structure. There is nothing to fix here on the fuzzer side, it is common practice to fix this in the target code.

Comment 5

[Christian Holler (:decoder)]

Attachment: Bug 1465440 - Disable CRC checks in FlacDemuxer for FUZZING. r?drno

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

There's a r+ patch which didn't land and no activity in this bug for 2 weeks.
:decoder, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 7

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/integration/autoland/rev/eb06624e60a07a85ad1981db4b93aae6c2d6d0d3
https://hg.mozilla.org/mozilla-central/rev/eb06624e60a0