1225306 - FFMPEG: use-of-uninitialized-value in [@avcodec_string]

Status: RESOLVED INVALID

(Core :: Audio/Video: Playback, defect, P1)

Description

[Tyson Smith [:tsmith]]

Attachment: call_stack.txt

Found fuzzing ffmpeg commit: 3692d859f45fa8765fa5a330e79108b03c17c6bd

Reproduced with the following command with MSan build:
./ffmpeg -nostats -v 0 -i test_case.vpx -f null -

Comment 1

[Tyson Smith [:tsmith]]

Attachment: test_case.vpx

Comment 2

[Tyson Smith [:tsmith]]

Attachment: call_stack_2.txt

Another one in utils.c

Comment 3

[Michael Niedermayer [:mn]]

not reproduceable with --disable-yasm (and reproduceable with yasm)

Comment 4

[Tyson Smith [:tsmith]]

(In reply to Michael Niedermayer [:mn] from comment #3)
> not reproduceable with --disable-yasm (and reproduceable with yasm)

Thanks Micheal. I have switched at a --disable-yasm build to avoid false positives.

Comment 5

[Tyson Smith [:tsmith]]

Actually I am still seeing this. Seems to be related to compiler optimizations. With optimizations disabled I have no issues but with -O3 this comes back. I am building with both --disable-asm and --disable-yasm.

I am building with clang3.7.

What are your thoughts Micheal?

Comment 6

[Tyson Smith [:tsmith]]

Attachment: call_stack.txt

Updated call stack with more info.

Comment 7

[Michael Niedermayer [:mn]]

I cannot reproduce an issue with -O3 and  clang version 3.8.0 (trunk 247874) which is what i used previously too but with -O1

Comment 8

[Jean-Yves Avenard [:jya]]

Ralph: Note that there's nothing we can do on this bug, the issue is upstream. Setting a priority will do little I think

Comment 9

[Tyson Smith [:tsmith]]

To avoid driving Michael crazy false positive I am blacklisting a bunch of this stuff for now.