Skip to content

AmAudio::decode: bound decoded PCM size against back buffer (remote heap overflow) #554

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
hecko wants to merge 1 commit into
base: master
Choose a base branch
from
Open

AmAudio::decode: bound decoded PCM size against back buffer (remote heap overflow) #554

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 14 additions & 1 deletion core/AmAudio.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -389,12 +389,25 @@ int AmAudio::decode(unsigned int size)
}

if(codec->decode){
// Bound the decoder's PCM output against the back buffer before the
// codec writes into it. The decoder writes into samples.back_buffer(),
// which only has AUDIO_BUFFER_SIZE bytes; an expanding codec (e.g. GSM,
// G.722) fed a large RTP payload can produce far more PCM than that and
// overflow the DblBuffer. bytes2samples() predicts the decoded sample
// count for the given encoded size.
unsigned int out_size = PCM16_S2B(bytes2samples(size));
if(out_size > AUDIO_BUFFER_SIZE){
ERROR("decoded buffer size for pcm16 (%u) exceeds allowed (%u)\n",
out_size, AUDIO_BUFFER_SIZE);
return -1;
}
Comment on lines +398 to +403

s = (*codec->decode)(samples.back_buffer(),samples,s,
fmt->channels,getSampleRate(),h_codec);
if(s<0) return s;
samples.swap();
}

return s;
}

Expand Down
Loading