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avcodec/wmalosslessdec: ensure channel count in the private context and decoder context are consistent

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Fixes: Out of array write
Fixes: 45613/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-4539073606320128
Fixes: 46008/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-4681245747970048

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2022-03-18 09:46:09 -03:00
parent 96ebf7dceb
commit 7c35aa60a5
1 changed files with 26 additions and 23 deletions
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49
libavcodec/wmalosslessdec.c
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@ -198,15 +198,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
return AVERROR_PATCHWELCOME;
}
s->max_frame_size = MAX_FRAMESIZE * avctx->ch_layout.nb_channels;
s->frame_data = av_mallocz(s->max_frame_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!s->frame_data)
return AVERROR(ENOMEM);
s->avctx = avctx;
ff_llauddsp_init(&s->dsp);
init_put_bits(&s->pb, s->frame_data, s->max_frame_size);
if (avctx->extradata_size >= 18) {
s->decode_flags = AV_RL16(edata_ptr + 14);
channel_mask = AV_RL32(edata_ptr + 2);
@ -231,6 +222,32 @@ static av_cold int decode_init(AVCodecContext *avctx)
return AVERROR_PATCHWELCOME;
}
if (channel_mask) {
av_channel_layout_uninit(&avctx->ch_layout);
av_channel_layout_from_mask(&avctx->ch_layout, channel_mask);
}
s->num_channels = avctx->ch_layout.nb_channels;
/* extract lfe channel position */
s->lfe_channel = -1;
if (channel_mask & 8) {
unsigned int mask;
for (mask = 1; mask < 16; mask <<= 1)
if (channel_mask & mask)
++s->lfe_channel;
}
s->max_frame_size = MAX_FRAMESIZE * avctx->ch_layout.nb_channels;
s->frame_data = av_mallocz(s->max_frame_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!s->frame_data)
return AVERROR(ENOMEM);
s->avctx = avctx;
ff_llauddsp_init(&s->dsp);
init_put_bits(&s->pb, s->frame_data, s->max_frame_size);
/* generic init */
s->log2_frame_size = av_log2(avctx->block_align) + 4;
@ -264,24 +281,10 @@ static av_cold int decode_init(AVCodecContext *avctx)
return AVERROR_INVALIDDATA;
}
s->num_channels = avctx->ch_layout.nb_channels;
/* extract lfe channel position */
s->lfe_channel = -1;
if (channel_mask & 8) {
unsigned int mask;
for (mask = 1; mask < 16; mask <<= 1)
if (channel_mask & mask)
++s->lfe_channel;
}
s->frame = av_frame_alloc();
if (!s->frame)
return AVERROR(ENOMEM);
av_channel_layout_uninit(&avctx->ch_layout);
av_channel_layout_from_mask(&avctx->ch_layout, channel_mask);
return 0;
}