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avcodec/iff: Check ham vs bpp 

This checks the ham value much stricter and avoids hitting cases which cannot be reached
with data from the libavformat demuxer.

Fixes: out of array access
Fixes: 15320/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5080476840099840
Fixes: 15423/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5630765833912320

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-06-22 19:21:50 +02:00
parent e9dd3c7126
commit f76d7352e0
1 changed files with 10 additions and 3 deletions
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13
libavcodec/iff.c
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@ -280,6 +280,16 @@ static int extract_header(AVCodecContext *const avctx,
for (i = 0; i < 16; i++)
s->tvdc[i] = bytestream_get_be16(&buf);
if (s->ham) {
if (s->bpp > 8) {
av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u\n", s->ham);
return AVERROR_INVALIDDATA;
} if (s->ham != (s->bpp > 6 ? 6 : 4)) {
av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u, BPP: %u\n", s->ham, s->bpp);
return AVERROR_INVALIDDATA;
}
}
if (s->masking == MASK_HAS_MASK) {
if (s->bpp >= 8 && !s->ham) {
avctx->pix_fmt = AV_PIX_FMT_RGB32;
@ -307,9 +317,6 @@ static int extract_header(AVCodecContext *const avctx,
if (!s->bpp || s->bpp > 32) {
av_log(avctx, AV_LOG_ERROR, "Invalid number of bitplanes: %u\n", s->bpp);
return AVERROR_INVALIDDATA;
} else if (s->ham >= 8) {
av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u\n", s->ham);
return AVERROR_INVALIDDATA;
}
av_freep(&s->ham_buf);