On Sun, Jun 23, 2019 at 10:45:56AM +0200, Michael Niedermayer wrote: > On Sun, Jun 23, 2019 at 06:33:02PM +1000, Peter Ross wrote: > > On Sun, Jun 23, 2019 at 12:30:54AM +0200, Michael Niedermayer wrote: > > > 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 <mich...@niedermayer.cc> > > > --- > > > libavcodec/iff.c | 15 ++++++++++++--- > > > 1 file changed, 12 insertions(+), 3 deletions(-) > > > > > > diff --git a/libavcodec/iff.c b/libavcodec/iff.c > > > index b43bd507b3..b065bbe598 100644 > > > --- a/libavcodec/iff.c > > > +++ b/libavcodec/iff.c > > > @@ -280,6 +280,18 @@ 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); > > > + s->ham = 0; > > > + 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); > > > + s->ham = 0; > > > + return AVERROR_INVALIDDATA; > > > + } > > > + } > > > > i am curious why we need to reset ham = 0? otherwise patch okay. > > That was just so as not to leave an invalid value in the context. It is > very likely not needed, I will remove it.
will apply without the ham = 0 [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB In a rich man's house there is no place to spit but his face. -- Diogenes of Sinope
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