From 2f00300b779e7b247c85db0d7daef448225105ff Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 1 May 2017 18:46:27 +0200 Subject: [PATCH] avcodec/vp3: Check remaining bits in unpack_dct_coeffs() Decreases the time spend decoding junk. May fix: 1283/clusterfuzz-testcase-minimized-6221126759874560 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vp3.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c index 86e5852e32..b10cb39f8a 100644 --- a/libavcodec/vp3.c +++ b/libavcodec/vp3.c @@ -1071,6 +1071,9 @@ static int unpack_dct_coeffs(Vp3DecodeContext *s, GetBitContext *gb) s->dct_tokens[0][0] = s->dct_tokens_base; + if (get_bits_left(gb) < 16) + return AVERROR_INVALIDDATA; + /* fetch the DC table indexes */ dc_y_table = get_bits(gb, 4); dc_c_table = get_bits(gb, 4); @@ -1080,6 +1083,8 @@ static int unpack_dct_coeffs(Vp3DecodeContext *s, GetBitContext *gb) 0, residual_eob_run); if (residual_eob_run < 0) return residual_eob_run; + if (get_bits_left(gb) < 8) + return AVERROR_INVALIDDATA; /* reverse prediction of the Y-plane DC coefficients */ reverse_dc_prediction(s, 0, s->fragment_width[0], s->fragment_height[0]); @@ -1102,6 +1107,8 @@ static int unpack_dct_coeffs(Vp3DecodeContext *s, GetBitContext *gb) s->fragment_width[1], s->fragment_height[1]); } + if (get_bits_left(gb) < 8) + return AVERROR_INVALIDDATA; /* fetch the AC table indexes */ ac_y_table = get_bits(gb, 4); ac_c_table = get_bits(gb, 4);