From eaa93175895568ef6c2542b13104874907d9c4ef Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 7 Jan 2018 20:43:24 +0100 Subject: [PATCH] avcodec/diracdec: Fix integer overflow with quant Fixes: signed integer overflow: 2 + 2147483646 cannot be represented in type 'int' Fixes: 4792/clusterfuzz-testcase-minimized-6322450775146496 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/diracdec.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c index 7157357d59..530e1c6ffd 100644 --- a/libavcodec/diracdec.c +++ b/libavcodec/diracdec.c @@ -509,16 +509,16 @@ static inline void codeblock(DiracContext *s, SubBand *b, } if (s->codeblock_mode && !(s->old_delta_quant && blockcnt_one)) { - int quant = b->quant; + int quant; if (is_arith) - quant += dirac_get_arith_int(c, CTX_DELTA_Q_F, CTX_DELTA_Q_DATA); + quant = dirac_get_arith_int(c, CTX_DELTA_Q_F, CTX_DELTA_Q_DATA); else - quant += dirac_get_se_golomb(gb); - if (quant < 0) { + quant = dirac_get_se_golomb(gb); + if (quant > INT_MAX - b->quant || b->quant + quant < 0) { av_log(s->avctx, AV_LOG_ERROR, "Invalid quant\n"); return; } - b->quant = quant; + b->quant += quant; } if (b->quant > (DIRAC_MAX_QUANT_INDEX - 1)) {