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 <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2018-01-07 20:43:24 +01:00
parent 1bcd7fefcb
commit eaa9317589

View File

@ -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)) {