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avcodec/lagarith: check scaled probabilities

Prevents infinite loop
Fixes Ticket2988

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-09-25 18:26:13 +02:00
parent ab6fbe8206
commit 45f0623ae3

View File

@ -174,7 +174,15 @@ static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb)
if (cumul_prob & (cumul_prob - 1)) {
uint64_t mul = softfloat_reciprocal(cumul_prob);
for (i = 1; i < 257; i++) {
for (i = 1; i <= 128; i++) {
rac->prob[i] = softfloat_mul(rac->prob[i], mul);
scaled_cumul_prob += rac->prob[i];
}
if (scaled_cumul_prob <= 0) {
av_log(rac->avctx, AV_LOG_ERROR, "Scaled probabilities invalid\n");
return AVERROR_INVALIDDATA;
}
for (; i < 257; i++) {
rac->prob[i] = softfloat_mul(rac->prob[i], mul);
scaled_cumul_prob += rac->prob[i];
}