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dca: Check scale_sum. 

Fixes a out of array read.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-02-29 20:47:47 +01:00
parent d6bc273bac
commit 51db9a97e9
1 changed files with 14 additions and 2 deletions
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16
libavcodec/dca.c
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@ -717,15 +717,19 @@ static int dca_subframe_header(DCAContext *s, int base_channel, int block_index)
for (j = base_channel; j < s->prim_channels; j++) {
const uint32_t *scale_table;
unsigned int scale_max;
int scale_sum;
memset(s->scale_factor[j], 0,
s->subband_activity[j] * sizeof(s->scale_factor[0][0][0]) * 2);
if (s->scalefactor_huffman[j] == 6)
if (s->scalefactor_huffman[j] == 6) {
scale_table = scale_factor_quant7;
else
scale_max = 127;
} else {
scale_table = scale_factor_quant6;
scale_max = 63;
}
/* When huffman coded, only the difference is encoded */
scale_sum = 0;
@ -733,12 +737,20 @@ static int dca_subframe_header(DCAContext *s, int base_channel, int block_index)
for (k = 0; k < s->subband_activity[j]; k++) {
if (k >= s->vq_start_subband[j] || s->bitalloc[j][k] > 0) {
scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j], scale_sum);
if (scale_sum > scale_max) {
av_log(s->avctx, AV_LOG_ERROR, "scale_sum out of range\n");
return AVERROR_INVALIDDATA;
}
s->scale_factor[j][k][0] = scale_table[scale_sum];
}
if (k < s->vq_start_subband[j] && s->transition_mode[j][k]) {
/* Get second scale factor */
scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j], scale_sum);
if (scale_sum > scale_max) {
av_log(s->avctx, AV_LOG_ERROR, "scale_sum out of range\n");
return AVERROR_INVALIDDATA;
}
s->scale_factor[j][k][1] = scale_table[scale_sum];
}
}