vp3dec: Check coefficient index in vp3_dequant()

Based on a patch by Michael Niedermayer <michaelni@gmx.at>

Fixes NGS00145, CVE-2011-4352

Found-by: Phillip Langlois
Signed-off-by: Reinhard Tartler <siretart@tauware.de>
This commit is contained in:
Reinhard Tartler 2011-12-04 10:10:33 +01:00
parent 6e24b9488e
commit 8b94df0f20

View File

@ -1363,6 +1363,10 @@ static inline int vp3_dequant(Vp3DecodeContext *s, Vp3Fragment *frag,
case 1: // zero run
s->dct_tokens[plane][i]++;
i += (token >> 2) & 0x7f;
if (i > 63) {
av_log(s->avctx, AV_LOG_ERROR, "Coefficient index overflow\n");
return i;
}
block[perm[i]] = (token >> 9) * dequantizer[perm[i]];
i++;
break;
@ -1566,7 +1570,10 @@ static void render_slice(Vp3DecodeContext *s, int slice)
/* invert DCT and place (or add) in final output */
if (s->all_fragments[i].coding_method == MODE_INTRA) {
vp3_dequant(s, s->all_fragments + i, plane, 0, block);
int index;
index = vp3_dequant(s, s->all_fragments + i, plane, 0, block);
if (index > 63)
continue;
if(s->avctx->idct_algo!=FF_IDCT_VP3)
block[0] += 128<<3;
s->dsp.idct_put(
@ -1574,7 +1581,10 @@ static void render_slice(Vp3DecodeContext *s, int slice)
stride,
block);
} else {
if (vp3_dequant(s, s->all_fragments + i, plane, 1, block)) {
int index = vp3_dequant(s, s->all_fragments + i, plane, 1, block);
if (index > 63)
continue;
if (index > 0) {
s->dsp.idct_add(
output_plane + first_pixel,
stride,