swscale/utils: More carefully merge and clear coefficients outside the input

Fixes out of array read
Fixes: asan_heap-oob_35ca682_1474_cov_3230122439_aletrek_tga_16bit.mov

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2015-02-24 00:32:39 +01:00
parent 4d1b017c38
commit 1895d414aa

View File

@ -612,14 +612,24 @@ static av_cold int initFilter(int16_t **outFilter, int32_t **filterPos,
if ((*filterPos)[i] + filterSize > srcW) {
int shift = (*filterPos)[i] + FFMIN(filterSize - srcW, 0);
int64_t acc = 0;
// move filter coefficients right to compensate for filterPos
for (j = filterSize - 2; j >= 0; j--) {
int right = FFMIN(j + shift, filterSize - 1);
filter[i * filterSize + right] += filter[i * filterSize + j];
filter[i * filterSize + j] = 0;
for (j = filterSize - 1; j >= 0; j--) {
if ((*filterPos)[i] + j >= srcW) {
acc += filter[i * filterSize + j];
filter[i * filterSize + j] = 0;
}
}
for (j = filterSize - 1; j >= 0; j--) {
if (j < shift) {
filter[i * filterSize + j] = 0;
} else {
filter[i * filterSize + j] = filter[i * filterSize + j - shift];
}
}
(*filterPos)[i]-= shift;
filter[i * filterSize + srcW - 1 - (*filterPos)[i]] += acc;
}
}