swr: reorder/redesign operations to avoid integer overflow.

This fixes a out of array read.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
pull/8/head
Michael Niedermayer 12 years ago
parent 0e482a8e49
commit 17da2d9eee
  1. 23
      libswresample/resample_template.c

@ -48,10 +48,16 @@ int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int
index += dst_index * dst_incr;
index += (frac + dst_index * (int64_t)dst_incr_frac) / c->src_incr;
frac = (frac + dst_index * (int64_t)dst_incr_frac) % c->src_incr;
av_assert2(index >= 0);
*consumed= index >> c->phase_shift;
index &= c->phase_mask;
}else if(compensation_distance == 0 && !c->linear && index >= 0){
int sample_index = 0;
for(dst_index=0; dst_index < dst_size; dst_index++){
FELEM *filter= ((FELEM*)c->filter_bank) + c->filter_alloc*(index & c->phase_mask);
int sample_index= index >> c->phase_shift;
FELEM *filter;
sample_index += index >> c->phase_shift;
index &= c->phase_mask;
filter= ((FELEM*)c->filter_bank) + c->filter_alloc*index;
if(sample_index + c->filter_length > src_size){
break;
@ -74,12 +80,17 @@ int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int
index++;
}
}
*consumed = sample_index;
}else{
int sample_index = 0;
for(dst_index=0; dst_index < dst_size; dst_index++){
FELEM *filter= ((FELEM*)c->filter_bank) + c->filter_alloc*(index & c->phase_mask);
int sample_index= index >> c->phase_shift;
FELEM *filter;
FELEM2 val=0;
sample_index += index >> c->phase_shift;
index &= c->phase_mask;
filter = ((FELEM*)c->filter_bank) + c->filter_alloc*index;
if(sample_index + c->filter_length > src_size || -sample_index >= src_size){
break;
}else if(sample_index < 0){
@ -113,9 +124,9 @@ int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int
dst_incr= c->ideal_dst_incr / c->src_incr;
}
}
*consumed= FFMAX(sample_index, 0);
index += FFMIN(sample_index, 0) << c->phase_shift;
}
*consumed= FFMAX(index, 0) >> c->phase_shift;
if(index>=0) index &= c->phase_mask;
if(compensation_distance){
compensation_distance -= dst_index;

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