dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-13 14:34:33 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

fix rescaling bug (uninitialized read, see bug #254).

Browse Source 
the x_add/x_sub increments were wrong for u/v in the upscaling case.
They shouldn't be left to the caller's discretion, but set up by
WebPRescalerInit to their exact necessary values.

-> Cleaned-up WebPRescalerInit() param list.
-> added safety asserts
-> removed the mips32/mips_r2 variant of "ImportRow" which were buggy prior

Change-Id: I347c75804d835811e7025de92a0758d7929dfc09
This commit is contained in:
Pascal Massimino
2015-08-05 15:11:48 +02:00
parent 99131e7f8c
commit 7df93893dc
8 changed files with 31 additions and 224 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
src/utils/rescaler.c
View File

@ -19,9 +19,11 @@
//------------------------------------------------------------------------------
void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
uint8_t* const dst, int dst_width, int dst_height,
int dst_stride, int num_channels, int x_add, int x_sub,
int y_add, int y_sub, int32_t* const work) {
uint8_t* const dst,
int dst_width, int dst_height, int dst_stride,
int num_channels, int32_t* const work) {
const int x_add = src_width, x_sub = dst_width;
const int y_add = src_height, y_sub = dst_height;
wrk->x_expand = (src_width < dst_width);
wrk->src_width = src_width;
wrk->src_height = src_height;
@ -36,11 +38,12 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
wrk->y_accum = y_add;
wrk->y_add = y_add;
wrk->y_sub = y_sub;
wrk->fx_scale = (1 << WEBP_RESCALER_RFIX) / x_sub;
wrk->fy_scale = (1 << WEBP_RESCALER_RFIX) / y_sub;
wrk->fxy_scale = wrk->x_expand ?
((int64_t)dst_height << WEBP_RESCALER_RFIX) / (x_sub * src_height) :
((int64_t)dst_height << WEBP_RESCALER_RFIX) / (x_add * src_height);
if (!wrk->x_expand) { // fx_scale is not used otherwise
wrk->fx_scale = (1 << WEBP_RESCALER_RFIX) / wrk->x_sub;
}
wrk->fy_scale = (1 << WEBP_RESCALER_RFIX) / wrk->y_sub;
wrk->fxy_scale =
((int64_t)dst_height << WEBP_RESCALER_RFIX) / (wrk->x_add * src_height);
wrk->irow = work;
wrk->frow = work + num_channels * dst_width;

2
src/utils/rescaler.h
View File

@ -46,8 +46,6 @@ void WebPRescalerInit(WebPRescaler* const rescaler,
uint8_t* const dst,
int dst_width, int dst_height, int dst_stride,
int num_channels,
int x_add, int x_sub,
int y_add, int y_sub,
int32_t* const work);
// Returns the number of input lines needed next to produce one output line,