[FFmpeg-devel] [PATCH] libswscale: avoid UB nullptr-with-offset.
jleconte
jleconte at google.com
Mon Dec 21 15:52:08 EET 2020
---
libswscale/slice.c | 12 +++++-------
libswscale/swscale_unscaled.c | 5 +++--
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/libswscale/slice.c b/libswscale/slice.c
index 7849b70f4d..b1cfc0e506 100644
--- a/libswscale/slice.c
+++ b/libswscale/slice.c
@@ -158,14 +158,12 @@ int ff_init_slice_from_src(SwsSlice * s, uint8_t *src[4], int stride[4], int src
chrY + chrH,
lumY + lumH};
- uint8_t *const src_[4] = {src[0] + (relative ? 0 : start[0]) * stride[0],
- src[1] + (relative ? 0 : start[1]) * stride[1],
- src[2] + (relative ? 0 : start[2]) * stride[2],
- src[3] + (relative ? 0 : start[3]) * stride[3]};
-
s->width = srcW;
for (i = 0; i < 4; ++i) {
+ if (!src[i])
+ continue;
+ uint8_t *const src_ = src[i] + (relative ? 0 : start[i]) * stride[i];
int j;
int first = s->plane[i].sliceY;
int n = s->plane[i].available_lines;
@@ -175,13 +173,13 @@ int ff_init_slice_from_src(SwsSlice * s, uint8_t *src[4], int stride[4], int src
if (start[i] >= first && n >= tot_lines) {
s->plane[i].sliceH = FFMAX(tot_lines, s->plane[i].sliceH);
for (j = 0; j < lines; j+= 1)
- s->plane[i].line[start[i] - first + j] = src_[i] + j * stride[i];
+ s->plane[i].line[start[i] - first + j] = src_ + j * stride[i];
} else {
s->plane[i].sliceY = start[i];
lines = lines > n ? n : lines;
s->plane[i].sliceH = lines;
for (j = 0; j < lines; j+= 1)
- s->plane[i].line[j] = src_[i] + j * stride[i];
+ s->plane[i].line[j] = src_ + j * stride[i];
}
}
diff --git a/libswscale/swscale_unscaled.c b/libswscale/swscale_unscaled.c
index 563de39696..39fb7cc87f 100644
--- a/libswscale/swscale_unscaled.c
+++ b/libswscale/swscale_unscaled.c
@@ -1806,6 +1806,9 @@ static int planarCopyWrapper(SwsContext *c, const uint8_t *src[],
const AVPixFmtDescriptor *desc_dst = av_pix_fmt_desc_get(c->dstFormat);
int plane, i, j;
for (plane = 0; plane < 4; plane++) {
+ if (!dst[plane])
+ continue;
+
int length = (plane == 0 || plane == 3) ? c->srcW : AV_CEIL_RSHIFT(c->srcW, c->chrDstHSubSample);
int y = (plane == 0 || plane == 3) ? srcSliceY: AV_CEIL_RSHIFT(srcSliceY, c->chrDstVSubSample);
int height = (plane == 0 || plane == 3) ? srcSliceH: AV_CEIL_RSHIFT(srcSliceH, c->chrDstVSubSample);
@@ -1813,8 +1816,6 @@ static int planarCopyWrapper(SwsContext *c, const uint8_t *src[],
uint8_t *dstPtr = dst[plane] + dstStride[plane] * y;
int shiftonly = plane == 1 || plane == 2 || (!c->srcRange && plane == 0);
- if (!dst[plane])
- continue;
// ignore palette for GRAY8
if (plane == 1 && !dst[2]) continue;
if (!src[plane] || (plane == 1 && !src[2])) {
--
2.29.2.684.gfbc64c5ab5-goog
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