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add WebPCheckCropDimensions()

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and avoid integer overflow in test of x/width and y/height parameters
against the image width/height

Bug: chromium:1196778, chromium:1196777, chromium:1196480
Change-Id: I7b8f1f4dbebfe073b1ba260b8317979488655dcc
This commit is contained in:
James Zern 2021-04-20 14:02:52 -07:00
parent 8fdaecb09d
commit 595fa13f83
3 changed files with 13 additions and 3 deletions
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3
src/dec/buffer_dec.c
View File

@ -188,8 +188,7 @@ VP8StatusCode WebPAllocateDecBuffer(int width, int height,
const int ch = options->crop_height;
const int x = options->crop_left & ~1;
const int y = options->crop_top & ~1;
if (x < 0 || y < 0 || cw <= 0 || ch <= 0 ||
x + cw > width || y + ch > height) {
if (!WebPCheckCropDimensions(width, height, x, y, cw, ch)) {
return VP8_STATUS_INVALID_PARAM; // out of frame boundary.
}
width = cw;

9
src/dec/webp_dec.c
View File

@ -785,6 +785,13 @@ VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
//------------------------------------------------------------------------------
// Cropping and rescaling.
int WebPCheckCropDimensions(int image_width, int image_height,
int x, int y, int w, int h) {
return !(x < 0 || y < 0 || w <= 0 || h <= 0 ||
x >= image_width || w > image_width || w > image_width - x ||
y >= image_height || h > image_height || h > image_height - y);
}
int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
VP8Io* const io, WEBP_CSP_MODE src_colorspace) {
const int W = io->width;
@ -802,7 +809,7 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
x &= ~1;
y &= ~1;
}
if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > W || y + h > H) {
if (!WebPCheckCropDimensions(W, H, x, y, w, h)) {
return 0; // out of frame boundary error
}
}

4
src/dec/webpi_dec.h
View File

@ -77,6 +77,10 @@ VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers);
//------------------------------------------------------------------------------
// Misc utils
// Returns true if crop dimensions are within image bounds.
int WebPCheckCropDimensions(int image_width, int image_height,
int x, int y, int w, int h);
// Initializes VP8Io with custom setup, io and teardown functions. The default
// hooks will use the supplied 'params' as io->opaque handle.
void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io);