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add more checks around picture allocation

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covers overflow corner cases for 32/64bit platforms.

Change-Id: I0c9169264c33a4e9d0bbfdb026fb0d82c7e56de8
This commit is contained in:
Pascal Massimino 2011-02-27 10:31:20 -08:00
parent b65a3e101e
commit 84b58ebba3
1 changed files with 10 additions and 4 deletions
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14
src/enc/picture.c
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@ -26,13 +26,19 @@ int WebPPictureAlloc(WebPPicture* const picture) {
const int height = picture->height;
const int uv_width = (width + 1) / 2;
const int uv_height = (height + 1) / 2;
const int y_size = width * height;
const int uv_size = uv_width * uv_height;
if (width <= 0 || height <= 0) return 0; // error
const uint64_t y_size = (uint64_t)width * height;
const uint64_t uv_size = (uint64_t)uv_width * uv_height;
const uint64_t total_size = y_size + 2 * uv_size;
// Security and validation checks
if (uv_width <= 0 || uv_height <= 0 || // check param error
y_size >= (1ULL << 40) || // check for reasonable global size
(size_t)total_size != total_size) { // check for overflow on 32bit
return 0;
}
picture->y_stride = width;
picture->uv_stride = uv_width;
WebPPictureFree(picture); // erase previous buffer
picture->y = (uint8_t*)malloc(y_size + 2 * uv_size);
picture->y = (uint8_t*)malloc(total_size);
if (picture->y == NULL) return 0;
picture->u = picture->y + y_size;
picture->v = picture->u + uv_size;