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(svn r22873) -Fix [FS#4747]: Validate image dimensions before loading…
…. (Based on patch by monoid)
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michicc committed Sep 2, 2011
1 parent 655d45e commit 6c7cbb1d46d266d33e49bd42a52e483296313882
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Showing 3 changed files with 35 additions and 3 deletions.
@@ -142,13 +142,24 @@ static bool ReadHeightmapPNG(char *filename, uint *x, uint *y, byte **map)
return false;
}

uint width = png_get_image_width(png_ptr, info_ptr);
uint height = png_get_image_height(png_ptr, info_ptr);

/* Check if image dimensions don't overflow a size_t to avoid memory corruption. */
if ((uint64)width * height >= (size_t)-1) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_HEIGHTMAP_TOO_LARGE, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}

if (map != NULL) {
*map = MallocT<byte>(png_get_image_width(png_ptr, info_ptr) * png_get_image_height(png_ptr, info_ptr));
*map = MallocT<byte>(width * height);
ReadHeightmapPNGImageData(*map, png_ptr, info_ptr);
}

*x = png_get_image_width(png_ptr, info_ptr);
*y = png_get_image_height(png_ptr, info_ptr);
*x = width;
*y = height;

fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
@@ -243,6 +254,14 @@ static bool ReadHeightmapBMP(char *filename, uint *x, uint *y, byte **map)
return false;
}

/* Check if image dimensions don't overflow a size_t to avoid memory corruption. */
if ((uint64)info.width * info.height >= (size_t)-1 / (info.bpp == 24 ? 3 : 1)) {
ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_HEIGHTMAP_TOO_LARGE, WL_ERROR);
fclose(f);
BmpDestroyData(&data);
return false;
}

if (map != NULL) {
if (!BmpReadBitmap(&buffer, &info, &data)) {
ShowErrorMessage(STR_ERROR_BMPMAP, STR_ERROR_BMPMAP_IMAGE_TYPE, WL_ERROR);
@@ -3452,6 +3452,8 @@ STR_ERROR_PNGMAP_MISC :{WHITE}... some
STR_ERROR_BMPMAP :{WHITE}Can't load landscape from BMP...
STR_ERROR_BMPMAP_IMAGE_TYPE :{WHITE}... could not convert image type

STR_ERROR_HEIGHTMAP_TOO_LARGE :{WHITE}... image is too large

STR_WARNING_HEIGHTMAP_SCALE_CAPTION :{WHITE}Scale warning
STR_WARNING_HEIGHTMAP_SCALE_MESSAGE :{YELLOW}Resizing source map too much is not recommended. Continue with the generation?

@@ -108,14 +108,25 @@ static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 i

sprite->height = png_get_image_height(png_ptr, info_ptr);
sprite->width = png_get_image_width(png_ptr, info_ptr);
/* Check if sprite dimensions aren't larger than what is allowed in GRF-files. */
if (sprite->height > UINT8_MAX || sprite->width > UINT16_MAX) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return false;
}
sprite->AllocateData(sprite->width * sprite->height);
} else if (sprite->height != png_get_image_height(png_ptr, info_ptr) || sprite->width != png_get_image_width(png_ptr, info_ptr)) {
/* Make sure the mask image isn't larger than the sprite image. */
DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't the same dimension as the masked sprite", id);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return true;
}

bit_depth = png_get_bit_depth(png_ptr, info_ptr);
colour_type = png_get_color_type(png_ptr, info_ptr);

if (mask && (bit_depth != 8 || colour_type != PNG_COLOR_TYPE_PALETTE)) {
DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return true;
}

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