+
+void /* PRIVATE */
+png_check_IHDR(png_structp png_ptr,
+ png_uint_32 width, png_uint_32 height, int bit_depth,
+ int color_type, int interlace_type, int compression_type,
+ int filter_type)
+{
+ int error = 0;
+
+ /* Check for width and height valid values */
+ if (width == 0)
+ {
+ png_warning(png_ptr, "Image width is zero in IHDR");
+ error = 1;
+ }
+
+ if (height == 0)
+ {
+ png_warning(png_ptr, "Image height is zero in IHDR");
+ error = 1;
+ }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+ if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX)
+#else
+ if (width > PNG_USER_WIDTH_MAX)
+#endif
+ {
+ png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+ error = 1;
+ }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+ if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)
+#else
+ if (height > PNG_USER_HEIGHT_MAX)
+#endif
+ {
+ png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+ error = 1;
+ }
+
+ if (width > PNG_UINT_31_MAX)
+ {
+ png_warning(png_ptr, "Invalid image width in IHDR");
+ error = 1;
+ }
+
+ if ( height > PNG_UINT_31_MAX)
+ {
+ png_warning(png_ptr, "Invalid image height in IHDR");
+ error = 1;
+ }
+
+ if ( width > (PNG_UINT_32_MAX
+ >> 3) /* 8-byte RGBA pixels */
+ - 64 /* bigrowbuf hack */
+ - 1 /* filter byte */
+ - 7*8 /* rounding of width to multiple of 8 pixels */
+ - 8) /* extra max_pixel_depth pad */
+ png_warning(png_ptr, "Width is too large for libpng to process pixels");
+
+ /* Check other values */
+ if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+ bit_depth != 8 && bit_depth != 16)
+ {
+ png_warning(png_ptr, "Invalid bit depth in IHDR");
+ error = 1;
+ }
+
+ if (color_type < 0 || color_type == 1 ||
+ color_type == 5 || color_type > 6)
+ {
+ png_warning(png_ptr, "Invalid color type in IHDR");
+ error = 1;
+ }
+
+ if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+ ((color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+ {
+ png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
+ error = 1;
+ }
+
+ if (interlace_type >= PNG_INTERLACE_LAST)
+ {
+ png_warning(png_ptr, "Unknown interlace method in IHDR");
+ error = 1;
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Unknown compression method in IHDR");
+ error = 1;
+ }
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ /* Accept filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not read a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
+ png_ptr->mng_features_permitted)
+ png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+
+ if (filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+ (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+ ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+ {
+ png_warning(png_ptr, "Unknown filter method in IHDR");
+ error = 1;
+ }
+
+ if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
+ {
+ png_warning(png_ptr, "Invalid filter method in IHDR");
+ error = 1;
+ }
+ }
+
+#else
+ if (filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Unknown filter method in IHDR");
+ error = 1;
+ }
+#endif
+
+ if (error == 1)
+ png_error(png_ptr, "Invalid IHDR data");
+}
projects / wxWidgets.git / blobdiff