[devel] Improve IHDR checking and error reporting

Move redundant IHDR checking into new png_check_IHDR() in png.c
and report all errors found in the IHDR data.  Report problems
with width and height separately.

1 files changed, 3 insertions, 69 deletions

diff --git a/pngset.c b/pngset.c
index 76bbbf1d3..87e209eef 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.4.0 [September 23, 2009]
+ * Last changed in libpng 1.4.0 [September 24, 2009]
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -227,74 +227,8 @@ png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   /* Check for width and height valid values */
-   if (width == 0 || height == 0)
-      png_error(png_ptr, "Image width or height is zero in IHDR");
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   if (width > png_ptr->user_width_max || height > png_ptr->user_height_max)
-      png_error(png_ptr, "image size exceeds user limits in IHDR");
-#else
-   if (width > PNG_USER_WIDTH_MAX || height > PNG_USER_HEIGHT_MAX)
-      png_error(png_ptr, "image size exceeds user limits in IHDR");
-#endif
-   if (width > PNG_UINT_31_MAX || height > PNG_UINT_31_MAX)
-      png_error(png_ptr, "Invalid image size in IHDR");
-   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_error(png_ptr, "Invalid bit depth in IHDR");
-
-   if (color_type < 0 || color_type == 1 ||
-       color_type == 5 || color_type > 6)
-      png_error(png_ptr, "Invalid color type in IHDR");
-
-   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_error(png_ptr, "Invalid color type/bit depth combination in IHDR");
-
-   if (interlace_type >= PNG_INTERLACE_LAST)
-      png_error(png_ptr, "Unknown interlace method in IHDR");
-
-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
-      png_error(png_ptr, "Unknown compression method in IHDR");
-
-#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_error(png_ptr, "Unknown filter method in IHDR");
-     if (png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)
-        png_warning(png_ptr, "Invalid filter method in IHDR");
-   }
-#else
-   if (filter_type != PNG_FILTER_TYPE_BASE)
-      png_error(png_ptr, "Unknown filter method in IHDR");
-#endif
+   png_check_IHDR (png_ptr, width, height, bit_depth, color_type,
+       interlace_type, compression_type, filter_type);
 
    info_ptr->width = width;
    info_ptr->height = height;