[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.

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.4.0beta82 - September 23, 2009
+Libpng 1.4.0beta82 - September 24, 2009
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -558,7 +558,9 @@ version 1.4.0beta81 [September 23, 2009]
   Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
   Eliminated unused png_ptr->row_buf_size
 
-version 1.4.0beta82 [September 23, 2009]
+version 1.4.0beta82 [September 24, 2009]
+  Move redundant IHDR checking into new png_check_IHDR() in png.c
+    and report all errors found in the IHDR data.
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.

CHANGES

@@ -2244,7 +2244,9 @@ version 1.4.0beta81 [September 23, 2009]
   Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
   Eliminated unused png_ptr->row_buf_size
 
-version 1.4.0beta82 [September 23, 2009]
+version 1.4.0beta82 [September 24, 2009]
+  Move redundant IHDR checking into new png_check_IHDR() in png.c
+    and report all errors found in the IHDR data.
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.

png.c

@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * 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.)
@@ -546,13 +546,13 @@ png_get_copyright(png_structp png_ptr)
 #else
 #ifdef __STDC__
    return ((png_charp) PNG_STRING_NEWLINE \
-     "libpng version x 1.4.0beta82 - September 23, 2009" PNG_STRING_NEWLINE \
+     "libpng version x 1.4.0beta82 - September 24, 2009" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2009 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE);
 #else
-      return ((png_charp) "libpng version 1.4.0beta82 - September 23, 2009\
+      return ((png_charp) "libpng version 1.4.0beta82 - September 24, 2009\
       Copyright (c) 1998-2009 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
@@ -766,4 +766,148 @@ png_check_cHRM_fixed(png_structp png_ptr,
 }
 #endif /* PNG_CHECK_cHRM_SUPPORTED */
 #endif /* PNG_cHRM_SUPPORTED */
+
+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)
+   {
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)
+   {
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
+   }
+
+#else
+   if (width > PNG_USER_WIDTH_MAX
+   {
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   if (height > PNG_USER_HEIGHT_MAX)
+   {
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
+   }
+#endif
+
+   if (height > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image height in IHDR");
+      error = 1;
+   }
+
+   if ( height > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image width 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");
+
+#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");
+}
 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */

pngget.c

@@ -1,7 +1,7 @@
 
 /* pngget.c - retrieval of values from 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.)
@@ -579,52 +579,44 @@ png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
    int *filter_type)
 
 {
+   int test_interlace_type = 0;
+   int test_compression_type = 0;
+   int test_filter_type = 0;
+
    png_debug1(1, "in %s retrieval function", "IHDR");
 
-   if (png_ptr != NULL && info_ptr != NULL && width != NULL && height != NULL &&
+   if (png_ptr == NULL || info_ptr == NULL || width == NULL ||
-      bit_depth != NULL && color_type != NULL)
+       height == NULL || bit_depth == NULL || color_type == NULL)
+      return (0);
+
+   *width = info_ptr->width;
+   *height = info_ptr->height;
+   *bit_depth = info_ptr->bit_depth;
+   *color_type = info_ptr->color_type;
+
+   if (compression_type != NULL)
    {
-      *width = info_ptr->width;
+      *compression_type = info_ptr->compression_type;
-      *height = info_ptr->height;
+      test_compression_type=*compression_type;
-      *bit_depth = info_ptr->bit_depth;
-      if (info_ptr->bit_depth < 1 || info_ptr->bit_depth > 16)
-         png_error(png_ptr, "Invalid bit depth");
-
-      *color_type = info_ptr->color_type;
-
-      if (info_ptr->color_type > 6)
-         png_error(png_ptr, "Invalid color type");
-
-      if (compression_type != NULL)
-         *compression_type = info_ptr->compression_type;
-
-      if (filter_type != NULL)
-         *filter_type = info_ptr->filter_type;
-
-      if (interlace_type != NULL)
-         *interlace_type = info_ptr->interlace_type;
-
-      /* Check for potential overflow of rowbytes */
-      if (*width == 0 || *width > PNG_UINT_31_MAX)
-        png_error(png_ptr, "Invalid image width");
-
-      if (*height == 0 || *height > PNG_UINT_31_MAX)
-        png_error(png_ptr, "Invalid image height");
-
-      if (info_ptr->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 too large for libpng to process image data");
-      }
-
-      return (1);
    }
-   return (0);
+
+   if (filter_type != NULL)
+   {
+      *filter_type = info_ptr->filter_type;
+      test_filter_type=*filter_type;
+   }
+
+   if (interlace_type != NULL)
+   {
+      *interlace_type = info_ptr->interlace_type;
+      test_interlace_type=*interlace_type;
+   }
+
+   png_check_IHDR (png_ptr, *width, *height, *bit_depth, *color_type,
+      info_ptr->interlace_type, info_ptr->compression_type,
+      info_ptr->filter_type);
+
+   return (1);
 }
 
 #ifdef PNG_oFFs_SUPPORTED

pngpriv.h

@@ -1,7 +1,7 @@
 
 /* pngpriv.h - private declarations for use inside libpng
  *
- * libpng version 1.4.0beta82 - September 23, 2009
+ * libpng version 1.4.0beta82 - September 24, 2009
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -810,13 +810,19 @@ PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
 
 /* Added at libpng version 1.4.0 */
 #ifdef PNG_cHRM_SUPPORTED
-PNG_EXTERN int png_check_cHRM_fixed  PNGARG((png_structp png_ptr,
+PNG_EXTERN int png_check_cHRM_fixed PNGARG((png_structp png_ptr,
    png_fixed_point int_white_x, png_fixed_point int_white_y,
    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
    png_fixed_point int_blue_y));
 #endif
 
+/* Added at libpng version 1.4.0 */
+PNG_EXTERN void png_check_IHDR PNGARG((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));
+
 #ifdef PNG_cHRM_SUPPORTED
 #ifdef PNG_CHECK_cHRM_SUPPORTED
 /* Added at libpng version 1.2.34 and 1.4.0 */

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 */
+   png_check_IHDR (png_ptr, width, height, bit_depth, color_type,
-   if (width == 0 || height == 0)
+       interlace_type, compression_type, filter_type);
-      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
 
    info_ptr->width = width;
    info_ptr->height = height;