140 lines
5.1 KiB
Diff
140 lines
5.1 KiB
Diff
diff --git a/pngrutil.c b/pngrutil.c
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index 1de7427..72a8b5e 100644
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--- a/pngrutil.c
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+++ b/pngrutil.c
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@@ -503,7 +503,7 @@ void /* PRIVATE */
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png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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{
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png_color palette[PNG_MAX_PALETTE_LENGTH];
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- int num, i;
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+ int max_palette_length, num, i;
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#ifdef PNG_POINTER_INDEXING_SUPPORTED
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png_colorp pal_ptr;
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#endif
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@@ -555,8 +555,21 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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}
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}
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+ /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
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num = (int)length / 3;
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+ /* If the palette has 256 or fewer entries but is too large for the bit depth,
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+ * we don't issue an error, to preserve the behavior of previous libpng versions.
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+ * We silently truncate the unused extra palette entries here.
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+ */
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+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
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+ max_palette_length = (1 << png_ptr->bit_depth);
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+ else
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+ max_palette_length = PNG_MAX_PALETTE_LENGTH;
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+
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+ if (num > max_palette_length)
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+ num = max_palette_length;
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+
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#ifdef PNG_POINTER_INDEXING_SUPPORTED
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for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
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{
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@@ -589,7 +602,7 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
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#endif
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{
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- png_crc_finish(png_ptr, 0);
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+ png_crc_finish(png_ptr, (int) length - num * 3);
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}
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#ifndef PNG_READ_OPT_PLTE_SUPPORTED
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else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */
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@@ -1097,7 +1110,7 @@ png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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/* There should be at least one zero (the compression type byte)
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* following the separator, and we should be on it
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*/
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- if ( profile >= png_ptr->chunkdata + slength - 1)
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+ if ( slength < 1 || profile >= png_ptr->chunkdata + slength - 1)
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{
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png_free(png_ptr, png_ptr->chunkdata);
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png_ptr->chunkdata = NULL;
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@@ -1225,7 +1238,7 @@ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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++entry_start;
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/* A sample depth should follow the separator, and we should be on it */
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- if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
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+ if (slength < 2 || entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
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{
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png_free(png_ptr, png_ptr->chunkdata);
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png_ptr->chunkdata = NULL;
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@@ -1699,7 +1712,7 @@ png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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/* We need to have at least 12 bytes after the purpose string
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in order to get the parameter information. */
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- if (endptr <= buf + 12)
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+ if (slength < 12 || endptr <= buf + 12)
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{
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png_warning(png_ptr, "Invalid pCAL data");
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png_free(png_ptr, png_ptr->chunkdata);
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@@ -2155,7 +2168,7 @@ png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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/* Empty loop */ ;
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/* zTXt must have some text after the chunkdataword */
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- if (text >= png_ptr->chunkdata + slength - 2)
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+ if (slength < 2 || text >= png_ptr->chunkdata + slength - 2)
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{
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png_warning(png_ptr, "Truncated zTXt chunk");
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png_free(png_ptr, png_ptr->chunkdata);
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@@ -2281,7 +2294,7 @@ png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
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* keyword
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*/
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- if (lang >= png_ptr->chunkdata + slength - 3)
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+ if (slength < 3 || lang >= png_ptr->chunkdata + slength - 3)
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{
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png_warning(png_ptr, "Truncated iTXt chunk");
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png_free(png_ptr, png_ptr->chunkdata);
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diff --git a/pngset.c b/pngset.c
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index 7a47b1e..54ac931 100644
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--- a/pngset.c
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+++ b/pngset.c
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@@ -446,12 +446,17 @@ png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
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png_colorp palette, int num_palette)
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{
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+ png_uint_32 max_palette_length;
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+
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png_debug1(1, "in %s storage function", "PLTE");
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if (png_ptr == NULL || info_ptr == NULL)
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return;
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- if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
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+ max_palette_length = (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
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+ (1 << info_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
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+
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+ if (num_palette < 0 || num_palette > (int) max_palette_length)
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{
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if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
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png_error(png_ptr, "Invalid palette length");
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diff --git a/pngwutil.c b/pngwutil.c
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index c75f53e..80128d6 100644
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--- a/pngwutil.c
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+++ b/pngwutil.c
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@@ -575,17 +575,20 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
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#ifdef PNG_USE_LOCAL_ARRAYS
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PNG_PLTE;
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#endif
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- png_uint_32 i;
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+ png_uint_32 max_palette_length, i;
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png_colorp pal_ptr;
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png_byte buf[3];
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png_debug(1, "in png_write_PLTE");
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+ max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
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+ (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
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+
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if ((
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#ifdef PNG_MNG_FEATURES_SUPPORTED
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!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
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#endif
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- num_pal == 0) || num_pal > 256)
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+ num_pal == 0) || num_pal > max_palette_length)
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{
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if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
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{
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