[libpng17] Rearrange terms to make it self-evident that overflow cannot happen

This commit is contained in:
Glenn Randers-Pehrson 2015-11-16 09:34:20 -06:00
parent c09b3ab2c7
commit 801608f8f4

View File

@ -1530,7 +1530,7 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr)
++entry_start;
/* A sample depth should follow the separator, and we should be on it */
if (length < 2 || entry_start > buffer + length - 2)
if (length < 2 || entry_start - buffer > length - 2)
{
png_chunk_benign_error(png_ptr, "malformed");
return;
@ -1948,7 +1948,7 @@ png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr)
/* We need to have at least 12 bytes after the purpose string
* in order to get the parameter information.
*/
if (png_ptr->chunk_length < 12 || endptr <= buf + 12)
if (png_ptr->chunk_length < 12 || endptr - buf <= 12)
{
png_chunk_benign_error(png_ptr, "invalid");
return;