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[libpng17] Added byte, short and other overflow checking

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Added 'assert' based overflow checking for debug builds for char
and short assignments. Simply ignore the error in release builds
(a truncated value will be used without warning). Controlled by
PNG_RANGE_CHECK_SUPPORTED.
This commit is contained in:
John Bowler
2015-03-22 15:57:53 -05:00
committed by Glenn Randers-Pehrson
parent 382de60042
commit 82fa6aed0e
14 changed files with 618 additions and 508 deletions
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54
pngerror.c
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@@ -454,7 +454,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
else
{
buffer[iout++] = (char)c;
buffer[iout++] = png_check_char(png_ptr, c);
}
}
@@ -1143,4 +1143,56 @@ PNG_FUNCTION(void, png_affirm,(png_const_structrp png_ptr,
# endif /* AFFIRM_ERROR */
}
#ifdef PNG_RANGE_CHECK_SUPPORTED
/* The character/byte checking APIs, these do their own calls to png_assert
* because the caller provides the position.
*/
char /* PRIVATE */
png_char_affirm(png_const_structrp png_ptr, unsigned int position, int c)
{
if (c >= CHAR_MIN && c <= CHAR_MAX)
return (char)/*SAFE*/c;
# if PNG_AFFIRM_ERROR
/* testing in RC: no condition */
png_affirm(png_ptr, position);
# else
png_affirm(png_ptr, "(char) range", position);
# endif
}
png_byte /* PRIVATE */
png_byte_affirm(png_const_structrp png_ptr, unsigned int position, int b)
{
/* For the type png_byte the limits.h values are ignored and we check
* against the values PNG expects to store in a byte:
*/
if (b >= 0 && b <= 255)
return (png_byte)/*SAFE*/b;
# if PNG_AFFIRM_ERROR
/* testing in RC: no condition */
png_affirm(png_ptr, position);
# else
png_affirm(png_ptr, "PNG byte range", position);
# endif
}
#if INT_MAX >= 65535
png_uint_16 /* PRIVATE */
png_u16_affirm(png_const_structrp png_ptr, unsigned int position, int b)
{
/* Check against the PNG 16-bit limit, as with png_byte. */
if (b >= 0 && b <= 65535)
return (png_uint_16)/*SAFE*/b;
# if PNG_AFFIRM_ERROR
/* testing in RC: no condition */
png_affirm(png_ptr, position);
# else
png_affirm(png_ptr, "PNG 16-bit range", position);
# endif
}
#endif /* INT_MAX >= 65535 */
#endif /* RANGE_CHECK */
#endif /* READ || WRITE */