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Tighten up vfprintf width, precision, and total length overflow handling.

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With help from Paul Eggert, Carlos O'Donell, and Roland McGrath.
	* stdio-common/printf-parse.h (read_int): Change return type to
	'int', return -1 on INT_MAX overflow.
	* stdio-common/vfprintf.c (vfprintf): Validate width and precision
	against overflow of INT_MAX.  Set errno to EOVERFLOW when 'done'
	overflows INT_MAX.  Check for overflow of in-format-string precision
	values properly.  Use EOVERFLOW rather than ERANGE throughout.  Use
	SIZE_MAX not INT_MAX for integer overflow test.
	* stdio-common/printf-parsemb.c: If read_int signals an overflow,
	skip the construct in the format string but do not record anything.
	* stdio-common/bug22.c: Adjust to test both width/prevision
	INT_MAX overflow as well as total length INT_MAX overflow.  Check
	explicitly for proper errno values.
This commit is contained in:
David S. Miller
2012-04-02 14:31:19 -07:00
parent 302cadd343
commit 135ffda8b8
5 changed files with 147 additions and 39 deletions
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23
stdio-common/printf-parse.h
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@ -68,16 +68,27 @@ union printf_arg
#ifndef DONT_NEED_READ_INT
/* Read a simple integer from a string and update the string pointer.
It is assumed that the first character is a digit. */
static unsigned int
static int
read_int (const UCHAR_T * *pstr)
{
unsigned int retval = **pstr - L_('0');
int retval = **pstr - L_('0');
while (ISDIGIT (*++(*pstr)))
{
retval *= 10;
retval += **pstr - L_('0');
}
if (retval >= 0)
{
if (INT_MAX / 10 < retval)
retval = -1;
else
{
int digit = **pstr - L_('0');
retval *= 10;
if (INT_MAX - digit < retval)
retval = -1;
else
retval += digit;
}
}
return retval;
}