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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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16
ChangeLog
View File

@ -1,3 +1,19 @@
2012-04-02 David S. Miller <davem@davemloft.net>
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.
2012-04-02 Thomas Schwinge <thomas@codesourcery.com>
* string/test-memcmp.c [! WIDE]: #include <limits.h> for CHAR_MIN,

28
stdio-common/bug22.c
View File

@ -1,12 +1,22 @@
/* BZ #5424 */
#include <stdio.h>
#include <errno.h>
/* INT_MAX + 1 */
#define N 2147483648
/* (INT_MAX / 2) + 2 */
#define N2 1073741825
/* INT_MAX - 3 */
#define N3 2147483644
#define STRINGIFY(S) #S
#define MAKE_STR(S) STRINGIFY(S)
#define SN MAKE_STR(N)
#define SN2 MAKE_STR(N2)
#define SN3 MAKE_STR(N3)
static int
do_test (void)
@ -20,11 +30,25 @@ do_test (void)
return 1;
}
ret = fprintf (fp, "%" SN "d%" SN "d", 1, 1);
ret = fprintf (fp, "%" SN "d", 1);
printf ("ret = %d\n", ret);
if (ret != -1 || errno != EOVERFLOW)
return 1;
ret = fprintf (fp, "%." SN "d", 1);
printf ("ret = %d\n", ret);
if (ret != -1 || errno != EOVERFLOW)
return 1;
ret = fprintf (fp, "%." SN3 "d", 1);
printf ("ret = %d\n", ret);
if (ret != -1 || errno != EOVERFLOW)
return 1;
ret = fprintf (fp, "%" SN2 "d%" SN2 "d", 1, 1);
printf ("ret = %d\n", ret);
return ret != -1;
return ret != -1 || errno != EOVERFLOW;
}
#define TIMEOUT 30

23
stdio-common/printf-parse.h
View File

@ -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;
}

42
stdio-common/printf-parsemb.c
View File

@ -87,12 +87,15 @@ __parse_one_specmb (const UCHAR_T *format, size_t posn,
n = read_int (&format);
if (n > 0 && *format == L_('$'))
if (n != 0 && *format == L_('$'))
/* Is positional parameter. */
{
++format; /* Skip the '$'. */
spec->data_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
if (n != -1)
{
spec->data_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
}
}
else
/* Oops; that was actually the width and/or 0 padding flag.
@ -160,10 +163,13 @@ __parse_one_specmb (const UCHAR_T *format, size_t posn,
/* The width argument might be found in a positional parameter. */
n = read_int (&format);
if (n > 0 && *format == L_('$'))
if (n != 0 && *format == L_('$'))
{
spec->width_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
if (n != -1)
{
spec->width_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
}
++format; /* Skip '$'. */
}
}
@ -177,9 +183,13 @@ __parse_one_specmb (const UCHAR_T *format, size_t posn,
}
}
else if (ISDIGIT (*format))
/* Constant width specification. */
spec->info.width = read_int (&format);
{
int n = read_int (&format);
/* Constant width specification. */
if (n != -1)
spec->info.width = n;
}
/* Get the precision. */
spec->prec_arg = -1;
/* -1 means none given; 0 means explicit 0. */
@ -196,10 +206,13 @@ __parse_one_specmb (const UCHAR_T *format, size_t posn,
{
n = read_int (&format);
if (n > 0 && *format == L_('$'))
if (n != 0 && *format == L_('$'))
{
spec->prec_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
if (n != -1)
{
spec->prec_arg = n - 1;
*max_ref_arg = MAX (*max_ref_arg, n);
}
++format;
}
}
@ -213,7 +226,12 @@ __parse_one_specmb (const UCHAR_T *format, size_t posn,
}
}
else if (ISDIGIT (*format))
spec->info.prec = read_int (&format);
{
int n = read_int (&format);
if (n != -1)
spec->info.prec = n;
}
else
/* "%.?" is treated like "%.0?". */
spec->info.prec = 0;

77
stdio-common/vfprintf.c
View File

@ -67,10 +67,10 @@
do { \
unsigned int _val = val; \
assert ((unsigned int) done < (unsigned int) INT_MAX); \
if (__builtin_expect ((unsigned int) INT_MAX - (unsigned int) done \
< _val, 0)) \
if (__builtin_expect (INT_MAX - done < _val, 0)) \
{ \
done = -1; \
__set_errno (EOVERFLOW); \
goto all_done; \
} \
done += _val; \
@ -141,12 +141,17 @@
do \
{ \
assert ((size_t) done <= (size_t) INT_MAX); \
if ((size_t) PUT (s, (String), (Len)) != (size_t) (Len) \
|| (size_t) INT_MAX - (size_t) done < (size_t) (Len)) \
if ((size_t) PUT (s, (String), (Len)) != (size_t) (Len)) \
{ \
done = -1; \
goto all_done; \
} \
if (__builtin_expect (INT_MAX - done < (Len), 0)) \
{ \
done = -1; \
__set_errno (EOVERFLOW); \
goto all_done; \
} \
done += (Len); \
} \
while (0)
@ -1435,10 +1440,21 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
const UCHAR_T *tmp; /* Temporary value. */
tmp = ++f;
if (ISDIGIT (*tmp) && read_int (&tmp) && *tmp == L_('$'))
/* The width comes from a positional parameter. */
goto do_positional;
if (ISDIGIT (*tmp))
{
int pos = read_int (&tmp);
if (pos == -1)
{
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
if (pos && *tmp == L_('$'))
/* The width comes from a positional parameter. */
goto do_positional;
}
width = va_arg (ap, int);
/* Negative width means left justified. */
@ -1449,9 +1465,9 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
left = 1;
}
if (__builtin_expect (width >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
if (__builtin_expect (width >= INT_MAX / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
@ -1481,9 +1497,10 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
LABEL (width):
width = read_int (&f);
if (__builtin_expect (width >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
if (__builtin_expect (width == -1
|| width >= INT_MAX / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
@ -1518,10 +1535,21 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
const UCHAR_T *tmp; /* Temporary value. */
tmp = ++f;
if (ISDIGIT (*tmp) && read_int (&tmp) > 0 && *tmp == L_('$'))
/* The precision comes from a positional parameter. */
goto do_positional;
if (ISDIGIT (*tmp))
{
int pos = read_int (&tmp);
if (pos == -1)
{
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
if (pos && *tmp == L_('$'))
/* The precision comes from a positional parameter. */
goto do_positional;
}
prec = va_arg (ap, int);
/* If the precision is negative the precision is omitted. */
@ -1529,15 +1557,26 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
prec = -1;
}
else if (ISDIGIT (*f))
prec = read_int (&f);
{
prec = read_int (&f);
/* The precision was specified in this case as an extremely
large positive value. */
if (prec == -1)
{
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
}
else
prec = 0;
if (prec > width
&& prec > sizeof (work_buffer) / sizeof (work_buffer[0]) - 32)
{
if (__builtin_expect (prec >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
if (__builtin_expect (prec >= INT_MAX / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}
@ -1710,9 +1749,9 @@ do_positional:
+ sizeof (*args_type));
/* Check for potential integer overflow. */
if (__builtin_expect (nargs > SIZE_MAX / bytes_per_arg, 0))
if (__builtin_expect (nargs > INT_MAX / bytes_per_arg, 0))
{
__set_errno (ERANGE);
__set_errno (EOVERFLOW);
done = -1;
goto all_done;
}