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authorDavid S. Miller <davem@davemloft.net>2012-04-02 14:31:19 -0700
committerDavid S. Miller <davem@davemloft.net>2012-04-02 14:31:19 -0700
commit135ffda8b84226a91c6062db69a61975b2f11cb6 (patch)
tree5aa71e41591bc7246f36bb55fbf7dc7daaefd9d1 /stdio-common
parent302cadd343d26cfa9b043c213c2a38de259464d8 (diff)
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Tighten up vfprintf width, precision, and total length overflow handling.
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.
Diffstat (limited to 'stdio-common')
-rw-r--r--stdio-common/bug22.c28
-rw-r--r--stdio-common/printf-parse.h23
-rw-r--r--stdio-common/printf-parsemb.c42
-rw-r--r--stdio-common/vfprintf.c77
4 files changed, 131 insertions, 39 deletions
diff --git a/stdio-common/bug22.c b/stdio-common/bug22.c
index 2228388b47..efd9501368 100644
--- a/stdio-common/bug22.c
+++ b/stdio-common/bug22.c
@@ -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
diff --git a/stdio-common/printf-parse.h b/stdio-common/printf-parse.h
index 72665dcec2..3aa0274249 100644
--- a/stdio-common/printf-parse.h
+++ b/stdio-common/printf-parse.h
@@ -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;
}
diff --git a/stdio-common/printf-parsemb.c b/stdio-common/printf-parsemb.c
index 2bdb5e65ab..a45ac74e06 100644
--- a/stdio-common/printf-parsemb.c
+++ b/stdio-common/printf-parsemb.c
@@ -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;
diff --git a/stdio-common/vfprintf.c b/stdio-common/vfprintf.c
index 1e904833a3..463f9c0062 100644
--- a/stdio-common/vfprintf.c
+++ b/stdio-common/vfprintf.c
@@ -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;
}