lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-08-08 17:42:12 +03:00
Code Activity

Check for integer overflows in formatting functions

Browse Source
This commit is contained in:
Andreas Schwab
2009-09-29 06:11:59 -07:00
committed by Ulrich Drepper
parent 9d076f21cd
commit 199eb0de8d
3 changed files with 45 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
ChangeLog
View File

@@ -1,3 +1,8 @@
2009-09-28 Andreas Schwab <schwab@redhat.com>
* stdio-common/printf_fp.c: Check for and avoid integer overflows.
* stdio-common/vfprintf.c: Likewise.
2009-09-28 Ulrich Drepper <drepper@redhat.com>
* locale/programs/locale-spec.c (locale_special): If nothing matches

11
stdio-common/printf_fp.c
View File

@@ -891,8 +891,15 @@ ___printf_fp (FILE *fp,
it is possible that we need two more characters in front of all the
other output. If the amount of memory we have to allocate is too
large use `malloc' instead of `alloca'. */
size_t wbuffer_to_alloc = (2 + (size_t) chars_needed) * sizeof (wchar_t);
buffer_malloced = ! __libc_use_alloca (chars_needed * 2 * sizeof (wchar_t));
if (__builtin_expect (chars_needed >= (size_t) -1 / sizeof (wchar_t) - 2
|| chars_needed < fracdig_max, 0))
{
/* Some overflow occurred. */
__set_errno (ERANGE);
return -1;
}
size_t wbuffer_to_alloc = (2 + chars_needed) * sizeof (wchar_t);
buffer_malloced = ! __libc_use_alloca (wbuffer_to_alloc);
if (__builtin_expect (buffer_malloced, 0))
{
wbuffer = (wchar_t *) malloc (wbuffer_to_alloc);

49
stdio-common/vfprintf.c
View File

@@ -1439,23 +1439,29 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
left = 1;
}
if (width + 32 >= (int) (sizeof (work_buffer)
/ sizeof (work_buffer[0])))
if (__builtin_expect (width >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
done = -1;
goto all_done;
}
if (width >= sizeof (work_buffer) / sizeof (work_buffer[0]) - 32)
{
/* We have to use a special buffer. The "32" is just a safe
bet for all the output which is not counted in the width. */
if (__libc_use_alloca ((width + 32) * sizeof (CHAR_T)))
workend = ((CHAR_T *) alloca ((width + 32) * sizeof (CHAR_T))
+ (width + 32));
size_t needed = ((size_t) width + 32) * sizeof (CHAR_T);
if (__libc_use_alloca (needed))
workend = (CHAR_T *) alloca (needed) + width + 32;
else
{
workstart = (CHAR_T *) malloc ((width + 32) * sizeof (CHAR_T));
workstart = (CHAR_T *) malloc (needed);
if (workstart == NULL)
{
done = -1;
goto all_done;
}
workend = workstart + (width + 32);
workend = workstart + width + 32;
}
}
}
@@ -1465,22 +1471,29 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
LABEL (width):
width = read_int (&f);
if (width + 32 >= (int) (sizeof (work_buffer) / sizeof (work_buffer[0])))
if (__builtin_expect (width >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
done = -1;
goto all_done;
}
if (width >= sizeof (work_buffer) / sizeof (work_buffer[0]) - 32)
{
/* We have to use a special buffer. The "32" is just a safe
bet for all the output which is not counted in the width. */
if (__libc_use_alloca ((width + 32) * sizeof (CHAR_T)))
workend = ((CHAR_T *) alloca ((width + 32) * sizeof (CHAR_T))
+ (width + 32));
size_t needed = ((size_t) width + 32) * sizeof (CHAR_T);
if (__libc_use_alloca (needed))
workend = (CHAR_T *) alloca (needed) + width + 32;
else
{
workstart = (CHAR_T *) malloc ((width + 32) * sizeof (CHAR_T));
workstart = (CHAR_T *) malloc (needed);
if (workstart == NULL)
{
done = -1;
goto all_done;
}
workend = workstart + (width + 32);
workend = workstart + width + 32;
}
}
if (*f == L_('$'))
@@ -1510,18 +1523,18 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
else
prec = 0;
if (prec > width
&& prec + 32 > (int)(sizeof (work_buffer) / sizeof (work_buffer[0])))
&& prec > sizeof (work_buffer) / sizeof (work_buffer[0]) - 32)
{
if (__builtin_expect (prec > ~((size_t) 0) / sizeof (CHAR_T) - 31,
0))
if (__builtin_expect (prec >= (size_t) -1 / sizeof (CHAR_T) - 32, 0))
{
__set_errno (ERANGE);
done = -1;
goto all_done;
}
size_t needed = ((size_t) prec + 32) * sizeof (CHAR_T);
if (__libc_use_alloca (needed))
workend = (((CHAR_T *) alloca (needed)) + ((size_t) prec + 32));
workend = (CHAR_T *) alloca (needed) + prec + 32;
else
{
workstart = (CHAR_T *) malloc (needed);
@@ -1530,7 +1543,7 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
done = -1;
goto all_done;
}
workend = workstart + ((size_t) prec + 32);
workend = workstart + prec + 32;
}
}
JUMP (*f, step2_jumps);