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Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319)

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The _chk variants of all of the printf functions become much simpler.
This is the last thing that we needed _IO_acquire_lock_clear_flags2
for, so it can go as well.  I took the opportunity to make the headers
included and the names of all local variables consistent across all the
affected files.

Since we ultimately want to get rid of __no_long_double as well, it
must be possible to get all of the nontrivial effects of the _chk
functions by calling the _internal functions with appropriate flags.
For most of the __(v)xprintf_chk functions, this is covered by
PRINTF_FORTIFY plus some up-front argument checks that can be
duplicated.  However, __(v)sprintf_chk installs a custom jump table so
that it can crash instead of overflowing the output buffer.  This
functionality is moved to __vsprintf_internal, which now has a
'maxlen' argument like __vsnprintf_internal; to get the unsafe
behavior of ordinary (v)sprintf, pass -1 for that argument.

obstack_printf_chk and obstack_vprintf_chk are no longer in the same
file.

As a side-effect of the unification of both fortified and non-fortified
vdprintf initialization, this patch fixes bug 11319 for __dprintf_chk
and __vdprintf_chk, which was previously fixed only for dprintf and
vdprintf by the commit

commit 7ca890b88e
Author: Ulrich Drepper <drepper@redhat.com>
Date:   Wed Feb 24 16:07:57 2010 -0800

    Fix reporting of I/O errors in *dprintf functions.

This patch adds a test case to avoid regressions.

Tested for powerpc and powerpc64le.
This commit is contained in:
Zack Weinberg
2018-03-07 14:32:03 -05:00
committed by Gabriel F. T. Gomes
parent 124fc732c1
commit 4e2f43f842
35 changed files with 413 additions and 551 deletions
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46
debug/vsnprintf_chk.c
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@@ -15,56 +15,22 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdarg.h>
#include <stdio.h>
#include "../libio/libioP.h"
#include "../libio/strfile.h"
#include <libio/libioP.h>
extern const struct _IO_jump_t _IO_strn_jumps libio_vtable attribute_hidden;
/* Write formatted output into S, according to the format
string FORMAT, writing no more than MAXLEN characters. */
/* VARARGS5 */
int
___vsnprintf_chk (char *s, size_t maxlen, int flags, size_t slen,
const char *format, va_list args)
___vsnprintf_chk (char *s, size_t maxlen, int flag, size_t slen,
const char *format, va_list ap)
{
/* XXX Maybe for less strict version do not fail immediately.
Though, maxlen is supposed to be the size of buffer pointed
to by s, so a conforming program can't pass such maxlen
to *snprintf. */
if (__glibc_unlikely (slen < maxlen))
__chk_fail ();
_IO_strnfile sf;
int ret;
#ifdef _IO_MTSAFE_IO
sf.f._sbf._f._lock = NULL;
#endif
/* We need to handle the special case where MAXLEN is 0. Use the
overflow buffer right from the start. */
if (maxlen == 0)
{
s = sf.overflow_buf;
maxlen = sizeof (sf.overflow_buf);
}
_IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
_IO_JUMPS (&sf.f._sbf) = &_IO_strn_jumps;
s[0] = '\0';
/* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
/* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
can only come from read-only format strings. */
if (flags > 0)
sf.f._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0;
_IO_str_init_static_internal (&sf.f, s, maxlen - 1, s);
ret = __vfprintf_internal (&sf.f._sbf._f, format, args, 0);
if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf)
*sf.f._sbf._f._IO_write_ptr = '\0';
return ret;
return __vsnprintf_internal (s, maxlen, format, ap, mode);
}
ldbl_hidden_def (___vsnprintf_chk, __vsnprintf_chk)
ldbl_strong_alias (___vsnprintf_chk, __vsnprintf_chk)