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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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96
debug/obprintf_chk.c
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@@ -17,99 +17,23 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdlib.h>
#include <libioP.h>
#include "../libio/strfile.h"
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <obstack.h>
#include <libio/libioP.h>
#include <stdarg.h>
#include <stdio_ext.h>
struct _IO_obstack_file
{
struct _IO_FILE_plus file;
struct obstack *obstack;
};
extern const struct _IO_jump_t _IO_obstack_jumps libio_vtable attribute_hidden;
int
__obstack_vprintf_chk (struct obstack *obstack, int flags, const char *format,
va_list args)
{
struct obstack_FILE
{
struct _IO_obstack_file ofile;
} new_f;
int result;
int size;
int room;
#ifdef _IO_MTSAFE_IO
new_f.ofile.file.file._lock = NULL;
#endif
_IO_no_init (&new_f.ofile.file.file, _IO_USER_LOCK, -1, NULL, NULL);
_IO_JUMPS (&new_f.ofile.file) = &_IO_obstack_jumps;
room = obstack_room (obstack);
size = obstack_object_size (obstack) + room;
if (size == 0)
{
/* We have to handle the allocation a bit different since the
`_IO_str_init_static' function would handle a size of zero
different from what we expect. */
/* Get more memory. */
obstack_make_room (obstack, 64);
/* Recompute how much room we have. */
room = obstack_room (obstack);
size = room;
assert (size != 0);
}
_IO_str_init_static_internal ((struct _IO_strfile_ *) &new_f.ofile,
obstack_base (obstack),
size, obstack_next_free (obstack));
/* Now allocate the rest of the current chunk. */
assert (size == (new_f.ofile.file.file._IO_write_end
- new_f.ofile.file.file._IO_write_base));
assert (new_f.ofile.file.file._IO_write_ptr
== (new_f.ofile.file.file._IO_write_base
+ obstack_object_size (obstack)));
obstack_blank_fast (obstack, room);
new_f.ofile.obstack = obstack;
/* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
can only come from read-only format strings. */
if (flags > 0)
new_f.ofile.file.file._flags2 |= _IO_FLAGS2_FORTIFY;
result = __vfprintf_internal (&new_f.ofile.file.file, format, args, 0);
/* Shrink the buffer to the space we really currently need. */
obstack_blank_fast (obstack, (new_f.ofile.file.file._IO_write_ptr
- new_f.ofile.file.file._IO_write_end));
return result;
}
libc_hidden_def (__obstack_vprintf_chk)
int
__obstack_printf_chk (struct obstack *obstack, int flags, const char *format,
__obstack_printf_chk (struct obstack *obstack, int flag, const char *format,
...)
{
int result;
/* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
can only come from read-only format strings. */
unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0;
va_list ap;
int ret;
va_start (ap, format);
result = __obstack_vprintf_chk (obstack, flags, format, ap);
ret = __obstack_vprintf_internal (obstack, format, ap, mode);
va_end (ap);
return result;
return ret;
}