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authorZack Weinberg <zackw@panix.com>2018-03-07 14:32:03 -0500
committerGabriel F. T. Gomes <gabriel@inconstante.eti.br>2018-12-05 18:15:43 -0200
commit4e2f43f842ef5e253cc23383645adbaa03cedb86 (patch)
treeca359423ba6ed4bb4d5ec247905a6ee13d456864 /debug/vsprintf_chk.c
parent124fc732c15ef37b7ee9db25b1e9f9b20c799623 (diff)
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Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319)
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 7ca890b88e6ab7624afb1742a9fffb37ad5b3fc3
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.
Diffstat (limited to 'debug/vsprintf_chk.c')
-rw-r--r--debug/vsprintf_chk.c69
1 files changed, 7 insertions, 62 deletions
diff --git a/debug/vsprintf_chk.c b/debug/vsprintf_chk.c
index 53f07236ae..c1b1a8da4f 100644
--- a/debug/vsprintf_chk.c
+++ b/debug/vsprintf_chk.c
@@ -15,75 +15,20 @@
    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"
-
-
-static int _IO_str_chk_overflow (FILE *fp, int c) __THROW;
-
-static int
-_IO_str_chk_overflow (FILE *fp, int c)
-{
-  /* When we come to here this means the user supplied buffer is
-     filled.  */
-  __chk_fail ();
-}
-
-
-static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable =
-{
-  JUMP_INIT_DUMMY,
-  JUMP_INIT(finish, _IO_str_finish),
-  JUMP_INIT(overflow, _IO_str_chk_overflow),
-  JUMP_INIT(underflow, _IO_str_underflow),
-  JUMP_INIT(uflow, _IO_default_uflow),
-  JUMP_INIT(pbackfail, _IO_str_pbackfail),
-  JUMP_INIT(xsputn, _IO_default_xsputn),
-  JUMP_INIT(xsgetn, _IO_default_xsgetn),
-  JUMP_INIT(seekoff, _IO_str_seekoff),
-  JUMP_INIT(seekpos, _IO_default_seekpos),
-  JUMP_INIT(setbuf, _IO_default_setbuf),
-  JUMP_INIT(sync, _IO_default_sync),
-  JUMP_INIT(doallocate, _IO_default_doallocate),
-  JUMP_INIT(read, _IO_default_read),
-  JUMP_INIT(write, _IO_default_write),
-  JUMP_INIT(seek, _IO_default_seek),
-  JUMP_INIT(close, _IO_default_close),
-  JUMP_INIT(stat, _IO_default_stat),
-  JUMP_INIT(showmanyc, _IO_default_showmanyc),
-  JUMP_INIT(imbue, _IO_default_imbue)
-};
-
+#include <libio/libioP.h>
 
 int
-___vsprintf_chk (char *s, int flags, size_t slen, const char *format,
-		 va_list args)
+___vsprintf_chk (char *s, int flag, size_t slen, const char *format,
+		 va_list ap)
 {
-  _IO_strfile f;
-  int ret;
-#ifdef _IO_MTSAFE_IO
-  f._sbf._f._lock = NULL;
-#endif
+  /* 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;
 
   if (slen == 0)
     __chk_fail ();
 
-  _IO_no_init (&f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
-  _IO_JUMPS (&f._sbf) = &_IO_str_chk_jumps;
-  s[0] = '\0';
-  _IO_str_init_static_internal (&f, s, slen - 1, s);
-
-  /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
-     can only come from read-only format strings.  */
-  if (flags > 0)
-    f._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
-
-  ret = __vfprintf_internal (&f._sbf._f, format, args, 0);
-
-  *f._sbf._f._IO_write_ptr = '\0';
-  return ret;
+  return __vsprintf_internal (s, slen, format, ap, mode);
 }
 ldbl_hidden_def (___vsprintf_chk, __vsprintf_chk)
 ldbl_strong_alias (___vsprintf_chk, __vsprintf_chk)