glibc/libio/tst-bz28828.c
José Bollo edc696a73a libio: Ensure output buffer for wchars (bug #28828)
The _IO_wfile_overflow does not check if the write pointer for wide
data is valid before access, different than _IO_file_overflow.  This
leads to crash on some cases, as described by bug 28828.

The minimal sequence to produce the crash was:

  #include <stdio.h>
  #include <wchar.h>
  int main (int ac, char **av)
  {
    setvbuf (stdout, NULL, _IOLBF, 0);
    fgetwc (stdin);
    fputwc (10, stdout); /*CRASH HERE!*/
    return 0;
  }

The "fgetwc(stdin);" is necessary since it triggers the bug by setting
the flag _IO_CURRENTLY_PUTTING on stdout indirectly (file wfileops.c,
function _IO_wfile_underflow, line 213).

Signed-off-by: Jose Bollo <jobol@nonadev.net>
2022-03-08 14:25:32 -03:00

33 lines
1.0 KiB
C

/* Unit test for BZ#28828.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <support/xstdio.h>
#include <support/check.h>
#include <wchar.h>
static int
do_test (void)
{
setvbuf (stdout, NULL, _IOLBF, 0);
fgetwc (stdin);
fputwc (10, stdout); /* It should not crash here. */
return 0;
}
#include <support/test-driver.c>