[PATCH 05/15] debug: Add fortify wprintf tests

[Siddhesh Poyarekar]

On 2023-12-21 13:59, Adhemerval Zanella wrote:
> Similar to other printf-like ones.  It requires to be in a different
> process so we can change the orientation of stdout.
> 
> Checked on aarch64, armhf, x86_64, and i686.
> ---
>   debug/Makefile           |   2 +
>   debug/tst-fortify-wide.c | 104 +++++++++++++++++++++++++++++++++++++++
>   2 files changed, 106 insertions(+)
>   create mode 100644 debug/tst-fortify-wide.c
> 
> diff --git a/debug/Makefile b/debug/Makefile
> index fdc250e209..ed90ef7030 100644
> --- a/debug/Makefile
> +++ b/debug/Makefile
> @@ -180,6 +180,7 @@ CPPFLAGS-tst-realpath-chk.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   CPPFLAGS-tst-chk-cancel.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   CFLAGS-tst-sprintf-fortify-rdonly.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   CFLAGS-tst-fortify-syslog.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
> +CFLAGS-tst-fortify-wide.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   
>   # _FORTIFY_SOURCE tests.
>   # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
> @@ -283,6 +284,7 @@ tests = \
>     tst-backtrace4 \
>     tst-backtrace5 \
>     tst-backtrace6 \
> +  tst-fortify-wide \
>     tst-longjmp_chk \
>     tst-longjmp_chk2 \
>     tst-realpath-chk \
> diff --git a/debug/tst-fortify-wide.c b/debug/tst-fortify-wide.c
> new file mode 100644
> index 0000000000..6947d04fa6
> --- /dev/null
> +++ b/debug/tst-fortify-wide.c
> @@ -0,0 +1,104 @@
> +/* Fortify check for wprintf.
> +   Copyright (C) 2004-2023 Free Software Foundation, Inc.
> +   Copyright The GNU Toolchain Authors.

It's a new test, so just 2023 and FSF?  Looks OK otherwise.

> +   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 <setjmp.h>
> +#include <stdio.h>
> +#include <wchar.h>
> +#include <unistd.h>
> +
> +#include <support/support.h>
> +
> +static volatile int chk_fail_ok;
> +static volatile int ret;
> +static jmp_buf chk_fail_buf;
> +
> +static void
> +handler (int sig)
> +{
> +  if (chk_fail_ok)
> +    {
> +      chk_fail_ok = 0;
> +      longjmp (chk_fail_buf, 1);
> +    }
> +  else
> +    _exit (127);
> +}
> +
> +static const wchar_t *wstr3 = L"%ls%n%ls%n";
> +static const wchar_t *wstr4 = L"Hello, ";
> +static const wchar_t *wstr5 = L"World!\n";
> +static wchar_t wbuf2[20] = L"%ls";
> +
> +#define WFAIL \
> +  do { wprintf (L"Failure on line %d\n", __LINE__); ret = 1; } while (0)
> +#define CHK_FAIL_START \
> +  chk_fail_ok = 1;				\
> +  if (! setjmp (chk_fail_buf))			\
> +    {
> +#define CHK_FAIL_END \
> +      chk_fail_ok = 0;				\
> +      WFAIL;					\
> +    }
> +
> +static int
> +do_test (void)
> +{
> +  set_fortify_handler (handler);
> +
> +  int n1, n2;
> +
> +  int orientation = fwide (stdout, 1);
> +  if (orientation <= 0)
> +    WFAIL;
> +
> +  /* Constant literals passed directly are always ok
> +     (even with warnings about possible bugs from GCC).  */
> +  if (wprintf (L"%ls%n%ls%n", wstr4, &n1, wstr5, &n2) != 14
> +      || n1 != 7 || n2 != 14)
> +    WFAIL;
> +
> +  /* In this case the format string is not known at compile time,
> +     but resides in read-only memory, so is ok.  */
> +  if (wprintf (wstr3, wstr4, &n1, wstr5, &n2) != 14
> +      || n1 != 7 || n2 != 14)
> +    WFAIL;
> +
> +  wcpcpy (&wbuf2[3], L"%n%ls%n");
> +  /* When the format string is writable and contains %n,
> +     with -D_FORTIFY_SOURCE=2 it causes __chk_fail.  */
> +  CHK_FAIL_START
> +  if (wprintf (wbuf2, wstr4, &n1, wstr5, &n1) != 14)
> +    WFAIL;
> +  CHK_FAIL_END
> +
> +  /* But if there is no %n, even writable format string
> +     should work.  */
> +  wbuf2[8] = L'\0';
> +  if (wprintf (&wbuf2[5], wstr5) != 7)
> +    WFAIL;
> +
> +  /* Check whether missing N$ formats are detected.  */
> +  CHK_FAIL_START
> +  wprintf (L"%3$d\n", 1, 2, 3, 4);
> +  CHK_FAIL_END
> +
> +  return ret;
> +}
> +
> +#include <support/test-driver.c>