debug/tst-fortify-wide.c

   1 /* Fortify check for wprintf.
   2    Copyright (C) 2023-2025 Free Software Foundation, Inc.
   3    Copyright The GNU Toolchain Authors.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <setjmp.h>
  21 #include <stdio.h>
  22 #include <wchar.h>
  23 #include <unistd.h>
  24
  25 #include <support/support.h>
  26
  27 static volatile int chk_fail_ok;
  28 static volatile int ret;
  29 static sigjmp_buf chk_fail_buf;
  30
  31 static void
  32 handler (int sig)
  33 {
  34   if (chk_fail_ok)
  35     {
  36       chk_fail_ok = 0;
  37       longjmp (chk_fail_buf, 1);
  38     }
  39   else
  40     _exit (127);
  41 }
  42
  43 static const wchar_t *wstr3 = L"%ls%n%ls%n";
  44 static const wchar_t *wstr4 = L"Hello, ";
  45 static const wchar_t *wstr5 = L"World!\n";
  46 static wchar_t wbuf2[20] = L"%ls";
  47
  48 #define WFAIL \
  49   do { wprintf (L"Failure on line %d\n", __LINE__); ret = 1; } while (0)
  50 #define CHK_FAIL_START \
  51   chk_fail_ok = 1;                              \
  52   if (! sigsetjmp (chk_fail_buf, 1))            \
  53     {
  54 #define CHK_FAIL_END \
  55       chk_fail_ok = 0;                          \
  56       WFAIL;                                    \
  57     }
  58
  59 static int
  60 do_test (void)
  61 {
  62   set_fortify_handler (handler);
  63
  64   int n1, n2;
  65
  66   int orientation = fwide (stdout, 1);
  67   if (orientation <= 0)
  68     WFAIL;
  69
  70   /* Constant literals passed directly are always ok
  71      (even with warnings about possible bugs from GCC).  */
  72   if (wprintf (L"%ls%n%ls%n", wstr4, &n1, wstr5, &n2) != 14
  73       || n1 != 7 || n2 != 14)
  74     WFAIL;
  75
  76   /* In this case the format string is not known at compile time,
  77      but resides in read-only memory, so is ok.  */
  78   if (wprintf (wstr3, wstr4, &n1, wstr5, &n2) != 14
  79       || n1 != 7 || n2 != 14)
  80     WFAIL;
  81
  82   wcpcpy (&wbuf2[3], L"%n%ls%n");
  83   /* When the format string is writable and contains %n,
  84      with -D_FORTIFY_SOURCE=2 it causes __chk_fail.  */
  85   CHK_FAIL_START
  86   if (wprintf (wbuf2, wstr4, &n1, wstr5, &n1) != 14)
  87     WFAIL;
  88   CHK_FAIL_END
  89
  90   /* But if there is no %n, even writable format string
  91      should work.  */
  92   wbuf2[8] = L'\0';
  93   if (wprintf (&wbuf2[5], wstr5) != 7)
  94     WFAIL;
  95
  96   /* Check whether missing N$ formats are detected.  */
  97   CHK_FAIL_START
  98   wprintf (L"%3$d\n", 1, 2, 3, 4);
  99   CHK_FAIL_END
 100
 101   return ret;
 102 }
 103
 104 #include <support/test-driver.c>