1/* Testcase for BZ 30932.
2 Copyright (C) 2023-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <setjmp.h>
21#include <stdbool.h>
22#include <stdio.h>
23#include <string.h>
24#include <sys/resource.h>
25#include <unistd.h>
26
27#include <support/check.h>
28#include <support/support.h>
29#include <support/temp_file.h>
30
31jmp_buf chk_fail_buf;
32bool chk_fail_ok;
33
34const char *str2 = "F";
35char buf2[10] = "%s";
36
37static int
38do_test (void)
39{
40 struct rlimit rl;
41 int max_fd = 24;
42
43 if (getrlimit (RLIMIT_NOFILE, rlimits: &rl) == -1)
44 FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
45
46 max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
47 rl.rlim_cur = max_fd;
48
49 if (setrlimit (RLIMIT_NOFILE, rlimits: &rl) == 1)
50 FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
51
52 /* Exhaust the file descriptor limit with temporary files. */
53 int nfiles = 0;
54 for (; nfiles < max_fd; nfiles++)
55 {
56 int fd = create_temp_file (base: "tst-sprintf-fortify-rdonly-.", NULL);
57 if (fd == -1)
58 {
59 if (errno != EMFILE)
60 FAIL_EXIT1 ("create_temp_file: %m");
61 break;
62 }
63 }
64 TEST_VERIFY_EXIT (nfiles != 0);
65
66 /* When the format string is writable and contains %n,
67 with -D_FORTIFY_SOURCE=2 it causes __chk_fail. However, if libc can not
68 open procfs to check if the input format string in within a writable
69 memory segment, the fortify version can not perform the check. */
70 char buf[128];
71 int n1;
72 int n2;
73
74 strcpy (buf2 + 2, "%n%s%n");
75 if (sprintf (buf, buf2, str2, &n1, str2, &n2) != 2
76 || n1 != 1 || n2 != 2)
77 FAIL_EXIT1 ("sprintf failed: %s %d %d", buf, n1, n2);
78
79 return 0;
80}
81
82#include <support/test-driver.c>
83

source code of glibc/debug/tst-sprintf-fortify-rdonly.c