Adding upstream version 1.9.15p5.upstream/1.9.15p5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 676 insertions, 0 deletions

diff --git a/src/regress/intercept/test_ptrace.c b/src/regress/intercept/test_ptrace.c
new file mode 100644
index 0000000..30b73e7
--- /dev/null
+++ b/src/regress/intercept/test_ptrace.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+/*
+ * Test program to exercise seccomp(2) and ptrace(2) intercept code.
+ *
+ * Usage: test_ptrace [-d 1-3] [command]
+ */
+
+/* Ignore architecture restrictions and define this unilaterally. */
+#define HAVE_PTRACE_INTERCEPT
+#include "exec_ptrace.c"
+
+static sig_atomic_t got_sigchld;
+static int debug;
+int sudo_debug_instance = SUDO_DEBUG_INSTANCE_INITIALIZER;
+
+sudo_dso_public int main(int argc, char *argv[]);
+
+static void
+handler(int signo)
+{
+    if (signo == SIGCHLD)
+	got_sigchld = 1;
+}
+
+void
+intercept_closure_reset(struct intercept_closure *closure)
+{
+    memset(closure, 0, sizeof(*closure));
+}
+
+bool
+intercept_check_policy(const char *command, int argc, char **argv, int envc,
+    char **envp, const char *runcwd, int *oldcwd, void *v)
+{
+    struct intercept_closure *closure = v;
+    struct stat sb1, sb2;
+    bool is_denied;
+    debug_decl(intercept_check_policy, SUDO_DEBUG_EXEC);
+
+    /* Fake policy decisions. */
+    is_denied = stat(command, &sb1) == 0 && stat("/usr/bin/who", &sb2) == 0 &&
+	sb1.st_ino == sb2.st_ino && sb1.st_dev == sb2.st_dev;
+    if (is_denied) {
+	sudo_debug_printf(SUDO_DEBUG_DIAG, "denied %s", command);
+	closure->state = POLICY_REJECT;
+    } else {
+	sudo_debug_printf(SUDO_DEBUG_DIAG, "allowed %s", command);
+	closure->state = POLICY_TEST;
+    }
+    *oldcwd = -1;
+
+    debug_return_bool(true);
+}
+
+static void
+init_debug_files(struct sudo_conf_debug_file_list *file_list,
+    struct sudo_debug_file *file)
+{
+    debug_decl(init_debug_files, SUDO_DEBUG_EXEC);
+
+    TAILQ_INIT(file_list);
+    switch (debug) {
+    case 0:
+	debug_return;
+    case 1:
+	file->debug_flags = (char *)"exec@diag";
+	break;
+    case 2:
+	file->debug_flags = (char *)"exec@info";
+	break;
+    default:
+	file->debug_flags = (char *)"exec@debug";
+	break;
+    }
+    file->debug_file = (char *)"/dev/stderr";
+    TAILQ_INSERT_HEAD(file_list, file, entries);
+
+    debug_return;
+}
+
+int
+sudo_sigaction(int signo, struct sigaction *sa, struct sigaction *osa)
+{
+    return sigaction(signo, sa, osa);
+}
+
+int
+main(int argc, char *argv[])
+{
+    struct sudo_conf_debug_file_list debug_files;
+    struct sudo_debug_file debug_file;
+    const char *base, *shell = _PATH_SUDO_BSHELL;
+    struct intercept_closure closure = { 0 };
+    const char *errstr;
+    sigset_t blocked, empty;
+    struct sigaction sa;
+    pid_t child, my_pid, pid, my_pgrp;
+    int ch, status;
+    debug_decl_vars(main, SUDO_DEBUG_MAIN);
+
+    initprogname(argc > 0 ? argv[0] : "test_ptrace");
+
+    if (!have_seccomp_action("trap"))
+	sudo_fatalx("SECCOMP_MODE_FILTER not available in this kernel");
+
+    while ((ch = getopt(argc, argv, "d:")) != -1) {
+	switch (ch) {
+	case 'd':
+	    debug = sudo_strtonum(optarg, 1, INT_MAX, &errstr);
+	    if (errstr != NULL)
+		sudo_fatalx(U_("%s: %s"), optarg, U_(errstr));
+	    break;
+	default:
+	    fprintf(stderr, "usage: %s [-d 1-3] [command]\n", getprogname());
+	    return EXIT_FAILURE;
+	}
+    }
+    argc -= optind;
+    argv += optind;
+
+    if (argc > 0)
+	shell = argv[0];
+    base = strrchr(shell, '/');
+    base = base ? base + 1 : shell;
+
+    /* Set debug level based on the debug flag. */
+    init_debug_files(&debug_files, &debug_file);
+    sudo_debug_instance = sudo_debug_register(getprogname(),
+	NULL, NULL, &debug_files, -1);
+    if (sudo_debug_instance == SUDO_DEBUG_INSTANCE_ERROR)
+	return EXIT_FAILURE;
+
+    /* Block SIGCHLD and SIGUSR during critical section. */
+    sigemptyset(&empty);
+    sigemptyset(&blocked);
+    sigaddset(&blocked, SIGCHLD);
+    sigaddset(&blocked, SIGUSR1);
+    sigprocmask(SIG_BLOCK, &blocked, NULL);
+
+    /* Signal handler sets a flag for SIGCHLD, nothing for SIGUSR1. */
+    memset(&sa, 0, sizeof(sa));
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = SA_RESTART;
+    sa.sa_handler = handler;
+    sigaction(SIGCHLD, &sa, NULL);
+    sigaction(SIGUSR1, &sa, NULL);
+
+    /* Fork a shell. */
+    my_pid = getpid();
+    my_pgrp = getpgrp();
+    child = fork();
+    switch (child) {
+    case -1:
+	sudo_fatal("fork");
+    case 0:
+	/* child */
+	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
+	    sudo_fatal("%s", "unable to set no_new_privs bit");
+	if (!set_exec_filter())
+	    _exit(EXIT_FAILURE);
+
+	/* Suspend child until tracer seizes control and sends SIGUSR1. */
+	sigsuspend(&empty);
+	execl(shell, base, NULL);
+	sudo_fatal("execl");
+    default:
+	/* Parent attaches to child and allows it to continue. */
+	if (exec_ptrace_seize(child) == -1)
+	    return EXIT_FAILURE;
+	break;
+    }
+
+    /* Wait for SIGCHLD. */
+    for (;;) {
+	sigsuspend(&empty);
+	if (!got_sigchld)
+	    continue;
+	got_sigchld = 0;
+
+	for (;;) {
+	    do {
+		pid = waitpid(-1, &status, __WALL|WNOHANG);
+	    } while (pid == -1 && errno == EINTR);
+	    if (pid <= 0) {
+		if (pid == -1 && errno != ECHILD)
+		    sudo_fatal("waitpid");
+		/* No child to wait for. */
+		break;
+	    }
+
+	    if (WIFEXITED(status)) {
+		sudo_debug_printf(SUDO_DEBUG_DIAG, "%d: exited %d",
+		    (int)pid, WEXITSTATUS(status));
+		if (pid == child)
+		    return WEXITSTATUS(status);
+	    } else if (WIFSIGNALED(status)) {
+		sudo_debug_printf(SUDO_DEBUG_DIAG, "%d: killed by signal %d",
+		    (int)pid, WTERMSIG(status));
+		if (pid == child)
+		    return WTERMSIG(status) | 128;
+	    } else if (WIFSTOPPED(status)) {
+		if (exec_ptrace_stopped(pid, status, &closure)) {
+		    if (pid == child) {
+			sudo_suspend_parent(WSTOPSIG(status), my_pid,
+			    my_pgrp, child, NULL, NULL);
+			if (kill(child, SIGCONT) != 0)
+			    sudo_warn("kill(%d, SIGCONT)", (int)child);
+		    }
+		}
+	    } else {
+		sudo_fatalx("%d: unknown status 0x%x", (int)pid, status);
+	    }
+	}
+    }
+}
diff --git a/src/regress/net_ifs/check_net_ifs.c b/src/regress/net_ifs/check_net_ifs.c
new file mode 100644
index 0000000..60adcfa
--- /dev/null
+++ b/src/regress/net_ifs/check_net_ifs.c
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2021-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include <compat/stdbool.h>
+#endif /* HAVE_STDBOOL_H */
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+
+#include <sudo_compat.h>
+#include <sudo_util.h>
+
+sudo_dso_public int main(int argc, char *argv[]);
+
+extern int get_net_ifs(char **addrinfo);
+
+int
+main(int argc, char *argv[])
+{
+    int ch, ninterfaces, errors = 0, ntests = 1;
+    char *interfaces = NULL;
+    bool verbose = false;
+
+    initprogname(argc > 0 ? argv[0] : "check_net_ifs");
+
+    while ((ch = getopt(argc, argv, "v")) != -1) {
+	switch (ch) {
+	case 'v':
+	    verbose = true;
+	    break;
+	default:
+	    fprintf(stderr, "usage: %s [-v]\n", getprogname());
+	    return EXIT_FAILURE;
+	}
+    }
+
+    ninterfaces = get_net_ifs(&interfaces);
+    switch (ninterfaces) {
+    case -1:
+	printf("FAIL: unable to get network interfaces\n");
+	errors++;
+	break;
+    case 0:
+	/* no interfaces or STUB_LOAD_INTERFACES defined. */
+	if (verbose)
+	    printf("OK: (0 interfaces)\n");
+	break;
+    default:
+	if (verbose) {
+	    printf("OK: (%d interface%s, %s)\n", ninterfaces,
+		ninterfaces > 1 ? "s" : "", interfaces);
+	}
+	break;
+    }
+    free(interfaces);
+
+    if (ntests != 0) {
+        printf("%s: %d tests run, %d errors, %d%% success rate\n",
+            getprogname(), ntests, errors, (ntests - errors) * 100 / ntests);
+    }
+    return errors;
+}
diff --git a/src/regress/noexec/check_noexec.c b/src/regress/noexec/check_noexec.c
new file mode 100644
index 0000000..a5f7ff4
--- /dev/null
+++ b/src/regress/noexec/check_noexec.c
@@ -0,0 +1,232 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2016, 2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include <compat/stdbool.h>
+#endif /* HAVE_STDBOOL_H */
+#include <string.h>
+#ifdef HAVE_WORDEXP_H
+# include <wordexp.h>
+#endif
+#include <signal.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+
+#include <sudo_compat.h>
+#include <sudo_fatal.h>
+#include <sudo_util.h>
+#include <sudo_queue.h>
+#include <sudo_exec.h>
+
+static bool verbose;
+
+sudo_dso_public int main(int argc, char *argv[], char *envp[]);
+
+static bool
+report_status(int status, const char *what)
+{
+    bool ret = false;
+
+    /* system() returns -1 for exec failure. */
+    if (status == -1) {
+	if (verbose)
+	    printf("%s: OK (%s)\n", getprogname(), what);
+	return true;
+    }
+
+    /* check exit value, expecting 127 for failure */
+    if (WIFEXITED(status)) {
+	int exitval = WEXITSTATUS(status);
+	if (exitval == 127) {
+	    if (verbose)
+		printf("%s: OK (%s)\n", getprogname(), what);
+	    ret = true;
+	} else {
+	    printf("%s: FAIL (%s) [%d]\n", getprogname(), what, exitval);
+	}
+    } else if (WIFSIGNALED(status)) {
+	printf("%s: FAIL (%s) [signal %d]\n", getprogname(), what,
+	    WTERMSIG(status));
+    } else {
+	/* should not happen */
+	printf("%s: FAIL (%s) [status %d]\n", getprogname(), what, status);
+    }
+
+    return ret;
+}
+
+static int
+try_execl(void)
+{
+    pid_t child, pid;
+    int status;
+
+    child = fork();
+    switch (child) {
+    case -1:
+	sudo_fatal_nodebug("fork");
+    case 0:
+	/* child */
+	/* Try to exec /bin/true, else exit with value 127. */
+	execl("/bin/true", "true", (char *)0);
+	_exit(127);
+    default:
+	/* parent */
+	do {
+	    pid = waitpid(child, &status, 0);
+	} while (pid == -1 && errno == EINTR);
+	if (pid == -1)
+	    sudo_fatal_nodebug("waitpid");
+
+	if (report_status(status, "execl"))
+	    return 0;
+	return 1;
+    }
+}
+
+static int
+try_system(void)
+{
+    int status;
+
+    /* Try to run /bin/true, system() returns 127 on exec failure. */
+    status = system("/bin/true > /dev/null 2>&1");
+
+    if (report_status(status, "system"))
+	return 0;
+    return 1;
+}
+
+#ifdef HAVE_WORDEXP_H
+static int
+try_wordexp(void)
+{
+    wordexp_t we;
+    int rc, ret = 1;
+
+    /*
+     * sudo_noexec.so prevents command substitution via the WRDE_NOCMD flag
+     * where possible.
+     */
+    rc = wordexp("$(/bin/echo foo)", &we, 0);
+    switch (rc) {
+    case -1:
+	/* sudo's wordexp() wrapper returns -1 if RTLD_NEXT is not supported. */
+    case 127:
+	/* Solaris 10 wordexp() returns 127 for execve() failure. */
+#ifdef WRDE_ERRNO
+    case WRDE_ERRNO:
+	/* Solaris 11 wordexp() returns WRDE_ERRNO for execve() failure. */
+#endif
+	if (verbose)
+	    printf("%s: OK (wordexp) [%d]\n", getprogname(), rc);
+	ret = 0;
+	break;
+    case WRDE_SYNTAX:
+	/* FreeBSD returns WRDE_SYNTAX if it can't write to the shell process */
+	if (verbose)
+	    printf("%s: OK (wordexp) [WRDE_SYNTAX]\n", getprogname());
+	ret = 0;
+	break;
+    case WRDE_CMDSUB:
+	if (verbose)
+	    printf("%s: OK (wordexp) [WRDE_CMDSUB]\n", getprogname());
+	ret = 0;
+	break;
+    case 0:
+	/*
+	 * On HP-UX 11.00 we don't seem to be able to add WRDE_NOCMD
+	 * but the execve() wrapper prevents the command substitution.
+	 */
+	if (we.we_wordc == 0) {
+	    if (verbose)
+		printf("%s: OK (wordexp) [%d]\n", getprogname(), rc);
+	    wordfree(&we);
+	    ret = 0;
+	    break;
+	}
+	wordfree(&we);
+	FALLTHROUGH;
+    default:
+	printf("%s: FAIL (wordexp) [%d]\n", getprogname(), rc);
+	break;
+    }
+    return ret;
+}
+#endif
+
+sudo_noreturn static void
+usage(void)
+{
+    fprintf(stderr, "usage: %s [-v] rexec | /path/to/sudo_noexec.so\n",
+	getprogname());
+    exit(EXIT_FAILURE);
+}
+
+int
+main(int argc, char *argv[], char *envp[])
+{
+    int ch, errors = 0, ntests = 0;
+
+    initprogname(argc > 0 ? argv[0] : "check_noexec");
+
+    while ((ch = getopt(argc, argv, "v")) != -1) {
+	switch (ch) {
+	case 'v':
+	    verbose = true;
+	    break;
+	default:
+	    usage();
+	}
+    }
+
+    if (argc - optind != 1)
+	usage();
+
+    /* Disable execution for post-exec and re-exec ourself. */
+    if (strcmp(argv[optind], "rexec") != 0) {
+	const char *noexec = argv[optind];
+	argv[optind] = (char *)"rexec";
+	execve(argv[0], argv, disable_execute(envp, noexec));
+	sudo_fatalx_nodebug("execve");
+    }
+
+    ntests++;
+    errors += try_execl();
+    ntests++;
+    errors += try_system();
+#ifdef HAVE_WORDEXP_H
+    ntests++;
+    errors += try_wordexp();
+#endif
+
+    if (ntests != 0) {
+        printf("%s: %d tests run, %d errors, %d%% success rate\n",
+            getprogname(), ntests, errors, (ntests - errors) * 100 / ntests);
+    }
+    return errors;
+}
diff --git a/src/regress/ttyname/check_ttyname.c b/src/regress/ttyname/check_ttyname.c
new file mode 100644
index 0000000..715423d
--- /dev/null
+++ b/src/regress/ttyname/check_ttyname.c
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2013-2020, 2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include <compat/stdbool.h>
+#endif /* HAVE_STDBOOL_H */
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+
+#include <sudo_compat.h>
+#include <sudo_fatal.h>
+#include <sudo_util.h>
+#include <sudo_debug.h>
+
+sudo_dso_public int main(int argc, char *argv[]);
+
+int sudo_debug_instance = SUDO_DEBUG_INSTANCE_INITIALIZER;
+extern char *get_process_ttyname(char *name, size_t namelen);
+
+static int
+match_ttys(const char *tty1, const char *tty2)
+{
+    struct stat sb1, sb2;
+
+    if (tty1 != NULL && tty2 != NULL) {
+	if (strcmp(tty1, tty2) == 0)
+	    return 0;
+	/* Could be the same device with a different name. */
+	if (stat(tty1, &sb1) == 0 && S_ISCHR(sb1.st_mode) &&
+	    stat(tty2, &sb2) == 0 && S_ISCHR(sb2.st_mode)) {
+	    if (sb1.st_rdev == sb2.st_rdev)
+		return 0;
+	}
+    } else if (tty1 == NULL && tty2 == NULL) {
+	return 0;
+    }
+
+    return 1;
+}
+
+int
+main(int argc, char *argv[])
+{
+    char *tty_libc = NULL, *tty_sudo = NULL;
+    char pathbuf[PATH_MAX];
+    bool verbose = false;
+    int ch, errors = 0, ntests = 1;
+
+    initprogname(argc > 0 ? argv[0] : "check_ttyname");
+
+    while ((ch = getopt(argc, argv, "v")) != -1) {
+	switch (ch) {
+	case 'v':
+	    verbose = true;
+	    break;
+	default:
+	    fprintf(stderr, "usage: %s [-v]\n", getprogname());
+	    return EXIT_FAILURE;
+	}
+    }
+
+    /* Lookup tty name using kernel info if possible. */
+    if (get_process_ttyname(pathbuf, sizeof(pathbuf)) != NULL)
+	tty_sudo = pathbuf;
+
+#if defined(HAVE_KINFO_PROC2_NETBSD) || \
+    defined(HAVE_KINFO_PROC_OPENBSD) || \
+    defined(HAVE_KINFO_PROC_FREEBSD) || \
+    defined(HAVE_KINFO_PROC_DFLY) || \
+    defined(HAVE_KINFO_PROC_44BSD) || \
+    defined(HAVE__TTYNAME_DEV) || defined(HAVE_STRUCT_PSINFO_PR_TTYDEV) || \
+    defined(HAVE_PSTAT_GETPROC) || defined(__linux__)
+
+    /* Lookup tty name attached to stdin via libc. */
+    tty_libc = ttyname(STDIN_FILENO);
+#endif
+
+    /* Compare libc and kernel ttys. */
+    if (match_ttys(tty_libc, tty_sudo) == 0) {
+	if (verbose)
+	    printf("%s: OK (%s)\n", getprogname(), tty_sudo ? tty_sudo : "none");
+    } else if (tty_libc == NULL) {
+	if (verbose)
+	    printf("%s: SKIP (%s)\n", getprogname(), tty_sudo ? tty_sudo : "none");
+	ntests = 0;
+    } else {
+	printf("%s: FAIL %s (sudo) vs. %s (libc)\n", getprogname(),
+	    tty_sudo ? tty_sudo : "none", tty_libc ? tty_libc : "none");
+	errors++;
+    }
+
+    if (ntests != 0) {
+	printf("%s: %d tests run, %d errors, %d%% success rate\n",
+	    getprogname(), ntests, errors, (ntests - errors) * 100 / ntests);
+    }
+    return errors;
+}