+/*
+ * Copyright (c) 1996, 1998-2005, 2007-2011
+ * Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * 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.
+ *
+ * Sponsored in part by the Defense Advanced Research Projects
+ * Agency (DARPA) and Air Force Research Laboratory, Air Force
+ * Materiel Command, USAF, under agreement number F39502-99-1-0512.
+ */
+
+#ifdef __TANDEM
+# include <floss.h>
+#endif
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <stdio.h>
+#ifdef STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#else
+# ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+# endif
+#endif /* STDC_HEADERS */
+#ifdef HAVE_STRING_H
+# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
+# include <memory.h>
+# endif
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif /* HAVE_UNISTD_H */
+#include <pwd.h>
+#include <errno.h>
+#include <signal.h>
+#include <fcntl.h>
+
+#include "sudo.h"
+
+static volatile sig_atomic_t signo[NSIG];
+
+static void handler(int);
+static char *getln(int, char *, size_t, int);
+static char *sudo_askpass(const char *, const char *);
+
+/*
+ * Like getpass(3) but with timeout and echo flags.
+ */
+char *
+tgetpass(const char *prompt, int timeout, int flags)
+{
+ sigaction_t sa, savealrm, saveint, savehup, savequit, saveterm;
+ sigaction_t savetstp, savettin, savettou, savepipe;
+ char *pass;
+ static const char *askpass;
+ static char buf[SUDO_PASS_MAX + 1];
+ int i, input, output, save_errno, neednl = 0, need_restart;
+ debug_decl(tgetpass, SUDO_DEBUG_CONV)
+
+ (void) fflush(stdout);
+
+ if (askpass == NULL) {
+ askpass = getenv_unhooked("SUDO_ASKPASS");
+ if (askpass == NULL || *askpass == '\0')
+ askpass = sudo_conf_askpass_path();
+ }
+
+ /* If no tty present and we need to disable echo, try askpass. */
+ if (!ISSET(flags, TGP_STDIN|TGP_ECHO|TGP_ASKPASS|TGP_NOECHO_TRY) &&
+ !tty_present()) {
+ if (askpass == NULL || getenv_unhooked("DISPLAY") == NULL) {
+ warningx(_("no tty present and no askpass program specified"));
+ debug_return_str(NULL);
+ }
+ SET(flags, TGP_ASKPASS);
+ }
+
+ /* If using a helper program to get the password, run it instead. */
+ if (ISSET(flags, TGP_ASKPASS)) {
+ if (askpass == NULL || *askpass == '\0')
+ errorx(1, _("no askpass program specified, try setting SUDO_ASKPASS"));
+ debug_return_str_masked(sudo_askpass(askpass, prompt));
+ }
+
+restart:
+ for (i = 0; i < NSIG; i++)
+ signo[i] = 0;
+ pass = NULL;
+ save_errno = 0;
+ need_restart = 0;
+ /* Open /dev/tty for reading/writing if possible else use stdin/stderr. */
+ if (ISSET(flags, TGP_STDIN) ||
+ (input = output = open(_PATH_TTY, O_RDWR|O_NOCTTY)) == -1) {
+ input = STDIN_FILENO;
+ output = STDERR_FILENO;
+ }
+
+ /*
+ * If we are using a tty but are not the foreground pgrp this will
+ * generate SIGTTOU, so do it *before* installing the signal handlers.
+ */
+ if (!ISSET(flags, TGP_ECHO)) {
+ if (ISSET(flags, TGP_MASK))
+ neednl = term_cbreak(input);
+ else
+ neednl = term_noecho(input);
+ }
+
+ /*
+ * Catch signals that would otherwise cause the user to end
+ * up with echo turned off in the shell.
+ */
+ zero_bytes(&sa, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_INTERRUPT; /* don't restart system calls */
+ sa.sa_handler = handler;
+ (void) sigaction(SIGALRM, &sa, &savealrm);
+ (void) sigaction(SIGINT, &sa, &saveint);
+ (void) sigaction(SIGHUP, &sa, &savehup);
+ (void) sigaction(SIGQUIT, &sa, &savequit);
+ (void) sigaction(SIGTERM, &sa, &saveterm);
+ (void) sigaction(SIGTSTP, &sa, &savetstp);
+ (void) sigaction(SIGTTIN, &sa, &savettin);
+ (void) sigaction(SIGTTOU, &sa, &savettou);
+
+ /* Ignore SIGPIPE in case stdin is a pipe and TGP_STDIN is set */
+ sa.sa_handler = SIG_IGN;
+ (void) sigaction(SIGPIPE, &sa, &savepipe);
+
+ if (prompt) {
+ if (write(output, prompt, strlen(prompt)) == -1)
+ goto restore;
+ }
+
+ if (timeout > 0)
+ alarm(timeout);
+ pass = getln(input, buf, sizeof(buf), ISSET(flags, TGP_MASK));
+ alarm(0);
+ save_errno = errno;
+
+ if (neednl || pass == NULL) {
+ if (write(output, "\n", 1) == -1)
+ goto restore;
+ }
+
+restore:
+ /* Restore old tty settings and signals. */
+ if (!ISSET(flags, TGP_ECHO))
+ term_restore(input, 1);
+ (void) sigaction(SIGALRM, &savealrm, NULL);
+ (void) sigaction(SIGINT, &saveint, NULL);
+ (void) sigaction(SIGHUP, &savehup, NULL);
+ (void) sigaction(SIGQUIT, &savequit, NULL);
+ (void) sigaction(SIGTERM, &saveterm, NULL);
+ (void) sigaction(SIGTSTP, &savetstp, NULL);
+ (void) sigaction(SIGTTIN, &savettin, NULL);
+ (void) sigaction(SIGTTOU, &savettou, NULL);
+ (void) sigaction(SIGTTOU, &savepipe, NULL);
+ if (input != STDIN_FILENO)
+ (void) close(input);
+
+ /*
+ * If we were interrupted by a signal, resend it to ourselves
+ * now that we have restored the signal handlers.
+ */
+ for (i = 0; i < NSIG; i++) {
+ if (signo[i]) {
+ kill(getpid(), i);
+ switch (i) {
+ case SIGTSTP:
+ case SIGTTIN:
+ case SIGTTOU:
+ need_restart = 1;
+ break;
+ }
+ }
+ }
+ if (need_restart)
+ goto restart;
+
+ if (save_errno)
+ errno = save_errno;
+
+ debug_return_str_masked(pass);
+}
+
+/*
+ * Fork a child and exec sudo-askpass to get the password from the user.
+ */
+static char *
+sudo_askpass(const char *askpass, const char *prompt)
+{
+ static char buf[SUDO_PASS_MAX + 1], *pass;
+ sigaction_t sa, saved_sa_pipe;
+ int pfd[2];
+ pid_t pid;
+ debug_decl(sudo_askpass, SUDO_DEBUG_CONV)
+
+ if (pipe(pfd) == -1)
+ error(1, _("unable to create pipe"));
+
+ if ((pid = fork()) == -1)
+ error(1, _("unable to fork"));
+
+ if (pid == 0) {
+ /* child, point stdout to output side of the pipe and exec askpass */
+ if (dup2(pfd[1], STDOUT_FILENO) == -1) {
+ warning("dup2");
+ _exit(255);
+ }
+ (void) setuid(ROOT_UID);
+ if (setgid(user_details.gid)) {
+ warning(_("unable to set gid to %u"), (unsigned int)user_details.gid);
+ _exit(255);
+ }
+ if (setuid(user_details.uid)) {
+ warning(_("unable to set uid to %u"), (unsigned int)user_details.uid);
+ _exit(255);
+ }
+ closefrom(STDERR_FILENO + 1);
+ execl(askpass, askpass, prompt, (char *)NULL);
+ warning(_("unable to run %s"), askpass);
+ _exit(255);
+ }
+
+ /* Ignore SIGPIPE in case child exits prematurely */
+ zero_bytes(&sa, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_INTERRUPT;
+ sa.sa_handler = SIG_IGN;
+ (void) sigaction(SIGPIPE, &sa, &saved_sa_pipe);
+
+ /* Get response from child (askpass) and restore SIGPIPE handler */
+ (void) close(pfd[1]);
+ pass = getln(pfd[0], buf, sizeof(buf), 0);
+ (void) close(pfd[0]);
+ (void) sigaction(SIGPIPE, &saved_sa_pipe, NULL);
+
+ if (pass == NULL)
+ errno = EINTR; /* make cancel button simulate ^C */
+
+ debug_return_str_masked(pass);
+}
+
+extern int term_erase, term_kill;
+
+static char *
+getln(int fd, char *buf, size_t bufsiz, int feedback)
+{
+ size_t left = bufsiz;
+ ssize_t nr = -1;
+ char *cp = buf;
+ char c = '\0';
+ debug_decl(getln, SUDO_DEBUG_CONV)
+
+ if (left == 0) {
+ errno = EINVAL;
+ debug_return_str(NULL); /* sanity */
+ }
+
+ while (--left) {
+ nr = read(fd, &c, 1);
+ if (nr != 1 || c == '\n' || c == '\r')
+ break;
+ if (feedback) {
+ if (c == term_kill) {
+ while (cp > buf) {
+ if (write(fd, "\b \b", 3) == -1)
+ break;
+ --cp;
+ }
+ left = bufsiz;
+ continue;
+ } else if (c == term_erase) {
+ if (cp > buf) {
+ if (write(fd, "\b \b", 3) == -1)
+ break;
+ --cp;
+ left++;
+ }
+ continue;
+ }
+ ignore_result(write(fd, "*", 1));
+ }
+ *cp++ = c;
+ }
+ *cp = '\0';
+ if (feedback) {
+ /* erase stars */
+ while (cp > buf) {
+ if (write(fd, "\b \b", 3) == -1)
+ break;
+ --cp;
+ }
+ }
+
+ debug_return_str_masked(nr == 1 ? buf : NULL);
+}
+
+static void
+handler(int s)
+{
+ if (s != SIGALRM)
+ signo[s] = 1;
+}
+
+int
+tty_present(void)
+{
+ int fd;
+ debug_decl(tty_present, SUDO_DEBUG_UTIL)
+
+ if ((fd = open(_PATH_TTY, O_RDWR|O_NOCTTY)) != -1)
+ close(fd);
+ debug_return_bool(fd != -1);
+}