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-rw-r--r--src/tgetpass.c450
1 files changed, 450 insertions, 0 deletions
diff --git a/src/tgetpass.c b/src/tgetpass.c
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index 0000000..87f01dc
--- /dev/null
+++ b/src/tgetpass.c
@@ -0,0 +1,450 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 1996, 1998-2005, 2007-2021
+ * 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.
+ *
+ * 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.
+ */
+
+/*
+ * 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
+ */
+
+#ifdef __TANDEM
+# include <floss.h>
+#endif
+
+#include <config.h>
+
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <fcntl.h>
+
+#include "sudo.h"
+#include "sudo_plugin.h"
+
+enum tgetpass_errval {
+ TGP_ERRVAL_NOERROR,
+ TGP_ERRVAL_TIMEOUT,
+ TGP_ERRVAL_NOPASSWORD,
+ TGP_ERRVAL_READERROR
+};
+
+static volatile sig_atomic_t signo[NSIG];
+
+static void tgetpass_handler(int);
+static char *getln(int, char *, size_t, bool, enum tgetpass_errval *);
+static char *sudo_askpass(const char *, const char *);
+
+static int
+suspend(int sig, struct sudo_conv_callback *callback)
+{
+ int ret = 0;
+ debug_decl(suspend, SUDO_DEBUG_CONV);
+
+ if (callback != NULL && SUDO_API_VERSION_GET_MAJOR(callback->version) != SUDO_CONV_CALLBACK_VERSION_MAJOR) {
+ sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+ "callback major version mismatch, expected %u, got %u",
+ SUDO_CONV_CALLBACK_VERSION_MAJOR,
+ SUDO_API_VERSION_GET_MAJOR(callback->version));
+ callback = NULL;
+ }
+
+ if (callback != NULL && callback->on_suspend != NULL) {
+ if (callback->on_suspend(sig, callback->closure) == -1)
+ ret = -1;
+ }
+ kill(getpid(), sig);
+ if (callback != NULL && callback->on_resume != NULL) {
+ if (callback->on_resume(sig, callback->closure) == -1)
+ ret = -1;
+ }
+ debug_return_int(ret);
+}
+
+static void
+tgetpass_display_error(enum tgetpass_errval errval)
+{
+ debug_decl(tgetpass_display_error, SUDO_DEBUG_CONV);
+
+ switch (errval) {
+ case TGP_ERRVAL_NOERROR:
+ break;
+ case TGP_ERRVAL_TIMEOUT:
+ sudo_warnx("%s", U_("timed out reading password"));
+ break;
+ case TGP_ERRVAL_NOPASSWORD:
+ sudo_warnx("%s", U_("no password was provided"));
+ break;
+ case TGP_ERRVAL_READERROR:
+ sudo_warn("%s", U_("unable to read password"));
+ break;
+ }
+ debug_return;
+}
+
+/*
+ * Like getpass(3) but with timeout and echo flags.
+ */
+char *
+tgetpass(const char *prompt, int timeout, int flags,
+ struct sudo_conv_callback *callback)
+{
+ struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
+ struct sigaction savetstp, savettin, savettou;
+ char *pass;
+ static const char *askpass;
+ static char buf[SUDO_CONV_REPL_MAX + 1];
+ int i, input, output, save_errno, ttyfd;
+ bool feedback, need_restart, neednl;
+ enum tgetpass_errval errval;
+ 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();
+ }
+
+restart:
+ /* Try to open /dev/tty if we are going to be using it for I/O. */
+ ttyfd = -1;
+ if (!ISSET(flags, TGP_STDIN|TGP_ASKPASS)) {
+ /* If no tty present and we need to disable echo, try askpass. */
+ ttyfd = open(_PATH_TTY, O_RDWR);
+ if (ttyfd == -1 && !ISSET(flags, TGP_ECHO|TGP_NOECHO_TRY)) {
+ if (askpass == NULL || getenv_unhooked("DISPLAY") == NULL) {
+ sudo_warnx("%s",
+ U_("a terminal is required to read the password; either use the -S option to read from standard input or configure an askpass helper"));
+ 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')
+ sudo_fatalx("%s",
+ U_("no askpass program specified, try setting SUDO_ASKPASS"));
+ debug_return_str_masked(sudo_askpass(askpass, prompt));
+ }
+
+ /* Reset state. */
+ for (i = 0; i < NSIG; i++)
+ signo[i] = 0;
+ pass = NULL;
+ save_errno = 0;
+ neednl = false;
+ need_restart = false;
+ feedback = false;
+
+ /* Use tty for reading/writing if available else use stdin/stderr. */
+ if (ttyfd == -1) {
+ input = STDIN_FILENO;
+ output = STDERR_FILENO;
+ /* Don't try to mask password if /dev/tty is not available. */
+ CLR(flags, TGP_MASK);
+ } else {
+ input = ttyfd;
+ output = ttyfd;
+ }
+
+ /*
+ * If we are using a tty but are not the foreground pgrp this will
+ * return EINTR. We send ourself SIGTTOU bracketed by callbacks.
+ */
+ if (!ISSET(flags, TGP_ECHO)) {
+ for (;;) {
+ if (ISSET(flags, TGP_MASK))
+ neednl = feedback = sudo_term_cbreak(input);
+ else
+ neednl = sudo_term_noecho(input);
+ if (neednl || errno != EINTR)
+ break;
+ /* Received SIGTTOU, suspend the process. */
+ if (suspend(SIGTTOU, callback) == -1) {
+ if (ttyfd != -1)
+ (void) close(ttyfd);
+ debug_return_ptr(NULL);
+ }
+ }
+ }
+
+ /*
+ * Catch signals that would otherwise cause the user to end
+ * up with echo turned off in the shell.
+ */
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0; /* don't restart system calls */
+ sa.sa_handler = tgetpass_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);
+
+ if (ISSET(flags, TGP_BELL) && output != STDERR_FILENO) {
+ /* Ring the bell if requested and there is a tty. */
+ if (write(output, "\a", 1) == -1)
+ goto restore;
+ }
+ if (prompt) {
+ if (write(output, prompt, strlen(prompt)) == -1)
+ goto restore;
+ }
+
+ if (timeout > 0)
+ alarm(timeout);
+ pass = getln(input, buf, sizeof(buf), feedback, &errval);
+ alarm(0);
+ save_errno = errno;
+
+ if (neednl || pass == NULL) {
+ if (write(output, "\n", 1) == -1)
+ goto restore;
+ }
+ tgetpass_display_error(errval);
+
+restore:
+ /* Restore old signal handlers. */
+ (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);
+
+ /* Restore old tty settings. */
+ if (!ISSET(flags, TGP_ECHO)) {
+ /* Restore old tty settings if possible. */
+ (void) sudo_term_restore(input, true);
+ }
+ if (ttyfd != -1)
+ (void) close(ttyfd);
+
+ /*
+ * 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]) {
+ switch (i) {
+ case SIGALRM:
+ break;
+ case SIGTSTP:
+ case SIGTTIN:
+ case SIGTTOU:
+ if (suspend(i, callback) == 0)
+ need_restart = true;
+ break;
+ default:
+ kill(getpid(), i);
+ 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_CONV_REPL_MAX + 1], *pass;
+ struct sigaction sa, savechld;
+ enum tgetpass_errval errval;
+ int pfd[2], status;
+ pid_t child;
+ debug_decl(sudo_askpass, SUDO_DEBUG_CONV);
+
+ /* Set SIGCHLD handler to default since we call waitpid() below. */
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ sa.sa_handler = SIG_DFL;
+ (void) sigaction(SIGCHLD, &sa, &savechld);
+
+ if (pipe2(pfd, O_CLOEXEC) == -1)
+ sudo_fatal("%s", U_("unable to create pipe"));
+
+ child = sudo_debug_fork();
+ if (child == -1)
+ sudo_fatal("%s", U_("unable to fork"));
+
+ if (child == 0) {
+ /* child, set stdout to write side of the pipe */
+ if (dup3(pfd[1], STDOUT_FILENO, 0) == -1) {
+ sudo_warn("dup3");
+ _exit(255);
+ }
+ if (setuid(ROOT_UID) == -1)
+ sudo_warn("setuid(%d)", ROOT_UID);
+ /* Close fds before uid change to prevent prlimit sabotage on Linux. */
+ closefrom(STDERR_FILENO + 1);
+ /* Run the askpass program with the user's original resource limits. */
+ restore_limits();
+ /* But avoid a setuid() failure on Linux due to RLIMIT_NPROC. */
+ unlimit_nproc();
+ if (setgid(user_details.cred.gid)) {
+ sudo_warn(U_("unable to set gid to %u"), (unsigned int)user_details.cred.gid);
+ _exit(255);
+ }
+ if (setuid(user_details.cred.uid)) {
+ sudo_warn(U_("unable to set uid to %u"), (unsigned int)user_details.cred.uid);
+ _exit(255);
+ }
+ restore_nproc();
+ execl(askpass, askpass, prompt, (char *)NULL);
+ sudo_warn(U_("unable to run %s"), askpass);
+ _exit(255);
+ }
+
+ /* Get response from child (askpass). */
+ (void) close(pfd[1]);
+ pass = getln(pfd[0], buf, sizeof(buf), 0, &errval);
+ (void) close(pfd[0]);
+
+ tgetpass_display_error(errval);
+
+ /* Wait for child to exit. */
+ for (;;) {
+ pid_t rv = waitpid(child, &status, 0);
+ if (rv == -1 && errno != EINTR)
+ break;
+ if (rv != -1 && !WIFSTOPPED(status))
+ break;
+ }
+
+ if (pass == NULL)
+ errno = EINTR; /* make cancel button simulate ^C */
+
+ /* Restore saved SIGCHLD handler. */
+ (void) sigaction(SIGCHLD, &savechld, NULL);
+
+ debug_return_str_masked(pass);
+}
+
+extern int sudo_term_eof, sudo_term_erase, sudo_term_kill;
+
+static char *
+getln(int fd, char *buf, size_t bufsiz, bool feedback,
+ enum tgetpass_errval *errval)
+{
+ size_t left = bufsiz;
+ ssize_t nr = -1;
+ char *cp = buf;
+ char c = '\0';
+ debug_decl(getln, SUDO_DEBUG_CONV);
+
+ *errval = TGP_ERRVAL_NOERROR;
+
+ if (left == 0) {
+ *errval = TGP_ERRVAL_READERROR;
+ errno = EINVAL;
+ debug_return_str(NULL);
+ }
+
+ while (--left) {
+ nr = read(fd, &c, 1);
+ if (nr != 1 || c == '\n' || c == '\r')
+ break;
+ if (feedback) {
+ if (c == sudo_term_eof) {
+ nr = 0;
+ break;
+ } else if (c == sudo_term_kill) {
+ while (cp > buf) {
+ if (write(fd, "\b \b", 3) == -1)
+ break;
+ cp--;
+ }
+ cp = buf;
+ left = bufsiz;
+ continue;
+ } else if (c == sudo_term_erase) {
+ if (cp > buf) {
+ ignore_result(write(fd, "\b \b", 3));
+ 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;
+ }
+ }
+
+ switch (nr) {
+ case -1:
+ /* Read error */
+ if (errno == EINTR) {
+ if (signo[SIGALRM] == 1)
+ *errval = TGP_ERRVAL_TIMEOUT;
+ } else {
+ *errval = TGP_ERRVAL_READERROR;
+ }
+ debug_return_str(NULL);
+ case 0:
+ /* EOF is only an error if no bytes were read. */
+ if (left == bufsiz - 1) {
+ *errval = TGP_ERRVAL_NOPASSWORD;
+ debug_return_str(NULL);
+ }
+ FALLTHROUGH;
+ default:
+ debug_return_str_masked(buf);
+ }
+}
+
+static void
+tgetpass_handler(int s)
+{
+ signo[s] = 1;
+}
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