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/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
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* Password-prompt - Read a password from the terminal and print it
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* Copyright © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
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* <https://www.fukt.bsnet.se/~teddy/>.
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#define _GNU_SOURCE /* getline() */
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#include <termios.h> /* struct termios, tcsetattr(),
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TCSAFLUSH, tcgetattr(), ECHO */
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#include <unistd.h> /* struct termios, tcsetattr(),
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STDIN_FILENO, TCSAFLUSH,
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#include <signal.h> /* sig_atomic_t, raise(), struct
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sigaction, sigemptyset(),
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sigaction(), sigaddset(), SIGINT,
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SIGQUIT, SIGHUP, SIGTERM,
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <sys/types.h> /* ssize_t */
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#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE,
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getopt_long, getenv() */
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#include <stdio.h> /* fprintf(), stderr, getline(),
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stdin, feof(), perror(), fputc(),
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stdout, getopt_long */
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#include <errno.h> /* errno, EINVAL */
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#include <iso646.h> /* or, not */
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#include <stdbool.h> /* bool, false, true */
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#include <string.h> /* strlen, rindex, strncmp, strcmp */
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#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
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argp_parse(), error_t,
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ARGP_KEY_ARG, ARGP_KEY_END,
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volatile sig_atomic_t quit_now = 0;
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const char *argp_program_version = "password-prompt " VERSION;
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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
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static void termination_handler(int signum){
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signal_received = signum;
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int main(int argc, char **argv){
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struct termios t_new, t_old;
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int status = EXIT_SUCCESS;
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struct sigaction old_action,
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new_action = { .sa_handler = termination_handler,
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struct argp_option options[] = {
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{ .name = "prefix", .key = 'p',
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.arg = "PREFIX", .flags = 0,
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.doc = "Prefix shown before the prompt", .group = 2 },
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{ .name = "debug", .key = 128,
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.doc = "Debug mode", .group = 3 },
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error_t parse_opt (int key, char *arg, struct argp_state *state){
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return ARGP_ERR_UNKNOWN;
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struct argp argp = { .options = options, .parser = parse_opt,
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.doc = "Mandos password-prompt -- Read and"
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" output a password" };
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ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
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if(ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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fprintf(stderr, "Starting %s\n", argv[0]);
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fprintf(stderr, "Storing current terminal attributes\n");
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if(tcgetattr(STDIN_FILENO, &t_old) != 0){
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sigemptyset(&new_action.sa_mask);
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sigaddset(&new_action.sa_mask, SIGINT);
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sigaddset(&new_action.sa_mask, SIGHUP);
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sigaddset(&new_action.sa_mask, SIGTERM);
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ret = sigaction(SIGINT, NULL, &old_action);
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/* Need to check if the handler is SIG_IGN before handling:
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| [[info:libc:Initial Signal Actions]] |
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| [[info:libc:Basic Signal Handling]] |
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &new_action, NULL);
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ret = sigaction(SIGHUP, NULL, &old_action);
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &new_action, NULL);
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ret = sigaction(SIGTERM, NULL, &old_action);
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &new_action, NULL);
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fprintf(stderr, "Removing echo flag from terminal attributes\n");
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t_new.c_lflag &= ~ECHO;
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if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
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perror("tcsetattr-echo");
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fprintf(stderr, "Waiting for input from stdin \n");
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fprintf(stderr, "Interrupted by signal, exiting.\n");
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status = EXIT_FAILURE;
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fprintf(stderr, "%s ", prefix);
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const char *cryptsource = getenv("cryptsource");
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const char *crypttarget = getenv("crypttarget");
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const char *const prompt
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= "Enter passphrase to unlock the disk";
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if(cryptsource == NULL){
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if(crypttarget == NULL){
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fprintf(stderr, "%s: ", prompt);
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fprintf(stderr, "%s (%s): ", prompt, crypttarget);
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if(crypttarget == NULL){
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fprintf(stderr, "%s %s: ", prompt, cryptsource);
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fprintf(stderr, "%s %s (%s): ", prompt, cryptsource,
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ret = getline(&buffer, &n, stdin);
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status = EXIT_SUCCESS;
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/* Make n = data size instead of allocated buffer size */
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/* Strip final newline */
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if(n>0 and buffer[n-1] == '\n'){
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buffer[n-1] = '\0'; /* not strictly necessary */
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ret = write(STDOUT_FILENO, buffer + written, n - written);
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status = EXIT_FAILURE;
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written += (size_t)ret;
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if(errno != EINTR and not feof(stdin)){
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status = EXIT_FAILURE;
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/* if(ret == 0), then the only sensible thing to do is to retry to
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if(debug and not quit_now){
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/* If quit_now is nonzero, we were interrupted by a signal, and
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will print that later, so no need to show this too. */
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fprintf(stderr, "getline() returned 0, retrying.\n");
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fprintf(stderr, "Restoring terminal attributes\n");
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if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
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perror("tcsetattr+echo");
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sigemptyset(&old_action.sa_mask);
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old_action.sa_handler = SIG_DFL;
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ret = sigaction(signal_received, &old_action, NULL);
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raise(signal_received);
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fprintf(stderr, "%s is exiting with status %d\n", argv[0],
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if(status == EXIT_SUCCESS){
added
removed
plugins.d/password-prompt.c
