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* Usplash - Read a password from usplash and output it
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* Copyright © 2008-2017 Teddy Hogeborn
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* Copyright © 2008-2017 Björn Påhlsson
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* This file is part of Mandos.
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* Mandos is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* Mandos is distributed in the hope that it will be useful, but
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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 Mandos. If not, see <http://www.gnu.org/licenses/>.
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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 <mandos@recompile.se>.
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* Contact the authors at <mandos@fukt.bsnet.se>.
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#define _GNU_SOURCE /* asprintf(), TEMP_FAILURE_RETRY() */
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#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
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#include <iso646.h> /* and, or, not*/
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#include <errno.h> /* errno, EINTR */
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#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
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#include <stddef.h> /* NULL */
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#include <string.h> /* strlen(), memcmp(), strerror() */
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#include <stdio.h> /* asprintf(), vasprintf(), vprintf(),
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#include <string.h> /* strlen(), memcmp() */
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#include <stdio.h> /* asprintf(), perror() */
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#include <unistd.h> /* close(), write(), readlink(),
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read(), STDOUT_FILENO, sleep(),
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fork(), setuid(), geteuid(),
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setsid(), chdir(), dup2(),
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STDERR_FILENO, execv() */
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#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
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EXIT_SUCCESS, malloc(), _exit(),
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EXIT_SUCCESS, malloc(), _exit() */
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#include <stdlib.h> /* getenv() */
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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#include <inttypes.h> /* intmax_t, strtoimax() */
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#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
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#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
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#include <argz.h> /* argz_count(), argz_extract() */
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#include <stdarg.h> /* va_list, va_start(), ... */
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sig_atomic_t interrupted_by_signal = 0;
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int signal_received;
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const char usplash_name[] = "/sbin/usplash";
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/* Function to use when printing errors */
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__attribute__((format (gnu_printf, 3, 4)))
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void error_plus(int status, int errnum, const char *formatstring,
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va_start(ap, formatstring);
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ret = vasprintf(&text, formatstring, ap);
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fprintf(stderr, "Mandos plugin %s: ",
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program_invocation_short_name);
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vfprintf(stderr, formatstring, ap);
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fprintf(stderr, ": ");
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fprintf(stderr, "%s\n", strerror(errnum));
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error(status, errno, "vasprintf while printing error");
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fprintf(stderr, "Mandos plugin ");
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error(status, errnum, "%s", text);
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static void termination_handler(int signum){
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if(interrupted_by_signal){
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sigemptyset(&new_action.sa_mask);
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ret = sigaddset(&new_action.sa_mask, SIGINT);
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error_plus(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGHUP);
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error_plus(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGTERM);
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error_plus(0, errno, "sigaddset");
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ret = sigaction(SIGINT, NULL, &old_action);
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if(errno != EINTR){
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error_plus(0, errno, "sigaction");
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/* If usplash was never accessed, we can stop now */
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if(not usplash_accessed){
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if(fifo_fd != -1){
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ret = close(fifo_fd);
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ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
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if(ret == -1 and errno != EINTR){
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error_plus(0, errno, "close");
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/* Close output FIFO */
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if(outfifo_fd != -1){
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ret = close(outfifo_fd);
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ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
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error_plus(0, errno, "close");
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/* Create argv for new usplash*/
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char **cmdline_argv = malloc((argz_count(cmdline, cmdline_len) + 1)
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* sizeof(char *)); /* Count args */
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if(cmdline_argv == NULL){
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error_plus(0, errno, "malloc");
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argz_extract(cmdline, cmdline_len, cmdline_argv); /* Create argv */
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/* Create argc and argv for new usplash*/
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int cmdline_argc = 0;
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char **cmdline_argv = malloc(sizeof(char *));
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while(position < cmdline_len){
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char **tmp = realloc(cmdline_argv,
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* (size_t)(cmdline_argc + 2)));
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cmdline_argv[cmdline_argc] = cmdline + position;
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position += strlen(cmdline + position) + 1;
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cmdline_argv[cmdline_argc] = NULL;
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/* Kill old usplash */
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kill(usplash_pid, SIGTERM);
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the real user ID (_mandos) */
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ret = setuid(geteuid());
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error_plus(0, errno, "setuid");
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ret = chdir("/");
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error_plus(0, errno, "chdir");
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/* if(fork() != 0){ */
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/* _exit(EXIT_SUCCESS); */
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
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error_plus(0, errno, "dup2");
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execv(usplash_name, cmdline_argv);
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if(not interrupted_by_signal){
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error_plus(0, errno, "execv");
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free(cmdline_argv);
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free(cmdline_argv);
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if(not usplash_write(&fifo_fd, "PULSATE", NULL)){
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if(errno != EINTR){
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error_plus(0, errno, "usplash_write");
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perror("usplash_write");
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/* Close FIFO (again) */
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ret = close(fifo_fd);
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if(ret == -1 and errno != EINTR){
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error_plus(0, errno, "close");
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ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
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if(ret == -1 and errno != EINTR){
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if(interrupted_by_signal){
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struct sigaction signal_action = { .sa_handler = SIG_DFL };