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- Committer: Teddy Hogeborn
- Date: 2008-09-21 12:20:55 UTC
- Revision ID: teddy@fukt.bsnet.se-20080921122055-vrs4tmw1az0yr92u
* mandos.xml (SECURITY): Minor wording improvement.
- files added:
- plugins.d/usplash
- files removed:
- NEWS
- files modified:
- .bzrignore
added
removed
plugins.d/splashy.c
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/* -*- coding: utf-8 -*- */
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/*
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* Passprompt - Read a password from splashy and output it
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*
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* Copyright © 2008 Teddy Hogeborn
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* Copyright © 2008 Björn Påhlsson
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*
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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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*
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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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*
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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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*
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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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*/
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#define _GNU_SOURCE /* asprintf() */
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#include <signal.h> /* sig_atomic_t, struct sigaction,
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sigemptyset(), sigaddset(), SIGINT,
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SIGHUP, SIGTERM, sigaction,
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SIG_IGN, kill(), SIGKILL */
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#include <stddef.h> /* NULL */
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#include <stdlib.h> /* getenv() */
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#include <stdio.h> /* asprintf(), perror() */
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#include <stdlib.h> /* EXIT_FAILURE, free(), strtoul(),
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EXIT_SUCCESS */
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#include <sys/types.h> /* pid_t, DIR, struct dirent,
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ssize_t */
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
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#include <iso646.h> /* not, or, and */
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#include <unistd.h> /* readlink(), fork(), execl(),
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sleep(), dup2() STDERR_FILENO,
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STDOUT_FILENO, _exit() */
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#include <string.h> /* memcmp() */
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#include <errno.h> /* errno */
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#include <sys/wait.h> /* waitpid(), WIFEXITED(),
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WEXITSTATUS() */
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sig_atomic_t interrupted_by_signal = 0;
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static void termination_handler(__attribute__((unused))int signum){
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interrupted_by_signal = 1;
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}
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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int ret = 0;
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/* Create prompt string */
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char *prompt = NULL;
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{
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const char *const cryptsource = getenv("cryptsource");
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const char *const crypttarget = getenv("crypttarget");
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const char *const prompt_start = "getpass "
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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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ret = asprintf(&prompt, "%s: ", prompt_start);
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} else {
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ret = asprintf(&prompt, "%s (%s): ", prompt_start,
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crypttarget);
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}
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} else {
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if(crypttarget == NULL){
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ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
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} else {
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ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
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cryptsource, crypttarget);
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}
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}
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if(ret == -1){
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return EXIT_FAILURE;
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}
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}
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/* Find splashy process */
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pid_t splashy_pid = 0;
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{
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const char splashy_name[] = "/sbin/splashy";
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DIR *proc_dir = opendir("/proc");
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if(proc_dir == NULL){
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free(prompt);
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perror("opendir");
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return EXIT_FAILURE;
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}
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for(struct dirent *proc_ent = readdir(proc_dir);
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proc_ent != NULL;
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proc_ent = readdir(proc_dir)){
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pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
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if(pid == 0){
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/* Not a process */
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continue;
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}
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/* Find the executable name by doing readlink() on the
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/proc/<pid>/exe link */
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char exe_target[sizeof(splashy_name)];
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ssize_t sret;
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{
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char *exe_link;
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ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
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if(ret == -1){
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perror("asprintf");
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free(prompt);
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closedir(proc_dir);
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return EXIT_FAILURE;
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}
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/* Check that it refers to a symlink owned by root:root */
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struct stat exe_stat;
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ret = lstat(exe_link, &exe_stat);
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if(ret == -1){
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perror("lstat");
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free(exe_link);
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free(prompt);
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closedir(proc_dir);
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return EXIT_FAILURE;
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}
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if(not S_ISLNK(exe_stat.st_mode)
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or exe_stat.st_uid != 0
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or exe_stat.st_gid != 0){
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free(exe_link);
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continue;
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}
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sret = readlink(exe_link, exe_target, sizeof(exe_target));
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free(exe_link);
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}
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if((sret == ((ssize_t)sizeof(exe_target)-1))
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and (memcmp(splashy_name, exe_target,
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sizeof(exe_target)-1) == 0)){
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splashy_pid = pid;
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break;
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}
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}
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closedir(proc_dir);
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}
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if(splashy_pid == 0){
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free(prompt);
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return EXIT_FAILURE;
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}
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/* Set up the signal handler */
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{
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struct sigaction old_action,
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new_action = { .sa_handler = termination_handler,
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.sa_flags = 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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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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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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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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}
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ret = sigaction(SIGHUP, NULL, &old_action);
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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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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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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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}
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ret = sigaction(SIGTERM, NULL, &old_action);
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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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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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if(ret == -1){
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perror("sigaction");
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free(prompt);
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return EXIT_FAILURE;
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}
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}
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}
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/* Fork off the splashy command to prompt for password */
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pid_t splashy_command_pid = 0;
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if(not interrupted_by_signal){
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splashy_command_pid = fork();
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if(splashy_command_pid == -1){
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if(not interrupted_by_signal){
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perror("fork");
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}
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return EXIT_FAILURE;
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}
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/* Child */
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if(splashy_command_pid == 0){
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const char splashy_command[] = "/sbin/splashy_update";
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ret = execl(splashy_command, splashy_command, prompt,
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(char *)NULL);
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if(not interrupted_by_signal){
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perror("execl");
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}
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free(prompt);
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_exit(EXIT_FAILURE);
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}
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}
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/* Parent */
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free(prompt);
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/* Wait for command to complete */
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if(not interrupted_by_signal and splashy_command_pid != 0){
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int status;
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ret = waitpid(splashy_command_pid, &status, 0);
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if(ret == -1){
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if(errno != EINTR){
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perror("waitpid");
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}
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if(errno == ECHILD){
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splashy_command_pid = 0;
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}
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} else {
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/* The child process has exited */
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splashy_command_pid = 0;
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if(not interrupted_by_signal and WIFEXITED(status)
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and WEXITSTATUS(status)==0){
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return EXIT_SUCCESS;
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}
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}
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}
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kill(splashy_pid, SIGTERM);
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if(interrupted_by_signal and splashy_command_pid != 0){
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kill(splashy_command_pid, SIGTERM);
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}
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sleep(2);
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while(kill(splashy_pid, 0) == 0){
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kill(splashy_pid, SIGKILL);
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sleep(1);
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}
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pid_t new_splashy_pid = fork();
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if(new_splashy_pid == 0){
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/* Child; will become new splashy process */
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/* Make the effective user ID (root) the only user ID instead of
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the real user ID (mandos) */
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ret = setuid(geteuid());
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if(ret == -1){
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perror("setuid");
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}
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setsid();
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ret = chdir("/");
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/* if(fork() != 0){ */
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/* _exit(EXIT_SUCCESS); */
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/* } */
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
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if(ret == -1){
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perror("dup2");
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_exit(EXIT_FAILURE);
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}
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execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
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if(not interrupted_by_signal){
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perror("execl");
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}
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_exit(EXIT_FAILURE);
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}
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return EXIT_FAILURE;
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}
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