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/*
* candy.c
*
* An example program for CERBERUS.
* ( http://sourceforge.jp/projects/tomoyo/document/winf2005-en.pdf )
*
* Copyright (C) 2005-2009 NTT DATA CORPORATION
*
* Version: 1.7.0 2009/09/03
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <pwd.h>
static const char *get_shell(void)
{
static char *shell = NULL;
if (!shell) {
struct passwd *pw = getpwuid(getuid());
shell = pw ? pw->pw_shell : "/bin/sh";
}
return shell;
}
static int get_start_time(pid_t pid, unsigned long long *t)
{
FILE *fp;
int i;
char *cp;
char buffer[1024];
memset(buffer, 0, sizeof(buffer));
snprintf(buffer, sizeof(buffer) - 1, "/proc/%d/stat", pid);
fp = fopen(buffer, "r");
if (!fp)
return EOF;
fgets(buffer, sizeof(buffer) - 1, fp);
fclose(fp);
for (i = 0; i < 21; i++) {
cp = strchr(buffer, ' ');
if (!cp)
return EOF;
memmove(buffer, cp + 1, strlen(cp + 1) + 1);
}
cp = strchr(buffer, ' ');
if (!cp)
return EOF;
*cp = '\0';
if (sscanf(buffer, "%llu", t) != 1)
return EOF;
return 0;
}
int main(int argc, char *argv[])
{
static char buffer[1024];
static const char *passwd = "CERBERUS\n";
int trial;
const char *shell = get_shell();
for (trial = 0; trial < 3; trial++) {
memset(buffer, 0, sizeof(buffer));
printf("Password: ");
fgets(buffer, sizeof(buffer) - 1, stdin);
if (shell && !strcmp(buffer, passwd)) {
unsigned long long t0;
unsigned long long t1;
if (get_start_time(getppid(), &t0) == 0 &&
get_start_time(getpid(), &t1) == 0) {
/* 10 sec */
if ((t1 - t0) < 1000)
execlp(shell, shell, NULL);
}
}
sleep(3);
}
printf("Authentication Failure\n");
return 0;
}
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