#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include <syslog.h>

int
main(int ac, char **av)
{
    char buf[1024];
    char *str;
    int n1;
    int n2;
    int n3;
    int n4;

    openlog("sshlockout", LOG_PID|LOG_CONS, LOG_AUTH);
    syslog(LOG_ERR, "sshlockout starting up");
    freopen("/dev/null", "w", stdout);
    freopen("/dev/null", "w", stderr);

    while (fgets(buf, sizeof(buf), stdin) != NULL) {
        if (strstr(buf, "sshd") == NULL)
            continue;
        if (strstr(buf, "Failed password") == NULL)
            continue;
        if ((str = strstr(buf, "Failed password for root from")) != NULL ||
            (str = strstr(buf, "Failed password for admin from")) != NULL
        ) {
            while (*str && (*str < '0' || *str > '9'))
                ++str;
            if (sscanf(str, "%d.%d.%d.%d", &n1, &n2, &n3, &n4) == 4) {
                syslog(LOG_ERR, "Detected ssh password login attempt for root, locking out %d.%d.%d.%d\n", n1, n2, n3, n4);
                snprintf(buf, sizeof(buf), "ipfw add 2100 deny tcp from %d.%d.%d.%d to me 22", n1, n2, n3, n4);
                system(buf);
            }
            continue;
        }
        if ((str = strstr(buf, "Failed password for invalid user")) != NULL) {
            str += 32;
            while (*str == ' ')
                ++str;
            while (*str && *str != ' ')
                ++str;
            if (strncmp(str, " from", 5) == 0 &&
                sscanf(str + 5, "%d.%d.%d.%d", &n1, &n2, &n3, &n4) == 4) {
                syslog(LOG_ERR, "Detected ssh password login attempt for an invalid user, locking out %d.%d.%d.%d\n", n1, n
2, n3, n4);
                snprintf(buf, sizeof(buf), "ipfw add 2100 deny tcp from %d.%d.%d.%d to me 22", n1, n2, n3, n4);
                system(buf);
            }
        }
    }
    syslog(LOG_ERR, "sshlockout exiting");
    return(0);
}