OpenWrt – Rev 1
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/*
* Client for the Emergency Access Daemon
* Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <t_pwd.h>
#include <t_read.h>
#include <t_sha.h>
#include <t_defines.h>
#include <t_client.h>
#include "ead.h"
#include "ead-crypt.h"
#include "pw_encrypt_md5.c"
#define EAD_TIMEOUT 400
#define EAD_TIMEOUT_LONG 2000
static char msgbuf[1500];
static struct ead_msg *msg = (struct ead_msg *) msgbuf;
static uint16_t nid = 0xffff;
struct sockaddr_in local, remote;
static int s = 0;
static int sockflags;
static struct in_addr serverip = {
.s_addr = 0x01010101 /* dummy */
};
static unsigned char *skey = NULL;
static unsigned char bbuf[MAXPARAMLEN];
static unsigned char saltbuf[MAXSALTLEN];
static char *username = NULL;
static char password[MAXPARAMLEN] = "";
static char pw_md5[MD5_OUT_BUFSIZE];
static char pw_salt[MAXSALTLEN];
static struct t_client *tc = NULL;
static struct t_num salt = { .data = saltbuf };
static struct t_num *A, B;
static struct t_preconf *tcp;
static int auth_type = EAD_AUTH_DEFAULT;
static int timeout = EAD_TIMEOUT;
static uint16_t sid = 0;
static void
set_nonblock(int enable)
{
if (enable == !!(sockflags & O_NONBLOCK))
return;
sockflags ^= O_NONBLOCK;
fcntl(s, F_SETFL, sockflags);
}
static int
send_packet(int type, bool (*handler)(void), unsigned int max)
{
struct timeval tv;
fd_set fds;
int nfds;
int len;
int res = 0;
type = htonl(type);
memcpy(&msg->ip, &serverip.s_addr, sizeof(msg->ip));
set_nonblock(0);
sendto(s, msgbuf, sizeof(struct ead_msg) + ntohl(msg->len), 0, (struct sockaddr *) &remote, sizeof(remote));
set_nonblock(1);
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
FD_ZERO(&fds);
do {
FD_SET(s, &fds);
nfds = select(s + 1, &fds, NULL, NULL, &tv);
if (nfds <= 0)
break;
if (!FD_ISSET(s, &fds))
break;
len = read(s, msgbuf, sizeof(msgbuf));
if (len < 0)
break;
if (len < sizeof(struct ead_msg))
continue;
if (len < sizeof(struct ead_msg) + ntohl(msg->len))
continue;
if (msg->magic != htonl(EAD_MAGIC))
continue;
if ((nid != 0xffff) && (ntohs(msg->nid) != nid))
continue;
if (msg->type != type)
continue;
if (handler())
res++;
if ((max > 0) && (res >= max))
break;
} while (1);
return res;
}
static void
prepare_password(void)
{
switch(auth_type) {
case EAD_AUTH_DEFAULT:
break;
case EAD_AUTH_MD5:
md5_crypt(pw_md5, (unsigned char *) password, (unsigned char *) pw_salt);
strncpy(password, pw_md5, sizeof(password));
break;
}
}
static bool
handle_pong(void)
{
struct ead_msg_pong *pong = EAD_DATA(msg, pong);
int len = ntohl(msg->len) - sizeof(struct ead_msg_pong);
if (len <= 0)
return false;
pong->name[len] = 0;
auth_type = ntohs(pong->auth_type);
if (nid == 0xffff)
printf("%04x: %s\n", ntohs(msg->nid), pong->name);
sid = msg->sid;
return true;
}
static bool
handle_prime(void)
{
struct ead_msg_salt *sb = EAD_DATA(msg, salt);
salt.len = sb->len;
memcpy(salt.data, sb->salt, salt.len);
if (auth_type == EAD_AUTH_MD5) {
memcpy(pw_salt, sb->ext_salt, MAXSALTLEN);
pw_salt[MAXSALTLEN - 1] = 0;
}
tcp = t_getpreparam(sb->prime);
tc = t_clientopen(username, &tcp->modulus, &tcp->generator, &salt);
if (!tc) {
fprintf(stderr, "Client open failed\n");
return false;
}
return true;
}
static bool
handle_b(void)
{
struct ead_msg_number *num = EAD_DATA(msg, number);
int len = ntohl(msg->len) - sizeof(struct ead_msg_number);
B.data = bbuf;
B.len = len;
memcpy(bbuf, num->data, len);
return true;
}
static bool
handle_none(void)
{
return true;
}
static bool
handle_done_auth(void)
{
struct ead_msg_auth *auth = EAD_DATA(msg, auth);
if (t_clientverify(tc, auth->data) != 0) {
fprintf(stderr, "Client auth verify failed\n");
return false;
}
return true;
}
static bool
handle_cmd_data(void)
{
struct ead_msg_cmd_data *cmd = EAD_ENC_DATA(msg, cmd_data);
int datalen = ead_decrypt_message(msg) - sizeof(struct ead_msg_cmd_data);
if (datalen < 0)
return false;
if (datalen > 0) {
write(1, cmd->data, datalen);
}
return !!cmd->done;
}
static int
send_ping(void)
{
msg->type = htonl(EAD_TYPE_PING);
msg->len = 0;
return send_packet(EAD_TYPE_PONG, handle_pong, (nid == 0xffff ? 0 : 1));
}
static int
send_username(void)
{
msg->type = htonl(EAD_TYPE_SET_USERNAME);
msg->len = htonl(sizeof(struct ead_msg_user));
strcpy(EAD_DATA(msg, user)->username, username);
return send_packet(EAD_TYPE_ACK_USERNAME, handle_none, 1);
}
static int
get_prime(void)
{
msg->type = htonl(EAD_TYPE_GET_PRIME);
msg->len = 0;
return send_packet(EAD_TYPE_PRIME, handle_prime, 1);
}
static int
send_a(void)
{
struct ead_msg_number *num = EAD_DATA(msg, number);
A = t_clientgenexp(tc);
msg->type = htonl(EAD_TYPE_SEND_A);
msg->len = htonl(sizeof(struct ead_msg_number) + A->len);
memcpy(num->data, A->data, A->len);
return send_packet(EAD_TYPE_SEND_B, handle_b, 1);
}
static int
send_auth(void)
{
struct ead_msg_auth *auth = EAD_DATA(msg, auth);
prepare_password();
t_clientpasswd(tc, password);
skey = t_clientgetkey(tc, &B);
if (!skey)
return 0;
ead_set_key(skey);
msg->type = htonl(EAD_TYPE_SEND_AUTH);
msg->len = htonl(sizeof(struct ead_msg_auth));
memcpy(auth->data, t_clientresponse(tc), sizeof(auth->data));
return send_packet(EAD_TYPE_DONE_AUTH, handle_done_auth, 1);
}
static int
send_command(const char *command)
{
struct ead_msg_cmd *cmd = EAD_ENC_DATA(msg, cmd);
msg->type = htonl(EAD_TYPE_SEND_CMD);
cmd->type = htons(EAD_CMD_NORMAL);
cmd->timeout = htons(10);
strncpy((char *)cmd->data, command, 1024);
ead_encrypt_message(msg, sizeof(struct ead_msg_cmd) + strlen(command) + 1);
return send_packet(EAD_TYPE_RESULT_CMD, handle_cmd_data, 1);
}
static int
usage(const char *prog)
{
fprintf(stderr, "Usage: %s [-s <addr>] [-b <addr>] <node> <username>[:<password>] <command>\n"
"\n"
"\t-s <addr>: Set the server's source address to <addr>\n"
"\t-b <addr>: Set the broadcast address to <addr>\n"
"\t<node>: Node ID (4 digits hex)\n"
"\t<username>: Username to authenticate with\n"
"\n"
"\tPassing no arguments shows a list of active nodes on the network\n"
"\n", prog);
return -1;
}
int main(int argc, char **argv)
{
int val = 1;
char *st = NULL;
const char *command = NULL;
const char *prog = argv[0];
int ch;
msg->magic = htonl(EAD_MAGIC);
msg->sid = 0;
memset(&local, 0, sizeof(local));
memset(&remote, 0, sizeof(remote));
remote.sin_family = AF_INET;
remote.sin_addr.s_addr = 0xffffffff;
remote.sin_port = htons(EAD_PORT);
local.sin_family = AF_INET;
local.sin_addr.s_addr = INADDR_ANY;
local.sin_port = 0;
while ((ch = getopt(argc, argv, "b:s:h")) != -1) {
switch(ch) {
case 's':
inet_aton(optarg, &serverip);
break;
case 'b':
inet_aton(optarg, &remote.sin_addr);
break;
case 'h':
return usage(prog);
}
}
argv += optind;
argc -= optind;
switch(argc) {
case 3:
command = argv[2];
/* fall through */
case 2:
username = argv[1];
st = strchr(username, ':');
if (st) {
*st = 0;
st++;
strncpy(password, st, sizeof(password));
password[sizeof(password) - 1] = 0;
/* hide command line password */
memset(st, 0, strlen(st));
}
/* fall through */
case 1:
nid = strtoul(argv[0], &st, 16);
if (st && st[0] != 0)
return usage(prog);
/* fall through */
case 0:
break;
default:
return usage(prog);
}
msg->nid = htons(nid);
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (s < 0) {
perror("socket");
return -1;
}
setsockopt(s, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
if (bind(s, (struct sockaddr *)&local, sizeof(local)) < 0) {
perror("bind");
return -1;
}
sockflags = fcntl(s, F_GETFL);
if (!send_ping()) {
fprintf(stderr, "No devices found\n");
return 1;
}
if (nid == 0xffff)
return 0;
if (!username || !password[0])
return 0;
if (!send_username()) {
fprintf(stderr, "Device did not accept user name\n");
return 1;
}
timeout = EAD_TIMEOUT_LONG;
if (!get_prime()) {
fprintf(stderr, "Failed to get user password info\n");
return 1;
}
if (!send_a()) {
fprintf(stderr, "Failed to send local authentication data\n");
return 1;
}
if (!send_auth()) {
fprintf(stderr, "Authentication failed\n");
return 1;
}
if (!command) {
fprintf(stderr, "Authentication succesful\n");
return 0;
}
if (!send_command(command)) {
fprintf(stderr, "Command failed\n");
return 1;
}
return 0;
}