/* Create the fwknop custom chains (at least those that are configured).
*/
static int
create_fw_chains(const fko_srv_options_t * const opts)
{
int i, got_err = 0;
for(i=0; i < NUM_FWKNOP_ACCESS_TYPES; i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
if(chain_exists(opts, i) == 0)
{
/* Create the chain
*/
if(! create_chain(opts, i))
got_err++;
/* Then create the jump rule to that chain if it
* doesn't already exist (which is possible)
*/
if(jump_rule_exists(opts, i) == 0)
if(! add_jump_rule(opts, i))
got_err++;
}
}
return(got_err);
}
static void
mk_chain(const fko_srv_options_t * const opts, const int chain_num)
{
/* Make sure the required chain and jump rule exist
*/
if(chain_exists(opts, chain_num) == 0)
create_chain(opts, chain_num);
if (jump_rule_exists(opts, chain_num) == 0)
add_jump_rule(opts, chain_num);
return;
}
static bool use_iptables() {
if(iptables_state == -1) {
if(geteuid() != 0) return (iptables_state = 0);
if(!chain_exists()) {
int res = shell("/sbin/iptables -N " CHAIN);
if(res != EXIT_SUCCESS) {
LL_PRINT("ERROR: Failed to create iptables chain "CHAIN);
return (iptables_state = 0);
}
}
// now add a jump to our chain at the start of the OUTPUT chain if it isn't in the chain already
int res = shell("/sbin/iptables -C OUTPUT -j " CHAIN " || /sbin/iptables -I OUTPUT 1 -j " CHAIN);
if(res != EXIT_SUCCESS) {
LL_PRINT("ERROR: Failed to insert rule in OUTPUT chain");
return (iptables_state = 0);
}
return (iptables_state = 1);
}
return iptables_state;
}
/* Rule Processing - Create an access request...
*/
int
process_spa_request(const fko_srv_options_t * const opts,
const acc_stanza_t * const acc, spa_data_t * const spadat)
{
char nat_ip[MAX_IPV4_STR_LEN] = {0};
char snat_target[SNAT_TARGET_BUFSIZE] = {0};
char rule_buf[CMD_BUFSIZE] = {0};
char *ndx;
unsigned int nat_port = 0;
acc_port_list_t *port_list = NULL;
acc_port_list_t *ple = NULL;
unsigned int fst_proto;
unsigned int fst_port;
struct fw_chain * const in_chain = &(opts->fw_config->chain[IPT_INPUT_ACCESS]);
struct fw_chain * const out_chain = &(opts->fw_config->chain[IPT_OUTPUT_ACCESS]);
struct fw_chain * const fwd_chain = &(opts->fw_config->chain[IPT_FORWARD_ACCESS]);
struct fw_chain * const dnat_chain = &(opts->fw_config->chain[IPT_DNAT_ACCESS]);
struct fw_chain *snat_chain; /* We assign this later (if we need to). */
int res = 0, is_err, snat_chain_num = 0;
time_t now;
unsigned int exp_ts;
/* Parse and expand our access message.
*/
if(expand_acc_port_list(&port_list, spadat->spa_message_remain) != 1)
{
/* technically we would already have exited with an error if there were
* any memory allocation errors (see the add_port_list() function), but
* for completeness...
*/
free_acc_port_list(port_list);
return res;
}
/* Start at the top of the proto-port list...
*/
ple = port_list;
/* Remember the first proto/port combo in case we need them
* for NAT access requests.
*/
fst_proto = ple->proto;
fst_port = ple->port;
/* Set our expire time value.
*/
time(&now);
exp_ts = now + spadat->fw_access_timeout;
/* For straight access requests, we currently support multiple proto/port
* request.
*/
if((spadat->message_type == FKO_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_ACCESS_MSG) && !acc->force_nat)
{
/* Check to make sure that the jump rules exist for each
* required chain
*/
if(chain_exists(opts, IPT_INPUT_ACCESS) == 0)
create_chain(opts, IPT_INPUT_ACCESS);
if(jump_rule_exists(opts, IPT_INPUT_ACCESS) == 0)
add_jump_rule(opts, IPT_INPUT_ACCESS);
if(strlen(out_chain->to_chain))
{
if(chain_exists(opts, IPT_OUTPUT_ACCESS) == 0)
create_chain(opts, IPT_OUTPUT_ACCESS);
if(jump_rule_exists(opts, IPT_OUTPUT_ACCESS) == 0)
add_jump_rule(opts, IPT_OUTPUT_ACCESS);
}
/* Create an access command for each proto/port for the source ip.
*/
while(ple != NULL)
{
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_RULE_ARGS,
in_chain->table,
ple->proto,
spadat->use_src_ip,
ple->port,
exp_ts,
in_chain->target
);
if(rule_exists(opts, in_chain, rule_buf,
ple->proto, spadat->use_src_ip, ple->port, exp_ts) == 0)
{
if(create_rule(opts, in_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added Rule to %s for %s, %s expires at %u",
in_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
in_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(in_chain->next_expire < now || exp_ts < in_chain->next_expire)
in_chain->next_expire = exp_ts;
}
}
/* If we have to make an corresponding OUTPUT rule if out_chain target
* is not NULL.
*/
if(strlen(out_chain->to_chain))
{
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_OUT_RULE_ARGS,
out_chain->table,
ple->proto,
spadat->use_src_ip,
ple->port,
exp_ts,
out_chain->target
);
if(rule_exists(opts, out_chain, rule_buf,
ple->proto, spadat->use_src_ip, ple->port, exp_ts) == 0)
{
if(create_rule(opts, out_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added Rule in %s for %s, %s expires at %u",
out_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
out_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted. */
if(out_chain->next_expire < now || exp_ts < out_chain->next_expire)
out_chain->next_expire = exp_ts;
}
}
}
ple = ple->next;
}
}
/* NAT requests... */
else if(spadat->message_type == FKO_LOCAL_NAT_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_LOCAL_NAT_ACCESS_MSG
|| spadat->message_type == FKO_NAT_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_NAT_ACCESS_MSG
|| acc->force_nat)
{
/* Parse out the NAT IP and Port components.
*/
if(acc->force_nat)
{
strlcpy(nat_ip, acc->force_nat_ip, sizeof(nat_ip));
nat_port = acc->force_nat_port;
}
else
{
ndx = strchr(spadat->nat_access, ',');
if(ndx != NULL)
{
strlcpy(nat_ip, spadat->nat_access, (ndx-spadat->nat_access)+1);
if (! is_valid_ipv4_addr(nat_ip))
{
log_msg(LOG_INFO, "Invalid NAT IP in SPA message");
free_acc_port_list(port_list);
return res;
}
nat_port = strtol_wrapper(ndx+1, 0, MAX_PORT, NO_EXIT_UPON_ERR, &is_err);
if(is_err != FKO_SUCCESS)
{
log_msg(LOG_INFO, "Invalid NAT port in SPA message");
free_acc_port_list(port_list);
res = is_err;
return res;
}
}
}
if(spadat->message_type == FKO_LOCAL_NAT_ACCESS_MSG)
{
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_RULE_ARGS,
in_chain->table,
fst_proto,
spadat->use_src_ip,
nat_port,
exp_ts,
in_chain->target
);
/* Check to make sure that the jump rules exist for each
* required chain
*/
if(chain_exists(opts, IPT_INPUT_ACCESS) == 0)
create_chain(opts, IPT_INPUT_ACCESS);
if(jump_rule_exists(opts, IPT_INPUT_ACCESS) == 0)
add_jump_rule(opts, IPT_INPUT_ACCESS);
if(rule_exists(opts, in_chain, rule_buf,
fst_proto, spadat->use_src_ip, nat_port, exp_ts) == 0)
{
if(create_rule(opts, in_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added Rule to %s for %s, %s expires at %u",
in_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
in_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(in_chain->next_expire < now || exp_ts < in_chain->next_expire)
in_chain->next_expire = exp_ts;
}
}
}
else if(strlen(fwd_chain->to_chain))
{
/* Make our FORWARD and NAT rules, and make sure the
* required chain and jump rule exists
*/
if(chain_exists(opts, IPT_FORWARD_ACCESS) == 0)
create_chain(opts, IPT_FORWARD_ACCESS);
if (jump_rule_exists(opts, IPT_FORWARD_ACCESS) == 0)
add_jump_rule(opts, IPT_FORWARD_ACCESS);
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_FWD_RULE_ARGS,
fwd_chain->table,
fst_proto,
spadat->use_src_ip,
nat_ip,
nat_port,
exp_ts,
fwd_chain->target
);
if(rule_exists(opts, fwd_chain, rule_buf, fst_proto,
spadat->use_src_ip, nat_port, exp_ts) == 0)
{
if(create_rule(opts, fwd_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added FORWARD Rule to %s for %s, %s expires at %u",
fwd_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
fwd_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(fwd_chain->next_expire < now || exp_ts < fwd_chain->next_expire)
fwd_chain->next_expire = exp_ts;
}
}
}
if(strlen(dnat_chain->to_chain))
{
/* Make sure the required chain and jump rule exist
*/
if(chain_exists(opts, IPT_DNAT_ACCESS) == 0)
create_chain(opts, IPT_DNAT_ACCESS);
if (jump_rule_exists(opts, IPT_DNAT_ACCESS) == 0)
add_jump_rule(opts, IPT_DNAT_ACCESS);
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_DNAT_RULE_ARGS,
dnat_chain->table,
fst_proto,
spadat->use_src_ip,
fst_port,
exp_ts,
dnat_chain->target,
nat_ip,
nat_port
);
if(rule_exists(opts, dnat_chain, rule_buf, fst_proto,
spadat->use_src_ip, fst_port, exp_ts) == 0)
{
if(create_rule(opts, dnat_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added DNAT Rule to %s for %s, %s expires at %u",
dnat_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
dnat_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(dnat_chain->next_expire < now || exp_ts < dnat_chain->next_expire)
dnat_chain->next_expire = exp_ts;
}
}
}
/* If SNAT (or MASQUERADE) is wanted, then we add those rules here as well.
*/
if(acc->force_snat || strncasecmp(opts->config[CONF_ENABLE_IPT_SNAT], "Y", 1) == 0)
{
/* Add SNAT or MASQUERADE rules.
*/
if(acc->force_snat && is_valid_ipv4_addr(acc->force_snat_ip))
{
/* Using static SNAT */
snat_chain = &(opts->fw_config->chain[IPT_SNAT_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-source %s:%i", acc->force_snat_ip, fst_port);
snat_chain_num = IPT_SNAT_ACCESS;
}
else if(acc->force_snat && acc->force_masquerade)
{
/* Using MASQUERADE */
snat_chain = &(opts->fw_config->chain[IPT_MASQUERADE_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-ports %i", fst_port);
snat_chain_num = IPT_MASQUERADE_ACCESS;
}
else if((opts->config[CONF_SNAT_TRANSLATE_IP] != NULL)
&& is_valid_ipv4_addr(opts->config[CONF_SNAT_TRANSLATE_IP]))
{
/* Using static SNAT */
snat_chain = &(opts->fw_config->chain[IPT_SNAT_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-source %s:%i", opts->config[CONF_SNAT_TRANSLATE_IP],
fst_port);
snat_chain_num = IPT_SNAT_ACCESS;
}
else
{
/* Using MASQUERADE */
snat_chain = &(opts->fw_config->chain[IPT_MASQUERADE_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-ports %i", fst_port);
snat_chain_num = IPT_MASQUERADE_ACCESS;
}
if(chain_exists(opts, snat_chain_num) == 0)
create_chain(opts, snat_chain_num);
if(jump_rule_exists(opts, snat_chain_num) == 0)
add_jump_rule(opts, snat_chain_num);
memset(rule_buf, 0, CMD_BUFSIZE);
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_SNAT_RULE_ARGS,
snat_chain->table,
fst_proto,
nat_ip,
nat_port,
exp_ts,
snat_chain->target,
snat_target
);
if(rule_exists(opts, snat_chain, rule_buf, fst_proto,
spadat->use_src_ip, nat_port, exp_ts) == 0)
{
if(create_rule(opts, snat_chain->to_chain, rule_buf))
{
log_msg(LOG_INFO, "Added SNAT Rule to %s for %s, %s expires at %u",
snat_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
snat_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(snat_chain->next_expire < now || exp_ts < snat_chain->next_expire)
snat_chain->next_expire = exp_ts;
}
}
}
}
/* Done with the port list for access rules.
*/
free_acc_port_list(port_list);
return(res);
}
