DeforaNetworks/fwknop
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fwknop/server/fw_util_iptables.c

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/*
*****************************************************************************
*
* File: fw_util_iptables.c
*
* Purpose: Fwknop routines for managing iptables firewall rules.
*
* Fwknop is developed primarily by the people listed in the file 'AUTHORS'.
* Copyright (C) 2009-2014 fwknop developers and contributors. For a full
* list of contributors, see the file 'CREDITS'.
*
* License (GNU General Public License):
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*****************************************************************************
*/
#include "fwknopd_common.h"
#ifdef FIREWALL_IPTABLES
#include "fw_util.h"
#include "utils.h"
#include "log_msg.h"
#include "extcmd.h"
#include "access.h"
static struct fw_config fwc;
static char cmd_buf[CMD_BUFSIZE];
static char err_buf[CMD_BUFSIZE];
static char cmd_out[STANDARD_CMD_OUT_BUFSIZE];
/* assume 'iptables -C' is offered since only older versions
* don't have this (see ipt_chk_support()).
*/
static int have_ipt_chk_support = 1;
static void
zero_cmd_buffers(void)
{
memset(cmd_buf, 0x0, CMD_BUFSIZE);
memset(err_buf, 0x0, CMD_BUFSIZE);
memset(cmd_out, 0x0, STANDARD_CMD_OUT_BUFSIZE);
}
static int pid_status = 0;
static void
chop_newline(char *str)
{
if(str[0] != 0x0 && str[strlen(str)-1] == 0x0a)
str[strlen(str)-1] = 0x0;
return;
}
static int
rule_exists_no_chk_support(const fko_srv_options_t * const opts,
const struct fw_chain * const fwc, const unsigned int proto,
const char * const ip, const unsigned int port,
const unsigned int exp_ts)
{
int rule_exists=0, rule_num=0, rtmp=0;
char cmd_buf[CMD_BUFSIZE] = {0};
char target_search[CMD_BUFSIZE] = {0};
char proto_search[CMD_BUFSIZE] = {0};
char ip_search[CMD_BUFSIZE] = {0};
char port_search[CMD_BUFSIZE] = {0};
char exp_ts_search[CMD_BUFSIZE] = {0};
#if CODE_COVERAGE
int pid_status = 0;
/* If we're maximizing code coverage, then exercise the run_extcmd_write()
* function which is normally only used for the PF firewall. This is to
* maximize code coverage in conjunction with the test suite, and is never
* compiled in for a production release of fwknop.
*/
if(run_extcmd_write("/bin/grep -v test", "/bin/echo test", &pid_status, opts) != 0)
log_msg(LOG_WARNING, "Code coverage: Could not execute command");
#endif
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
fwc->table,
fwc->to_chain
);
if(proto == IPPROTO_TCP)
snprintf(proto_search, CMD_BUFSIZE-1, " tcp ");
else if(proto == IPPROTO_UDP)
snprintf(proto_search, CMD_BUFSIZE-1, " udp ");
else if(proto == IPPROTO_ICMP)
snprintf(proto_search, CMD_BUFSIZE-1, " icmp ");
else
snprintf(proto_search, CMD_BUFSIZE-1, " %u ", proto);
snprintf(port_search, CMD_BUFSIZE-1, ":%u ", port);
snprintf(target_search, CMD_BUFSIZE-1, " %s ", fwc->target);
snprintf(ip_search, CMD_BUFSIZE-1, " %s ", ip);
snprintf(exp_ts_search, CMD_BUFSIZE-1, "%u ", exp_ts);
/* search for each of the substrings, and require the returned
* rule number to be the same across all searches to return true
*/
rtmp = search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, exp_ts_search, &pid_status, opts);
if(rtmp > 0)
{
rule_num = rtmp;
rtmp = search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, proto_search, &pid_status, opts);
if(rtmp == rule_num)
rtmp = search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, ip_search, &pid_status, opts);
if(rtmp == rule_num)
rtmp = search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, target_search, &pid_status, opts);
if(rtmp == rule_num)
rtmp = search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, port_search, &pid_status, opts);
if(rtmp == rule_num)
rule_exists = 1;
}
if(rule_exists)
log_msg(LOG_DEBUG,
"rule_exists_no_chk_support() %s %u -> %s expires: %u rule (already exists",
proto_search, port, ip, exp_ts);
else
log_msg(LOG_DEBUG,
"rule_exists_no_chk_support() %s %u -> %s expires: %u rule does not exist",
proto_search, port, ip, exp_ts);
return(rule_exists);
}
static int
rule_exists_chk_support(const fko_srv_options_t * const opts,
const char * const chain, const char * const rule)
{
int rule_exists = 0;
int res = 0;
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_CHK_RULE_ARGS,
opts->fw_config->fw_command, chain, rule);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "rule_exists_chk_support() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res) && strlen(err_buf))
{
log_msg(LOG_DEBUG, "rule_exists_chk_support() Rule : '%s' in %s does not exist",
rule, chain);
}
else
{
rule_exists = 1;
log_msg(LOG_DEBUG, "rule_exists_chk_support() Rule : '%s' in %s already exists",
rule, chain);
}
return(rule_exists);
}
static int
rule_exists(const fko_srv_options_t * const opts,
const struct fw_chain * const fwc, const char * const rule,
const unsigned int proto, const char * const ip,
const unsigned int port, const unsigned int exp_ts)
{
int rule_exists = 0;
if(have_ipt_chk_support == 1)
rule_exists = rule_exists_chk_support(opts, fwc->to_chain, rule);
else
rule_exists = rule_exists_no_chk_support(opts, fwc, proto, ip, port, exp_ts);
if(rule_exists == 1)
log_msg(LOG_DEBUG, "rule_exists() Rule : '%s' in %s already exists",
rule, fwc->to_chain);
else
log_msg(LOG_DEBUG, "rule_exists() Rule : '%s' in %s does not exist",
rule, fwc->to_chain);
return(rule_exists);
}
static void
ipt_chk_support(const fko_srv_options_t * const opts)
{
int res = 1;
struct fw_chain *in_chain = &(opts->fw_config->chain[IPT_INPUT_ACCESS]);
zero_cmd_buffers();
/* Add a harmless rule to the iptables INPUT chain and see if iptables
* supports '-C' to check for it. Set "have_ipt_chk_support" accordingly,
* delete the rule, and return.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_TMP_CHK_RULE_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain,
1, /* first rule */
in_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "ipt_chk_support() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
zero_cmd_buffers();
/* Now see if '-C' works - any output indicates failure
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_TMP_VERIFY_CHK_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain,
in_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "ipt_chk_support() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res) && strlen(err_buf))
{
log_msg(LOG_DEBUG, "ipt_chk_support() -C not supported");
have_ipt_chk_support = 0;
}
else
{
log_msg(LOG_DEBUG, "ipt_chk_support() -C supported");
have_ipt_chk_support = 1;
}
/* Delete the tmp rule
*/
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_RULE_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain,
1
);
run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
return;
}
static int
comment_match_exists(const fko_srv_options_t * const opts)
{
int res = 1;
char *ndx = NULL;
struct fw_chain *in_chain = &(opts->fw_config->chain[IPT_INPUT_ACCESS]);
zero_cmd_buffers();
/* Add a harmless rule to the iptables INPUT chain that uses the comment
* match and make sure it exists. If not, return zero. Otherwise, delete
* the rule and return true.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_TMP_COMMENT_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain,
1, /* first rule */
in_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "comment_match_exists() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain
);
res = run_extcmd(cmd_buf, cmd_out, STANDARD_CMD_OUT_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(cmd_out);
if(!EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, cmd_out);
ndx = strstr(cmd_out, TMP_COMMENT);
if(ndx == NULL)
res = 0; /* did not find the tmp comment */
else
res = 1;
if(res == 1)
{
/* Delete the tmp comment rule
*/
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_RULE_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->from_chain,
1
);
run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
}
return res;
}
static int
add_jump_rule(const fko_srv_options_t * const opts, const int chain_num)
{
int res = 0;
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_JUMP_RULE_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].from_chain,
fwc.chain[chain_num].jump_rule_pos,
fwc.chain[chain_num].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
log_msg(LOG_DEBUG, "add_jump_rule() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
log_msg(LOG_INFO, "Added jump rule from chain: %s to chain: %s",
fwc.chain[chain_num].from_chain,
fwc.chain[chain_num].to_chain);
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
return res;
}
static int
chain_exists(const fko_srv_options_t * const opts, const int chain_num)
{
int res = 0;
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_CHAIN_EXISTS_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "chain_exists() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
log_msg(LOG_DEBUG, "'%s' table '%s' chain exists",
fwc.chain[chain_num].table,
fwc.chain[chain_num].to_chain);
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
return res;
}
static int
jump_rule_exists_chk_support(const fko_srv_options_t * const opts, const int chain_num)
{
int exists = 0;
char rule_buf[CMD_BUFSIZE] = {0};
snprintf(rule_buf, CMD_BUFSIZE-1, IPT_CHK_JUMP_RULE_ARGS,
fwc.chain[chain_num].table,
fwc.chain[chain_num].to_chain
);
if(rule_exists_chk_support(opts, fwc.chain[chain_num].from_chain, rule_buf) == 1)
{
log_msg(LOG_DEBUG, "jump_rule_exists_chk_support() jump rule found");
exists = 1;
}
else
log_msg(LOG_DEBUG, "jump_rule_exists_chk_support() jump rule not found");
return exists;
}
static int
jump_rule_exists_no_chk_support(const fko_srv_options_t * const opts, const int chain_num)
{
int exists = 0;
char cmd_buf[CMD_BUFSIZE] = {0};
char chain_search[CMD_BUFSIZE] = {0};
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].from_chain
);
/* include spaces on either side as produced by 'iptables -L' output
*/
snprintf(chain_search, CMD_BUFSIZE-1, " %s ",
fwc.chain[chain_num].to_chain);
if(search_extcmd(cmd_buf, WANT_STDERR,
NO_TIMEOUT, chain_search, &pid_status, opts) > 0)
exists = 1;
if(exists)
log_msg(LOG_DEBUG, "jump_rule_exists_no_chk_support() jump rule found");
else
log_msg(LOG_DEBUG, "jump_rule_exists_no_chk_support() jump rule not found");
return(exists);
}
static int
jump_rule_exists(const fko_srv_options_t * const opts, const int chain_num)
{
int exists = 0;
if(have_ipt_chk_support == 1)
exists = jump_rule_exists_chk_support(opts, chain_num);
else
exists = jump_rule_exists_no_chk_support(opts, chain_num);
return exists;
}
/* Print all firewall rules currently instantiated by the running fwknopd
* daemon to stdout.
*/
int
fw_dump_rules(const fko_srv_options_t * const opts)
{
int i, res, got_err = 0;
struct fw_chain *ch = opts->fw_config->chain;
if (opts->fw_list_all == 1)
{
fprintf(stdout, "Listing all iptables rules in applicable tables...\n");
fflush(stdout);
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
zero_cmd_buffers();
/* Create the list command
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_ALL_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table
);
res = run_extcmd(cmd_buf, NULL, 0, NO_STDERR,
NO_TIMEOUT, &pid_status, opts);
log_msg(LOG_DEBUG, "fw_dump_rules() CMD: '%s' (res: %d)",
cmd_buf, res);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
got_err++;
}
}
}
else
{
fprintf(stdout, "Listing rules in fwknopd iptables chains...\n");
fflush(stdout);
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
zero_cmd_buffers();
/* Create the list command
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain
);
fprintf(stdout, "\n");
fflush(stdout);
res = run_extcmd(cmd_buf, NULL, 0, NO_STDERR,
NO_TIMEOUT, &pid_status, opts);
log_msg(LOG_DEBUG, "fw_dump_rules() CMD: '%s' (res: %d)",
cmd_buf, res);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
got_err++;
}
}
}
return(got_err);
}
/* Quietly flush and delete all fwknop custom chains.
*/
static void
delete_all_chains(const fko_srv_options_t * const opts)
{
int i, res, cmd_ctr = 0;
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
/* First look for a jump rule to this chain and remove it if it
* is there.
*/
cmd_ctr = 0;
while(cmd_ctr < CMD_LOOP_TRIES && (jump_rule_exists(opts, i) == 1))
{
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_JUMP_RULE_ARGS,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].from_chain,
fwc.chain[i].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "delete_all_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
cmd_ctr++;
}
zero_cmd_buffers();
/* Now flush and remove the chain.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_FLUSH_CHAIN_ARGS,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, WANT_STDERR,
NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "delete_all_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_CHAIN_ARGS,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, WANT_STDERR,
NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "delete_all_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
return;
}
static int
create_chain(const fko_srv_options_t * const opts, const int chain_num)
{
int res = 0;
zero_cmd_buffers();
/* Create the custom chain.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_NEW_CHAIN_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, WANT_STDERR,
NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "create_chain() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
return res;
}
/* 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(! EXTCMD_IS_SUCCESS(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(! EXTCMD_IS_SUCCESS(add_jump_rule(opts, i)))
got_err++;
}
}
return(got_err);
}
static int
set_fw_chain_conf(const int type, const char * const conf_str)
{
int i, j, is_err;
char tbuf[MAX_LINE_LEN] = {0};
const char *ndx = conf_str;
char *chain_fields[FW_NUM_CHAIN_FIELDS];
struct fw_chain *chain = &(fwc.chain[type]);
if(conf_str == NULL)
{
log_msg(LOG_ERR, "[*] NULL conf_str");
return 0;
}
chain->type = type;
if(ndx != NULL)
chain_fields[0] = tbuf;
i = 0;
j = 1;
while(*ndx != '\0')
{
if(*ndx != ' ')
{
if(*ndx == ',')
{
tbuf[i] = '\0';
chain_fields[j++] = &(tbuf[++i]);
}
else
tbuf[i++] = *ndx;
}
if(*ndx != '\0'
&& *ndx != ' '
&& *ndx != ','
&& *ndx != '_'
&& isalnum(*ndx) == 0)
{
log_msg(LOG_ERR, "[*] Custom chain config parse error: "
"invalid character '%c' for chain type %i, "
"line: %s", *ndx, type, conf_str);
return 0;
}
ndx++;
}
/* Sanity check - j should be the number of chain fields
* (excluding the type).
*/
if(j != FW_NUM_CHAIN_FIELDS)
{
log_msg(LOG_ERR, "[*] Custom chain config parse error: "
"wrong number of fields for chain type %i, "
"line: %s", type, conf_str);
return 0;
}
/* Pull and set Target */
strlcpy(chain->target, chain_fields[0], sizeof(chain->target));
/* Pull and set Table */
strlcpy(chain->table, chain_fields[1], sizeof(chain->table));
/* Pull and set From_chain */
strlcpy(chain->from_chain, chain_fields[2], sizeof(chain->from_chain));
/* Pull and set Jump_rule_position */
chain->jump_rule_pos = strtol_wrapper(chain_fields[3],
0, RCHK_MAX_IPT_RULE_NUM, NO_EXIT_UPON_ERR, &is_err);
if(is_err != FKO_SUCCESS)
{
log_msg(LOG_ERR, "[*] invalid jump rule position in Line: %s",
conf_str);
return 0;
}
/* Pull and set To_chain */
strlcpy(chain->to_chain, chain_fields[4], sizeof(chain->to_chain));
/* Pull and set to_chain rule position */
chain->rule_pos = strtol_wrapper(chain_fields[5],
0, RCHK_MAX_IPT_RULE_NUM, NO_EXIT_UPON_ERR, &is_err);
if(is_err != FKO_SUCCESS)
{
log_msg(LOG_ERR, "[*] invalid to_chain rule position in Line: %s",
conf_str);
return 0;
}
return 1;
}
int
fw_config_init(fko_srv_options_t * const opts)
{
memset(&fwc, 0x0, sizeof(struct fw_config));
/* Set our firewall exe command path (iptables in most cases).
*/
strlcpy(fwc.fw_command, opts->config[CONF_FIREWALL_EXE], sizeof(fwc.fw_command));
#if HAVE_LIBFIU
fiu_return_on("fw_config_init", 0);
#endif
/* Pull the fwknop chain config info and setup our internal
* config struct. The IPT_INPUT is the only one that is
* required. The rest are optional.
*/
if(set_fw_chain_conf(IPT_INPUT_ACCESS, opts->config[CONF_IPT_INPUT_ACCESS]) != 1)
return 0;
/* The FWKNOP_OUTPUT_ACCESS requires ENABLE_IPT_OUTPUT_ACCESS be Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_OUTPUT], "Y", 1)==0)
if(set_fw_chain_conf(IPT_OUTPUT_ACCESS, opts->config[CONF_IPT_OUTPUT_ACCESS]) != 1)
return 0;
/* The remaining access chains require ENABLE_IPT_FORWARDING = Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_FORWARDING], "Y", 1)==0)
{
if(set_fw_chain_conf(IPT_FORWARD_ACCESS, opts->config[CONF_IPT_FORWARD_ACCESS]) != 1)
return 0;
if(set_fw_chain_conf(IPT_DNAT_ACCESS, opts->config[CONF_IPT_DNAT_ACCESS]) != 1)
return 0;
/* SNAT (whichever mode) requires ENABLE_IPT_SNAT = Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_SNAT], "Y", 1)==0)
{
if(opts->config[CONF_SNAT_TRANSLATE_IP] == NULL
|| ! is_valid_ipv4_addr(opts->config[CONF_SNAT_TRANSLATE_IP]))
{
fwc.use_masquerade = 1;
if(set_fw_chain_conf(IPT_MASQUERADE_ACCESS, opts->config[CONF_IPT_MASQUERADE_ACCESS]) != 1)
return 0;
}
else
{
if(is_valid_ipv4_addr(opts->config[CONF_SNAT_TRANSLATE_IP]))
{
if(set_fw_chain_conf(IPT_SNAT_ACCESS, opts->config[CONF_IPT_SNAT_ACCESS]) != 1)
return 0;
}
else
{
return 0;
}
}
}
}
/* Let us find it via our opts struct as well.
*/
opts->fw_config = &fwc;
return 1;
}
int
fw_initialize(const fko_srv_options_t * const opts)
{
int res = 1;
/* See if iptables offers the '-C' argument (older versions don't). If not,
* then switch to parsing iptables -L output to find rules.
*/
if(opts->ipt_disable_check_support)
have_ipt_chk_support = 0;
else
ipt_chk_support(opts);
/* Flush the chains (just in case) so we can start fresh.
*/
if(strncasecmp(opts->config[CONF_FLUSH_IPT_AT_INIT], "Y", 1) == 0)
delete_all_chains(opts);
/* Now create any configured chains.
*/
if(create_fw_chains(opts) != 0)
{
log_msg(LOG_WARNING,
"Warning: Errors detected during fwknop custom chain creation");
res = 0;
}
/* Make sure that the 'comment' match is available
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_COMMENT_CHECK], "Y", 1) == 0)
{
if(comment_match_exists(opts) == 1)
{
log_msg(LOG_INFO, "iptables 'comment' match is available");
}
else
{
log_msg(LOG_WARNING, "Warning: Could not use the 'comment' match");
res = 0;
}
}
return(res);
}
int
fw_cleanup(const fko_srv_options_t * const opts)
{
if(strncasecmp(opts->config[CONF_FLUSH_IPT_AT_EXIT], "N", 1) == 0
&& opts->fw_flush == 0)
return(0);
delete_all_chains(opts);
return(0);
}
static int
create_rule(const fko_srv_options_t * const opts,
const char * const fw_chain, const char * const fw_rule)
{
int res = 0;
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s -A %s %s", opts->fw_config->fw_command, fw_chain, fw_rule);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, WANT_STDERR,
NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "create_rule() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_DEBUG, "create_rule() Rule: '%s' added to %s", fw_rule, fw_chain);
res = 1;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
return res;
}
/****************************************************************************/
/* 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);
}
/* Iterate over the configure firewall access chains and purge expired
* firewall rules.
*/
void
check_firewall_rules(const fko_srv_options_t * const opts)
{
char exp_str[12] = {0};
char rule_num_str[6] = {0};
char *ndx, *rn_start, *rn_end, *tmp_mark;
int i, res, rn_offset, rule_num, is_err;
time_t now, rule_exp, min_exp = 0;
struct fw_chain *ch = opts->fw_config->chain;
time(&now);
/* Iterate over each chain and look for active rules to delete.
*/
for(i=0; i < NUM_FWKNOP_ACCESS_TYPES; i++)
{
/* If there are no active rules or we have not yet
* reached our expected next expire time, continue.
*/
if(ch[i].active_rules == 0 || ch[i].next_expire > now)
continue;
zero_cmd_buffers();
rn_offset = 0;
/* There should be a rule to delete. Get the current list of
* rules for this chain and delete the ones that are expired.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain
);
res = run_extcmd(cmd_buf, cmd_out, STANDARD_CMD_OUT_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(cmd_out);
log_msg(LOG_DEBUG, "check_firewall_rules() CMD: '%s' (res: %d, cmd_out: %s)",
cmd_buf, res, cmd_out);
if(!EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, cmd_out);
continue;
}
log_msg(LOG_DEBUG, "RES=%i, CMD_BUF: %s\nRULES LIST: %s", res, cmd_buf, cmd_out);
ndx = strstr(cmd_out, EXPIRE_COMMENT_PREFIX);
if(ndx == NULL)
{
/* we did not find an expected rule.
*/
log_msg(LOG_ERR,
"Did not find expire comment in rules list %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
continue;
}
/* walk the list and process rules as needed.
*/
while (ndx != NULL) {
/* Jump forward and extract the timestamp
*/
ndx += strlen(EXPIRE_COMMENT_PREFIX);
/* remember this spot for when we look for the next
* rule.
*/
tmp_mark = ndx;
strlcpy(exp_str, ndx, sizeof(exp_str));
rule_exp = (time_t)atoll(exp_str);
if(rule_exp <= now)
{
/* Backtrack and get the rule number and delete it.
*/
rn_start = ndx;
while(--rn_start > cmd_out)
{
if(*rn_start == '\n')
break;
}
if(*rn_start != '\n')
{
/* This should not happen. But if it does, complain,
* decrement the active rule value, and go on.
*/
log_msg(LOG_ERR,
"Rule parse error while finding rule line start in chain %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
break;
}
rn_start++;
rn_end = strchr(rn_start, ' ');
if(rn_end == NULL)
{
/* This should not happen. But if it does, complain,
* decrement the active rule value, and go on.
*/
log_msg(LOG_ERR,
"Rule parse error while finding rule number in chain %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
break;
}
strlcpy(rule_num_str, rn_start, (rn_end - rn_start)+1);
rule_num = strtol_wrapper(rule_num_str, rn_offset, RCHK_MAX_IPT_RULE_NUM,
NO_EXIT_UPON_ERR, &is_err);
if(is_err != FKO_SUCCESS)
{
log_msg(LOG_ERR,
"Rule parse error while finding rule number in chain %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
break;
}
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_RULE_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain,
rule_num - rn_offset
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE,
WANT_STDERR, NO_TIMEOUT, &pid_status, opts);
chop_newline(err_buf);
log_msg(LOG_DEBUG, "check_firewall_rules() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Removed rule %s from %s with expire time of %u",
rule_num_str, ch[i].to_chain, rule_exp
);
rn_offset++;
if (ch[i].active_rules > 0)
ch[i].active_rules--;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
else
{
/* Track the minimum future rule expire time.
*/
if(rule_exp > now)
min_exp = (min_exp < rule_exp) ? min_exp : rule_exp;
}
/* Push our tracking index forward beyond (just processed) _exp_
* string so we can continue to the next rule in the list.
*/
ndx = strstr(tmp_mark, EXPIRE_COMMENT_PREFIX);
}
/* Set the next pending expire time accordingly. 0 if there are no
* more rules, or whatever the next expected (min_exp) time will be.
*/
if(ch[i].active_rules < 1)
ch[i].next_expire = 0;
else if(min_exp)
ch[i].next_expire = min_exp;
}
}
int
validate_ipt_chain_conf(const char * const chain_str)
{
int j, rv = 1;
const char *ndx = chain_str;
j = 1;
while(*ndx != '\0')
{
if(*ndx == ',')
j++;
if(*ndx != '\0'
&& *ndx != ' '
&& *ndx != ','
&& *ndx != '_'
&& isalnum(*ndx) == 0)
{
rv = 0;
break;
}
ndx++;
}
/* Sanity check - j should be the number of chain fields
* (excluding the type).
*/
if(j != FW_NUM_CHAIN_FIELDS)
rv = 0;
return rv;
}
#endif /* FIREWALL_IPTABLES */
/***EOF***/
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