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fw_util_iptables.c
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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 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 srcip,
const char * const dstip,
const unsigned int port,
const char * const natip,
const unsigned int nat_port,
const unsigned int exp_ts)
{
int rule_exists=0;
char ipt_line_buf[CMD_BUFSIZE] = {0};
char target_search[CMD_BUFSIZE] = {0};
char proto_search[CMD_BUFSIZE] = {0};
char srcip_search[CMD_BUFSIZE] = {0};
char dstip_search[CMD_BUFSIZE] = {0};
char natip_search[CMD_BUFSIZE] = {0};
char port_search[CMD_BUFSIZE] = {0};
char nat_port_search[CMD_BUFSIZE] = {0};
char exp_ts_search[CMD_BUFSIZE] = {0};
char *ndx = NULL;
#if CODE_COVERAGE
/* 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, "[ignore] Code coverage: Executed 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, "dpt:%u ", port);
snprintf(nat_port_search, CMD_BUFSIZE-1, ":%u", nat_port);
snprintf(target_search, CMD_BUFSIZE-1, " %s ", fwc->target);
if (srcip != NULL)
snprintf(srcip_search, CMD_BUFSIZE-1, " %s ", srcip);
if (dstip != NULL)
snprintf(dstip_search, CMD_BUFSIZE-1, " %s ", dstip);
if (natip != NULL)
snprintf(dstip_search, CMD_BUFSIZE-1, " to:%s", natip);
snprintf(exp_ts_search, CMD_BUFSIZE-1, "%u ", exp_ts);
/* search for each of the substrings - the rule expiration time is the
* primary search method
*/
if(search_extcmd_getline(cmd_buf, ipt_line_buf,
CMD_BUFSIZE, NO_TIMEOUT, exp_ts_search, &pid_status, opts))
{
chop_newline(ipt_line_buf);
/* we have an iptables policy rule that matches the
* expiration time, so make sure this rule matches the
* other fields too. If not, then it is for different
* access requested by a separate SPA packet.
*/
if(((proto == ANY_PROTO) ? 1 : (strstr(ipt_line_buf, proto_search) != NULL))
&& ((srcip == NULL) ? 1 : (strstr(ipt_line_buf, srcip_search) != NULL))
&& ((dstip == NULL) ? 1 : (strstr(ipt_line_buf, dstip_search) != NULL))
&& ((natip == NULL) ? 1 : (strstr(ipt_line_buf, natip_search) != NULL))
&& (strstr(ipt_line_buf, target_search) != NULL)
&& ((port == ANY_PORT) ? 1 : (strstr(ipt_line_buf, port_search) != NULL)))
{
rule_exists = 1;
}
}
/* If there is a nat port, we have to qualify it as part
* of the 'to:<ip>:<port>' portion of the rule (at the end)
*/
if(rule_exists && nat_port != NAT_ANY_PORT)
{
ndx = strstr(ipt_line_buf, " to:");
/* Make sure there isn't a duplicate " to:" string (i.e. if someone
* was trying to be tricky with the iptables comment match).
*/
if(ndx != NULL && (strstr((ndx+strlen(" to:")), " to:") == NULL))
{
ndx = strstr((ndx+strlen(" to:")), nat_port_search);
if (ndx == NULL)
{
rule_exists = 0;
}
else if((*(ndx+strlen(nat_port_search)) != '\0')
&& (*(ndx+strlen(nat_port_search)) != ' '))
{
rule_exists = 0;
}
}
else
{
rule_exists = 0;
}
}
if(rule_exists)
log_msg(LOG_DEBUG,
"rule_exists_no_chk_support() %s %u -> %s expires: %u rule already exists",
proto_search, port, srcip, exp_ts);
else
log_msg(LOG_DEBUG,
"rule_exists_no_chk_support() %s %u -> %s expires: %u rule does not exist",
proto_search, port, srcip, 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 srcip,
const char * const dstip,
const unsigned int port,
const char * const nat_ip,
const unsigned int nat_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, srcip,
(opts->fw_config->use_destination ? dstip : NULL), port,
nat_ip, nat_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, "comment_match_exists() 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, rv = 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);
rv = 1;
}
else
log_msg(LOG_ERR, "add_jump_rule() Error %i from cmd:'%s': %s",
res, cmd_buf, err_buf);
return rv;
}
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, "chain_exists() 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 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, "fw_dump_rules() 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, "fw_dump_rules() 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, "delete_all_chains() 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, "delete_all_chains() 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, "delete_all_chains() 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, rv = 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))
rv = 1;
else
log_msg(LOG_ERR, "create_chain() Error %i from cmd:'%s': %s",
res, cmd_buf, err_buf);
return rv;
}
static int
mk_chain(const fko_srv_options_t * const opts, const int chain_num)
{
int err = 0;
/* Make sure the required chain and jump rule exist
*/
if(! chain_exists(opts, chain_num))
if(! create_chain(opts, chain_num))
err++;
if (! jump_rule_exists(opts, chain_num))
if(! add_jump_rule(opts, chain_num))
err++;
return err;
}
/* 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;
got_err += mk_chain(opts, i);
}
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 == 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;
/* Requires ENABLE_IPT_SNAT = Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_SNAT], "Y", 1)==0)
{
/* Support both SNAT and MASQUERADE - this will be controlled
* via the access.conf configuration for individual rules
*/
if(set_fw_chain_conf(IPT_MASQUERADE_ACCESS,
opts->config[CONF_IPT_MASQUERADE_ACCESS]) != 1)
return 0;
if(set_fw_chain_conf(IPT_SNAT_ACCESS,
opts->config[CONF_IPT_SNAT_ACCESS]) != 1)
return 0;
}
}
if(strncasecmp(opts->config[CONF_ENABLE_DESTINATION_RULE], "Y", 1)==0)
{
fwc.use_destination = 1;
}
/* 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,
"fw_initialize() 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)",