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miniupnp/miniupnpd/upnpredirect.c
Pali Rohár 8e10a1aeab miniupnpd: Disable port forwarding when we are behind restrictive nat with reserved / private IP address 
In this case port forwarding is impossible, so rather return error code to the client instead of silently trying to do something and informing clients that port forwarding is enabled.
2018-05-19 13:32:04 +02:00

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/* $Id: upnpredirect.c,v 1.93 2018/03/12 22:41:53 nanard Exp $ */
/* vim: tabstop=4 shiftwidth=4 noexpandtab
* MiniUPnP project
* http://miniupnp.free.fr/ or https://miniupnp.tuxfamily.org/
* (c) 2006-2018 Thomas Bernard
* This software is subject to the conditions detailed
* in the LICENCE file provided within the distribution */
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include "macros.h"
#include "config.h"
#include "upnpredirect.h"
#include "upnpglobalvars.h"
#include "upnpevents.h"
#include "portinuse.h"
#include "upnputils.h"
#if defined(USE_NETFILTER)
#include "netfilter/iptcrdr.h"
#endif
#if defined(USE_PF)
#include "pf/obsdrdr.h"
#endif
#if defined(USE_IPF)
#include "ipf/ipfrdr.h"
#endif
#if defined(USE_IPFW)
#include "ipfw/ipfwrdr.h"
#endif
#ifdef USE_MINIUPNPDCTL
#include <stdio.h>
#include <unistd.h>
#endif
#ifdef ENABLE_LEASEFILE
#include <sys/stat.h>
#endif
/* from <inttypes.h> */
#ifndef PRIu64
#define PRIu64 "llu"
#endif
/* proto_atoi()
* convert the string "UDP" or "TCP" to IPPROTO_UDP and IPPROTO_UDP */
static int
proto_atoi(const char * protocol)
{
int proto = IPPROTO_TCP;
if(strcasecmp(protocol, "UDP") == 0)
proto = IPPROTO_UDP;
#ifdef IPPROTO_UDPLITE
else if(strcasecmp(protocol, "UDPLITE") == 0)
proto = IPPROTO_UDPLITE;
#endif /* IPPROTO_UDPLITE */
return proto;
}
/* proto_itoa()
* convert IPPROTO_UDP, IPPROTO_UDP, etc. to "UDP", "TCP" */
static const char *
proto_itoa(int proto)
{
const char * protocol;
switch(proto) {
case IPPROTO_UDP:
protocol = "UDP";
break;
case IPPROTO_TCP:
protocol = "TCP";
break;
#ifdef IPPROTO_UDPLITE
case IPPROTO_UDPLITE:
protocol = "UDPLITE";
break;
#endif /* IPPROTO_UDPLITE */
default:
protocol = "*UNKNOWN*";
}
return protocol;
}
#ifdef ENABLE_LEASEFILE
static int
lease_file_add(unsigned short eport,
const char * iaddr,
unsigned short iport,
int proto,
const char * desc,
unsigned int timestamp)
{
FILE * fd;
if (lease_file == NULL) return 0;
fd = fopen( lease_file, "a");
if (fd==NULL) {
syslog(LOG_ERR, "could not open lease file: %s", lease_file);
return -1;
}
/* convert our time to unix time
* if LEASEFILE_USE_REMAINING_TIME is defined, only the remaining time is stored */
if (timestamp != 0) {
timestamp -= upnp_time();
#ifndef LEASEFILE_USE_REMAINING_TIME
timestamp += time(NULL);
#endif
}
fprintf(fd, "%s:%hu:%s:%hu:%u:%s\n",
proto_itoa(proto), eport, iaddr, iport,
timestamp, desc);
fclose(fd);
return 0;
}
static int
lease_file_remove(unsigned short eport, int proto)
{
FILE* fd, *fdt;
int tmp;
char buf[512];
char str[32];
char tmpfilename[128];
int str_size, buf_size;
if (lease_file == NULL) return 0;
if (strlen( lease_file) + 7 > sizeof(tmpfilename)) {
syslog(LOG_ERR, "Lease filename is too long");
return -1;
}
snprintf( tmpfilename, sizeof(tmpfilename), "%sXXXXXX", lease_file);
fd = fopen( lease_file, "r");
if (fd==NULL) {
return 0;
}
snprintf( str, sizeof(str), "%s:%u", proto_itoa(proto), eport);
str_size = strlen(str);
tmp = mkstemp(tmpfilename);
if (tmp==-1) {
fclose(fd);
syslog(LOG_ERR, "could not open temporary lease file");
return -1;
}
fchmod(tmp, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
fdt = fdopen(tmp, "a");
buf[sizeof(buf)-1] = 0;
while( fgets(buf, sizeof(buf)-1, fd) != NULL) {
buf_size = strlen(buf);
if (buf_size < str_size || strncmp(str, buf, str_size)!=0) {
fwrite(buf, buf_size, 1, fdt);
}
}
fclose(fdt);
fclose(fd);
if (rename(tmpfilename, lease_file) < 0) {
syslog(LOG_ERR, "could not rename temporary lease file to %s", lease_file);
remove(tmpfilename);
}
return 0;
}
/* reload_from_lease_file()
* read lease_file and add the rules contained
*/
int reload_from_lease_file()
{
FILE * fd;
char * p;
unsigned short eport, iport;
char * proto;
char * iaddr;
char * desc;
char * rhost;
unsigned int leaseduration;
unsigned int timestamp;
time_t current_time;
#ifndef LEASEFILE_USE_REMAINING_TIME
time_t current_unix_time;
#endif
char line[128];
int r;
if(!lease_file) return -1;
fd = fopen( lease_file, "r");
if (fd==NULL) {
syslog(LOG_ERR, "could not open lease file: %s", lease_file);
return -1;
}
if(unlink(lease_file) < 0) {
syslog(LOG_WARNING, "could not unlink file %s : %m", lease_file);
}
current_time = upnp_time();
#ifndef LEASEFILE_USE_REMAINING_TIME
current_unix_time = time(NULL);
#endif
while(fgets(line, sizeof(line), fd)) {
syslog(LOG_DEBUG, "parsing lease file line '%s'", line);
proto = line;
p = strchr(line, ':');
if(!p) {
syslog(LOG_ERR, "unrecognized data in lease file");
continue;
}
*(p++) = '\0';
iaddr = strchr(p, ':');
if(!iaddr) {
syslog(LOG_ERR, "unrecognized data in lease file");
continue;
}
*(iaddr++) = '\0';
eport = (unsigned short)atoi(p);
p = strchr(iaddr, ':');
if(!p) {
syslog(LOG_ERR, "unrecognized data in lease file");
continue;
}
*(p++) = '\0';
iport = (unsigned short)atoi(p);
p = strchr(p, ':');
if(!p) {
syslog(LOG_ERR, "unrecognized data in lease file");
continue;
}
*(p++) = '\0';
desc = strchr(p, ':');
if(!desc) {
syslog(LOG_ERR, "unrecognized data in lease file");
continue;
}
*(desc++) = '\0';
/*timestamp = (unsigned int)atoi(p);*/
timestamp = (unsigned int)strtoul(p, NULL, 10);
/* trim description */
while(isspace(*desc))
desc++;
p = desc;
while(*(p+1))
p++;
while(isspace(*p) && (p > desc))
*(p--) = '\0';
if(timestamp > 0) {
#ifdef LEASEFILE_USE_REMAINING_TIME
leaseduration = timestamp;
timestamp += current_time; /* convert to our time */
#else
if(timestamp <= (unsigned int)current_unix_time) {
syslog(LOG_NOTICE, "already expired lease in lease file");
continue;
} else {
leaseduration = timestamp - current_unix_time;
timestamp = leaseduration + current_time; /* convert to our time */
}
#endif
} else {
leaseduration = 0; /* default value */
}
rhost = NULL;
r = upnp_redirect(rhost, eport, iaddr, iport, proto, desc, leaseduration);
if(r == -1) {
syslog(LOG_ERR, "Failed to redirect %hu -> %s:%hu protocol %s",
eport, iaddr, iport, proto);
} else if(r == -2) {
/* Add the redirection again to the lease file */
lease_file_add(eport, iaddr, iport, proto_atoi(proto),
desc, timestamp);
}
}
fclose(fd);
return 0;
}
#ifdef LEASEFILE_USE_REMAINING_TIME
void lease_file_rewrite(void)
{
int index;
unsigned short eport, iport;
int proto;
char iaddr[32];
char desc[64];
char rhost[40];
unsigned int timestamp;
if (lease_file == NULL) return;
remove(lease_file);
for(index = 0; ; index++) {
if(get_redirect_rule_by_index(index, 0/*ifname*/, &eport, iaddr, sizeof(iaddr),
&iport, &proto, desc, sizeof(desc),
rhost, sizeof(rhost), &timestamp,
0, 0) < 0)
break;
if(lease_file_add(eport, iaddr, iport, proto, desc, timestamp) < 0)
break;
}
}
#endif
#endif
/* upnp_redirect()
* calls OS/fw dependent implementation of the redirection.
* protocol should be the string "TCP" or "UDP"
* returns: 0 on success
* -1 failed to redirect
* -2 already redirected
* -3 permission check failed
* -4 already redirected (other mechanism)
*/
int
upnp_redirect(const char * rhost, unsigned short eport,
const char * iaddr, unsigned short iport,
const char * protocol, const char * desc,
unsigned int leaseduration)
{
int proto, r;
char iaddr_old[32];
char rhost_old[32];
unsigned short iport_old;
struct in_addr address;
unsigned int timestamp;
proto = proto_atoi(protocol);
if(inet_aton(iaddr, &address) <= 0) {
syslog(LOG_ERR, "inet_aton(%s) FAILED", iaddr);
return -1;
}
if(!check_upnp_rule_against_permissions(upnppermlist, num_upnpperm,
eport, address, iport)) {
syslog(LOG_INFO, "redirection permission check failed for "
"%hu->%s:%hu %s", eport, iaddr, iport, protocol);
return -3;
}
/* IGDv1 (WANIPConnection:1 Service Template Version 1.01 / Nov 12, 2001)
* - 2.2.20.PortMappingDescription :
* Overwriting Previous / Existing Port Mappings:
* If the RemoteHost, ExternalPort, PortMappingProtocol and InternalClient
* are exactly the same as an existing mapping, the existing mapping values
* for InternalPort, PortMappingDescription, PortMappingEnabled and
* PortMappingLeaseDuration are overwritten.
* Rejecting a New Port Mapping:
* In cases where the RemoteHost, ExternalPort and PortMappingProtocol
* are the same as an existing mapping, but the InternalClient is
* different, the action is rejected with an appropriate error.
* Add or Reject New Port Mapping behavior based on vendor implementation:
* In cases where the ExternalPort, PortMappingProtocol and InternalClient
* are the same, but RemoteHost is different, the vendor can choose to
* support both mappings simultaneously, or reject the second mapping
* with an appropriate error.
*
* - 2.4.16.AddPortMapping
* This action creates a new port mapping or overwrites an existing
* mapping with the same internal client. If the ExternalPort and
* PortMappingProtocol pair is already mapped to another internal client,
* an error is returned.
*
* IGDv2 (WANIPConnection:2 Service Standardized DCP (SDCP) Sep 10, 2010)
* Protocol ExternalPort RemoteHost InternalClient Result
* = = ≠ ≠ Failure
* = = ≠ = Failure or success
* (vendor specific)
* = = = ≠ Failure
* = = = = Success (overwrite)
*/
rhost_old[0] = '\0';
r = get_redirect_rule(ext_if_name, eport, proto,
iaddr_old, sizeof(iaddr_old), &iport_old, 0, 0,
rhost_old, sizeof(rhost_old),
&timestamp, 0, 0);
if(r == 0) {
if(strcmp(iaddr, iaddr_old)==0 &&
((rhost == NULL && rhost_old[0]=='\0') ||
(rhost && (strcmp(rhost, "*") == 0) && rhost_old[0]=='\0') ||
(rhost && (strcmp(rhost, rhost_old) == 0)))) {
syslog(LOG_INFO, "updating existing port mapping %hu %s (rhost '%s') => %s:%hu",
eport, protocol, rhost_old, iaddr_old, iport_old);
timestamp = (leaseduration > 0) ? upnp_time() + leaseduration : 0;
if(iport != iport_old) {
r = update_portmapping(ext_if_name, eport, proto, iport, desc, timestamp);
} else {
r = update_portmapping_desc_timestamp(ext_if_name, eport, proto, desc, timestamp);
}
#ifdef ENABLE_LEASEFILE
if(r == 0) {
lease_file_remove(eport, proto);
lease_file_add(eport, iaddr, iport, proto, desc, timestamp);
}
#endif /* ENABLE_LEASEFILE */
return r;
} else {
syslog(LOG_INFO, "port %hu %s (rhost '%s') already redirected to %s:%hu",
eport, protocol, rhost_old, iaddr_old, iport_old);
return -2;
}
#ifdef CHECK_PORTINUSE
} else if (port_in_use(ext_if_name, eport, proto, iaddr, iport) > 0) {
syslog(LOG_INFO, "port %hu protocol %s already in use",
eport, protocol);
return -4;
#endif /* CHECK_PORTINUSE */
} else {
timestamp = (leaseduration > 0) ? upnp_time() + leaseduration : 0;
syslog(LOG_INFO, "redirecting port %hu to %s:%hu protocol %s for: %s",
eport, iaddr, iport, protocol, desc);
return upnp_redirect_internal(rhost, eport, iaddr, iport, proto,
desc, timestamp);
}
}
int
upnp_redirect_internal(const char * rhost, unsigned short eport,
const char * iaddr, unsigned short iport,
int proto, const char * desc,
unsigned int timestamp)
{
/*syslog(LOG_INFO, "redirecting port %hu to %s:%hu protocol %s for: %s",
eport, iaddr, iport, protocol, desc); */
if(disable_port_forwarding)
return -1;
if(add_redirect_rule2(ext_if_name, rhost, eport, iaddr, iport, proto,
desc, timestamp) < 0) {
return -1;
}
#ifdef ENABLE_LEASEFILE
lease_file_add( eport, iaddr, iport, proto, desc, timestamp);
#endif
/* syslog(LOG_INFO, "creating pass rule to %s:%hu protocol %s for: %s",
iaddr, iport, protocol, desc);*/
if(add_filter_rule2(ext_if_name, rhost, iaddr, eport, iport, proto, desc) < 0) {
/* clean up the redirect rule */
#if !defined(__linux__)
delete_redirect_rule(ext_if_name, eport, proto);
#endif
return -1;
}
if(timestamp > 0) {
if(!nextruletoclean_timestamp || (timestamp < nextruletoclean_timestamp))
nextruletoclean_timestamp = timestamp;
}
#ifdef ENABLE_EVENTS
/* the number of port mappings changed, we must
* inform the subscribers */
upnp_event_var_change_notify(EWanIPC);
#endif
return 0;
}
/* Firewall independent code which call the FW dependent code. */
int
upnp_get_redirection_infos(unsigned short eport, const char * protocol,
unsigned short * iport,
char * iaddr, int iaddrlen,
char * desc, int desclen,
char * rhost, int rhostlen,
unsigned int * leaseduration)
{
int r;
unsigned int timestamp;
time_t current_time;
if(desc && (desclen > 0))
desc[0] = '\0';
if(rhost && (rhostlen > 0))
rhost[0] = '\0';
r = get_redirect_rule(ext_if_name, eport, proto_atoi(protocol),
iaddr, iaddrlen, iport, desc, desclen,
rhost, rhostlen, &timestamp,
0, 0);
if(r == 0 &&
timestamp > 0 &&
timestamp > (unsigned int)(current_time = upnp_time())) {
*leaseduration = timestamp - current_time;
} else {
*leaseduration = 0;
}
return r;
}
int
upnp_get_redirection_infos_by_index(int index,
unsigned short * eport, char * protocol,
unsigned short * iport,
char * iaddr, int iaddrlen,
char * desc, int desclen,
char * rhost, int rhostlen,
unsigned int * leaseduration)
{
/*char ifname[IFNAMSIZ];*/
int proto = 0;
unsigned int timestamp;
time_t current_time;
if(desc && (desclen > 0))
desc[0] = '\0';
if(rhost && (rhostlen > 0))
rhost[0] = '\0';
if(get_redirect_rule_by_index(index, 0/*ifname*/, eport, iaddr, iaddrlen,
iport, &proto, desc, desclen,
rhost, rhostlen, &timestamp,
0, 0) < 0)
return -1;
else
{
current_time = upnp_time();
*leaseduration = (timestamp > (unsigned int)current_time)
? (timestamp - current_time)
: 0;
if(proto == IPPROTO_TCP)
memcpy(protocol, "TCP", 4);
#ifdef IPPROTO_UDPLITE
else if(proto == IPPROTO_UDPLITE)
memcpy(protocol, "UDPLITE", 8);
#endif /* IPPROTO_UDPLITE */
else
memcpy(protocol, "UDP", 4);
return 0;
}
}
/* called from natpmp.c too */
int
_upnp_delete_redir(unsigned short eport, int proto)
{
int r;
#if defined(__linux__)
r = delete_redirect_and_filter_rules(eport, proto);
#elif defined(USE_PF)
r = delete_redirect_and_filter_rules(ext_if_name, eport, proto);
#else
r = delete_redirect_rule(ext_if_name, eport, proto);
delete_filter_rule(ext_if_name, eport, proto);
#endif
#ifdef ENABLE_LEASEFILE
lease_file_remove( eport, proto);
#endif
#ifdef ENABLE_EVENTS
upnp_event_var_change_notify(EWanIPC);
#endif
return r;
}
int
upnp_delete_redirection(unsigned short eport, const char * protocol)
{
syslog(LOG_INFO, "removing redirect rule port %hu %s", eport, protocol);
return _upnp_delete_redir(eport, proto_atoi(protocol));
}
/* upnp_get_portmapping_number_of_entries()
* TODO: improve this code. */
int
upnp_get_portmapping_number_of_entries()
{
int n = 0, r = 0;
unsigned short eport, iport;
char protocol[4], iaddr[32], desc[64], rhost[32];
unsigned int leaseduration;
do {
protocol[0] = '\0'; iaddr[0] = '\0'; desc[0] = '\0';
r = upnp_get_redirection_infos_by_index(n, &eport, protocol, &iport,
iaddr, sizeof(iaddr),
desc, sizeof(desc),
rhost, sizeof(rhost),
&leaseduration);
n++;
} while(r==0);
return (n-1);
}
/* functions used to remove unused rules
* As a side effect, delete expired rules (based on LeaseDuration) */
struct rule_state *
get_upnp_rules_state_list(int max_rules_number_target)
{
/*char ifname[IFNAMSIZ];*/
int proto;
unsigned short iport;
unsigned int timestamp;
struct rule_state * tmp;
struct rule_state * list = 0;
struct rule_state * * p;
int i = 0;
time_t current_time;
/*ifname[0] = '\0';*/
tmp = malloc(sizeof(struct rule_state));
if(!tmp)
return 0;
current_time = upnp_time();
nextruletoclean_timestamp = 0;
while(get_redirect_rule_by_index(i, /*ifname*/0, &tmp->eport, 0, 0,
&iport, &proto, 0, 0, 0,0, &timestamp,
&tmp->packets, &tmp->bytes) >= 0)
{
tmp->to_remove = 0;
if(timestamp > 0) {
/* need to remove this port mapping ? */
if(timestamp <= (unsigned int)current_time)
tmp->to_remove = 1;
else if((nextruletoclean_timestamp <= (unsigned int)current_time)
|| (timestamp < nextruletoclean_timestamp))
nextruletoclean_timestamp = timestamp;
}
tmp->proto = (short)proto;
/* add tmp to list */
tmp->next = list;
list = tmp;
/* prepare next iteration */
i++;
tmp = malloc(sizeof(struct rule_state));
if(!tmp)
break;
}
#ifdef PCP_PEER
i=0;
while(get_peer_rule_by_index(i, /*ifname*/0, &tmp->eport, 0, 0,
&iport, &proto, 0, 0, 0,0,0, &timestamp,
&tmp->packets, &tmp->bytes) >= 0)
{
tmp->to_remove = 0;
if(timestamp > 0) {
/* need to remove this port mapping ? */
if(timestamp <= (unsigned int)current_time)
tmp->to_remove = 1;
else if((nextruletoclean_timestamp <= (unsigned int)current_time)
|| (timestamp < nextruletoclean_timestamp))
nextruletoclean_timestamp = timestamp;
}
tmp->proto = (short)proto;
/* add tmp to list */
tmp->next = list;
list = tmp;
/* prepare next iteration */
i++;
tmp = malloc(sizeof(struct rule_state));
if(!tmp)
break;
}
#endif
free(tmp);
/* remove the redirections that need to be removed */
for(p = &list, tmp = list; tmp; tmp = *p)
{
if(tmp->to_remove)
{
syslog(LOG_NOTICE, "remove port mapping %hu %s because it has expired",
tmp->eport, proto_itoa(tmp->proto));
_upnp_delete_redir(tmp->eport, tmp->proto);
*p = tmp->next;
free(tmp);
i--;
} else {
p = &(tmp->next);
}
}
/* return empty list if not enough redirections */
if(i<=max_rules_number_target)
while(list)
{
tmp = list;
list = tmp->next;
free(tmp);
}
/* return list */
return list;
}
void
remove_unused_rules(struct rule_state * list)
{
char ifname[IFNAMSIZ];
unsigned short iport;
struct rule_state * tmp;
u_int64_t packets;
u_int64_t bytes;
unsigned int timestamp;
int n = 0;
while(list)
{
/* remove the rule if no traffic has used it */
if(get_redirect_rule(ifname, list->eport, list->proto,
0, 0, &iport, 0, 0, 0, 0, &timestamp,
&packets, &bytes) >= 0)
{
if(packets == list->packets && bytes == list->bytes)
{
syslog(LOG_DEBUG, "removing unused mapping %hu %s : still "
"%" PRIu64 "packets %" PRIu64 "bytes",
list->eport, proto_itoa(list->proto),
packets, bytes);
_upnp_delete_redir(list->eport, list->proto);
n++;
}
}
tmp = list;
list = tmp->next;
free(tmp);
}
if(n>0)
syslog(LOG_NOTICE, "removed %d unused rules", n);
}
/* upnp_get_portmappings_in_range()
* return a list of all "external" ports for which a port
* mapping exists */
unsigned short *
upnp_get_portmappings_in_range(unsigned short startport,
unsigned short endport,
const char * protocol,
unsigned int * number)
{
int proto;
proto = proto_atoi(protocol);
if(!number)
return NULL;
return get_portmappings_in_range(startport, endport, proto, number);
}
/* stuff for miniupnpdctl */
#ifdef USE_MINIUPNPDCTL
void
write_ruleset_details(int s)
{
int proto = 0;
unsigned short eport, iport;
char desc[64];
char iaddr[32];
char rhost[32];
unsigned int timestamp;
u_int64_t packets;
u_int64_t bytes;
int i = 0;
char buffer[256];
int n;
write(s, "Ruleset :\n", 10);
while(get_redirect_rule_by_index(i, 0/*ifname*/, &eport, iaddr, sizeof(iaddr),
&iport, &proto, desc, sizeof(desc),
rhost, sizeof(rhost),
&timestamp,
&packets, &bytes) >= 0)
{
n = snprintf(buffer, sizeof(buffer),
"%2d %s %s:%hu->%s:%hu "
"'%s' %u %" PRIu64 " %" PRIu64 "\n",
/*"'%s' %llu %llu\n",*/
i, proto_itoa(proto), rhost,
eport, iaddr, iport, desc, timestamp, packets, bytes);
write(s, buffer, n);
i++;
}
}
#endif
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