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upnppermissions.c
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upnppermissions.c
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/* $Id: upnppermissions.c,v 1.18 2014/03/07 10:43:29 nanard Exp $ */
/* MiniUPnP project
* http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
* (c) 2006-2014 Thomas Bernard
* This software is subject to the conditions detailed
* in the LICENCE file provided within the distribution */
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <syslog.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include "config.h"
#include "upnppermissions.h"
/* read_permission_line()
* parse the a permission line which format is :
* (deny|allow) [0-9]+(-[0-9]+) ip/mask [0-9]+(-[0-9]+)
* ip/mask is either 192.168.1.1/24 or 192.168.1.1/255.255.255.0
*/
int
read_permission_line(struct upnpperm * perm,
char * p)
{
char * q;
int n_bits;
int i;
/* first token: (allow|deny) */
while(isspace(*p))
p++;
if(0 == memcmp(p, "allow", 5))
{
perm->type = UPNPPERM_ALLOW;
p += 5;
}
else if(0 == memcmp(p, "deny", 4))
{
perm->type = UPNPPERM_DENY;
p += 4;
}
else
{
return -1;
}
while(isspace(*p))
p++;
/* second token: eport or eport_min-eport_max */
if(!isdigit(*p))
return -1;
for(q = p; isdigit(*q); q++);
if(*q=='-')
{
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->eport_min = (u_short)i;
q++;
p = q;
while(isdigit(*q))
q++;
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->eport_max = (u_short)i;
if(perm->eport_min > perm->eport_max)
return -1;
}
else if(isspace(*q))
{
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->eport_min = perm->eport_max = (u_short)i;
}
else
{
return -1;
}
p = q + 1;
while(isspace(*p))
p++;
/* third token: ip/mask */
if(!isdigit(*p))
return -1;
for(q = p; isdigit(*q) || (*q == '.'); q++);
if(*q=='/')
{
*q = '\0';
if(!inet_aton(p, &perm->address))
return -1;
q++;
p = q;
while(isdigit(*q))
q++;
if(*q == '.')
{
while(*q == '.' || isdigit(*q))
q++;
if(!isspace(*q))
return -1;
*q = '\0';
if(!inet_aton(p, &perm->mask))
return -1;
}
else if(!isspace(*q))
return -1;
else
{
*q = '\0';
n_bits = atoi(p);
if(n_bits > 32)
return -1;
perm->mask.s_addr = htonl(n_bits ? (0xffffffffu << (32 - n_bits)) : 0);
}
}
else if(isspace(*q))
{
*q = '\0';
if(!inet_aton(p, &perm->address))
return -1;
perm->mask.s_addr = 0xffffffffu;
}
else
{
return -1;
}
p = q + 1;
/* fourth token: iport or iport_min-iport_max */
while(isspace(*p))
p++;
if(!isdigit(*p))
return -1;
for(q = p; isdigit(*q); q++);
if(*q=='-')
{
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->iport_min = (u_short)i;
q++;
p = q;
while(isdigit(*q))
q++;
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->iport_max = (u_short)i;
if(perm->iport_min > perm->iport_max)
return -1;
}
else if(isspace(*q) || *q == '\0')
{
*q = '\0';
i = atoi(p);
if(i > 65535)
return -1;
perm->iport_min = perm->iport_max = (u_short)i;
}
else
{
return -1;
}
#ifdef DEBUG
printf("perm rule added : %s %hu-%hu %08x/%08x %hu-%hu\n",
(perm->type==UPNPPERM_ALLOW)?"allow":"deny",
perm->eport_min, perm->eport_max, ntohl(perm->address.s_addr),
ntohl(perm->mask.s_addr), perm->iport_min, perm->iport_max);
#endif
return 0;
}
#ifdef USE_MINIUPNPDCTL
void
write_permlist(int fd, const struct upnpperm * permary,
int nperms)
{
int l;
const struct upnpperm * perm;
int i;
char buf[128];
write(fd, "Permissions :\n", 14);
for(i = 0; i<nperms; i++)
{
perm = permary + i;
l = snprintf(buf, sizeof(buf), "%02d %s %hu-%hu %08x/%08x %hu-%hu\n",
i,
(perm->type==UPNPPERM_ALLOW)?"allow":"deny",
perm->eport_min, perm->eport_max, ntohl(perm->address.s_addr),
ntohl(perm->mask.s_addr), perm->iport_min, perm->iport_max);
if(l<0)
return;
write(fd, buf, l);
}
}
#endif
/* match_permission()
* returns: 1 if eport, address, iport matches the permission rule
* 0 if no match */
static int
match_permission(const struct upnpperm * perm,
u_short eport, struct in_addr address, u_short iport)
{
if( (eport < perm->eport_min) || (perm->eport_max < eport))
return 0;
if( (iport < perm->iport_min) || (perm->iport_max < iport))
return 0;
if( (address.s_addr & perm->mask.s_addr)
!= (perm->address.s_addr & perm->mask.s_addr) )
return 0;
return 1;
}
#if 0
/* match_permission_internal()
* returns: 1 if address, iport matches the permission rule
* 0 if no match */
static int
match_permission_internal(const struct upnpperm * perm,
struct in_addr address, u_short iport)
{
if( (iport < perm->iport_min) || (perm->iport_max < iport))
return 0;
if( (address.s_addr & perm->mask.s_addr)
!= (perm->address.s_addr & perm->mask.s_addr) )
return 0;
return 1;
}
#endif
int
check_upnp_rule_against_permissions(const struct upnpperm * permary,
int n_perms,
u_short eport, struct in_addr address,
u_short iport)
{
int i;
for(i=0; i<n_perms; i++)
{
if(match_permission(permary + i, eport, address, iport))
{
syslog(LOG_DEBUG,
"UPnP permission rule %d matched : port mapping %s",
i, (permary[i].type == UPNPPERM_ALLOW)?"accepted":"rejected"
);
return (permary[i].type == UPNPPERM_ALLOW);
}
}
syslog(LOG_DEBUG, "no permission rule matched : accept by default (n_perms=%d)", n_perms);
return 1; /* Default : accept */
}