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whitelist.cc
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whitelist.cc
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/* ---------------------------------------------------------------------------
* couriergrey - Greylisting filter for Courier
* Copyright (C) 2007-2012 Matthias Wimmer <[email protected]>
*
* 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 Library General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
* ---------------------------------------------------------------------------
* vi: sw=4:tabstop=8
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "whitelist.h"
#include <iostream>
#include <cstring>
#include <cerrno>
#include <unistd.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <cstdio>
#include <poll.h>
#include <glibmm.h>
#include <sstream>
#include <fstream>
#include <list>
#include <syslog.h>
#include <netinet/in.h>
#include <stdexcept>
namespace couriergrey {
void whitelist::dump() const {
std::clog << "Dumping parsed whitelist:" << std::endl;
for (std::list<std::pair<struct ::in6_addr, int> >::const_iterator p = whitelisted_addresses.begin(); p!= whitelisted_addresses.end(); ++p) {
char address[INET6_ADDRSTRLEN];
::inet_ntop(AF_INET6, &(p->first), address, sizeof(address));
std::clog << address << "/" << (p->second) << std::endl;
}
std::clog << "***** END *****" << std::endl;
}
whitelist::whitelist(std::string const& whitelistfile) : whitelistfile(whitelistfile) {
parse_whitelist();
}
bool whitelist::is_whitelisted(Glib::ustring const& address) const {
// convert address
struct ::in6_addr parsed_address = parse_address(address);
// check if any whitelist entry matches
for (std::list<std::pair<struct ::in6_addr, int> >::const_iterator p = whitelisted_addresses.begin(); p!= whitelisted_addresses.end(); ++p) {
if (is_in_same_net(parsed_address, p->first, p->second))
return true;
}
return false;
}
bool whitelist::is_in_same_net(struct ::in6_addr const& addr1, struct ::in6_addr const& addr2, int netsize) const {
int i = 0;
if (netsize > 128 || netsize < 0)
throw std::invalid_argument("invalid netsize");
for (i = 0; i < netsize/8; i++) {
if (addr1.s6_addr[i] != addr2.s6_addr[i])
return false;
}
if (netsize%8 == 0)
return true;
u_int8_t mask = 0xff << (8 - netsize%8);
return ((addr1.s6_addr[i]&mask) == (addr2.s6_addr[i]&mask));
}
struct ::in6_addr whitelist::parse_address (Glib::ustring const& address) const {
// first try to parse as IPv6 address
struct ::in6_addr parsed_address;
if (::inet_pton(AF_INET6, address.c_str(), &parsed_address) <= 0) {
// not an IPv6 address, try as IPv4 address
Glib::ustring mapped_ipv4 = "::ffff:";
mapped_ipv4 += address;
if (::inet_pton(AF_INET6, mapped_ipv4.c_str(), &parsed_address) <= 0) {
throw std::invalid_argument("not a valid IPv4 or IPv6 address");
}
}
return parsed_address;
}
void whitelist::parse_whitelist() {
std::ifstream wlfile(whitelistfile.c_str());
while (wlfile) {
// get a line from the whitelist file
std::string line;
std::getline(wlfile, line);
// remove comments
std::string::size_type comment_start;
comment_start = line.find('#');
if (comment_start != std::string::npos) {
line.erase(comment_start, std::string::npos);
}
// trim
std::string::size_type first_nws = line.find_first_not_of(" \t");
if (first_nws == std::string::npos)
continue;
line.erase(0, first_nws);
std::string::size_type last_nws = line.find_last_not_of(" \t");
if (last_nws == std::string::npos)
continue;
line.erase(last_nws+1, std::string::npos);
// address or net? Calculate netsize ...
int netsize = 128;
std::string::size_type netsize_pos = line.find('/');
if (netsize_pos != std::string::npos) {
// parse network size
std::istringstream netsize_stream(line.substr(netsize_pos+1));
netsize_stream >> netsize;
// remove network size for further processing
line.erase(netsize_pos);
}
// shortened form of IPv4 class A, B or C networks? (only if no IPv6 address an no netsize given)
if (netsize_pos == std::string::npos && line.find(':') == std::string::npos) {
int separator_count = 0;
for (std::string::size_type temp_pos = line.find('.'); temp_pos != std::string::npos; temp_pos = line.find('.', temp_pos+1)) {
separator_count++;
}
// extend to full IPv4 address and update network size
if (separator_count >= 0 && separator_count < 3) {
netsize -= 8*(3-separator_count);
for (int i=separator_count; i<3; i++) {
line += ".0";
}
}
}
// line should now be an address
try {
struct ::in6_addr parsed_address = parse_address(line);
// we may have to correct the netsize for IPv4 addresses if they have been specified in the range 0 ... 32
if (IN6_IS_ADDR_V4MAPPED(&parsed_address)) {
if (netsize <= 32) {
netsize += 128-32;
}
}
// limit valid range of netsizes
if (netsize < 0)
netsize = 0;
if (netsize > 128)
netsize = 128;
// remember the address
std::pair<struct ::in6_addr, int> new_address_mask_pair(parsed_address, netsize);
whitelisted_addresses.push_back(new_address_mask_pair);
} catch (std::invalid_argument iae) {
::syslog(LOG_INFO, "read whitelist line, which could not be parsed as address, skipping: %s", line.c_str());
}
}
wlfile.close();
}
}