475 lines
13 KiB
C++
475 lines
13 KiB
C++
#include <arpa/inet.h>
|
|
#include <type_traits>
|
|
#include <tins/tins.h>
|
|
#include <libmnl/libmnl.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/netfilter/nfnetlink.h>
|
|
#include <linux/types.h>
|
|
#include <linux/netfilter/nfnetlink_queue.h>
|
|
#include <libnetfilter_queue/libnetfilter_queue.h>
|
|
#include <linux/netfilter/nfnetlink_conntrack.h>
|
|
#include <stdexcept>
|
|
#include <iostream>
|
|
#include <cstring>
|
|
#include <cstdlib>
|
|
#include <cerrno>
|
|
#include <sstream>
|
|
#include <thread>
|
|
#include <mutex>
|
|
#include <jpcre2.hpp>
|
|
|
|
|
|
using namespace std;
|
|
using namespace Tins;
|
|
typedef jpcre2::select<char> jp;
|
|
mutex stdout_mutex;
|
|
|
|
|
|
bool unhexlify(string const &hex, string &newString) {
|
|
try{
|
|
int len = hex.length();
|
|
for(int i=0; i< len; i+=2)
|
|
{
|
|
std::string byte = hex.substr(i,2);
|
|
char chr = (char) (int)strtol(byte.c_str(), NULL, 16);
|
|
newString.push_back(chr);
|
|
}
|
|
return true;
|
|
}
|
|
catch (...){
|
|
return false;
|
|
}
|
|
}
|
|
|
|
|
|
typedef pair<string,jp::Regex> regex_rule_pair;
|
|
typedef vector<regex_rule_pair> regex_rule_vector;
|
|
struct regex_rules{
|
|
regex_rule_vector output_whitelist, input_whitelist, output_blacklist, input_blacklist;
|
|
|
|
regex_rule_vector* getByCode(char code){
|
|
switch(code){
|
|
case 'C': // Client to server Blacklist
|
|
return &input_blacklist; break;
|
|
case 'c': // Client to server Whitelist
|
|
return &input_whitelist; break;
|
|
case 'S': // Server to client Blacklist
|
|
return &output_blacklist; break;
|
|
case 's': // Server to client Whitelist
|
|
return &output_whitelist; break;
|
|
}
|
|
throw invalid_argument( "Expected 'C' 'c' 'S' or 's'" );
|
|
}
|
|
|
|
int add(const char* arg){
|
|
//Integrity checks
|
|
size_t arg_len = strlen(arg);
|
|
if (arg_len < 2 || arg_len%2 != 0){
|
|
cerr << "[warning] [regex_rules.add] invalid arg passed (" << arg << "), skipping..." << endl;
|
|
return -1;
|
|
}
|
|
if (arg[0] != '0' && arg[0] != '1'){
|
|
cerr << "[warning] [regex_rules.add] invalid is_case_sensitive (" << arg[0] << ") in '" << arg << "', must be '1' or '0', skipping..." << endl;
|
|
return -1;
|
|
}
|
|
if (arg[1] != 'C' && arg[1] != 'c' && arg[1] != 'S' && arg[1] != 's'){
|
|
cerr << "[warning] [regex_rules.add] invalid filter_type (" << arg[1] << ") in '" << arg << "', must be 'C', 'c', 'S' or 's', skipping..." << endl;
|
|
return -1;
|
|
}
|
|
string hex(arg+2), expr;
|
|
if (!unhexlify(hex, expr)){
|
|
cerr << "[warning] [regex_rules.add] invalid hex regex value (" << hex << "), skipping..." << endl;
|
|
return -1;
|
|
}
|
|
//Push regex
|
|
jp::Regex regex(expr,arg[0] == '1'?"gS":"giS");
|
|
if (regex){
|
|
cerr << "[info] [regex_rules.add] adding new regex filter: '" << expr << "'" << endl;
|
|
getByCode(arg[1])->push_back(make_pair(string(arg), regex));
|
|
} else {
|
|
cerr << "[warning] [regex_rules.add] compiling of '" << expr << "' regex failed, skipping..." << endl;
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
bool check(unsigned char* data, const size_t& bytes_transferred, const bool in_input){
|
|
string str_data((char *) data, bytes_transferred);
|
|
for (regex_rule_pair ele:(in_input?input_blacklist:output_blacklist)){
|
|
try{
|
|
if(ele.second.match(str_data)){
|
|
unique_lock<mutex> lck(stdout_mutex);
|
|
cout << "BLOCKED " << ele.first << endl;
|
|
return false;
|
|
}
|
|
} catch(...){
|
|
cerr << "[info] [regex_rules.check] Error while matching blacklist regex: " << ele.first << endl;
|
|
}
|
|
}
|
|
for (regex_rule_pair ele:(in_input?input_whitelist:output_whitelist)){
|
|
try{
|
|
cerr << "[debug] [regex_rules.check] regex whitelist match " << ele.second.getPattern() << endl;
|
|
if(!ele.second.match(str_data)){
|
|
unique_lock<mutex> lck(stdout_mutex);
|
|
cout << "BLOCKED " << ele.first << endl;
|
|
return false;
|
|
}
|
|
} catch(...){
|
|
cerr << "[info] [regex_rules.check] Error while matching whitelist regex: " << ele.first << endl;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
};
|
|
|
|
|
|
|
|
shared_ptr<regex_rules> regex_config;
|
|
|
|
typedef bool NetFilterQueueCallback(const uint8_t*,uint32_t);
|
|
|
|
PDU * find_transport_layer(PDU* pkt){
|
|
while(pkt != NULL){
|
|
if (pkt->pdu_type() == PDU::TCP || pkt->pdu_type() == PDU::UDP) {
|
|
return pkt;
|
|
}
|
|
pkt = pkt->inner_pdu();
|
|
}
|
|
return pkt;
|
|
}
|
|
|
|
template <NetFilterQueueCallback callback_func>
|
|
class NetfilterQueue {
|
|
public:
|
|
size_t BUF_SIZE = 0xffff + (MNL_SOCKET_BUFFER_SIZE/2);
|
|
char *buf = NULL;
|
|
unsigned int portid;
|
|
u_int16_t queue_num;
|
|
struct mnl_socket* nl = NULL;
|
|
|
|
NetfilterQueue(u_int16_t queue_num): queue_num(queue_num) {
|
|
|
|
nl = mnl_socket_open(NETLINK_NETFILTER);
|
|
|
|
if (nl == NULL) { throw runtime_error( "mnl_socket_open" );}
|
|
|
|
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
|
|
mnl_socket_close(nl);
|
|
throw runtime_error( "mnl_socket_bind" );
|
|
}
|
|
portid = mnl_socket_get_portid(nl);
|
|
|
|
buf = (char*) malloc(BUF_SIZE);
|
|
|
|
if (!buf) {
|
|
mnl_socket_close(nl);
|
|
throw runtime_error( "allocate receive buffer" );
|
|
}
|
|
|
|
if (send_config_cmd(NFQNL_CFG_CMD_BIND) < 0) {
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
//TEST if BIND was successful
|
|
if (send_config_cmd(NFQNL_CFG_CMD_NONE) < 0) { // SEND A NONE cmmand to generate an error meessage
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
if (recv_packet() == -1) { //RECV the error message
|
|
_clear();
|
|
throw std::runtime_error( "mnl_socket_recvfrom" );
|
|
}
|
|
|
|
struct nlmsghdr *nlh = (struct nlmsghdr *) buf;
|
|
|
|
if (nlh->nlmsg_type != NLMSG_ERROR) {
|
|
_clear();
|
|
throw runtime_error( "unexpected packet from kernel (expected NLMSG_ERROR packet)" );
|
|
}
|
|
//nfqnl_msg_config_cmd
|
|
nlmsgerr* error_msg = (nlmsgerr *)mnl_nlmsg_get_payload(nlh);
|
|
|
|
// error code taken from the linux kernel:
|
|
// https://elixir.bootlin.com/linux/v5.18.12/source/include/linux/errno.h#L27
|
|
#define ENOTSUPP 524 /* Operation is not supported */
|
|
|
|
if (error_msg->error != -ENOTSUPP) {
|
|
_clear();
|
|
throw std::invalid_argument( "queueid is already busy" );
|
|
}
|
|
//END TESTING BIND
|
|
nlh = nfq_nlmsg_put(buf, NFQNL_MSG_CONFIG, queue_num);
|
|
nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff);
|
|
|
|
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(NFQA_CFG_F_GSO));
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(NFQA_CFG_F_GSO));
|
|
|
|
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void run(){
|
|
/*
|
|
* ENOBUFS is signalled to userspace when packets were lost
|
|
* on kernel side. In most cases, userspace isn't interested
|
|
* in this information, so turn it off.
|
|
*/
|
|
int ret = 1;
|
|
mnl_socket_setsockopt(nl, NETLINK_NO_ENOBUFS, &ret, sizeof(int));
|
|
|
|
for (;;) {
|
|
ret = recv_packet();
|
|
if (ret == -1) {
|
|
throw std::runtime_error( "mnl_socket_recvfrom" );
|
|
}
|
|
|
|
ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, nl);
|
|
if (ret < 0){
|
|
throw std::runtime_error( "mnl_cb_run" );
|
|
}
|
|
}
|
|
}
|
|
|
|
~NetfilterQueue() {
|
|
send_config_cmd(NFQNL_CFG_CMD_UNBIND);
|
|
_clear();
|
|
}
|
|
private:
|
|
|
|
ssize_t send_config_cmd(nfqnl_msg_config_cmds cmd){
|
|
struct nlmsghdr *nlh = nfq_nlmsg_put(buf, NFQNL_MSG_CONFIG, queue_num);
|
|
nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, cmd);
|
|
return mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
|
|
}
|
|
|
|
ssize_t recv_packet(){
|
|
return mnl_socket_recvfrom(nl, buf, BUF_SIZE);
|
|
}
|
|
|
|
void _clear(){
|
|
if (buf != NULL) {
|
|
free(buf);
|
|
buf = NULL;
|
|
}
|
|
mnl_socket_close(nl);
|
|
}
|
|
|
|
static int queue_cb(const struct nlmsghdr *nlh, void *data)
|
|
{
|
|
struct mnl_socket* nl = (struct mnl_socket*)data;
|
|
//Extract attributes from the nlmsghdr
|
|
struct nlattr *attr[NFQA_MAX+1] = {};
|
|
|
|
if (nfq_nlmsg_parse(nlh, attr) < 0) {
|
|
perror("problems parsing");
|
|
return MNL_CB_ERROR;
|
|
}
|
|
if (attr[NFQA_PACKET_HDR] == NULL) {
|
|
fputs("metaheader not set\n", stderr);
|
|
return MNL_CB_ERROR;
|
|
}
|
|
//Get Payload
|
|
uint16_t plen = mnl_attr_get_payload_len(attr[NFQA_PAYLOAD]);
|
|
void *payload = mnl_attr_get_payload(attr[NFQA_PAYLOAD]);
|
|
|
|
//Return result to the kernel
|
|
struct nfqnl_msg_packet_hdr *ph = (nfqnl_msg_packet_hdr*) mnl_attr_get_payload(attr[NFQA_PACKET_HDR]);
|
|
struct nfgenmsg *nfg = (nfgenmsg *)mnl_nlmsg_get_payload(nlh);
|
|
char buf[MNL_SOCKET_BUFFER_SIZE];
|
|
struct nlmsghdr *nlh_verdict;
|
|
struct nlattr *nest;
|
|
|
|
nlh_verdict = nfq_nlmsg_put(buf, NFQNL_MSG_VERDICT, ntohs(nfg->res_id));
|
|
|
|
/*
|
|
This define allow to avoid to allocate new heap memory for each packet.
|
|
The code under this comment is replicated for ipv6 and ip
|
|
Better solutions are welcome. :)
|
|
*/
|
|
#define PKT_HANDLE \
|
|
PDU *transport_layer = find_transport_layer(&packet); \
|
|
if(transport_layer->inner_pdu() == nullptr || transport_layer == nullptr){ \
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_ACCEPT ); \
|
|
}else{ \
|
|
int size = transport_layer->inner_pdu()->size(); \
|
|
if(callback_func((const uint8_t*)payload+plen - size, size)){ \
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_ACCEPT ); \
|
|
} else{ \
|
|
if (transport_layer->pdu_type() == PDU::TCP){ \
|
|
((TCP *)transport_layer)->release_inner_pdu(); \
|
|
((TCP *)transport_layer)->set_flag(TCP::FIN,1); \
|
|
((TCP *)transport_layer)->set_flag(TCP::ACK,1); \
|
|
((TCP *)transport_layer)->set_flag(TCP::SYN,0); \
|
|
nfq_nlmsg_verdict_put_pkt(nlh_verdict, packet.serialize().data(), packet.size()); \
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_ACCEPT ); \
|
|
}else{ \
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_DROP ); \
|
|
} \
|
|
} \
|
|
}
|
|
|
|
// Check IP protocol version
|
|
if ( (((uint8_t*)payload)[0] & 0xf0) == 0x40 ){
|
|
IP packet = IP((uint8_t*)payload,plen);
|
|
PKT_HANDLE
|
|
}else{
|
|
IPv6 packet = IPv6((uint8_t*)payload,plen);
|
|
PKT_HANDLE
|
|
}
|
|
|
|
/* example to set the connmark. First, start NFQA_CT section: */
|
|
nest = mnl_attr_nest_start(nlh_verdict, NFQA_CT);
|
|
|
|
/* then, add the connmark attribute: */
|
|
mnl_attr_put_u32(nlh_verdict, CTA_MARK, htonl(42));
|
|
/* more conntrack attributes, e.g. CTA_LABELS could be set here */
|
|
|
|
/* end conntrack section */
|
|
mnl_attr_nest_end(nlh_verdict, nest);
|
|
|
|
if (mnl_socket_sendto(nl, nlh_verdict, nlh_verdict->nlmsg_len) < 0) {
|
|
throw std::runtime_error( "mnl_socket_send" );
|
|
}
|
|
|
|
return MNL_CB_OK;
|
|
}
|
|
|
|
};
|
|
|
|
template <NetFilterQueueCallback func>
|
|
class NFQueueSequence{
|
|
private:
|
|
vector<NetfilterQueue<func> *> nfq;
|
|
uint16_t _init;
|
|
uint16_t _end;
|
|
vector<thread> threads;
|
|
public:
|
|
static const int QUEUE_BASE_NUM = 1000;
|
|
|
|
NFQueueSequence(uint16_t seq_len){
|
|
if (seq_len <= 0) throw invalid_argument("seq_len <= 0");
|
|
nfq = vector<NetfilterQueue<func>*>(seq_len);
|
|
_init = QUEUE_BASE_NUM;
|
|
while(nfq[0] == NULL){
|
|
if (_init+seq_len-1 >= 65536){
|
|
throw runtime_error("NFQueueSequence: too many queues!");
|
|
}
|
|
for (int i=0;i<seq_len;i++){
|
|
try{
|
|
nfq[i] = new NetfilterQueue<func>(_init+i);
|
|
}catch(const invalid_argument e){
|
|
for(int j = 0; j < i; j++) {
|
|
delete nfq[j];
|
|
nfq[j] = nullptr;
|
|
}
|
|
_init += seq_len - i;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
_end = _init + seq_len - 1;
|
|
}
|
|
|
|
void start(){
|
|
if (threads.size() != 0) throw runtime_error("NFQueueSequence: already started!");
|
|
for (int i=0;i<nfq.size();i++){
|
|
threads.push_back(thread(&NetfilterQueue<func>::run, nfq[i]));
|
|
}
|
|
}
|
|
|
|
void join(){
|
|
for (int i=0;i<nfq.size();i++){
|
|
threads[i].join();
|
|
}
|
|
threads.clear();
|
|
}
|
|
|
|
uint16_t init(){
|
|
return _init;
|
|
}
|
|
uint16_t end(){
|
|
return _end;
|
|
}
|
|
|
|
~NFQueueSequence(){
|
|
for (int i=0;i<nfq.size();i++){
|
|
delete nfq[i];
|
|
}
|
|
}
|
|
};
|
|
|
|
bool is_sudo(){
|
|
return getuid() == 0;
|
|
}
|
|
|
|
void config_updater (){
|
|
string line, data;
|
|
while (true){
|
|
getline(cin, line);
|
|
if (cin.bad()){
|
|
cerr << "[fatal] [upfdater] cin.bad() != 0" << endl;
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
cerr << "[info] [updater] Updating configuration with line " << line << endl;
|
|
istringstream config_stream(line);
|
|
regex_rules *regex_new_config = new regex_rules();
|
|
while(!config_stream.eof()){
|
|
config_stream >> data;
|
|
regex_new_config->add(data.c_str());
|
|
}
|
|
regex_config.reset(regex_new_config);
|
|
cerr << "[info] [updater] Config update done" << endl;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
template <bool is_input>
|
|
bool filter_callback(const uint8_t *data, uint32_t len){
|
|
shared_ptr<regex_rules> current_config = regex_config;
|
|
return current_config->check((unsigned char *)data, len, is_input);
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
if(!is_sudo()){
|
|
cerr << "[fatal] [main] You must be root to run this program" << endl;
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
int n_of_queue = 1;
|
|
if (argc >= 2) n_of_queue = atoi(argv[1]);
|
|
regex_config.reset(new regex_rules());
|
|
NFQueueSequence<filter_callback<true>> input_queues(n_of_queue);
|
|
input_queues.start();
|
|
NFQueueSequence<filter_callback<false>> output_queues(n_of_queue);
|
|
output_queues.start();
|
|
|
|
cout << "QUEUES INPUT " << input_queues.init() << " " << input_queues.end() << " OUTPUT " << output_queues.init() << " " << output_queues.end() << endl;
|
|
|
|
config_updater();
|
|
}
|
|
|
|
|
|
/*
|
|
|
|
libpcre2-dev
|
|
libnetfilter-queue-dev
|
|
libtins-dev
|
|
libmnl-dev
|
|
|
|
c++ nfqueue.cpp -o nfqueue -pthread -lpcre2-8 -ltins -lnetfilter_queue -lmnl
|
|
|
|
WORKDIR /tmp/
|
|
RUN git clone --branch release https://github.com/jpcre2/jpcre2
|
|
WORKDIR /tmp/jpcre2
|
|
RUN ./configure; make; make install
|
|
WORKDIR /
|
|
|
|
*/ |