-/* Copyright (c) 2014, Ralf Jung <post@ralfj.de>
-* All rights reserved.
-*
-* Redistribution and use in source and binary forms, with or without
-* modification, are permitted provided that the following conditions are met:
-*
-* 1. Redistributions of source code must retain the above copyright notice, this
-* list of conditions and the following disclaimer.
-* 2. Redistributions in binary form must reproduce the above copyright notice,
-* this list of conditions and the following disclaimer in the documentation
-* and/or other materials provided with the distribution.
-*
-* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
-* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*
-* The views and conclusions contained in the software and documentation are those
-* of the authors and should not be interpreted as representing official policies,
-* either expressed or implied, of the FreeBSD Project.
-*/
-
-#include <iostream>
-#include <fstream>
-#include <sys/wait.h>
-
-#include <boost/regex.hpp>
-#include <boost/program_options.hpp>
-#include <boost/property_tree/ptree.hpp>
-#include <boost/property_tree/ini_parser.hpp>
-#include <boost/iostreams/device/file_descriptor.hpp>
-#include <boost/iostreams/stream.hpp>
-
-namespace pt = boost::property_tree;
-namespace po = boost::program_options;
-using std::string;
-using boost::regex;
-using boost::optional;
-
-static void write(int fd, const char *str)
-{
- size_t len = strlen(str);
- ssize_t written = write(fd, str, len);
- if (written < 0 || (size_t)written != len) {
- std::cerr << "Error writing pipe." << std::endl;
- exit(1);
- }
-}
-
-int main(int argc, const char ** argv)
-{
- try {
- static const regex regex_ipv4("\\d{1,3}(\\.\\d{1,3}){3}|");
- static const regex regex_ipv6("[a-fA-F0-9]{1,4}(:[a-fA-F0-9]{1,4}){7}|");
- static const regex regex_password("[a-zA-Z0-9.:;,_-]+");
- static const regex regex_domain("[a-zA-Z0-9.]+");
-
- // Declare the supported options.
- po::options_description desc("Allowed options");
- desc.add_options()
- ("help", "produce help message")
- ("domain", po::value<string>()->required(), "the domain to update")
- ("password", po::value<string>()->required(), "the password for the domain")
- ("ipv4", po::value<string>(), "the new IPv4 address (empty to delete the A record)")
- ("ipv6", po::value<string>(), "the new IPv6 address (empty to delete the AAAA record)")
- ;
-
- // parse arguments
- po::variables_map vm;
- po::store(po::parse_command_line(argc, argv, desc), vm);
- po::notify(vm);
- if (vm.count("help")) {
- std::cout << "dyn-nsupdate -- a safe setuid wrapper for nsupdate" << std::endl << std::endl;
- std::cout << desc << "\n";
- return 1;
- }
- string domain = vm["domain"].as<string>();
- string password = vm["password"].as<string>();
- bool haveIPv4 = vm.count("ipv4");
- string ipv4 = haveIPv4 ? vm["ipv4"].as<string>() : "";
- bool haveIPv6 = vm.count("ipv6");
- string ipv6 = haveIPv6 ? vm["ipv6"].as<string>() : "";
-
- /* Validate input */
- if (!regex_match(ipv4, regex_ipv4)) {
- throw std::runtime_error("Invalid IPv4 address" + ipv4);
- }
- if (!regex_match(ipv6, regex_ipv6)) {
- throw std::runtime_error("Invalid IPv6 address: " + ipv6);
- }
- if (!regex_match(domain, regex_domain)) {
- throw std::runtime_error("Invalid Domain: " + domain);
- }
- if (!regex_match(password, regex_password)) {
- throw std::runtime_error("Invalid Password: " + password);
- }
-
- /* read configuration */
- pt::ptree config;
- pt::ini_parser::read_ini(CONFIG_FILE, config);
- std::string nsupdate = config.get<std::string>("nsupdate");
- unsigned server_port = config.get<unsigned>("port", 53);
-
- /* Given the domain, check whether the password matches */
- optional<std::string> correct_password = config.get_optional<std::string>(pt::ptree::path_type(domain+"/password", '/'));
- if (!correct_password || *correct_password != password) {
- std::cerr << "Password incorrect." << std::endl;
- exit(1);
- }
-
- /* preapre the pipe */
- int pipe_ends[2];
- if (pipe(pipe_ends) < 0) {
- std::cerr << "Error opening pipe." << std::endl;
- exit(1);
- }
-
- /* Launch nsupdate */
- pid_t child_pid = fork();
- if (child_pid < 0) {
- std::cerr << "Error while forking." << std::endl;
- exit(1);
- }
- if (child_pid == 0) {
- /* We're in the child */
- /* Close write end, use read end as stdin */
- close(pipe_ends[1]);
- if (dup2(pipe_ends[0], fileno(stdin)) < 0) {
- std::cerr << "There was an error redirecting stdin." << std::endl;
- exit(1);
- }
- /* exec nsupdate */
- execl(nsupdate.c_str(), nsupdate.c_str(), "-p", std::to_string(server_port).c_str(), "-l", (char *)NULL);
- /* There was an error */
- std::cerr << "There was an error executing nsupdate." << std::endl;
- exit(1);
- }
-
- /* Send it the command */
- if (haveIPv4) {
- write(pipe_ends[1], "update delete ");
- write(pipe_ends[1], domain.c_str());
- write(pipe_ends[1], ". A\n");
-
- if (!ipv4.empty()) {
- write(pipe_ends[1], "update add ");
- write(pipe_ends[1], domain.c_str());
- write(pipe_ends[1], ". 60 A ");
- write(pipe_ends[1], ipv4.c_str());
- write(pipe_ends[1], "\n");
- }
- }
-
- if (haveIPv6) {
- write(pipe_ends[1], "update delete ");
- write(pipe_ends[1], domain.c_str());
- write(pipe_ends[1], ". AAAA\n");
-
- if (!ipv6.empty()) {
- write(pipe_ends[1], "update add ");
- write(pipe_ends[1], domain.c_str());
- write(pipe_ends[1], ". 60 AAAA ");
- write(pipe_ends[1], ipv6.c_str());
- write(pipe_ends[1], "\n");
- }
- }
-
- write(pipe_ends[1], "send\n");
-
- /* Close both ends */
- close(pipe_ends[0]);
- close(pipe_ends[1]);
-
- /* Wait for child to be gone */
- int child_status;
- waitpid(child_pid, &child_status, 0);
- if (child_status != 0) {
- std::cerr << "There was an error in the child." << std::endl;
- exit(1);
- }
- }
- catch(std::exception &e) {
- std::cout << e.what() << "\n";
- return 1;
- }
-
- return 0;
-}
projects / dyn-nsupdate.git / blobdiff