X-Git-Url: https://git.ralfj.de/dyn-nsupdate.git/blobdiff_plain/7d0063d7a7006bfb7b8a3051f42285f894183d1c..b3b6845d29bd9dda2717ef25ac9afd4d442f97ef:/dyn-nsupdate.cpp diff --git a/dyn-nsupdate.cpp b/dyn-nsupdate.cpp index cdd1dc4..d133369 100644 --- a/dyn-nsupdate.cpp +++ b/dyn-nsupdate.cpp @@ -1,56 +1,194 @@ +/* Copyright (c) 2014, Ralf Jung +* 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 #include +#include #include +#include #include #include +#include +#include -using namespace boost; +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) { - static const regex regex_ip("\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3}"); - static const regex regex_user("[a-zA-Z]+"); - - - if (argc != 5) { - std::cerr << "Usage: " << argv[0] << " " << std::endl; - return 1; - } - - /* Obtain and validate inpit */ - std::string user = argv[1]; - std::string password = argv[2]; - std::string domain = argv[3]; - std::string ip = argv[4]; - - if (!regex_match(ip, regex_ip)) { - std::cerr << "Invalid IP address " << ip << "." << std::endl; - return 1; - } - if (!regex_match(user, regex_user)) { - std::cerr << "Invalid username " << user << "." << std::endl; - return 1; - } - - /* read configuration */ - property_tree::ptree config; - property_tree::ini_parser::read_ini(CONFIG_FILE, config); - std::string keyfile = config.get("key"); - - /* Check username, password, domain */ - optional correct_password = config.get_optional(user+".password"); - if (!correct_password || *correct_password != password) { - std::cerr << "Username or password incorrect." << std::endl; - return 1; - } - if (config.get(user+".domain") != domain) { - std::cerr << "Domain incorrect." << std::endl; - return 1; - } - - std::cout << "It's all right, using key " << keyfile << std::endl; - - - return 0; + 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()->required(), "the domain to update") + ("password", po::value()->required(), "the password for the domain") + ("ipv4", po::value(), "the new IPv4 address (empty to delete the A record)") + ("ipv6", po::value(), "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 password = vm["password"].as(); + bool haveIPv4 = vm.count("ipv4"); + string ipv4 = haveIPv4 ? vm["ipv4"].as() : ""; + bool haveIPv6 = vm.count("ipv6"); + string ipv6 = haveIPv6 ? vm["ipv6"].as() : ""; + + /* 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("nsupdate"); + unsigned server_port = config.get("port", 53); + + /* Given the domain, check whether the password matches */ + optional correct_password = config.get_optional(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; }