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Diffstat (limited to '')
| -rw-r--r-- | src/resolve/test-resolved-stream.c | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/src/resolve/test-resolved-stream.c b/src/resolve/test-resolved-stream.c new file mode 100644 index 0000000..96395ad --- /dev/null +++ b/src/resolve/test-resolved-stream.c @@ -0,0 +1,395 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <arpa/inet.h> +#include <fcntl.h> +#include <net/if.h> +#include <net/if_arp.h> +#include <pthread.h> +#include <signal.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/prctl.h> +#include <sys/socket.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "fd-util.h" +#include "log.h" +#include "macro.h" +#include "path-util.h" +#include "process-util.h" +#include "resolved-dns-packet.h" +#include "resolved-dns-question.h" +#include "resolved-dns-rr.h" +#if ENABLE_DNS_OVER_TLS +#include "resolved-dnstls.h" +#endif +#include "resolved-dns-server.h" +#include "resolved-dns-stream.h" +#include "resolved-manager.h" +#include "sd-event.h" +#include "sparse-endian.h" +#include "tests.h" + +static union sockaddr_union server_address; + +/* Bytes of the questions & answers used in the test, including TCP DNS 2-byte length prefix */ +static const uint8_t QUESTION_A[] = { + 0x00, 0x1D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 'e', + 'x' , 'a' , 'm' , 'p' , 'l' , 'e' , 0x03, 'c' , 'o' , 'm' , 0x00, 0x00, 0x01, 0x00, 0x01 +}; +static const uint8_t QUESTION_AAAA[] = { + 0x00, 0x1D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 'e', + 'x' , 'a' , 'm' , 'p' , 'l' , 'e' , 0x03, 'c' , 'o' , 'm' , 0x00, 0x00, 0x1C, 0x00, 0x01 +}; +static const uint8_t ANSWER_A[] = { + 0x00, 0x2D, 0x00, 0x00, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x07, 'e', + 'x' , 'a' , 'm' , 'p' , 'l' , 'e' , 0x03, 'c' , 'o' , 'm' , 0x00, 0x00, 0x01, 0x00, 0x01, 0xC0, + 0x0C, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x52, 0x8D, 0x00, 0x04, 0x5D, 0xB8, 0xD8, 0x22, +}; +static const uint8_t ANSWER_AAAA[] = { + 0x00, 0x39, 0x00, 0x00, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x07, 'e', + 'x' , 'a' , 'm' , 'p' , 'l' , 'e' , 0x03, 'c' , 'o' , 'm' , 0x00, 0x00, 0x1C, 0x00, 0x01, 0xC0, + 0x0C, 0x00, 0x1C, 0x00, 0x01, 0x00, 0x00, 0x54, 0x4B, 0x00, 0x10, 0x26, 0x06, 0x28, 0x00, 0x02, + 0x20, 0x00, 0x01, 0x02, 0x48, 0x18, 0x93, 0x25, 0xC8, 0x19, 0x46, +}; + +/** + * A mock TCP DNS server that asserts certain questions are received + * and replies with the same answer every time. + */ +static void receive_and_check_question(int fd, const uint8_t *expected_question, + size_t question_size) { + uint8_t *actual_question; + size_t n_read = 0; + + actual_question = newa(uint8_t, question_size); + while (n_read < question_size) { + ssize_t r = read(fd, actual_question + n_read, question_size - n_read); + assert_se(r >= 0); + n_read += (size_t)r; + } + assert_se(n_read == question_size); + + assert_se(memcmp(expected_question, actual_question, question_size) == 0); +} + +static void send_answer(int fd, const uint8_t *answer, size_t answer_size) { + assert_se(write(fd, answer, answer_size) == (ssize_t)answer_size); +} + +/* Sends two answers together in a single write operation, + * so they hopefully end up in a single TCP packet / TLS record */ +static void send_answers_together(int fd, + const uint8_t *answer1, size_t answer1_size, + const uint8_t *answer2, size_t answer2_size) { + uint8_t *answer; + size_t answer_size = answer1_size + answer2_size; + + answer = newa(uint8_t, answer_size); + memcpy(answer, answer1, answer1_size); + memcpy(answer + answer1_size, answer2, answer2_size); + assert_se(write(fd, answer, answer_size) == (ssize_t)answer_size); +} + +static void server_handle(int fd) { + receive_and_check_question(fd, QUESTION_A, sizeof(QUESTION_A)); + send_answer(fd, ANSWER_A, sizeof(ANSWER_A)); + + receive_and_check_question(fd, QUESTION_AAAA, sizeof(QUESTION_AAAA)); + send_answer(fd, ANSWER_AAAA, sizeof(ANSWER_AAAA)); + + receive_and_check_question(fd, QUESTION_A, sizeof(QUESTION_A)); + receive_and_check_question(fd, QUESTION_AAAA, sizeof(QUESTION_AAAA)); + send_answers_together(fd, ANSWER_A, sizeof(ANSWER_A), + ANSWER_AAAA, sizeof(ANSWER_AAAA)); +} + +static void *tcp_dns_server(void *p) { + _cleanup_close_ int bindfd = -1, acceptfd = -1; + + assert_se((bindfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0)) >= 0); + assert_se(setsockopt(bindfd, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) >= 0); + assert_se(bind(bindfd, &server_address.sa, SOCKADDR_LEN(server_address)) >= 0); + assert_se(listen(bindfd, 1) >= 0); + assert_se((acceptfd = accept(bindfd, NULL, NULL)) >= 0); + server_handle(acceptfd); + return NULL; +} + +#if ENABLE_DNS_OVER_TLS +/* + * Spawns a DNS TLS server using the command line "openssl s_server" tool. + */ +static void *tls_dns_server(void *p) { + pid_t openssl_pid; + int r; + _cleanup_close_ int fd_server = -1, fd_tls = -1; + _cleanup_free_ char *cert_path = NULL, *key_path = NULL; + _cleanup_free_ char *bind_str = NULL; + + assert_se(get_testdata_dir("test-resolve/selfsigned.cert", &cert_path) >= 0); + assert_se(get_testdata_dir("test-resolve/selfsigned.key", &key_path) >= 0); + + assert_se(asprintf(&bind_str, "%s:%d", + IN_ADDR_TO_STRING(server_address.in.sin_family, + sockaddr_in_addr(&server_address.sa)), + be16toh(server_address.in.sin_port)) >= 0); + + /* We will hook one of the socketpair ends to OpenSSL's TLS server + * stdin/stdout, so we will be able to read and write plaintext + * from the other end's file descriptor like an usual TCP server */ + { + int fd[2]; + assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) >= 0); + fd_server = fd[0]; + fd_tls = fd[1]; + } + + r = safe_fork_full("(test-resolved-stream-tls-openssl)", (int[]) { fd_server, fd_tls }, 2, + FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_LOG|FORK_REOPEN_LOG, &openssl_pid); + assert_se(r >= 0); + if (r == 0) { + /* Child */ + assert_se(dup2(fd_tls, STDIN_FILENO) >= 0); + assert_se(dup2(fd_tls, STDOUT_FILENO) >= 0); + close(TAKE_FD(fd_server)); + close(TAKE_FD(fd_tls)); + + execlp("openssl", "openssl", "s_server", "-accept", bind_str, + "-key", key_path, "-cert", cert_path, + "-quiet", "-naccept", "1", NULL); + log_error("exec failed, is something wrong with the 'openssl' command?"); + _exit(EXIT_FAILURE); + } else { + pthread_mutex_t *server_lock = (pthread_mutex_t *)p; + + server_handle(fd_server); + + /* Once the test is done kill the TLS server to release the port */ + assert_se(pthread_mutex_lock(server_lock) == 0); + assert_se(kill(openssl_pid, SIGTERM) >= 0); + assert_se(waitpid(openssl_pid, NULL, 0) >= 0); + assert_se(pthread_mutex_unlock(server_lock) == 0); + } + + return NULL; +} +#endif + +static const char *TEST_DOMAIN = "example.com"; +static const uint64_t EVENT_TIMEOUT_USEC = 5 * 1000 * 1000; + +static void send_simple_question(DnsStream *stream, uint16_t type) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; + _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; + + assert_se(dns_packet_new(&p, DNS_PROTOCOL_DNS, 0, DNS_PACKET_SIZE_MAX) >= 0); + assert_se(question = dns_question_new(1)); + assert_se(key = dns_resource_key_new(DNS_CLASS_IN, type, TEST_DOMAIN)); + assert_se(dns_question_add(question, key, 0) >= 0); + assert_se(dns_packet_append_question(p, question) >= 0); + DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(question)); + assert_se(dns_stream_write_packet(stream, p) >= 0); +} + +static const size_t MAX_RECEIVED_PACKETS = 2; +static DnsPacket *received_packets[2] = {}; +static size_t n_received_packets = 0; + +static int on_stream_packet(DnsStream *stream, DnsPacket *p) { + assert_se(n_received_packets < MAX_RECEIVED_PACKETS); + assert_se(received_packets[n_received_packets++] = dns_packet_ref(p)); + return 0; +} + +static int on_stream_complete_do_nothing(DnsStream *s, int error) { + return 0; +} + +static void test_dns_stream(bool tls) { + Manager manager = {}; + _cleanup_(dns_stream_unrefp) DnsStream *stream = NULL; + _cleanup_(sd_event_unrefp) sd_event *event = NULL; + _cleanup_close_ int clientfd = -1; + int r; + + void *(*server_entrypoint)(void *); + pthread_t server_thread; + pthread_mutex_t server_lock; + + log_info("test-resolved-stream: Started %s test", tls ? "TLS" : "TCP"); + +#if ENABLE_DNS_OVER_TLS + if (tls) + /* For TLS mode, use DNS_OVER_TLS_OPPORTUNISTIC instead of DNS_OVER_TLS_YES, just to make + * certificate validation more lenient, allowing us to use self-signed certificates. We + * never downgrade, everything we test always goes over TLS */ + manager.dns_over_tls_mode = DNS_OVER_TLS_OPPORTUNISTIC; +#endif + + assert_se(sd_event_new(&event) >= 0); + manager.event = event; + + /* Set up a mock DNS (over TCP or TLS) server */ + server_entrypoint = tcp_dns_server; +#if ENABLE_DNS_OVER_TLS + if (tls) + server_entrypoint = tls_dns_server; +#endif + assert_se(pthread_mutex_init(&server_lock, NULL) == 0); + assert_se(pthread_mutex_lock(&server_lock) == 0); + assert_se(pthread_create(&server_thread, NULL, server_entrypoint, &server_lock) == 0); + + /* Create a socket client and connect to the TCP or TLS server + * The server may not be up immediately, so try to connect a few times before failing */ + assert_se((clientfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0)) >= 0); + + for (int i = 0; i < 100; i++) { + r = connect(clientfd, &server_address.sa, SOCKADDR_LEN(server_address)); + if (r >= 0) + break; + usleep(EVENT_TIMEOUT_USEC / 100); + } + assert_se(r >= 0); + + /* systemd-resolved uses (and requires) the socket to be in nonblocking mode */ + assert_se(fcntl(clientfd, F_SETFL, O_NONBLOCK) >= 0); + + /* Initialize DNS stream (disabling the default self-destruction + behaviour when no complete callback is set) */ + assert_se(dns_stream_new(&manager, &stream, DNS_STREAM_LOOKUP, DNS_PROTOCOL_DNS, + TAKE_FD(clientfd), NULL, on_stream_packet, on_stream_complete_do_nothing, + DNS_STREAM_DEFAULT_TIMEOUT_USEC) >= 0); +#if ENABLE_DNS_OVER_TLS + if (tls) { + DnsServer server = { + .manager = &manager, + .family = server_address.sa.sa_family, + .address = *sockaddr_in_addr(&server_address.sa), + }; + + assert_se(dnstls_manager_init(&manager) >= 0); + assert_se(dnstls_stream_connect_tls(stream, &server) >= 0); + } +#endif + + /* Test: Question of type A and associated answer */ + log_info("test-resolved-stream: A record"); + send_simple_question(stream, DNS_TYPE_A); + while (n_received_packets != 1) + assert_se(sd_event_run(event, EVENT_TIMEOUT_USEC) >= 1); + assert_se(DNS_PACKET_DATA(received_packets[0])); + assert_se(memcmp(DNS_PACKET_DATA(received_packets[0]), + ANSWER_A + 2, sizeof(ANSWER_A) - 2) == 0); + dns_packet_unref(TAKE_PTR(received_packets[0])); + n_received_packets = 0; + + /* Test: Question of type AAAA and associated answer */ + log_info("test-resolved-stream: AAAA record"); + send_simple_question(stream, DNS_TYPE_AAAA); + while (n_received_packets != 1) + assert_se(sd_event_run(event, EVENT_TIMEOUT_USEC) >= 1); + assert_se(DNS_PACKET_DATA(received_packets[0])); + assert_se(memcmp(DNS_PACKET_DATA(received_packets[0]), + ANSWER_AAAA + 2, sizeof(ANSWER_AAAA) - 2) == 0); + dns_packet_unref(TAKE_PTR(received_packets[0])); + n_received_packets = 0; + + /* Test: Question of type A and AAAA and associated answers + * Both answers are sent back in a single packet or TLS record + * (tests the fix of PR #22132: "Fix DoT timeout on multiple answer records") */ + log_info("test-resolved-stream: A + AAAA record"); + send_simple_question(stream, DNS_TYPE_A); + send_simple_question(stream, DNS_TYPE_AAAA); + + while (n_received_packets != 2) + assert_se(sd_event_run(event, EVENT_TIMEOUT_USEC) >= 1); + assert_se(DNS_PACKET_DATA(received_packets[0])); + assert_se(DNS_PACKET_DATA(received_packets[1])); + assert_se(memcmp(DNS_PACKET_DATA(received_packets[0]), + ANSWER_A + 2, sizeof(ANSWER_A) - 2) == 0); + assert_se(memcmp(DNS_PACKET_DATA(received_packets[1]), + ANSWER_AAAA + 2, sizeof(ANSWER_AAAA) - 2) == 0); + dns_packet_unref(TAKE_PTR(received_packets[0])); + dns_packet_unref(TAKE_PTR(received_packets[1])); + n_received_packets = 0; + +#if ENABLE_DNS_OVER_TLS + if (tls) + dnstls_manager_free(&manager); +#endif + + /* Stop the DNS server */ + assert_se(pthread_mutex_unlock(&server_lock) == 0); + assert_se(pthread_join(server_thread, NULL) == 0); + assert_se(pthread_mutex_destroy(&server_lock) == 0); + + log_info("test-resolved-stream: Finished %s test", tls ? "TLS" : "TCP"); +} + +static void try_isolate_network(void) { + _cleanup_close_ int socket_fd = -1; + int r; + + /* First test if CLONE_NEWUSER/CLONE_NEWNET can actually work for us, i.e. we can open the namespaces + * and then still access the build dir we are run from. We do that in a child process since it's + * nasty if we have to go back from the namespace once we entered it and realized it cannot work. */ + r = safe_fork("(usernstest)", FORK_DEATHSIG|FORK_LOG|FORK_WAIT, NULL); + if (r == 0) { /* child */ + _cleanup_free_ char *rt = NULL, *d = NULL; + + if (unshare(CLONE_NEWUSER | CLONE_NEWNET) < 0) { + log_warning_errno(errno, "test-resolved-stream: Can't create user and network ns, running on host: %m"); + _exit(EXIT_FAILURE); + } + + assert_se(get_process_exe(0, &rt) >= 0); + assert_se(path_extract_directory(rt, &d) >= 0); + + if (access(d, F_OK) < 0) { + log_warning_errno(errno, "test-resolved-stream: Can't access /proc/self/exe from user/network ns, running on host: %m"); + _exit(EXIT_FAILURE); + } + + _exit(EXIT_SUCCESS); + } + if (r == -EPROTO) /* EPROTO means nonzero exit code of child, i.e. the tests in the child failed */ + return; + assert_se(r > 0); + + /* Now that we know that the unshare() is safe, let's actually do it */ + assert_se(unshare(CLONE_NEWUSER | CLONE_NEWNET) >= 0); + + /* Bring up the loopback interfaceon the newly created network namespace */ + struct ifreq req = { .ifr_ifindex = 1 }; + assert_se((socket_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0)) >= 0); + assert_se(ioctl(socket_fd, SIOCGIFNAME, &req) >= 0); + assert_se(ioctl(socket_fd, SIOCGIFFLAGS, &req) >= 0); + assert_se(FLAGS_SET(req.ifr_flags, IFF_LOOPBACK)); + req.ifr_flags |= IFF_UP; + assert_se(ioctl(socket_fd, SIOCSIFFLAGS, &req) >= 0); +} + +int main(int argc, char **argv) { + server_address = (union sockaddr_union) { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(12345), + .in.sin_addr.s_addr = htobe32(INADDR_LOOPBACK) + }; + + test_setup_logging(LOG_DEBUG); + + try_isolate_network(); + + test_dns_stream(false); +#if ENABLE_DNS_OVER_TLS + if (system("openssl version >/dev/null 2>&1") != 0) + return log_tests_skipped("Skipping TLS test since the 'openssl' command does not seem to be available"); + test_dns_stream(true); +#endif + + return 0; +} |