[thirdparty/systemd.git] / src / resolve / resolved-dnstls-gnutls.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#if !ENABLE_DNS_OVER_TLS || !DNS_OVER_TLS_USE_GNUTLS
#error This source file requires DNS-over-TLS to be enabled and GnuTLS to be available.
#endif

#include <gnutls/socket.h>

#include "resolved-dns-stream.h"
#include "resolved-dnstls.h"

DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t, gnutls_deinit);

static ssize_t dnstls_stream_writev(gnutls_transport_ptr_t p, const giovec_t *iov, int iovcnt) {
        int r;

        assert(p);

        r = dns_stream_writev((DnsStream*) p, (const struct iovec*) iov, iovcnt, DNS_STREAM_WRITE_TLS_DATA);
        if (r < 0) {
                errno = -r;
                return -1;
        }

        return r;
}

int dnstls_stream_connect_tls(DnsStream *stream, DnsServer *server) {
        _cleanup_(gnutls_deinitp) gnutls_session_t gs;
        int r;

        assert(stream);
        assert(server);

        r = gnutls_init(&gs, GNUTLS_CLIENT | GNUTLS_ENABLE_FALSE_START | GNUTLS_NONBLOCK);
        if (r < 0)
                return r;

        /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
        r = gnutls_priority_set_direct(gs, "NORMAL:-VERS-ALL:+VERS-TLS1.2", NULL);
        if (r < 0)
                return r;

        r = gnutls_credentials_set(gs, GNUTLS_CRD_CERTIFICATE, stream->manager->dnstls_data.cert_cred);
        if (r < 0)
                return r;

        if (server->dnstls_data.session_data.size > 0) {
                gnutls_session_set_data(gs, server->dnstls_data.session_data.data, server->dnstls_data.session_data.size);

                // Clear old session ticket
                gnutls_free(server->dnstls_data.session_data.data);
                server->dnstls_data.session_data.data = NULL;
                server->dnstls_data.session_data.size = 0;
        }

        if (server->manager->dns_over_tls_mode == DNS_OVER_TLS_YES)
                gnutls_session_set_verify_cert(gs, NULL, 0);

        gnutls_handshake_set_timeout(gs, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

        gnutls_transport_set_ptr2(gs, (gnutls_transport_ptr_t) (long) stream->fd, stream);
        gnutls_transport_set_vec_push_function(gs, &dnstls_stream_writev);

        stream->encrypted = true;
        stream->dnstls_data.handshake = gnutls_handshake(gs);
        if (stream->dnstls_data.handshake < 0 && gnutls_error_is_fatal(stream->dnstls_data.handshake))
                return -ECONNREFUSED;

        stream->dnstls_data.session = TAKE_PTR(gs);

        return 0;
}

void dnstls_stream_free(DnsStream *stream) {
        assert(stream);
        assert(stream->encrypted);

        if (stream->dnstls_data.session)
                gnutls_deinit(stream->dnstls_data.session);
}

int dnstls_stream_on_io(DnsStream *stream, uint32_t revents) {
        int r;

        assert(stream);
        assert(stream->encrypted);
        assert(stream->dnstls_data.session);

        if (stream->dnstls_data.shutdown) {
                r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
                if (r == GNUTLS_E_AGAIN) {
                        stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
                        return -EAGAIN;
                } else if (r < 0)
                        log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));

                stream->dnstls_events = 0;
                stream->dnstls_data.shutdown = false;
                dns_stream_unref(stream);
                return DNSTLS_STREAM_CLOSED;
        } else if (stream->dnstls_data.handshake < 0) {
                stream->dnstls_data.handshake = gnutls_handshake(stream->dnstls_data.session);
                if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN) {
                        stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
                        return -EAGAIN;
                } else if (stream->dnstls_data.handshake < 0) {
                        log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream->dnstls_data.handshake));
                        if (gnutls_error_is_fatal(stream->dnstls_data.handshake))
                                return -ECONNREFUSED;
                }

                stream->dnstls_events = 0;
        }

        return 0;
}

int dnstls_stream_shutdown(DnsStream *stream, int error) {
        int r;

        assert(stream);
        assert(stream->encrypted);
        assert(stream->dnstls_data.session);

        /* Store TLS Ticket for faster successive TLS handshakes */
        if (stream->server && stream->server->dnstls_data.session_data.size == 0 && stream->dnstls_data.handshake == GNUTLS_E_SUCCESS)
                gnutls_session_get_data2(stream->dnstls_data.session, &stream->server->dnstls_data.session_data);

        if (IN_SET(error, ETIMEDOUT, 0)) {
                r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
                if (r == GNUTLS_E_AGAIN) {
                        if (!stream->dnstls_data.shutdown) {
                                stream->dnstls_data.shutdown = true;
                                dns_stream_ref(stream);
                                return -EAGAIN;
                        }
                } else if (r < 0)
                        log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
        }

        return 0;
}

ssize_t dnstls_stream_write(DnsStream *stream, const char *buf, size_t count) {
        ssize_t ss;

        assert(stream);
        assert(stream->encrypted);
        assert(stream->dnstls_data.session);
        assert(buf);

        ss = gnutls_record_send(stream->dnstls_data.session, buf, count);
        if (ss < 0)
                switch(ss) {
                case GNUTLS_E_INTERRUPTED:
                        return -EINTR;
                case GNUTLS_E_AGAIN:
                        return -EAGAIN;
                default:
                        return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
                                               "Failed to invoke gnutls_record_send: %s",
                                               gnutls_strerror(ss));
                }

        return ss;
}

ssize_t dnstls_stream_read(DnsStream *stream, void *buf, size_t count) {
        ssize_t ss;

        assert(stream);
        assert(stream->encrypted);
        assert(stream->dnstls_data.session);
        assert(buf);

        ss = gnutls_record_recv(stream->dnstls_data.session, buf, count);
        if (ss < 0)
                switch(ss) {
                case GNUTLS_E_INTERRUPTED:
                        return -EINTR;
                case GNUTLS_E_AGAIN:
                        return -EAGAIN;
                default:
                        return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
                                               "Failed to invoke gnutls_record_recv: %s",
                                               gnutls_strerror(ss));
                }

        return ss;
}

void dnstls_server_free(DnsServer *server) {
        assert(server);

        if (server->dnstls_data.session_data.data)
                gnutls_free(server->dnstls_data.session_data.data);
}

int dnstls_manager_init(Manager *manager) {
        int r;
        assert(manager);

        r = gnutls_certificate_allocate_credentials(&manager->dnstls_data.cert_cred);
        if (r < 0)
                return -ENOMEM;

        r = gnutls_certificate_set_x509_system_trust(manager->dnstls_data.cert_cred);
        if (r < 0)
                log_warning("Failed to load system trust store: %s", gnutls_strerror(r));

        return 0;
}

void dnstls_manager_free(Manager *manager) {
        assert(manager);

        if (manager->dnstls_data.cert_cred)
                gnutls_certificate_free_credentials(manager->dnstls_data.cert_cred);
}
Commit	Line	Data
6016fcb0 IT	1	/* SPDX-License-Identifier: LGPL-2.1+ */
6016fcb0 IT	2
096cbdce	3	#if !ENABLE_DNS_OVER_TLS \|\| !DNS_OVER_TLS_USE_GNUTLS
6016fcb0 IT	4	#error This source file requires DNS-over-TLS to be enabled and GnuTLS to be available.
	5	#endif
	6
6016fcb0 IT	7	#include <gnutls/socket.h>
6016fcb0 IT	8
72938b93 YW	9	#include "resolved-dns-stream.h"
	10	#include "resolved-dnstls.h"
	11
6016fcb0 IT	12	DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t, gnutls_deinit);
	13
	14	static ssize_t dnstls_stream_writev(gnutls_transport_ptr_t p, const giovec_t *iov, int iovcnt) {
	15	int r;
	16
	17	assert(p);
	18
	19	r = dns_stream_writev((DnsStream) p, (const struct iovec) iov, iovcnt, DNS_STREAM_WRITE_TLS_DATA);
	20	if (r < 0) {
	21	errno = -r;
	22	return -1;
	23	}
	24
	25	return r;
	26	}
	27
	28	int dnstls_stream_connect_tls(DnsStream stream, DnsServer server) {
	29	_cleanup_(gnutls_deinitp) gnutls_session_t gs;
	30	int r;
	31
	32	assert(stream);
	33	assert(server);
	34
	35	r = gnutls_init(&gs, GNUTLS_CLIENT \| GNUTLS_ENABLE_FALSE_START \| GNUTLS_NONBLOCK);
	36	if (r < 0)
	37	return r;
	38
	39	/* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
	40	r = gnutls_priority_set_direct(gs, "NORMAL:-VERS-ALL:+VERS-TLS1.2", NULL);
	41	if (r < 0)
	42	return r;
	43
e22c5b20	44	r = gnutls_credentials_set(gs, GNUTLS_CRD_CERTIFICATE, stream->manager->dnstls_data.cert_cred);
6016fcb0 IT	45	if (r < 0)
	46	return r;
	47
	48	if (server->dnstls_data.session_data.size > 0) {
	49	gnutls_session_set_data(gs, server->dnstls_data.session_data.data, server->dnstls_data.session_data.size);
	50
	51	// Clear old session ticket
	52	gnutls_free(server->dnstls_data.session_data.data);
	53	server->dnstls_data.session_data.data = NULL;
	54	server->dnstls_data.session_data.size = 0;
	55	}
	56
4310bfc2 IT	57	if (server->manager->dns_over_tls_mode == DNS_OVER_TLS_YES)
	58	gnutls_session_set_verify_cert(gs, NULL, 0);
	59
6016fcb0 IT	60	gnutls_handshake_set_timeout(gs, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
	61
	62	gnutls_transport_set_ptr2(gs, (gnutls_transport_ptr_t) (long) stream->fd, stream);
	63	gnutls_transport_set_vec_push_function(gs, &dnstls_stream_writev);
	64
	65	stream->encrypted = true;
	66	stream->dnstls_data.handshake = gnutls_handshake(gs);
	67	if (stream->dnstls_data.handshake < 0 && gnutls_error_is_fatal(stream->dnstls_data.handshake))
	68	return -ECONNREFUSED;
	69
	70	stream->dnstls_data.session = TAKE_PTR(gs);
	71
	72	return 0;
	73	}
	74
	75	void dnstls_stream_free(DnsStream *stream) {
	76	assert(stream);
	77	assert(stream->encrypted);
	78
	79	if (stream->dnstls_data.session)
	80	gnutls_deinit(stream->dnstls_data.session);
	81	}
	82
04c4d919	83	int dnstls_stream_on_io(DnsStream *stream, uint32_t revents) {
6016fcb0 IT	84	int r;
	85
	86	assert(stream);
	87	assert(stream->encrypted);
	88	assert(stream->dnstls_data.session);
	89
	90	if (stream->dnstls_data.shutdown) {
	91	r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
ba6aaf57 IT	92	if (r == GNUTLS_E_AGAIN) {
ba6aaf57 IT	93	stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
6016fcb0	94	return -EAGAIN;
ba6aaf57	95	} else if (r < 0)
6016fcb0 IT	96	log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
6016fcb0 IT	97
ba6aaf57	98	stream->dnstls_events = 0;
6016fcb0 IT	99	stream->dnstls_data.shutdown = false;
	100	dns_stream_unref(stream);
	101	return DNSTLS_STREAM_CLOSED;
	102	} else if (stream->dnstls_data.handshake < 0) {
	103	stream->dnstls_data.handshake = gnutls_handshake(stream->dnstls_data.session);
ba6aaf57 IT	104	if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN) {
ba6aaf57 IT	105	stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
6016fcb0	106	return -EAGAIN;
ba6aaf57	107	} else if (stream->dnstls_data.handshake < 0) {
6016fcb0 IT	108	log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream->dnstls_data.handshake));
	109	if (gnutls_error_is_fatal(stream->dnstls_data.handshake))
	110	return -ECONNREFUSED;
	111	}
ba6aaf57 IT	112
ba6aaf57 IT	113	stream->dnstls_events = 0;
6016fcb0 IT	114	}
	115
	116	return 0;
	117	}
	118
	119	int dnstls_stream_shutdown(DnsStream *stream, int error) {
	120	int r;
	121
	122	assert(stream);
	123	assert(stream->encrypted);
	124	assert(stream->dnstls_data.session);
	125
5238e957	126	/* Store TLS Ticket for faster successive TLS handshakes */
6016fcb0 IT	127	if (stream->server && stream->server->dnstls_data.session_data.size == 0 && stream->dnstls_data.handshake == GNUTLS_E_SUCCESS)
	128	gnutls_session_get_data2(stream->dnstls_data.session, &stream->server->dnstls_data.session_data);
	129
	130	if (IN_SET(error, ETIMEDOUT, 0)) {
	131	r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
	132	if (r == GNUTLS_E_AGAIN) {
	133	if (!stream->dnstls_data.shutdown) {
	134	stream->dnstls_data.shutdown = true;
	135	dns_stream_ref(stream);
	136	return -EAGAIN;
	137	}
	138	} else if (r < 0)
	139	log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
	140	}
	141
	142	return 0;
	143	}
	144
	145	ssize_t dnstls_stream_write(DnsStream stream, const char buf, size_t count) {
	146	ssize_t ss;
	147
	148	assert(stream);
	149	assert(stream->encrypted);
	150	assert(stream->dnstls_data.session);
	151	assert(buf);
	152
	153	ss = gnutls_record_send(stream->dnstls_data.session, buf, count);
	154	if (ss < 0)
	155	switch(ss) {
	156	case GNUTLS_E_INTERRUPTED:
	157	return -EINTR;
	158	case GNUTLS_E_AGAIN:
	159	return -EAGAIN;
	160	default:
baaa35ad ZJS	161	return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
	162	"Failed to invoke gnutls_record_send: %s",
	163	gnutls_strerror(ss));
6016fcb0 IT	164	}
	165
	166	return ss;
	167	}
	168
	169	ssize_t dnstls_stream_read(DnsStream stream, void buf, size_t count) {
	170	ssize_t ss;
	171
	172	assert(stream);
	173	assert(stream->encrypted);
	174	assert(stream->dnstls_data.session);
	175	assert(buf);
	176
	177	ss = gnutls_record_recv(stream->dnstls_data.session, buf, count);
	178	if (ss < 0)
	179	switch(ss) {
	180	case GNUTLS_E_INTERRUPTED:
	181	return -EINTR;
	182	case GNUTLS_E_AGAIN:
	183	return -EAGAIN;
	184	default:
baaa35ad ZJS	185	return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
	186	"Failed to invoke gnutls_record_recv: %s",
	187	gnutls_strerror(ss));
6016fcb0 IT	188	}
	189
	190	return ss;
	191	}
	192
e22c5b20	193	void dnstls_server_free(DnsServer *server) {
6016fcb0 IT	194	assert(server);
6016fcb0 IT	195
e22c5b20 IT	196	if (server->dnstls_data.session_data.data)
e22c5b20 IT	197	gnutls_free(server->dnstls_data.session_data.data);
6016fcb0 IT	198	}
6016fcb0 IT	199
71a681ae	200	int dnstls_manager_init(Manager *manager) {
e22c5b20 IT	201	int r;
e22c5b20 IT	202	assert(manager);
6016fcb0	203
71a681ae	204	r = gnutls_certificate_allocate_credentials(&manager->dnstls_data.cert_cred);
e22c5b20	205	if (r < 0)
71a681ae IT	206	return -ENOMEM;
71a681ae IT	207
4310bfc2 IT	208	r = gnutls_certificate_set_x509_system_trust(manager->dnstls_data.cert_cred);
	209	if (r < 0)
	210	log_warning("Failed to load system trust store: %s", gnutls_strerror(r));
	211
71a681ae	212	return 0;
e22c5b20	213	}
6016fcb0	214
e22c5b20 IT	215	void dnstls_manager_free(Manager *manager) {
	216	assert(manager);
	217
	218	if (manager->dnstls_data.cert_cred)
	219	gnutls_certificate_free_credentials(manager->dnstls_data.cert_cred);
6016fcb0	220	}