[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 PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2"
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, PRIORTY_STRING, 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
68805580	12	#define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2"
6016fcb0 IT	13	DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t, gnutls_deinit);
	14
	15	static ssize_t dnstls_stream_writev(gnutls_transport_ptr_t p, const giovec_t *iov, int iovcnt) {
	16	int r;
	17
	18	assert(p);
	19
	20	r = dns_stream_writev((DnsStream) p, (const struct iovec) iov, iovcnt, DNS_STREAM_WRITE_TLS_DATA);
	21	if (r < 0) {
	22	errno = -r;
	23	return -1;
	24	}
	25
	26	return r;
	27	}
	28
	29	int dnstls_stream_connect_tls(DnsStream stream, DnsServer server) {
	30	_cleanup_(gnutls_deinitp) gnutls_session_t gs;
	31	int r;
	32
	33	assert(stream);
	34	assert(server);
	35
	36	r = gnutls_init(&gs, GNUTLS_CLIENT \| GNUTLS_ENABLE_FALSE_START \| GNUTLS_NONBLOCK);
	37	if (r < 0)
	38	return r;
	39
	40	/* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
9c0624dc	41	r = gnutls_priority_set_direct(gs, PRIORTY_STRING, NULL);
6016fcb0 IT	42	if (r < 0)
	43	return r;
	44
e22c5b20	45	r = gnutls_credentials_set(gs, GNUTLS_CRD_CERTIFICATE, stream->manager->dnstls_data.cert_cred);
6016fcb0 IT	46	if (r < 0)
	47	return r;
	48
	49	if (server->dnstls_data.session_data.size > 0) {
	50	gnutls_session_set_data(gs, server->dnstls_data.session_data.data, server->dnstls_data.session_data.size);
	51
	52	// Clear old session ticket
	53	gnutls_free(server->dnstls_data.session_data.data);
	54	server->dnstls_data.session_data.data = NULL;
	55	server->dnstls_data.session_data.size = 0;
	56	}
	57
4310bfc2 IT	58	if (server->manager->dns_over_tls_mode == DNS_OVER_TLS_YES)
	59	gnutls_session_set_verify_cert(gs, NULL, 0);
	60
6016fcb0 IT	61	gnutls_handshake_set_timeout(gs, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
	62
	63	gnutls_transport_set_ptr2(gs, (gnutls_transport_ptr_t) (long) stream->fd, stream);
	64	gnutls_transport_set_vec_push_function(gs, &dnstls_stream_writev);
	65
	66	stream->encrypted = true;
	67	stream->dnstls_data.handshake = gnutls_handshake(gs);
	68	if (stream->dnstls_data.handshake < 0 && gnutls_error_is_fatal(stream->dnstls_data.handshake))
	69	return -ECONNREFUSED;
	70
	71	stream->dnstls_data.session = TAKE_PTR(gs);
	72
	73	return 0;
	74	}
	75
	76	void dnstls_stream_free(DnsStream *stream) {
	77	assert(stream);
	78	assert(stream->encrypted);
	79
	80	if (stream->dnstls_data.session)
	81	gnutls_deinit(stream->dnstls_data.session);
	82	}
	83
04c4d919	84	int dnstls_stream_on_io(DnsStream *stream, uint32_t revents) {
6016fcb0 IT	85	int r;
	86
	87	assert(stream);
	88	assert(stream->encrypted);
	89	assert(stream->dnstls_data.session);
	90
	91	if (stream->dnstls_data.shutdown) {
	92	r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
ba6aaf57 IT	93	if (r == GNUTLS_E_AGAIN) {
ba6aaf57 IT	94	stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
6016fcb0	95	return -EAGAIN;
ba6aaf57	96	} else if (r < 0)
6016fcb0 IT	97	log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
6016fcb0 IT	98
ba6aaf57	99	stream->dnstls_events = 0;
6016fcb0 IT	100	stream->dnstls_data.shutdown = false;
	101	dns_stream_unref(stream);
	102	return DNSTLS_STREAM_CLOSED;
	103	} else if (stream->dnstls_data.handshake < 0) {
	104	stream->dnstls_data.handshake = gnutls_handshake(stream->dnstls_data.session);
ba6aaf57 IT	105	if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN) {
ba6aaf57 IT	106	stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
6016fcb0	107	return -EAGAIN;
ba6aaf57	108	} else if (stream->dnstls_data.handshake < 0) {
6016fcb0 IT	109	log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream->dnstls_data.handshake));
	110	if (gnutls_error_is_fatal(stream->dnstls_data.handshake))
	111	return -ECONNREFUSED;
	112	}
ba6aaf57 IT	113
ba6aaf57 IT	114	stream->dnstls_events = 0;
6016fcb0 IT	115	}
	116
	117	return 0;
	118	}
	119
	120	int dnstls_stream_shutdown(DnsStream *stream, int error) {
	121	int r;
	122
	123	assert(stream);
	124	assert(stream->encrypted);
	125	assert(stream->dnstls_data.session);
	126
5238e957	127	/* Store TLS Ticket for faster successive TLS handshakes */
6016fcb0 IT	128	if (stream->server && stream->server->dnstls_data.session_data.size == 0 && stream->dnstls_data.handshake == GNUTLS_E_SUCCESS)
	129	gnutls_session_get_data2(stream->dnstls_data.session, &stream->server->dnstls_data.session_data);
	130
	131	if (IN_SET(error, ETIMEDOUT, 0)) {
	132	r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
	133	if (r == GNUTLS_E_AGAIN) {
	134	if (!stream->dnstls_data.shutdown) {
	135	stream->dnstls_data.shutdown = true;
	136	dns_stream_ref(stream);
	137	return -EAGAIN;
	138	}
	139	} else if (r < 0)
	140	log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
	141	}
	142
	143	return 0;
	144	}
	145
	146	ssize_t dnstls_stream_write(DnsStream stream, const char buf, size_t count) {
	147	ssize_t ss;
	148
	149	assert(stream);
	150	assert(stream->encrypted);
	151	assert(stream->dnstls_data.session);
	152	assert(buf);
	153
	154	ss = gnutls_record_send(stream->dnstls_data.session, buf, count);
	155	if (ss < 0)
	156	switch(ss) {
	157	case GNUTLS_E_INTERRUPTED:
	158	return -EINTR;
	159	case GNUTLS_E_AGAIN:
	160	return -EAGAIN;
	161	default:
baaa35ad ZJS	162	return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
	163	"Failed to invoke gnutls_record_send: %s",
	164	gnutls_strerror(ss));
6016fcb0 IT	165	}
	166
	167	return ss;
	168	}
	169
	170	ssize_t dnstls_stream_read(DnsStream stream, void buf, size_t count) {
	171	ssize_t ss;
	172
	173	assert(stream);
	174	assert(stream->encrypted);
	175	assert(stream->dnstls_data.session);
	176	assert(buf);
	177
	178	ss = gnutls_record_recv(stream->dnstls_data.session, buf, count);
	179	if (ss < 0)
	180	switch(ss) {
	181	case GNUTLS_E_INTERRUPTED:
	182	return -EINTR;
	183	case GNUTLS_E_AGAIN:
	184	return -EAGAIN;
	185	default:
baaa35ad ZJS	186	return log_debug_errno(SYNTHETIC_ERRNO(EPIPE),
	187	"Failed to invoke gnutls_record_recv: %s",
	188	gnutls_strerror(ss));
6016fcb0 IT	189	}
	190
	191	return ss;
	192	}
	193
e22c5b20	194	void dnstls_server_free(DnsServer *server) {
6016fcb0 IT	195	assert(server);
6016fcb0 IT	196
e22c5b20 IT	197	if (server->dnstls_data.session_data.data)
e22c5b20 IT	198	gnutls_free(server->dnstls_data.session_data.data);
6016fcb0 IT	199	}
6016fcb0 IT	200
71a681ae	201	int dnstls_manager_init(Manager *manager) {
e22c5b20 IT	202	int r;
e22c5b20 IT	203	assert(manager);
6016fcb0	204
71a681ae	205	r = gnutls_certificate_allocate_credentials(&manager->dnstls_data.cert_cred);
e22c5b20	206	if (r < 0)
71a681ae IT	207	return -ENOMEM;
71a681ae IT	208
4310bfc2 IT	209	r = gnutls_certificate_set_x509_system_trust(manager->dnstls_data.cert_cred);
	210	if (r < 0)
	211	log_warning("Failed to load system trust store: %s", gnutls_strerror(r));
	212
71a681ae	213	return 0;
e22c5b20	214	}
6016fcb0	215
e22c5b20 IT	216	void dnstls_manager_free(Manager *manager) {
	217	assert(manager);
	218
	219	if (manager->dnstls_data.cert_cred)
	220	gnutls_certificate_free_credentials(manager->dnstls_data.cert_cred);
6016fcb0	221	}