1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 #if !ENABLE_DNS_OVER_TLS || !DNS_OVER_TLS_USE_GNUTLS
4 #error This source file requires DNS-over-TLS to be enabled and GnuTLS to be available.
7 #include <gnutls/socket.h>
9 #include "resolved-dns-stream.h"
10 #include "resolved-dnstls.h"
12 #if GNUTLS_VERSION_NUMBER >= 0x030600
13 #define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2"
15 #define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.2"
17 DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t
, gnutls_deinit
);
19 static ssize_t
dnstls_stream_writev(gnutls_transport_ptr_t p
, const giovec_t
*iov
, int iovcnt
) {
24 r
= dns_stream_writev((DnsStream
*) p
, (const struct iovec
*) iov
, iovcnt
, DNS_STREAM_WRITE_TLS_DATA
);
33 int dnstls_stream_connect_tls(DnsStream
*stream
, DnsServer
*server
) {
34 _cleanup_(gnutls_deinitp
) gnutls_session_t gs
;
40 r
= gnutls_init(&gs
, GNUTLS_CLIENT
| GNUTLS_ENABLE_FALSE_START
| GNUTLS_NONBLOCK
);
44 /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
45 r
= gnutls_priority_set_direct(gs
, PRIORTY_STRING
, NULL
);
49 r
= gnutls_credentials_set(gs
, GNUTLS_CRD_CERTIFICATE
, stream
->manager
->dnstls_data
.cert_cred
);
53 if (server
->dnstls_data
.session_data
.size
> 0) {
54 gnutls_session_set_data(gs
, server
->dnstls_data
.session_data
.data
, server
->dnstls_data
.session_data
.size
);
56 // Clear old session ticket
57 gnutls_free(server
->dnstls_data
.session_data
.data
);
58 server
->dnstls_data
.session_data
.data
= NULL
;
59 server
->dnstls_data
.session_data
.size
= 0;
62 if (server
->manager
->dns_over_tls_mode
== DNS_OVER_TLS_YES
)
63 gnutls_session_set_verify_cert(gs
, NULL
, 0);
65 gnutls_handshake_set_timeout(gs
, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT
);
67 gnutls_transport_set_ptr2(gs
, (gnutls_transport_ptr_t
) (long) stream
->fd
, stream
);
68 gnutls_transport_set_vec_push_function(gs
, &dnstls_stream_writev
);
70 stream
->encrypted
= true;
71 stream
->dnstls_data
.handshake
= gnutls_handshake(gs
);
72 if (stream
->dnstls_data
.handshake
< 0 && gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
75 stream
->dnstls_data
.session
= TAKE_PTR(gs
);
80 void dnstls_stream_free(DnsStream
*stream
) {
82 assert(stream
->encrypted
);
84 if (stream
->dnstls_data
.session
)
85 gnutls_deinit(stream
->dnstls_data
.session
);
88 int dnstls_stream_on_io(DnsStream
*stream
, uint32_t revents
) {
92 assert(stream
->encrypted
);
93 assert(stream
->dnstls_data
.session
);
95 if (stream
->dnstls_data
.shutdown
) {
96 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
97 if (r
== GNUTLS_E_AGAIN
) {
98 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
101 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
103 stream
->dnstls_events
= 0;
104 stream
->dnstls_data
.shutdown
= false;
105 dns_stream_unref(stream
);
106 return DNSTLS_STREAM_CLOSED
;
107 } else if (stream
->dnstls_data
.handshake
< 0) {
108 stream
->dnstls_data
.handshake
= gnutls_handshake(stream
->dnstls_data
.session
);
109 if (stream
->dnstls_data
.handshake
== GNUTLS_E_AGAIN
) {
110 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
112 } else if (stream
->dnstls_data
.handshake
< 0) {
113 log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream
->dnstls_data
.handshake
));
114 if (gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
115 return -ECONNREFUSED
;
118 stream
->dnstls_events
= 0;
124 int dnstls_stream_shutdown(DnsStream
*stream
, int error
) {
128 assert(stream
->encrypted
);
129 assert(stream
->dnstls_data
.session
);
131 /* Store TLS Ticket for faster successive TLS handshakes */
132 if (stream
->server
&& stream
->server
->dnstls_data
.session_data
.size
== 0 && stream
->dnstls_data
.handshake
== GNUTLS_E_SUCCESS
)
133 gnutls_session_get_data2(stream
->dnstls_data
.session
, &stream
->server
->dnstls_data
.session_data
);
135 if (IN_SET(error
, ETIMEDOUT
, 0)) {
136 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
137 if (r
== GNUTLS_E_AGAIN
) {
138 if (!stream
->dnstls_data
.shutdown
) {
139 stream
->dnstls_data
.shutdown
= true;
140 dns_stream_ref(stream
);
144 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
150 ssize_t
dnstls_stream_write(DnsStream
*stream
, const char *buf
, size_t count
) {
154 assert(stream
->encrypted
);
155 assert(stream
->dnstls_data
.session
);
158 ss
= gnutls_record_send(stream
->dnstls_data
.session
, buf
, count
);
161 case GNUTLS_E_INTERRUPTED
:
166 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
167 "Failed to invoke gnutls_record_send: %s",
168 gnutls_strerror(ss
));
174 ssize_t
dnstls_stream_read(DnsStream
*stream
, void *buf
, size_t count
) {
178 assert(stream
->encrypted
);
179 assert(stream
->dnstls_data
.session
);
182 ss
= gnutls_record_recv(stream
->dnstls_data
.session
, buf
, count
);
185 case GNUTLS_E_INTERRUPTED
:
190 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
191 "Failed to invoke gnutls_record_recv: %s",
192 gnutls_strerror(ss
));
198 void dnstls_server_free(DnsServer
*server
) {
201 if (server
->dnstls_data
.session_data
.data
)
202 gnutls_free(server
->dnstls_data
.session_data
.data
);
205 int dnstls_manager_init(Manager
*manager
) {
209 r
= gnutls_certificate_allocate_credentials(&manager
->dnstls_data
.cert_cred
);
213 r
= gnutls_certificate_set_x509_system_trust(manager
->dnstls_data
.cert_cred
);
215 log_warning("Failed to load system trust store: %s", gnutls_strerror(r
));
220 void dnstls_manager_free(Manager
*manager
) {
223 if (manager
->dnstls_data
.cert_cred
)
224 gnutls_certificate_free_credentials(manager
->dnstls_data
.cert_cred
);