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 #define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2"
13 DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t
, gnutls_deinit
);
15 static ssize_t
dnstls_stream_writev(gnutls_transport_ptr_t p
, const giovec_t
*iov
, int iovcnt
) {
20 r
= dns_stream_writev((DnsStream
*) p
, (const struct iovec
*) iov
, iovcnt
, DNS_STREAM_WRITE_TLS_DATA
);
29 int dnstls_stream_connect_tls(DnsStream
*stream
, DnsServer
*server
) {
30 _cleanup_(gnutls_deinitp
) gnutls_session_t gs
;
36 r
= gnutls_init(&gs
, GNUTLS_CLIENT
| GNUTLS_ENABLE_FALSE_START
| GNUTLS_NONBLOCK
);
40 /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
41 r
= gnutls_priority_set_direct(gs
, PRIORTY_STRING
, NULL
);
45 r
= gnutls_credentials_set(gs
, GNUTLS_CRD_CERTIFICATE
, stream
->manager
->dnstls_data
.cert_cred
);
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
);
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;
58 if (server
->manager
->dns_over_tls_mode
== DNS_OVER_TLS_YES
) {
59 stream
->dnstls_data
.validation
.type
= GNUTLS_DT_IP_ADDRESS
;
60 if (server
->family
== AF_INET
) {
61 stream
->dnstls_data
.validation
.data
= (unsigned char*) &server
->address
.in
.s_addr
;
62 stream
->dnstls_data
.validation
.size
= 4;
64 stream
->dnstls_data
.validation
.data
= server
->address
.in6
.s6_addr
;
65 stream
->dnstls_data
.validation
.size
= 16;
67 gnutls_session_set_verify_cert2(gs
, &stream
->dnstls_data
.validation
, 1, 0);
70 gnutls_handshake_set_timeout(gs
, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT
);
72 gnutls_transport_set_ptr2(gs
, (gnutls_transport_ptr_t
) (long) stream
->fd
, stream
);
73 gnutls_transport_set_vec_push_function(gs
, &dnstls_stream_writev
);
75 stream
->encrypted
= true;
76 stream
->dnstls_data
.handshake
= gnutls_handshake(gs
);
77 if (stream
->dnstls_data
.handshake
< 0 && gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
80 stream
->dnstls_data
.session
= TAKE_PTR(gs
);
85 void dnstls_stream_free(DnsStream
*stream
) {
87 assert(stream
->encrypted
);
89 if (stream
->dnstls_data
.session
)
90 gnutls_deinit(stream
->dnstls_data
.session
);
93 int dnstls_stream_on_io(DnsStream
*stream
, uint32_t revents
) {
97 assert(stream
->encrypted
);
98 assert(stream
->dnstls_data
.session
);
100 if (stream
->dnstls_data
.shutdown
) {
101 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
102 if (r
== GNUTLS_E_AGAIN
) {
103 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
106 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
108 stream
->dnstls_events
= 0;
109 stream
->dnstls_data
.shutdown
= false;
110 dns_stream_unref(stream
);
111 return DNSTLS_STREAM_CLOSED
;
112 } else if (stream
->dnstls_data
.handshake
< 0) {
113 stream
->dnstls_data
.handshake
= gnutls_handshake(stream
->dnstls_data
.session
);
114 if (stream
->dnstls_data
.handshake
== GNUTLS_E_AGAIN
) {
115 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
117 } else if (stream
->dnstls_data
.handshake
< 0) {
118 log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream
->dnstls_data
.handshake
));
119 if (gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
120 return -ECONNREFUSED
;
123 stream
->dnstls_events
= 0;
129 int dnstls_stream_shutdown(DnsStream
*stream
, int error
) {
133 assert(stream
->encrypted
);
134 assert(stream
->dnstls_data
.session
);
136 /* Store TLS Ticket for faster successive TLS handshakes */
137 if (stream
->server
&& stream
->server
->dnstls_data
.session_data
.size
== 0 && stream
->dnstls_data
.handshake
== GNUTLS_E_SUCCESS
)
138 gnutls_session_get_data2(stream
->dnstls_data
.session
, &stream
->server
->dnstls_data
.session_data
);
140 if (IN_SET(error
, ETIMEDOUT
, 0)) {
141 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
142 if (r
== GNUTLS_E_AGAIN
) {
143 if (!stream
->dnstls_data
.shutdown
) {
144 stream
->dnstls_data
.shutdown
= true;
145 dns_stream_ref(stream
);
149 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
155 ssize_t
dnstls_stream_write(DnsStream
*stream
, const char *buf
, size_t count
) {
159 assert(stream
->encrypted
);
160 assert(stream
->dnstls_data
.session
);
163 ss
= gnutls_record_send(stream
->dnstls_data
.session
, buf
, count
);
166 case GNUTLS_E_INTERRUPTED
:
171 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
172 "Failed to invoke gnutls_record_send: %s",
173 gnutls_strerror(ss
));
179 ssize_t
dnstls_stream_read(DnsStream
*stream
, void *buf
, size_t count
) {
183 assert(stream
->encrypted
);
184 assert(stream
->dnstls_data
.session
);
187 ss
= gnutls_record_recv(stream
->dnstls_data
.session
, buf
, count
);
190 case GNUTLS_E_INTERRUPTED
:
195 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
196 "Failed to invoke gnutls_record_recv: %s",
197 gnutls_strerror(ss
));
203 void dnstls_server_free(DnsServer
*server
) {
206 if (server
->dnstls_data
.session_data
.data
)
207 gnutls_free(server
->dnstls_data
.session_data
.data
);
210 int dnstls_manager_init(Manager
*manager
) {
214 r
= gnutls_certificate_allocate_credentials(&manager
->dnstls_data
.cert_cred
);
218 r
= gnutls_certificate_set_x509_system_trust(manager
->dnstls_data
.cert_cred
);
220 log_warning("Failed to load system trust store: %s", gnutls_strerror(r
));
225 void dnstls_manager_free(Manager
*manager
) {
228 if (manager
->dnstls_data
.cert_cred
)
229 gnutls_certificate_free_credentials(manager
->dnstls_data
.cert_cred
);