1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
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"
11 #include "resolved-manager.h"
13 #define TLS_PROTOCOL_PRIORITY "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2"
14 DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t
, gnutls_deinit
);
16 static ssize_t
dnstls_stream_writev(gnutls_transport_ptr_t p
, const giovec_t
*iov
, int iovcnt
) {
21 r
= dns_stream_writev((DnsStream
*) p
, (const struct iovec
*) iov
, iovcnt
, DNS_STREAM_WRITE_TLS_DATA
);
30 int dnstls_stream_connect_tls(DnsStream
*stream
, DnsServer
*server
) {
31 _cleanup_(gnutls_deinitp
) gnutls_session_t gs
= NULL
;
37 r
= gnutls_init(&gs
, GNUTLS_CLIENT
| GNUTLS_ENABLE_FALSE_START
| GNUTLS_NONBLOCK
);
41 /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
42 r
= gnutls_priority_set_direct(gs
, TLS_PROTOCOL_PRIORITY
, NULL
);
46 r
= gnutls_credentials_set(gs
, GNUTLS_CRD_CERTIFICATE
, stream
->manager
->dnstls_data
.cert_cred
);
50 if (server
->dnstls_data
.session_data
.size
> 0) {
51 gnutls_session_set_data(gs
, server
->dnstls_data
.session_data
.data
, server
->dnstls_data
.session_data
.size
);
53 // Clear old session ticket
54 gnutls_free(server
->dnstls_data
.session_data
.data
);
55 server
->dnstls_data
.session_data
.data
= NULL
;
56 server
->dnstls_data
.session_data
.size
= 0;
59 if (server
->manager
->dns_over_tls_mode
== DNS_OVER_TLS_YES
) {
60 if (server
->server_name
)
61 gnutls_session_set_verify_cert(gs
, server
->server_name
, 0);
63 stream
->dnstls_data
.validation
.type
= GNUTLS_DT_IP_ADDRESS
;
64 if (server
->family
== AF_INET
) {
65 stream
->dnstls_data
.validation
.data
= (unsigned char*) &server
->address
.in
.s_addr
;
66 stream
->dnstls_data
.validation
.size
= 4;
68 stream
->dnstls_data
.validation
.data
= server
->address
.in6
.s6_addr
;
69 stream
->dnstls_data
.validation
.size
= 16;
71 gnutls_session_set_verify_cert2(gs
, &stream
->dnstls_data
.validation
, 1, 0);
75 if (server
->server_name
) {
76 r
= gnutls_server_name_set(gs
, GNUTLS_NAME_DNS
, server
->server_name
, strlen(server
->server_name
));
78 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL
), "Failed to set server name: %s", gnutls_strerror(r
));
81 gnutls_handshake_set_timeout(gs
, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT
);
83 gnutls_transport_set_ptr2(gs
, (gnutls_transport_ptr_t
) (long) stream
->fd
, stream
);
84 gnutls_transport_set_vec_push_function(gs
, &dnstls_stream_writev
);
86 stream
->encrypted
= true;
87 stream
->dnstls_data
.handshake
= gnutls_handshake(gs
);
88 if (stream
->dnstls_data
.handshake
< 0 && gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
91 stream
->dnstls_data
.session
= TAKE_PTR(gs
);
96 void dnstls_stream_free(DnsStream
*stream
) {
98 assert(stream
->encrypted
);
100 if (stream
->dnstls_data
.session
)
101 gnutls_deinit(stream
->dnstls_data
.session
);
104 int dnstls_stream_on_io(DnsStream
*stream
, uint32_t revents
) {
108 assert(stream
->encrypted
);
109 assert(stream
->dnstls_data
.session
);
111 if (stream
->dnstls_data
.shutdown
) {
112 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
113 if (r
== GNUTLS_E_AGAIN
) {
114 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
117 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
119 stream
->dnstls_events
= 0;
120 stream
->dnstls_data
.shutdown
= false;
121 dns_stream_unref(stream
);
122 return DNSTLS_STREAM_CLOSED
;
123 } else if (stream
->dnstls_data
.handshake
< 0) {
124 stream
->dnstls_data
.handshake
= gnutls_handshake(stream
->dnstls_data
.session
);
125 if (stream
->dnstls_data
.handshake
== GNUTLS_E_AGAIN
) {
126 stream
->dnstls_events
= gnutls_record_get_direction(stream
->dnstls_data
.session
) == 1 ? EPOLLOUT
: EPOLLIN
;
128 } else if (stream
->dnstls_data
.handshake
< 0) {
129 log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream
->dnstls_data
.handshake
));
130 if (gnutls_error_is_fatal(stream
->dnstls_data
.handshake
))
131 return -ECONNREFUSED
;
134 stream
->dnstls_events
= 0;
140 int dnstls_stream_shutdown(DnsStream
*stream
, int error
) {
144 assert(stream
->encrypted
);
145 assert(stream
->dnstls_data
.session
);
147 /* Store TLS Ticket for faster successive TLS handshakes */
148 if (stream
->server
&& stream
->server
->dnstls_data
.session_data
.size
== 0 && stream
->dnstls_data
.handshake
== GNUTLS_E_SUCCESS
)
149 gnutls_session_get_data2(stream
->dnstls_data
.session
, &stream
->server
->dnstls_data
.session_data
);
151 if (IN_SET(error
, ETIMEDOUT
, 0)) {
152 r
= gnutls_bye(stream
->dnstls_data
.session
, GNUTLS_SHUT_RDWR
);
153 if (r
== GNUTLS_E_AGAIN
) {
154 if (!stream
->dnstls_data
.shutdown
) {
155 stream
->dnstls_data
.shutdown
= true;
156 dns_stream_ref(stream
);
160 log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r
));
166 ssize_t
dnstls_stream_write(DnsStream
*stream
, const char *buf
, size_t count
) {
170 assert(stream
->encrypted
);
171 assert(stream
->dnstls_data
.session
);
174 ss
= gnutls_record_send(stream
->dnstls_data
.session
, buf
, count
);
177 case GNUTLS_E_INTERRUPTED
:
182 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
183 "Failed to invoke gnutls_record_send: %s",
184 gnutls_strerror(ss
));
190 ssize_t
dnstls_stream_read(DnsStream
*stream
, void *buf
, size_t count
) {
194 assert(stream
->encrypted
);
195 assert(stream
->dnstls_data
.session
);
198 ss
= gnutls_record_recv(stream
->dnstls_data
.session
, buf
, count
);
201 case GNUTLS_E_INTERRUPTED
:
206 return log_debug_errno(SYNTHETIC_ERRNO(EPIPE
),
207 "Failed to invoke gnutls_record_recv: %s",
208 gnutls_strerror(ss
));
214 void dnstls_server_free(DnsServer
*server
) {
217 if (server
->dnstls_data
.session_data
.data
)
218 gnutls_free(server
->dnstls_data
.session_data
.data
);
221 int dnstls_manager_init(Manager
*manager
) {
225 r
= gnutls_certificate_allocate_credentials(&manager
->dnstls_data
.cert_cred
);
229 r
= gnutls_certificate_set_x509_system_trust(manager
->dnstls_data
.cert_cred
);
231 log_warning("Failed to load system trust store: %s", gnutls_strerror(r
));
236 void dnstls_manager_free(Manager
*manager
) {
239 if (manager
->dnstls_data
.cert_cred
)
240 gnutls_certificate_free_credentials(manager
->dnstls_data
.cert_cred
);