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6016fcb0 IT |
1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
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> |
8 | ||
72938b93 YW |
9 | #include "resolved-dns-stream.h" |
10 | #include "resolved-dnstls.h" | |
11 | ||
9c0624dc | 12 | #if GNUTLS_VERSION_NUMBER >= 0x030600 |
68805580 | 13 | #define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2" |
9c0624dc IT |
14 | #else |
15 | #define PRIORTY_STRING "NORMAL:-VERS-ALL:+VERS-TLS1.2" | |
16 | #endif | |
6016fcb0 IT |
17 | DEFINE_TRIVIAL_CLEANUP_FUNC(gnutls_session_t, gnutls_deinit); |
18 | ||
19 | static ssize_t dnstls_stream_writev(gnutls_transport_ptr_t p, const giovec_t *iov, int iovcnt) { | |
20 | int r; | |
21 | ||
22 | assert(p); | |
23 | ||
24 | r = dns_stream_writev((DnsStream*) p, (const struct iovec*) iov, iovcnt, DNS_STREAM_WRITE_TLS_DATA); | |
25 | if (r < 0) { | |
26 | errno = -r; | |
27 | return -1; | |
28 | } | |
29 | ||
30 | return r; | |
31 | } | |
32 | ||
33 | int dnstls_stream_connect_tls(DnsStream *stream, DnsServer *server) { | |
34 | _cleanup_(gnutls_deinitp) gnutls_session_t gs; | |
35 | int r; | |
36 | ||
37 | assert(stream); | |
38 | assert(server); | |
39 | ||
40 | r = gnutls_init(&gs, GNUTLS_CLIENT | GNUTLS_ENABLE_FALSE_START | GNUTLS_NONBLOCK); | |
41 | if (r < 0) | |
42 | return r; | |
43 | ||
44 | /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */ | |
9c0624dc | 45 | r = gnutls_priority_set_direct(gs, PRIORTY_STRING, NULL); |
6016fcb0 IT |
46 | if (r < 0) |
47 | return r; | |
48 | ||
e22c5b20 | 49 | r = gnutls_credentials_set(gs, GNUTLS_CRD_CERTIFICATE, stream->manager->dnstls_data.cert_cred); |
6016fcb0 IT |
50 | if (r < 0) |
51 | return r; | |
52 | ||
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); | |
55 | ||
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; | |
60 | } | |
61 | ||
4310bfc2 IT |
62 | if (server->manager->dns_over_tls_mode == DNS_OVER_TLS_YES) |
63 | gnutls_session_set_verify_cert(gs, NULL, 0); | |
64 | ||
6016fcb0 IT |
65 | gnutls_handshake_set_timeout(gs, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT); |
66 | ||
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); | |
69 | ||
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)) | |
73 | return -ECONNREFUSED; | |
74 | ||
75 | stream->dnstls_data.session = TAKE_PTR(gs); | |
76 | ||
77 | return 0; | |
78 | } | |
79 | ||
80 | void dnstls_stream_free(DnsStream *stream) { | |
81 | assert(stream); | |
82 | assert(stream->encrypted); | |
83 | ||
84 | if (stream->dnstls_data.session) | |
85 | gnutls_deinit(stream->dnstls_data.session); | |
86 | } | |
87 | ||
04c4d919 | 88 | int dnstls_stream_on_io(DnsStream *stream, uint32_t revents) { |
6016fcb0 IT |
89 | int r; |
90 | ||
91 | assert(stream); | |
92 | assert(stream->encrypted); | |
93 | assert(stream->dnstls_data.session); | |
94 | ||
95 | if (stream->dnstls_data.shutdown) { | |
96 | r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR); | |
ba6aaf57 IT |
97 | if (r == GNUTLS_E_AGAIN) { |
98 | stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN; | |
6016fcb0 | 99 | return -EAGAIN; |
ba6aaf57 | 100 | } else if (r < 0) |
6016fcb0 IT |
101 | log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r)); |
102 | ||
ba6aaf57 | 103 | stream->dnstls_events = 0; |
6016fcb0 IT |
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); | |
ba6aaf57 IT |
109 | if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN) { |
110 | stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN; | |
6016fcb0 | 111 | return -EAGAIN; |
ba6aaf57 | 112 | } else if (stream->dnstls_data.handshake < 0) { |
6016fcb0 IT |
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; | |
116 | } | |
ba6aaf57 IT |
117 | |
118 | stream->dnstls_events = 0; | |
6016fcb0 IT |
119 | } |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | int dnstls_stream_shutdown(DnsStream *stream, int error) { | |
125 | int r; | |
126 | ||
127 | assert(stream); | |
128 | assert(stream->encrypted); | |
129 | assert(stream->dnstls_data.session); | |
130 | ||
5238e957 | 131 | /* Store TLS Ticket for faster successive TLS handshakes */ |
6016fcb0 IT |
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); | |
134 | ||
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); | |
141 | return -EAGAIN; | |
142 | } | |
143 | } else if (r < 0) | |
144 | log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r)); | |
145 | } | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | ssize_t dnstls_stream_write(DnsStream *stream, const char *buf, size_t count) { | |
151 | ssize_t ss; | |
152 | ||
153 | assert(stream); | |
154 | assert(stream->encrypted); | |
155 | assert(stream->dnstls_data.session); | |
156 | assert(buf); | |
157 | ||
158 | ss = gnutls_record_send(stream->dnstls_data.session, buf, count); | |
159 | if (ss < 0) | |
160 | switch(ss) { | |
161 | case GNUTLS_E_INTERRUPTED: | |
162 | return -EINTR; | |
163 | case GNUTLS_E_AGAIN: | |
164 | return -EAGAIN; | |
165 | default: | |
baaa35ad ZJS |
166 | return log_debug_errno(SYNTHETIC_ERRNO(EPIPE), |
167 | "Failed to invoke gnutls_record_send: %s", | |
168 | gnutls_strerror(ss)); | |
6016fcb0 IT |
169 | } |
170 | ||
171 | return ss; | |
172 | } | |
173 | ||
174 | ssize_t dnstls_stream_read(DnsStream *stream, void *buf, size_t count) { | |
175 | ssize_t ss; | |
176 | ||
177 | assert(stream); | |
178 | assert(stream->encrypted); | |
179 | assert(stream->dnstls_data.session); | |
180 | assert(buf); | |
181 | ||
182 | ss = gnutls_record_recv(stream->dnstls_data.session, buf, count); | |
183 | if (ss < 0) | |
184 | switch(ss) { | |
185 | case GNUTLS_E_INTERRUPTED: | |
186 | return -EINTR; | |
187 | case GNUTLS_E_AGAIN: | |
188 | return -EAGAIN; | |
189 | default: | |
baaa35ad ZJS |
190 | return log_debug_errno(SYNTHETIC_ERRNO(EPIPE), |
191 | "Failed to invoke gnutls_record_recv: %s", | |
192 | gnutls_strerror(ss)); | |
6016fcb0 IT |
193 | } |
194 | ||
195 | return ss; | |
196 | } | |
197 | ||
e22c5b20 | 198 | void dnstls_server_free(DnsServer *server) { |
6016fcb0 IT |
199 | assert(server); |
200 | ||
e22c5b20 IT |
201 | if (server->dnstls_data.session_data.data) |
202 | gnutls_free(server->dnstls_data.session_data.data); | |
6016fcb0 IT |
203 | } |
204 | ||
71a681ae | 205 | int dnstls_manager_init(Manager *manager) { |
e22c5b20 IT |
206 | int r; |
207 | assert(manager); | |
6016fcb0 | 208 | |
71a681ae | 209 | r = gnutls_certificate_allocate_credentials(&manager->dnstls_data.cert_cred); |
e22c5b20 | 210 | if (r < 0) |
71a681ae IT |
211 | return -ENOMEM; |
212 | ||
4310bfc2 IT |
213 | r = gnutls_certificate_set_x509_system_trust(manager->dnstls_data.cert_cred); |
214 | if (r < 0) | |
215 | log_warning("Failed to load system trust store: %s", gnutls_strerror(r)); | |
216 | ||
71a681ae | 217 | return 0; |
e22c5b20 | 218 | } |
6016fcb0 | 219 | |
e22c5b20 IT |
220 | void dnstls_manager_free(Manager *manager) { |
221 | assert(manager); | |
222 | ||
223 | if (manager->dnstls_data.cert_cred) | |
224 | gnutls_certificate_free_credentials(manager->dnstls_data.cert_cred); | |
6016fcb0 | 225 | } |