1 /* Copyright (c) 2018, Google Inc.
2  *
3  * Permission to use, copy, modify, and/or distribute this software for any
4  * purpose with or without fee is hereby granted, provided that the above
5  * copyright notice and this permission notice appear in all copies.
6  *
7  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14 
15 #include <openssl/ssl.h>
16 
17 #include <openssl/bytestring.h>
18 
19 #include "internal.h"
20 
21 
22 namespace bssl {
23 
24 constexpr int kHandoffVersion = 0;
25 constexpr int kHandbackVersion = 0;
26 
SSL_serialize_handoff(const SSL * ssl,CBB * out)27 bool SSL_serialize_handoff(const SSL *ssl, CBB *out) {
28   const SSL3_STATE *const s3 = ssl->s3;
29   if (!ssl->server ||
30       s3->hs == nullptr ||
31       s3->rwstate != SSL_HANDOFF) {
32     return false;
33   }
34 
35   CBB seq;
36   Span<const uint8_t> transcript = s3->hs->transcript.buffer();
37   if (!CBB_add_asn1(out, &seq, CBS_ASN1_SEQUENCE) ||
38       !CBB_add_asn1_uint64(&seq, kHandoffVersion) ||
39       !CBB_add_asn1_octet_string(&seq, transcript.data(), transcript.size()) ||
40       !CBB_add_asn1_octet_string(&seq,
41                                  reinterpret_cast<uint8_t *>(s3->hs_buf->data),
42                                  s3->hs_buf->length) ||
43       !CBB_flush(out)) {
44     return false;
45   }
46 
47   return true;
48 }
49 
SSL_decline_handoff(SSL * ssl)50 bool SSL_decline_handoff(SSL *ssl) {
51   const SSL3_STATE *const s3 = ssl->s3;
52   if (!ssl->server ||
53       s3->hs == nullptr ||
54       s3->rwstate != SSL_HANDOFF) {
55     return false;
56   }
57 
58   ssl->handoff = false;
59   return true;
60 }
61 
SSL_apply_handoff(SSL * ssl,Span<const uint8_t> handoff)62 bool SSL_apply_handoff(SSL *ssl, Span<const uint8_t> handoff) {
63   if (ssl->method->is_dtls) {
64     return false;
65   }
66 
67   CBS seq, handoff_cbs(handoff);
68   uint64_t handoff_version;
69   if (!CBS_get_asn1(&handoff_cbs, &seq, CBS_ASN1_SEQUENCE) ||
70       !CBS_get_asn1_uint64(&seq, &handoff_version) ||
71       handoff_version != kHandoffVersion) {
72     return false;
73   }
74 
75   CBS transcript, hs_buf;
76   if (!CBS_get_asn1(&seq, &transcript, CBS_ASN1_OCTETSTRING) ||
77       !CBS_get_asn1(&seq, &hs_buf, CBS_ASN1_OCTETSTRING)) {
78     return false;
79   }
80 
81   SSL_set_accept_state(ssl);
82 
83   SSL3_STATE *const s3 = ssl->s3;
84   s3->v2_hello_done = true;
85   s3->has_message = true;
86 
87   s3->hs_buf.reset(BUF_MEM_new());
88   if (!s3->hs_buf ||
89       !BUF_MEM_append(s3->hs_buf.get(), CBS_data(&hs_buf), CBS_len(&hs_buf))) {
90     return false;
91   }
92 
93   if (CBS_len(&transcript) != 0) {
94     s3->hs->transcript.Update(transcript);
95     s3->is_v2_hello = true;
96     ssl_do_msg_callback(ssl, 0 /* read */, 0 /* V2ClientHello */, transcript);
97   }
98 
99   return true;
100 }
101 
SSL_serialize_handback(const SSL * ssl,CBB * out)102 bool SSL_serialize_handback(const SSL *ssl, CBB *out) {
103   if (!ssl->server ||
104       !ssl->s3->initial_handshake_complete ||
105       ssl->method->is_dtls ||
106       ssl->version < TLS1_VERSION) {
107     return false;
108   }
109 
110   const SSL3_STATE *const s3 = ssl->s3;
111   size_t hostname_len = 0;
112   if (s3->hostname) {
113     hostname_len = strlen(s3->hostname.get());
114   }
115 
116   size_t iv_len = 0;
117   const uint8_t *read_iv = nullptr, *write_iv = nullptr;
118   if (ssl->version == TLS1_VERSION &&
119       SSL_CIPHER_is_block_cipher(s3->aead_read_ctx->cipher()) &&
120       (!s3->aead_read_ctx->GetIV(&read_iv, &iv_len) ||
121        !s3->aead_write_ctx->GetIV(&write_iv, &iv_len))) {
122     return false;
123   }
124 
125   CBB seq;
126   if (!CBB_add_asn1(out, &seq, CBS_ASN1_SEQUENCE) ||
127       !CBB_add_asn1_uint64(&seq, kHandbackVersion) ||
128       !CBB_add_asn1_uint64(&seq, ssl->version) ||
129       !CBB_add_asn1_uint64(&seq, ssl->conf_max_version) ||
130       !CBB_add_asn1_uint64(&seq, ssl->conf_min_version) ||
131       !CBB_add_asn1_uint64(&seq, ssl->max_send_fragment) ||
132       !CBB_add_asn1_octet_string(&seq, s3->read_sequence,
133                                  sizeof(s3->read_sequence)) ||
134       !CBB_add_asn1_octet_string(&seq, s3->write_sequence,
135                                  sizeof(s3->write_sequence)) ||
136       !CBB_add_asn1_octet_string(&seq, s3->server_random,
137                                  sizeof(s3->server_random)) ||
138       !CBB_add_asn1_octet_string(&seq, s3->client_random,
139                                  sizeof(s3->client_random)) ||
140       !CBB_add_asn1_octet_string(&seq, read_iv, iv_len) ||
141       !CBB_add_asn1_octet_string(&seq, write_iv, iv_len) ||
142       !CBB_add_asn1_bool(&seq, s3->session_reused) ||
143       !CBB_add_asn1_bool(&seq, s3->send_connection_binding) ||
144       !CBB_add_asn1_bool(&seq, s3->tlsext_channel_id_valid) ||
145       !ssl_session_serialize(s3->established_session.get(), &seq) ||
146       !CBB_add_asn1_octet_string(&seq, s3->next_proto_negotiated.data(),
147                                  s3->next_proto_negotiated.size()) ||
148       !CBB_add_asn1_octet_string(&seq, s3->alpn_selected.data(),
149                                  s3->alpn_selected.size()) ||
150       !CBB_add_asn1_octet_string(
151           &seq, reinterpret_cast<uint8_t *>(s3->hostname.get()),
152           hostname_len) ||
153       !CBB_add_asn1_octet_string(&seq, s3->tlsext_channel_id,
154                                  sizeof(s3->tlsext_channel_id)) ||
155       !CBB_add_asn1_uint64(&seq, ssl->options) ||
156       !CBB_add_asn1_uint64(&seq, ssl->mode) ||
157       !CBB_add_asn1_uint64(&seq, ssl->max_cert_list) ||
158       !CBB_add_asn1_bool(&seq, ssl->quiet_shutdown) ||
159       !CBB_add_asn1_bool(&seq, ssl->tlsext_channel_id_enabled) ||
160       !CBB_add_asn1_bool(&seq, ssl->retain_only_sha256_of_client_certs) ||
161       !CBB_flush(out)) {
162     return false;
163   }
164 
165   return true;
166 }
167 
SSL_apply_handback(SSL * ssl,Span<const uint8_t> handback)168 bool SSL_apply_handback(SSL *ssl, Span<const uint8_t> handback) {
169   if (ssl->do_handshake != nullptr ||
170       ssl->method->is_dtls) {
171     return false;
172   }
173 
174   SSL3_STATE *const s3 = ssl->s3;
175   uint64_t handback_version, version, conf_max_version, conf_min_version,
176       max_send_fragment, options, mode, max_cert_list;
177   CBS seq, read_seq, write_seq, server_rand, client_rand, read_iv, write_iv,
178       next_proto, alpn, hostname, channel_id;
179   int session_reused, send_connection_binding, channel_id_valid,
180       quiet_shutdown, channel_id_enabled, retain_only_sha256;
181 
182   CBS handback_cbs(handback);
183   if (!CBS_get_asn1(&handback_cbs, &seq, CBS_ASN1_SEQUENCE) ||
184       !CBS_get_asn1_uint64(&seq, &handback_version) ||
185       handback_version != kHandbackVersion) {
186     return false;
187   }
188 
189   if (!CBS_get_asn1_uint64(&seq, &version) ||
190       !CBS_get_asn1_uint64(&seq, &conf_max_version) ||
191       !CBS_get_asn1_uint64(&seq, &conf_min_version) ||
192       !CBS_get_asn1_uint64(&seq, &max_send_fragment) ||
193       !CBS_get_asn1(&seq, &read_seq, CBS_ASN1_OCTETSTRING) ||
194       CBS_len(&read_seq) != sizeof(s3->read_sequence) ||
195       !CBS_get_asn1(&seq, &write_seq, CBS_ASN1_OCTETSTRING) ||
196       CBS_len(&write_seq) != sizeof(s3->write_sequence) ||
197       !CBS_get_asn1(&seq, &server_rand, CBS_ASN1_OCTETSTRING) ||
198       CBS_len(&server_rand) != sizeof(s3->server_random) ||
199       !CBS_copy_bytes(&server_rand, s3->server_random,
200                       sizeof(s3->server_random)) ||
201       !CBS_get_asn1(&seq, &client_rand, CBS_ASN1_OCTETSTRING) ||
202       CBS_len(&client_rand) != sizeof(s3->client_random) ||
203       !CBS_copy_bytes(&client_rand, s3->client_random,
204                       sizeof(s3->client_random)) ||
205       !CBS_get_asn1(&seq, &read_iv, CBS_ASN1_OCTETSTRING) ||
206       !CBS_get_asn1(&seq, &write_iv, CBS_ASN1_OCTETSTRING) ||
207       !CBS_get_asn1_bool(&seq, &session_reused) ||
208       !CBS_get_asn1_bool(&seq, &send_connection_binding) ||
209       !CBS_get_asn1_bool(&seq, &channel_id_valid)) {
210     return false;
211   }
212 
213   s3->established_session =
214       SSL_SESSION_parse(&seq, ssl->ctx->x509_method, ssl->ctx->pool);
215 
216   if (!s3->established_session ||
217       !CBS_get_asn1(&seq, &next_proto, CBS_ASN1_OCTETSTRING) ||
218       !CBS_get_asn1(&seq, &alpn, CBS_ASN1_OCTETSTRING) ||
219       !CBS_get_asn1(&seq, &hostname, CBS_ASN1_OCTETSTRING) ||
220       !CBS_get_asn1(&seq, &channel_id, CBS_ASN1_OCTETSTRING) ||
221       CBS_len(&channel_id) != sizeof(s3->tlsext_channel_id) ||
222       !CBS_copy_bytes(&channel_id, s3->tlsext_channel_id,
223                       sizeof(s3->tlsext_channel_id)) ||
224       !CBS_get_asn1_uint64(&seq, &options) ||
225       !CBS_get_asn1_uint64(&seq, &mode) ||
226       !CBS_get_asn1_uint64(&seq, &max_cert_list) ||
227       !CBS_get_asn1_bool(&seq, &quiet_shutdown) ||
228       !CBS_get_asn1_bool(&seq, &channel_id_enabled) ||
229       !CBS_get_asn1_bool(&seq, &retain_only_sha256)) {
230     return false;
231   }
232 
233   ssl->version = version;
234   ssl->conf_max_version = conf_max_version;
235   ssl->conf_min_version = conf_min_version;
236   ssl->max_send_fragment = max_send_fragment;
237   ssl->do_handshake = ssl_server_handshake;
238   ssl->server = true;
239   ssl->options = options;
240   ssl->mode = mode;
241   ssl->max_cert_list = max_cert_list;
242 
243   s3->hs.reset();
244   s3->have_version = true;
245   s3->initial_handshake_complete = true;
246   s3->session_reused = session_reused;
247   s3->send_connection_binding = send_connection_binding;
248   s3->tlsext_channel_id_valid = channel_id_valid;
249   s3->next_proto_negotiated.CopyFrom(next_proto);
250   s3->alpn_selected.CopyFrom(alpn);
251 
252   const size_t hostname_len = CBS_len(&hostname);
253   if (hostname_len == 0) {
254     s3->hostname.reset();
255   } else {
256     char *hostname_str = nullptr;
257     if (!CBS_strdup(&hostname, &hostname_str)) {
258       return false;
259     }
260     s3->hostname.reset(hostname_str);
261   }
262 
263   ssl->quiet_shutdown = quiet_shutdown;
264   ssl->tlsext_channel_id_enabled = channel_id_enabled;
265   ssl->retain_only_sha256_of_client_certs = retain_only_sha256;
266 
267   Array<uint8_t> key_block;
268   if (!tls1_configure_aead(ssl, evp_aead_open, &key_block,
269                            s3->established_session->cipher, read_iv) ||
270       !tls1_configure_aead(ssl, evp_aead_seal, &key_block,
271                            s3->established_session->cipher, write_iv)) {
272     return false;
273   }
274 
275   if (!CBS_copy_bytes(&read_seq, s3->read_sequence,
276                       sizeof(s3->read_sequence)) ||
277       !CBS_copy_bytes(&write_seq, s3->write_sequence,
278                       sizeof(s3->write_sequence))) {
279     return false;
280   }
281 
282   return true;
283 }
284 
285 }  // namespace bssl
286