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path: root/src/lib/libssl/tls13_key_schedule.c
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Diffstat (limited to 'src/lib/libssl/tls13_key_schedule.c')
-rw-r--r--src/lib/libssl/tls13_key_schedule.c458
1 files changed, 0 insertions, 458 deletions
diff --git a/src/lib/libssl/tls13_key_schedule.c b/src/lib/libssl/tls13_key_schedule.c
deleted file mode 100644
index 05bcf0f006..0000000000
--- a/src/lib/libssl/tls13_key_schedule.c
+++ /dev/null
@@ -1,458 +0,0 @@
1/* $OpenBSD: tls13_key_schedule.c,v 1.18 2022/11/26 16:08:56 tb Exp $ */
2/*
3 * Copyright (c) 2018, Bob Beck <beck@openbsd.org>
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
12 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
14 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
15 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <string.h>
19#include <stdlib.h>
20
21#include <openssl/hkdf.h>
22
23#include "bytestring.h"
24#include "ssl_local.h"
25#include "tls13_internal.h"
26
27int
28tls13_secret_init(struct tls13_secret *secret, size_t len)
29{
30 if (secret->data != NULL)
31 return 0;
32
33 if ((secret->data = calloc(1, len)) == NULL)
34 return 0;
35 secret->len = len;
36
37 return 1;
38}
39
40void
41tls13_secret_cleanup(struct tls13_secret *secret)
42{
43 freezero(secret->data, secret->len);
44 secret->data = NULL;
45 secret->len = 0;
46}
47
48/*
49 * Allocate a set of secrets for a key schedule using
50 * a size of hash_length from RFC 8446 section 7.1.
51 */
52struct tls13_secrets *
53tls13_secrets_create(const EVP_MD *digest, int resumption)
54{
55 struct tls13_secrets *secrets = NULL;
56 EVP_MD_CTX *mdctx = NULL;
57 unsigned int mdlen;
58 size_t hash_length;
59
60 hash_length = EVP_MD_size(digest);
61
62 if ((secrets = calloc(1, sizeof(struct tls13_secrets))) == NULL)
63 goto err;
64
65 if (!tls13_secret_init(&secrets->zeros, hash_length))
66 goto err;
67 if (!tls13_secret_init(&secrets->empty_hash, hash_length))
68 goto err;
69
70 if (!tls13_secret_init(&secrets->extracted_early, hash_length))
71 goto err;
72 if (!tls13_secret_init(&secrets->binder_key, hash_length))
73 goto err;
74 if (!tls13_secret_init(&secrets->client_early_traffic, hash_length))
75 goto err;
76 if (!tls13_secret_init(&secrets->early_exporter_master, hash_length))
77 goto err;
78 if (!tls13_secret_init(&secrets->derived_early, hash_length))
79 goto err;
80 if (!tls13_secret_init(&secrets->extracted_handshake, hash_length))
81 goto err;
82 if (!tls13_secret_init(&secrets->client_handshake_traffic, hash_length))
83 goto err;
84 if (!tls13_secret_init(&secrets->server_handshake_traffic, hash_length))
85 goto err;
86 if (!tls13_secret_init(&secrets->derived_handshake, hash_length))
87 goto err;
88 if (!tls13_secret_init(&secrets->extracted_master, hash_length))
89 goto err;
90 if (!tls13_secret_init(&secrets->client_application_traffic, hash_length))
91 goto err;
92 if (!tls13_secret_init(&secrets->server_application_traffic, hash_length))
93 goto err;
94 if (!tls13_secret_init(&secrets->exporter_master, hash_length))
95 goto err;
96 if (!tls13_secret_init(&secrets->resumption_master, hash_length))
97 goto err;
98
99 /*
100 * Calculate the hash of a zero-length string - this is needed during
101 * the "derived" step for key extraction.
102 */
103 if ((mdctx = EVP_MD_CTX_new()) == NULL)
104 goto err;
105 if (!EVP_DigestInit_ex(mdctx, digest, NULL))
106 goto err;
107 if (!EVP_DigestUpdate(mdctx, secrets->zeros.data, 0))
108 goto err;
109 if (!EVP_DigestFinal_ex(mdctx, secrets->empty_hash.data, &mdlen))
110 goto err;
111 EVP_MD_CTX_free(mdctx);
112 mdctx = NULL;
113
114 if (secrets->empty_hash.len != mdlen)
115 goto err;
116
117 secrets->digest = digest;
118 secrets->resumption = resumption;
119 secrets->init_done = 1;
120
121 return secrets;
122
123 err:
124 tls13_secrets_destroy(secrets);
125 EVP_MD_CTX_free(mdctx);
126
127 return NULL;
128}
129
130void
131tls13_secrets_destroy(struct tls13_secrets *secrets)
132{
133 if (secrets == NULL)
134 return;
135
136 /* you can never be too sure :) */
137 tls13_secret_cleanup(&secrets->zeros);
138 tls13_secret_cleanup(&secrets->empty_hash);
139
140 tls13_secret_cleanup(&secrets->extracted_early);
141 tls13_secret_cleanup(&secrets->binder_key);
142 tls13_secret_cleanup(&secrets->client_early_traffic);
143 tls13_secret_cleanup(&secrets->early_exporter_master);
144 tls13_secret_cleanup(&secrets->derived_early);
145 tls13_secret_cleanup(&secrets->extracted_handshake);
146 tls13_secret_cleanup(&secrets->client_handshake_traffic);
147 tls13_secret_cleanup(&secrets->server_handshake_traffic);
148 tls13_secret_cleanup(&secrets->derived_handshake);
149 tls13_secret_cleanup(&secrets->extracted_master);
150 tls13_secret_cleanup(&secrets->client_application_traffic);
151 tls13_secret_cleanup(&secrets->server_application_traffic);
152 tls13_secret_cleanup(&secrets->exporter_master);
153 tls13_secret_cleanup(&secrets->resumption_master);
154
155 freezero(secrets, sizeof(struct tls13_secrets));
156}
157
158int
159tls13_hkdf_expand_label(struct tls13_secret *out, const EVP_MD *digest,
160 const struct tls13_secret *secret, const char *label,
161 const struct tls13_secret *context)
162{
163 return tls13_hkdf_expand_label_with_length(out, digest, secret, label,
164 strlen(label), context);
165}
166
167int
168tls13_hkdf_expand_label_with_length(struct tls13_secret *out,
169 const EVP_MD *digest, const struct tls13_secret *secret,
170 const uint8_t *label, size_t label_len, const struct tls13_secret *context)
171{
172 const char tls13_plabel[] = "tls13 ";
173 uint8_t *hkdf_label = NULL;
174 size_t hkdf_label_len;
175 CBB cbb, child;
176 int ret;
177
178 if (!CBB_init(&cbb, 256))
179 goto err;
180
181 if (out->data == NULL || out->len == 0)
182 goto err;
183
184 if (!CBB_add_u16(&cbb, out->len))
185 goto err;
186 if (!CBB_add_u8_length_prefixed(&cbb, &child))
187 goto err;
188 if (!CBB_add_bytes(&child, tls13_plabel, strlen(tls13_plabel)))
189 goto err;
190 if (!CBB_add_bytes(&child, label, label_len))
191 goto err;
192 if (!CBB_add_u8_length_prefixed(&cbb, &child))
193 goto err;
194 if (!CBB_add_bytes(&child, context->data, context->len))
195 goto err;
196 if (!CBB_finish(&cbb, &hkdf_label, &hkdf_label_len))
197 goto err;
198
199 ret = HKDF_expand(out->data, out->len, digest, secret->data,
200 secret->len, hkdf_label, hkdf_label_len);
201
202 free(hkdf_label);
203 return(ret);
204 err:
205 CBB_cleanup(&cbb);
206 return(0);
207}
208
209int
210tls13_derive_secret(struct tls13_secret *out, const EVP_MD *digest,
211 const struct tls13_secret *secret, const char *label,
212 const struct tls13_secret *context)
213{
214 return tls13_hkdf_expand_label(out, digest, secret, label, context);
215}
216
217int
218tls13_derive_secret_with_label_length(struct tls13_secret *out,
219 const EVP_MD *digest, const struct tls13_secret *secret, const uint8_t *label,
220 size_t label_len, const struct tls13_secret *context)
221{
222 return tls13_hkdf_expand_label_with_length(out, digest, secret, label,
223 label_len, context);
224}
225
226int
227tls13_derive_early_secrets(struct tls13_secrets *secrets,
228 uint8_t *psk, size_t psk_len, const struct tls13_secret *context)
229{
230 if (!secrets->init_done || secrets->early_done)
231 return 0;
232
233 if (!HKDF_extract(secrets->extracted_early.data,
234 &secrets->extracted_early.len, secrets->digest, psk, psk_len,
235 secrets->zeros.data, secrets->zeros.len))
236 return 0;
237
238 if (secrets->extracted_early.len != secrets->zeros.len)
239 return 0;
240
241 if (!tls13_derive_secret(&secrets->binder_key, secrets->digest,
242 &secrets->extracted_early,
243 secrets->resumption ? "res binder" : "ext binder",
244 &secrets->empty_hash))
245 return 0;
246 if (!tls13_derive_secret(&secrets->client_early_traffic,
247 secrets->digest, &secrets->extracted_early, "c e traffic",
248 context))
249 return 0;
250 if (!tls13_derive_secret(&secrets->early_exporter_master,
251 secrets->digest, &secrets->extracted_early, "e exp master",
252 context))
253 return 0;
254 if (!tls13_derive_secret(&secrets->derived_early,
255 secrets->digest, &secrets->extracted_early, "derived",
256 &secrets->empty_hash))
257 return 0;
258
259 /* RFC 8446 recommends */
260 if (!secrets->insecure)
261 explicit_bzero(secrets->extracted_early.data,
262 secrets->extracted_early.len);
263 secrets->early_done = 1;
264 return 1;
265}
266
267int
268tls13_derive_handshake_secrets(struct tls13_secrets *secrets,
269 const uint8_t *ecdhe, size_t ecdhe_len,
270 const struct tls13_secret *context)
271{
272 if (!secrets->init_done || !secrets->early_done ||
273 secrets->handshake_done)
274 return 0;
275
276 if (!HKDF_extract(secrets->extracted_handshake.data,
277 &secrets->extracted_handshake.len, secrets->digest,
278 ecdhe, ecdhe_len, secrets->derived_early.data,
279 secrets->derived_early.len))
280 return 0;
281
282 if (secrets->extracted_handshake.len != secrets->zeros.len)
283 return 0;
284
285 /* XXX */
286 if (!secrets->insecure)
287 explicit_bzero(secrets->derived_early.data,
288 secrets->derived_early.len);
289
290 if (!tls13_derive_secret(&secrets->client_handshake_traffic,
291 secrets->digest, &secrets->extracted_handshake, "c hs traffic",
292 context))
293 return 0;
294 if (!tls13_derive_secret(&secrets->server_handshake_traffic,
295 secrets->digest, &secrets->extracted_handshake, "s hs traffic",
296 context))
297 return 0;
298 if (!tls13_derive_secret(&secrets->derived_handshake,
299 secrets->digest, &secrets->extracted_handshake, "derived",
300 &secrets->empty_hash))
301 return 0;
302
303 /* RFC 8446 recommends */
304 if (!secrets->insecure)
305 explicit_bzero(secrets->extracted_handshake.data,
306 secrets->extracted_handshake.len);
307
308 secrets->handshake_done = 1;
309
310 return 1;
311}
312
313int
314tls13_derive_application_secrets(struct tls13_secrets *secrets,
315 const struct tls13_secret *context)
316{
317 if (!secrets->init_done || !secrets->early_done ||
318 !secrets->handshake_done || secrets->schedule_done)
319 return 0;
320
321 if (!HKDF_extract(secrets->extracted_master.data,
322 &secrets->extracted_master.len, secrets->digest,
323 secrets->zeros.data, secrets->zeros.len,
324 secrets->derived_handshake.data, secrets->derived_handshake.len))
325 return 0;
326
327 if (secrets->extracted_master.len != secrets->zeros.len)
328 return 0;
329
330 /* XXX */
331 if (!secrets->insecure)
332 explicit_bzero(secrets->derived_handshake.data,
333 secrets->derived_handshake.len);
334
335 if (!tls13_derive_secret(&secrets->client_application_traffic,
336 secrets->digest, &secrets->extracted_master, "c ap traffic",
337 context))
338 return 0;
339 if (!tls13_derive_secret(&secrets->server_application_traffic,
340 secrets->digest, &secrets->extracted_master, "s ap traffic",
341 context))
342 return 0;
343 if (!tls13_derive_secret(&secrets->exporter_master,
344 secrets->digest, &secrets->extracted_master, "exp master",
345 context))
346 return 0;
347 if (!tls13_derive_secret(&secrets->resumption_master,
348 secrets->digest, &secrets->extracted_master, "res master",
349 context))
350 return 0;
351
352 /* RFC 8446 recommends */
353 if (!secrets->insecure)
354 explicit_bzero(secrets->extracted_master.data,
355 secrets->extracted_master.len);
356
357 secrets->schedule_done = 1;
358
359 return 1;
360}
361
362int
363tls13_update_client_traffic_secret(struct tls13_secrets *secrets)
364{
365 struct tls13_secret context = { .data = "", .len = 0 };
366
367 if (!secrets->init_done || !secrets->early_done ||
368 !secrets->handshake_done || !secrets->schedule_done)
369 return 0;
370
371 return tls13_hkdf_expand_label(&secrets->client_application_traffic,
372 secrets->digest, &secrets->client_application_traffic,
373 "traffic upd", &context);
374}
375
376int
377tls13_update_server_traffic_secret(struct tls13_secrets *secrets)
378{
379 struct tls13_secret context = { .data = "", .len = 0 };
380
381 if (!secrets->init_done || !secrets->early_done ||
382 !secrets->handshake_done || !secrets->schedule_done)
383 return 0;
384
385 return tls13_hkdf_expand_label(&secrets->server_application_traffic,
386 secrets->digest, &secrets->server_application_traffic,
387 "traffic upd", &context);
388}
389
390int
391tls13_exporter(struct tls13_ctx *ctx, const uint8_t *label, size_t label_len,
392 const uint8_t *context_value, size_t context_value_len, uint8_t *out,
393 size_t out_len)
394{
395 struct tls13_secret context, export_out, export_secret;
396 struct tls13_secrets *secrets = ctx->hs->tls13.secrets;
397 EVP_MD_CTX *md_ctx = NULL;
398 unsigned int md_out_len;
399 int md_len;
400 int ret = 0;
401
402 /*
403 * RFC 8446 Section 7.5.
404 */
405
406 memset(&context, 0, sizeof(context));
407 memset(&export_secret, 0, sizeof(export_secret));
408
409 export_out.data = out;
410 export_out.len = out_len;
411
412 if (!ctx->handshake_completed)
413 return 0;
414
415 md_len = EVP_MD_size(secrets->digest);
416 if (md_len <= 0 || md_len > EVP_MAX_MD_SIZE)
417 goto err;
418
419 if (!tls13_secret_init(&export_secret, md_len))
420 goto err;
421 if (!tls13_secret_init(&context, md_len))
422 goto err;
423
424 /* In TLSv1.3 no context is equivalent to an empty context. */
425 if (context_value == NULL) {
426 context_value = "";
427 context_value_len = 0;
428 }
429
430 if ((md_ctx = EVP_MD_CTX_new()) == NULL)
431 goto err;
432 if (!EVP_DigestInit_ex(md_ctx, secrets->digest, NULL))
433 goto err;
434 if (!EVP_DigestUpdate(md_ctx, context_value, context_value_len))
435 goto err;
436 if (!EVP_DigestFinal_ex(md_ctx, context.data, &md_out_len))
437 goto err;
438 if (md_len != md_out_len)
439 goto err;
440
441 if (!tls13_derive_secret_with_label_length(&export_secret,
442 secrets->digest, &secrets->exporter_master, label, label_len,
443 &secrets->empty_hash))
444 goto err;
445
446 if (!tls13_hkdf_expand_label(&export_out, secrets->digest,
447 &export_secret, "exporter", &context))
448 goto err;
449
450 ret = 1;
451
452 err:
453 EVP_MD_CTX_free(md_ctx);
454 tls13_secret_cleanup(&context);
455 tls13_secret_cleanup(&export_secret);
456
457 return ret;
458}
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2026-02-11 15:12:55 +0000