2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/evp.h>
13 #include <openssl/kdf.h>
15 #define TLS13_MAX_LABEL_LEN 246
17 /* Always filled with zeros */
18 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
20 static const unsigned char keylabel[] = "key";
21 static const unsigned char ivlabel[] = "iv";
22 static const unsigned char finishedlabel[] = "finished";
25 * Given a |secret|; a |label| of length |labellen|; and a |hash| of the
26 * handshake messages, derive a new secret |outlen| bytes long and store it in
27 * the location pointed to be |out|. The |hash| value may be NULL.
29 * Returns 1 on success 0 on failure.
31 static int tls13_hkdf_expand(SSL *s, const unsigned char *secret,
32 const unsigned char *label, size_t labellen,
33 const unsigned char *hash,
34 unsigned char *out, size_t outlen)
36 const unsigned char label_prefix[] = "TLS 1.3, ";
37 const EVP_MD *md = ssl_handshake_md(s);
38 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
43 * 2 bytes for length of whole HkdfLabel + 1 byte for length of combined
44 * prefix and label + bytes for the label itself + bytes for the hash
46 unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
47 + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
54 hashlen = EVP_MD_size(md);
56 if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
57 || !WPACKET_put_bytes_u16(&pkt, outlen)
58 || !WPACKET_start_sub_packet_u8(&pkt)
59 || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
60 || !WPACKET_memcpy(&pkt, label, labellen)
61 || !WPACKET_close(&pkt)
62 || !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen)
63 || !WPACKET_get_total_written(&pkt, &hkdflabellen)
64 || !WPACKET_finish(&pkt)) {
65 WPACKET_cleanup(&pkt);
69 ret = EVP_PKEY_derive_init(pctx) <= 0
70 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
72 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
73 || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
74 || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
75 || EVP_PKEY_derive(pctx, out, &outlen) <= 0;
77 EVP_PKEY_CTX_free(pctx);
83 * Given a input secret |insecret| and a |label| of length |labellen|, derive a
84 * new |secret|. This will be the length of the current hash output size and
85 * will be based on the current state of the handshake hashes.
87 * Returns 1 on success 0 on failure.
89 int tls13_derive_secret(SSL *s, const unsigned char *insecret,
90 const unsigned char *label, size_t labellen,
91 unsigned char *secret)
93 unsigned char hash[EVP_MAX_MD_SIZE];
96 if (!ssl3_digest_cached_records(s, 1))
99 if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen))
102 return tls13_hkdf_expand(s, insecret, label, labellen, hash, secret,
107 * Given a |secret| generate a |key| of length |keylen| bytes.
109 * Returns 1 on success 0 on failure.
111 int tls13_derive_key(SSL *s, const unsigned char *secret, unsigned char *key,
114 return tls13_hkdf_expand(s, secret, keylabel, sizeof(keylabel) - 1, NULL,
119 * Given a |secret| generate an |iv| of length |ivlen| bytes.
121 * Returns 1 on success 0 on failure.
123 int tls13_derive_iv(SSL *s, const unsigned char *secret, unsigned char *iv,
126 return tls13_hkdf_expand(s, secret, ivlabel, sizeof(ivlabel) - 1, NULL,
130 static int tls13_derive_finishedkey(SSL *s, const unsigned char *secret,
131 unsigned char *fin, size_t finlen)
133 return tls13_hkdf_expand(s, secret, finishedlabel,
134 sizeof(finishedlabel) - 1, NULL, fin, finlen);
138 * Given the previous secret |prevsecret| and a new input secret |insecret| of
139 * length |insecretlen|, generate a new secret and store it in the location
140 * pointed to by |outsecret|.
142 * Returns 1 on success 0 on failure.
144 static int tls13_generate_secret(SSL *s, const unsigned char *prevsecret,
145 const unsigned char *insecret,
147 unsigned char *outsecret)
149 const EVP_MD *md = ssl_handshake_md(s);
150 size_t mdlen, prevsecretlen;
152 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
157 mdlen = EVP_MD_size(md);
159 if (insecret == NULL) {
160 insecret = default_zeros;
163 if (prevsecret == NULL) {
164 prevsecret = default_zeros;
167 prevsecretlen = mdlen;
170 ret = EVP_PKEY_derive_init(pctx) <= 0
171 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
173 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
174 || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
175 || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
177 || EVP_PKEY_derive(pctx, outsecret, &mdlen)
180 EVP_PKEY_CTX_free(pctx);
185 * Given an input secret |insecret| of length |insecretlen| generate the early
188 * Returns 1 on success 0 on failure.
190 int tls13_generate_early_secret(SSL *s, const unsigned char *insecret,
193 return tls13_generate_secret(s, NULL, insecret, insecretlen,
194 (unsigned char *)&s->early_secret);
198 * Given an input secret |insecret| of length |insecretlen| generate the
199 * handshake secret. This requires the early secret to already have been
202 * Returns 1 on success 0 on failure.
204 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
207 return tls13_generate_secret(s, s->early_secret, insecret, insecretlen,
208 (unsigned char *)&s->handshake_secret);
212 * Given the handshake secret |prev| of length |prevlen| generate the master
213 * secret and store its length in |*secret_size|
215 * Returns 1 on success 0 on failure.
217 int tls13_generate_master_secret(SSL *s, unsigned char *out,
218 unsigned char *prev, size_t prevlen,
221 *secret_size = EVP_MD_size(ssl_handshake_md(s));
222 return tls13_generate_secret(s, prev, NULL, 0, out);
226 * Generates the mac for the Finished message.
228 * Returns the length of the MAC or 0 on error.
230 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
233 const EVP_MD *md = ssl_handshake_md(s);
234 unsigned char hash[EVP_MAX_MD_SIZE];
235 size_t hashlen, ret = 0;
236 EVP_PKEY *key = NULL;
237 EVP_MD_CTX *ctx = EVP_MD_CTX_new();
239 if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen))
242 if (str == s->method->ssl3_enc->server_finished_label)
243 key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
244 s->server_finished_secret, hashlen);
246 key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
247 s->client_finished_secret, hashlen);
251 || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
252 || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
253 || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0)
259 EVP_MD_CTX_free(ctx);
264 * There isn't really a key block in TLSv1.3, but we still need this function
265 * for initialising the cipher and hash.
267 * Returns 1 on success or 0 on failure.
269 int tls13_setup_key_block(SSL *s)
273 int mac_type = NID_undef;
275 s->session->cipher = s->s3->tmp.new_cipher;
276 if (!ssl_cipher_get_evp
277 (s->session, &c, &hash, &mac_type, NULL, NULL, 0)) {
278 SSLerr(SSL_F_TLS13_SETUP_KEY_BLOCK, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
282 s->s3->tmp.new_sym_enc = c;
283 s->s3->tmp.new_hash = hash;
288 const unsigned char client_handshake_traffic[] =
289 "client handshake traffic secret";
290 const unsigned char client_application_traffic[] =
291 "client application traffic secret";
292 const unsigned char server_handshake_traffic[] =
293 "server handshake traffic secret";
294 const unsigned char server_application_traffic[] =
295 "server application traffic secret";
297 int tls13_change_cipher_state(SSL *s, int which)
299 unsigned char key[EVP_MAX_KEY_LENGTH];
300 unsigned char iv[EVP_MAX_IV_LENGTH];
301 unsigned char secret[EVP_MAX_MD_SIZE];
302 unsigned char *insecret;
303 unsigned char *finsecret = NULL;
304 EVP_CIPHER_CTX *ciph_ctx;
305 const EVP_CIPHER *ciph = s->s3->tmp.new_sym_enc;;
306 size_t ivlen, keylen, finsecretlen;
307 const unsigned char *label;
310 if (which & SSL3_CC_READ) {
311 if (s->enc_read_ctx != NULL) {
312 EVP_CIPHER_CTX_reset(s->enc_read_ctx);
314 s->enc_read_ctx = EVP_CIPHER_CTX_new();
315 if (s->enc_read_ctx == NULL) {
316 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
320 ciph_ctx = s->enc_read_ctx;
322 RECORD_LAYER_reset_read_sequence(&s->rlayer);
324 if (s->enc_write_ctx != NULL) {
325 EVP_CIPHER_CTX_reset(s->enc_write_ctx);
327 s->enc_write_ctx = EVP_CIPHER_CTX_new();
328 if (s->enc_write_ctx == NULL) {
329 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
333 ciph_ctx = s->enc_write_ctx;
335 RECORD_LAYER_reset_write_sequence(&s->rlayer);
338 if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
339 || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
340 if (which & SSL3_CC_HANDSHAKE) {
341 insecret = s->handshake_secret;
342 finsecret = s->client_finished_secret;
343 finsecretlen = sizeof(s->client_finished_secret);
344 label = client_handshake_traffic;
345 labellen = sizeof(client_handshake_traffic) - 1;
347 insecret = s->session->master_key;
348 label = client_application_traffic;
349 labellen = sizeof(client_application_traffic) - 1;
352 if (which & SSL3_CC_HANDSHAKE) {
353 insecret = s->handshake_secret;
354 finsecret = s->server_finished_secret;
355 finsecretlen = sizeof(s->server_finished_secret);
356 label = server_handshake_traffic;
357 labellen = sizeof(server_handshake_traffic) - 1;
359 insecret = s->session->master_key;
360 label = server_application_traffic;
361 labellen = sizeof(server_application_traffic) - 1;
365 if (!tls13_derive_secret(s, insecret, label, labellen, secret)) {
366 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
370 /* TODO(size_t): convert me */
371 keylen = EVP_CIPHER_key_length(ciph);
373 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE)
374 ivlen = EVP_GCM_TLS_FIXED_IV_LEN;
375 else if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE)
376 ivlen = EVP_CCM_TLS_FIXED_IV_LEN;
378 ivlen = EVP_CIPHER_iv_length(ciph);
380 if (!tls13_derive_key(s, secret, key, keylen)
381 || !tls13_derive_iv(s, secret, iv, ivlen)
382 || (finsecret != NULL && !tls13_derive_finishedkey(s, secret,
385 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
389 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE) {
390 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, key, NULL,
391 (which & SSL3_CC_WRITE))
392 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_GCM_SET_IV_FIXED,
394 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
397 } else if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
399 if (s->s3->tmp.new_cipher->algorithm_enc
400 & (SSL_AES128CCM8 | SSL_AES256CCM8))
404 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL,
405 (which & SSL3_CC_WRITE))
406 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, 12,
408 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG, taglen,
410 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_CCM_SET_IV_FIXED,
412 || !EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1)) {
413 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
417 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, key, iv,
418 (which & SSL3_CC_WRITE))) {
419 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
424 #ifdef OPENSSL_SSL_TRACE_CRYPTO
425 if (s->msg_callback) {
426 int wh = which & SSL3_CC_WRITE ? TLS1_RT_CRYPTO_WRITE : 0;
429 s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_KEY,
430 key, ciph->key_len, s, s->msg_callback_arg);
432 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE)
433 wh |= TLS1_RT_CRYPTO_FIXED_IV;
435 wh |= TLS1_RT_CRYPTO_IV;
436 s->msg_callback(2, s->version, wh, iv, ivlen, s,
437 s->msg_callback_arg);
442 OPENSSL_cleanse(secret, sizeof(secret));
443 OPENSSL_cleanse(key, sizeof(key));
444 OPENSSL_cleanse(iv, sizeof(iv));
448 OPENSSL_cleanse(secret, sizeof(secret));
449 OPENSSL_cleanse(key, sizeof(key));
450 OPENSSL_cleanse(iv, sizeof(iv));