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";
24 * Given a |secret|; a |label| of length |labellen|; and a |hash| of the
25 * handshake messages, derive a new secret |outlen| bytes long and store it in
26 * the location pointed to be |out|. The |hash| value may be NULL.
28 * Returns 1 on success 0 on failure.
30 static int tls13_hkdf_expand(SSL *s, const unsigned char *secret,
31 const unsigned char *label, size_t labellen,
32 const unsigned char *hash,
33 unsigned char *out, size_t outlen)
35 const unsigned char label_prefix[] = "TLS 1.3, ";
36 const EVP_MD *md = ssl_handshake_md(s);
37 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
42 * 2 bytes for length of whole HkdfLabel + 1 byte for length of combined
43 * prefix and label + bytes for the label itself + bytes for the hash
45 unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
46 + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
53 hashlen = EVP_MD_size(md);
55 if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
56 || !WPACKET_put_bytes_u16(&pkt, outlen)
57 || !WPACKET_start_sub_packet_u8(&pkt)
58 || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
59 || !WPACKET_memcpy(&pkt, label, labellen)
60 || !WPACKET_close(&pkt)
61 || !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen)
62 || !WPACKET_get_total_written(&pkt, &hkdflabellen)
63 || !WPACKET_finish(&pkt)) {
64 WPACKET_cleanup(&pkt);
68 ret = EVP_PKEY_derive_init(pctx) <= 0
69 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
71 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
72 || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
73 || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
74 || EVP_PKEY_derive(pctx, out, &outlen) <= 0;
76 EVP_PKEY_CTX_free(pctx);
82 * Given a input secret |insecret| and a |label| of length |labellen|, derive a
83 * new |secret|. This will be the length of the current hash output size and
84 * will be based on the current state of the handshake hashes.
86 * Returns 1 on success 0 on failure.
88 int tls13_derive_secret(SSL *s, const unsigned char *insecret,
89 const unsigned char *label, size_t labellen,
90 unsigned char *secret)
92 unsigned char hash[EVP_MAX_MD_SIZE];
95 if (!ssl3_digest_cached_records(s, 1))
98 if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen))
101 return tls13_hkdf_expand(s, insecret, label, labellen, hash, secret,
106 * Given a |secret| generate a |key| of length |keylen| bytes.
108 * Returns 1 on success 0 on failure.
110 int tls13_derive_key(SSL *s, const unsigned char *secret, unsigned char *key,
113 return tls13_hkdf_expand(s, secret, keylabel, sizeof(keylabel) - 1, NULL,
118 * Given a |secret| generate an |iv| of length |ivlen| bytes.
120 * Returns 1 on success 0 on failure.
122 int tls13_derive_iv(SSL *s, const unsigned char *secret, unsigned char *iv,
125 return tls13_hkdf_expand(s, secret, ivlabel, sizeof(ivlabel) - 1, NULL,
130 * Given the previous secret |prevsecret| and a new input secret |insecret| of
131 * length |insecretlen|, generate a new secret and store it in the location
132 * pointed to by |outsecret|.
134 * Returns 1 on success 0 on failure.
136 static int tls13_generate_secret(SSL *s, const unsigned char *prevsecret,
137 const unsigned char *insecret,
139 unsigned char *outsecret)
141 const EVP_MD *md = ssl_handshake_md(s);
142 size_t mdlen, prevsecretlen;
144 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
149 mdlen = EVP_MD_size(md);
151 if (insecret == NULL) {
152 insecret = default_zeros;
155 if (prevsecret == NULL) {
156 prevsecret = default_zeros;
159 prevsecretlen = mdlen;
162 ret = EVP_PKEY_derive_init(pctx) <= 0
163 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
165 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
166 || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
167 || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
169 || EVP_PKEY_derive(pctx, outsecret, &mdlen)
172 EVP_PKEY_CTX_free(pctx);
177 * Given an input secret |insecret| of length |insecretlen| generate the early
180 * Returns 1 on success 0 on failure.
182 int tls13_generate_early_secret(SSL *s, const unsigned char *insecret,
185 return tls13_generate_secret(s, NULL, insecret, insecretlen,
186 (unsigned char *)&s->early_secret);
190 * Given an input secret |insecret| of length |insecretlen| generate the
191 * handshake secret. This requires the early secret to already have been
194 * Returns 1 on success 0 on failure.
196 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
199 return tls13_generate_secret(s, s->early_secret, insecret, insecretlen,
200 (unsigned char *)&s->handshake_secret);
204 * Given the handshake secret |prev| of length |prevlen| generate the master
205 * secret and store its length in |*secret_size|
207 * Returns 1 on success 0 on failure.
209 int tls13_generate_master_secret(SSL *s, unsigned char *out,
210 unsigned char *prev, size_t prevlen,
213 *secret_size = EVP_MD_size(ssl_handshake_md(s));
214 return tls13_generate_secret(s, prev, NULL, 0, out);
217 const unsigned char client_handshake_traffic[] =
218 "client handshake traffic secret";
219 const unsigned char client_application_traffic[] =
220 "client application traffic secret";
221 const unsigned char server_handshake_traffic[] =
222 "server handshake traffic secret";
223 const unsigned char server_application_traffic[] =
224 "server application traffic secret";
226 int tls13_change_cipher_state(SSL *s, int which)
228 unsigned char key[EVP_MAX_KEY_LENGTH];
229 unsigned char iv[EVP_MAX_IV_LENGTH];
230 unsigned char secret[EVP_MAX_MD_SIZE];
231 unsigned char *insecret;
232 EVP_CIPHER_CTX *ciph_ctx;
233 const EVP_CIPHER *ciph = s->s3->tmp.new_sym_enc;;
234 size_t ivlen, keylen;
235 const unsigned char *label;
238 if (which & SSL3_CC_READ) {
239 if (s->enc_read_ctx != NULL) {
240 EVP_CIPHER_CTX_reset(s->enc_read_ctx);
242 s->enc_read_ctx = EVP_CIPHER_CTX_new();
243 if (s->enc_read_ctx == NULL) {
244 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
248 ciph_ctx = s->enc_read_ctx;
250 RECORD_LAYER_reset_read_sequence(&s->rlayer);
252 if (s->enc_write_ctx != NULL) {
253 EVP_CIPHER_CTX_reset(s->enc_write_ctx);
255 s->enc_write_ctx = EVP_CIPHER_CTX_new();
256 if (s->enc_write_ctx == NULL) {
257 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
261 ciph_ctx = s->enc_write_ctx;
263 RECORD_LAYER_reset_write_sequence(&s->rlayer);
266 if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
267 || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
268 if (which & SSL3_CC_HANDSHAKE) {
269 insecret = s->handshake_secret;
270 label = client_handshake_traffic;
271 labellen = sizeof(client_handshake_traffic) - 1;
273 insecret = s->session->master_key;
274 label = client_application_traffic;
275 labellen = sizeof(client_application_traffic) - 1;
278 if (which & SSL3_CC_HANDSHAKE) {
279 insecret = s->handshake_secret;
280 label = server_handshake_traffic;
281 labellen = sizeof(server_handshake_traffic) - 1;
283 insecret = s->session->master_key;
284 label = server_application_traffic;
285 labellen = sizeof(server_application_traffic) - 1;
289 if (!tls13_derive_secret(s, insecret, label, labellen, secret)) {
290 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
294 /* TODO(size_t): convert me */
295 keylen = EVP_CIPHER_key_length(ciph);
297 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE)
298 ivlen = EVP_GCM_TLS_FIXED_IV_LEN;
299 else if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE)
300 ivlen = EVP_CCM_TLS_FIXED_IV_LEN;
302 ivlen = EVP_CIPHER_iv_length(ciph);
304 if (!tls13_derive_key(s, secret, key, keylen)
305 || !tls13_derive_iv(s, secret, iv, ivlen)) {
306 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
310 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE) {
311 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, key, NULL,
312 (which & SSL3_CC_WRITE))
313 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_GCM_SET_IV_FIXED,
315 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
318 } else if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
320 if (s->s3->tmp.new_cipher->algorithm_enc
321 & (SSL_AES128CCM8 | SSL_AES256CCM8))
325 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL,
326 (which & SSL3_CC_WRITE))
327 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, 12,
329 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG, taglen,
331 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_CCM_SET_IV_FIXED,
333 || !EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1)) {
334 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
338 if (!EVP_CipherInit_ex(ciph_ctx, ciph, NULL, key, iv,
339 (which & SSL3_CC_WRITE))) {
340 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_EVP_LIB);
345 #ifdef OPENSSL_SSL_TRACE_CRYPTO
346 if (s->msg_callback) {
347 int wh = which & SSL3_CC_WRITE ? TLS1_RT_CRYPTO_WRITE : 0;
350 s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_KEY,
351 key, ciph->key_len, s, s->msg_callback_arg);
353 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_GCM_MODE)
354 wh |= TLS1_RT_CRYPTO_FIXED_IV;
356 wh |= TLS1_RT_CRYPTO_IV;
357 s->msg_callback(2, s->version, wh, iv, ivlen, s,
358 s->msg_callback_arg);
363 OPENSSL_cleanse(secret, sizeof(secret));
364 OPENSSL_cleanse(key, sizeof(key));
365 OPENSSL_cleanse(iv, sizeof(iv));
369 OPENSSL_cleanse(secret, sizeof(secret));
370 OPENSSL_cleanse(key, sizeof(key));
371 OPENSSL_cleanse(iv, sizeof(iv));