Use a fetched cipher for the TLSv1.3 early secret
[openssl.git] / ssl / tls13_enc.c
1 /*
2  * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (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
8  */
9
10 #include <stdlib.h>
11 #include "ssl_local.h"
12 #include "internal/cryptlib.h"
13 #include <openssl/evp.h>
14 #include <openssl/kdf.h>
15 #include <openssl/core_names.h>
16
17 #define TLS13_MAX_LABEL_LEN     249
18
19 /* Always filled with zeros */
20 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
21
22 /*
23  * Given a |secret|; a |label| of length |labellen|; and |data| of length
24  * |datalen| (e.g. typically a hash of the handshake messages), derive a new
25  * secret |outlen| bytes long and store it in the location pointed to be |out|.
26  * The |data| value may be zero length. Any errors will be treated as fatal if
27  * |fatal| is set. Returns 1 on success  0 on failure.
28  */
29 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
30                              const unsigned char *label, size_t labellen,
31                              const unsigned char *data, size_t datalen,
32                              unsigned char *out, size_t outlen, int fatal)
33 {
34 #ifdef CHARSET_EBCDIC
35     static const unsigned char label_prefix[] = { 0x74, 0x6C, 0x73, 0x31, 0x33, 0x20, 0x00 };
36 #else
37     static const unsigned char label_prefix[] = "tls13 ";
38 #endif
39     EVP_KDF *kdf = EVP_KDF_fetch(s->ctx->libctx, OSSL_KDF_NAME_HKDF,
40                                  s->ctx->propq);
41     EVP_KDF_CTX *kctx;
42     OSSL_PARAM params[5], *p = params;
43     int mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
44     const char *mdname = EVP_MD_name(md);
45     int ret;
46     size_t hkdflabellen;
47     size_t hashlen;
48     /*
49      * 2 bytes for length of derived secret + 1 byte for length of combined
50      * prefix and label + bytes for the label itself + 1 byte length of hash
51      * + bytes for the hash itself
52      */
53     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t)
54                             + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN
55                             + 1 + EVP_MAX_MD_SIZE];
56     WPACKET pkt;
57
58     kctx = EVP_KDF_CTX_new(kdf);
59     EVP_KDF_free(kdf);
60     if (kctx == NULL)
61         return 0;
62
63     if (labellen > TLS13_MAX_LABEL_LEN) {
64         if (fatal) {
65             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
66                      ERR_R_INTERNAL_ERROR);
67         } else {
68             /*
69              * Probably we have been called from SSL_export_keying_material(),
70              * or SSL_export_keying_material_early().
71              */
72             SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
73         }
74         EVP_KDF_CTX_free(kctx);
75         return 0;
76     }
77
78     hashlen = EVP_MD_size(md);
79
80     if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
81             || !WPACKET_put_bytes_u16(&pkt, outlen)
82             || !WPACKET_start_sub_packet_u8(&pkt)
83             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
84             || !WPACKET_memcpy(&pkt, label, labellen)
85             || !WPACKET_close(&pkt)
86             || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
87             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
88             || !WPACKET_finish(&pkt)) {
89         EVP_KDF_CTX_free(kctx);
90         WPACKET_cleanup(&pkt);
91         if (fatal)
92             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
93                      ERR_R_INTERNAL_ERROR);
94         else
95             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
96         return 0;
97     }
98
99     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
100     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
101                                             (char *)mdname, 0);
102     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
103                                              (unsigned char *)secret, hashlen);
104     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
105                                              hkdflabel, hkdflabellen);
106     *p++ = OSSL_PARAM_construct_end();
107
108     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
109         || EVP_KDF_derive(kctx, out, outlen) <= 0;
110
111     EVP_KDF_CTX_free(kctx);
112
113     if (ret != 0) {
114         if (fatal)
115             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
116                      ERR_R_INTERNAL_ERROR);
117         else
118             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
119     }
120
121     return ret == 0;
122 }
123
124 /*
125  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
126  * success  0 on failure.
127  */
128 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
129                      unsigned char *key, size_t keylen)
130 {
131 #ifdef CHARSET_EBCDIC
132   static const unsigned char keylabel[] ={ 0x6B, 0x65, 0x79, 0x00 };
133 #else
134   static const unsigned char keylabel[] = "key";
135 #endif
136
137     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
138                              NULL, 0, key, keylen, 1);
139 }
140
141 /*
142  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
143  * success  0 on failure.
144  */
145 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
146                     unsigned char *iv, size_t ivlen)
147 {
148 #ifdef CHARSET_EBCDIC
149   static const unsigned char ivlabel[] = { 0x69, 0x76, 0x00 };
150 #else
151   static const unsigned char ivlabel[] = "iv";
152 #endif
153
154     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
155                              NULL, 0, iv, ivlen, 1);
156 }
157
158 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
159                              const unsigned char *secret,
160                              unsigned char *fin, size_t finlen)
161 {
162 #ifdef CHARSET_EBCDIC
163   static const unsigned char finishedlabel[] = { 0x66, 0x69, 0x6E, 0x69, 0x73, 0x68, 0x65, 0x64, 0x00 };
164 #else
165   static const unsigned char finishedlabel[] = "finished";
166 #endif
167
168     return tls13_hkdf_expand(s, md, secret, finishedlabel,
169                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
170 }
171
172 /*
173  * Given the previous secret |prevsecret| and a new input secret |insecret| of
174  * length |insecretlen|, generate a new secret and store it in the location
175  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
176  */
177 int tls13_generate_secret(SSL *s, const EVP_MD *md,
178                           const unsigned char *prevsecret,
179                           const unsigned char *insecret,
180                           size_t insecretlen,
181                           unsigned char *outsecret)
182 {
183     size_t mdlen, prevsecretlen;
184     int mdleni;
185     int ret;
186     EVP_KDF *kdf;
187     EVP_KDF_CTX *kctx;
188     OSSL_PARAM params[5], *p = params;
189     int mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
190     const char *mdname = EVP_MD_name(md);
191 #ifdef CHARSET_EBCDIC
192     static const char derived_secret_label[] = { 0x64, 0x65, 0x72, 0x69, 0x76, 0x65, 0x64, 0x00 };
193 #else
194     static const char derived_secret_label[] = "derived";
195 #endif
196     unsigned char preextractsec[EVP_MAX_MD_SIZE];
197
198     kdf = EVP_KDF_fetch(s->ctx->libctx, OSSL_KDF_NAME_HKDF, s->ctx->propq);
199     kctx = EVP_KDF_CTX_new(kdf);
200     EVP_KDF_free(kdf);
201     if (kctx == NULL) {
202         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
203                  ERR_R_INTERNAL_ERROR);
204         return 0;
205     }
206
207     mdleni = EVP_MD_size(md);
208     /* Ensure cast to size_t is safe */
209     if (!ossl_assert(mdleni >= 0)) {
210         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
211                  ERR_R_INTERNAL_ERROR);
212         EVP_KDF_CTX_free(kctx);
213         return 0;
214     }
215     mdlen = (size_t)mdleni;
216
217     if (insecret == NULL) {
218         insecret = default_zeros;
219         insecretlen = mdlen;
220     }
221     if (prevsecret == NULL) {
222         prevsecret = default_zeros;
223         prevsecretlen = 0;
224     } else {
225         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
226         unsigned char hash[EVP_MAX_MD_SIZE];
227
228         /* The pre-extract derive step uses a hash of no messages */
229         if (mctx == NULL
230                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
231                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
232             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
233                      ERR_R_INTERNAL_ERROR);
234             EVP_MD_CTX_free(mctx);
235             EVP_KDF_CTX_free(kctx);
236             return 0;
237         }
238         EVP_MD_CTX_free(mctx);
239
240         /* Generate the pre-extract secret */
241         if (!tls13_hkdf_expand(s, md, prevsecret,
242                                (unsigned char *)derived_secret_label,
243                                sizeof(derived_secret_label) - 1, hash, mdlen,
244                                preextractsec, mdlen, 1)) {
245             /* SSLfatal() already called */
246             EVP_KDF_CTX_free(kctx);
247             return 0;
248         }
249
250         prevsecret = preextractsec;
251         prevsecretlen = mdlen;
252     }
253
254     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
255     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
256                                             (char *)mdname, 0);
257     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
258                                              (unsigned char *)insecret,
259                                              insecretlen);
260     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
261                                              (unsigned char *)prevsecret,
262                                              prevsecretlen);
263     *p++ = OSSL_PARAM_construct_end();
264
265     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
266         || EVP_KDF_derive(kctx, outsecret, mdlen) <= 0;
267
268     if (ret != 0)
269         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
270                  ERR_R_INTERNAL_ERROR);
271
272     EVP_KDF_CTX_free(kctx);
273     if (prevsecret == preextractsec)
274         OPENSSL_cleanse(preextractsec, mdlen);
275     return ret == 0;
276 }
277
278 /*
279  * Given an input secret |insecret| of length |insecretlen| generate the
280  * handshake secret. This requires the early secret to already have been
281  * generated. Returns 1 on success  0 on failure.
282  */
283 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
284                                 size_t insecretlen)
285 {
286     /* Calls SSLfatal() if required */
287     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
288                                  insecret, insecretlen,
289                                  (unsigned char *)&s->handshake_secret);
290 }
291
292 /*
293  * Given the handshake secret |prev| of length |prevlen| generate the master
294  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
295  * failure.
296  */
297 int tls13_generate_master_secret(SSL *s, unsigned char *out,
298                                  unsigned char *prev, size_t prevlen,
299                                  size_t *secret_size)
300 {
301     const EVP_MD *md = ssl_handshake_md(s);
302
303     *secret_size = EVP_MD_size(md);
304     /* Calls SSLfatal() if required */
305     return tls13_generate_secret(s, md, prev, NULL, 0, out);
306 }
307
308 /*
309  * Generates the mac for the Finished message. Returns the length of the MAC or
310  * 0 on error.
311  */
312 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
313                              unsigned char *out)
314 {
315     const char *mdname = EVP_MD_name(ssl_handshake_md(s));
316     EVP_MAC *hmac = EVP_MAC_fetch(s->ctx->libctx, "HMAC", s->ctx->propq);
317     unsigned char hash[EVP_MAX_MD_SIZE];
318     unsigned char finsecret[EVP_MAX_MD_SIZE];
319     size_t hashlen, ret = 0;
320     EVP_MAC_CTX *ctx = NULL;
321     OSSL_PARAM params[4], *p = params;
322
323     if (hmac == NULL) {
324         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
325                  ERR_R_INTERNAL_ERROR);
326         goto err;
327     }
328
329     /* Safe to cast away const here since we're not "getting" any data */
330     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_DIGEST,
331                                             (char *)mdname, 0);
332     if (s->ctx->propq != NULL)
333         *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_PROPERTIES,
334                                                 (char *)s->ctx->propq,
335                                                 0);
336
337     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
338         /* SSLfatal() already called */
339         goto err;
340     }
341
342     if (str == s->method->ssl3_enc->server_finished_label) {
343         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
344                                                  s->server_finished_secret,
345                                                  hashlen);
346     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
347         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
348                                                  s->client_finished_secret,
349                                                  hashlen);
350     } else {
351         if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
352                                       s->client_app_traffic_secret,
353                                       finsecret, hashlen))
354             goto err;
355
356         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY, finsecret,
357                                                  hashlen);
358     }
359     *p++ = OSSL_PARAM_construct_end();
360
361     ctx = EVP_MAC_CTX_new(hmac);
362     if (ctx == NULL
363             || !EVP_MAC_CTX_set_params(ctx, params)
364             || !EVP_MAC_init(ctx)
365             || !EVP_MAC_update(ctx, hash, hashlen)
366                /* outsize as per sizeof(peer_finish_md) */
367             || !EVP_MAC_final(ctx, out, &hashlen, EVP_MAX_MD_SIZE * 2)) {
368         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
369                  ERR_R_INTERNAL_ERROR);
370         goto err;
371     }
372
373     ret = hashlen;
374  err:
375     OPENSSL_cleanse(finsecret, sizeof(finsecret));
376     EVP_MAC_CTX_free(ctx);
377     EVP_MAC_free(hmac);
378     return ret;
379 }
380
381 /*
382  * There isn't really a key block in TLSv1.3, but we still need this function
383  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
384  */
385 int tls13_setup_key_block(SSL *s)
386 {
387     const EVP_CIPHER *c;
388     const EVP_MD *hash;
389
390     s->session->cipher = s->s3.tmp.new_cipher;
391     if (!ssl_cipher_get_evp(s->ctx, s->session, &c, &hash, NULL, NULL, NULL,
392                             0)) {
393         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
394                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
395         return 0;
396     }
397
398     ssl_evp_cipher_free(s->s3.tmp.new_sym_enc);
399     s->s3.tmp.new_sym_enc = c;
400     ssl_evp_md_free(s->s3.tmp.new_hash);
401     s->s3.tmp.new_hash = hash;
402
403     return 1;
404 }
405
406 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
407                                     const EVP_CIPHER *ciph,
408                                     const unsigned char *insecret,
409                                     const unsigned char *hash,
410                                     const unsigned char *label,
411                                     size_t labellen, unsigned char *secret,
412                                     unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
413 {
414     unsigned char key[EVP_MAX_KEY_LENGTH];
415     size_t ivlen, keylen, taglen;
416     int hashleni = EVP_MD_size(md);
417     size_t hashlen;
418
419     /* Ensure cast to size_t is safe */
420     if (!ossl_assert(hashleni >= 0)) {
421         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
422                  ERR_R_EVP_LIB);
423         goto err;
424     }
425     hashlen = (size_t)hashleni;
426
427     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
428                            secret, hashlen, 1)) {
429         /* SSLfatal() already called */
430         goto err;
431     }
432
433     /* TODO(size_t): convert me */
434     keylen = EVP_CIPHER_key_length(ciph);
435     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
436         uint32_t algenc;
437
438         ivlen = EVP_CCM_TLS_IV_LEN;
439         if (s->s3.tmp.new_cipher == NULL) {
440             /* We've not selected a cipher yet - we must be doing early data */
441             algenc = s->session->cipher->algorithm_enc;
442         } else {
443             algenc = s->s3.tmp.new_cipher->algorithm_enc;
444         }
445         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
446             taglen = EVP_CCM8_TLS_TAG_LEN;
447          else
448             taglen = EVP_CCM_TLS_TAG_LEN;
449     } else {
450         ivlen = EVP_CIPHER_iv_length(ciph);
451         taglen = 0;
452     }
453
454     if (!tls13_derive_key(s, md, secret, key, keylen)
455             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
456         /* SSLfatal() already called */
457         goto err;
458     }
459
460     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
461         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
462         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
463                                                 taglen, NULL))
464         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
465         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
466                  ERR_R_EVP_LIB);
467         goto err;
468     }
469
470     return 1;
471  err:
472     OPENSSL_cleanse(key, sizeof(key));
473     return 0;
474 }
475
476 int tls13_change_cipher_state(SSL *s, int which)
477 {
478 #ifdef CHARSET_EBCDIC
479   static const unsigned char client_early_traffic[]       = {0x63, 0x20, 0x65, 0x20,       /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
480   static const unsigned char client_handshake_traffic[]   = {0x63, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
481   static const unsigned char client_application_traffic[] = {0x63, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
482   static const unsigned char server_handshake_traffic[]   = {0x73, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
483   static const unsigned char server_application_traffic[] = {0x73, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
484   static const unsigned char exporter_master_secret[] = {0x65, 0x78, 0x70, 0x20,                    /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
485   static const unsigned char resumption_master_secret[] = {0x72, 0x65, 0x73, 0x20,                  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
486   static const unsigned char early_exporter_master_secret[] = {0x65, 0x20, 0x65, 0x78, 0x70, 0x20,  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
487 #else
488     static const unsigned char client_early_traffic[] = "c e traffic";
489     static const unsigned char client_handshake_traffic[] = "c hs traffic";
490     static const unsigned char client_application_traffic[] = "c ap traffic";
491     static const unsigned char server_handshake_traffic[] = "s hs traffic";
492     static const unsigned char server_application_traffic[] = "s ap traffic";
493     static const unsigned char exporter_master_secret[] = "exp master";
494     static const unsigned char resumption_master_secret[] = "res master";
495     static const unsigned char early_exporter_master_secret[] = "e exp master";
496 #endif
497     unsigned char *iv;
498     unsigned char secret[EVP_MAX_MD_SIZE];
499     unsigned char hashval[EVP_MAX_MD_SIZE];
500     unsigned char *hash = hashval;
501     unsigned char *insecret;
502     unsigned char *finsecret = NULL;
503     const char *log_label = NULL;
504     EVP_CIPHER_CTX *ciph_ctx;
505     size_t finsecretlen = 0;
506     const unsigned char *label;
507     size_t labellen, hashlen = 0;
508     int ret = 0;
509     const EVP_MD *md = NULL;
510     const EVP_CIPHER *cipher = NULL;
511
512     if (which & SSL3_CC_READ) {
513         if (s->enc_read_ctx != NULL) {
514             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
515         } else {
516             s->enc_read_ctx = EVP_CIPHER_CTX_new();
517             if (s->enc_read_ctx == NULL) {
518                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
519                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
520                 goto err;
521             }
522         }
523         ciph_ctx = s->enc_read_ctx;
524         iv = s->read_iv;
525
526         RECORD_LAYER_reset_read_sequence(&s->rlayer);
527     } else {
528         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
529         if (s->enc_write_ctx != NULL) {
530             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
531         } else {
532             s->enc_write_ctx = EVP_CIPHER_CTX_new();
533             if (s->enc_write_ctx == NULL) {
534                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
535                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
536                 goto err;
537             }
538         }
539         ciph_ctx = s->enc_write_ctx;
540         iv = s->write_iv;
541
542         RECORD_LAYER_reset_write_sequence(&s->rlayer);
543     }
544
545     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
546             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
547         if (which & SSL3_CC_EARLY) {
548             EVP_MD_CTX *mdctx = NULL;
549             long handlen;
550             void *hdata;
551             unsigned int hashlenui;
552             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
553
554             insecret = s->early_secret;
555             label = client_early_traffic;
556             labellen = sizeof(client_early_traffic) - 1;
557             log_label = CLIENT_EARLY_LABEL;
558
559             handlen = BIO_get_mem_data(s->s3.handshake_buffer, &hdata);
560             if (handlen <= 0) {
561                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
562                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
563                          SSL_R_BAD_HANDSHAKE_LENGTH);
564                 goto err;
565             }
566
567             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
568                     && s->max_early_data > 0
569                     && s->session->ext.max_early_data == 0) {
570                 /*
571                  * If we are attempting to send early data, and we've decided to
572                  * actually do it but max_early_data in s->session is 0 then we
573                  * must be using an external PSK.
574                  */
575                 if (!ossl_assert(s->psksession != NULL
576                         && s->max_early_data ==
577                            s->psksession->ext.max_early_data)) {
578                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
579                              SSL_F_TLS13_CHANGE_CIPHER_STATE,
580                              ERR_R_INTERNAL_ERROR);
581                     goto err;
582                 }
583                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
584             }
585             if (sslcipher == NULL) {
586                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
587                          SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
588                 goto err;
589             }
590
591             /*
592              * We need to calculate the handshake digest using the digest from
593              * the session. We haven't yet selected our ciphersuite so we can't
594              * use ssl_handshake_md().
595              */
596             mdctx = EVP_MD_CTX_new();
597             if (mdctx == NULL) {
598                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
599                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
600                 goto err;
601             }
602
603             /*
604              * This ups the ref count on cipher so we better make sure we free
605              * it again
606              */
607             if (!ssl_cipher_get_evp_cipher(s->ctx, sslcipher, &cipher)) {
608                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
609                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
610                          SSL_R_ALGORITHM_FETCH_FAILED);
611                 goto err;
612             }
613
614             md = ssl_md(s->ctx, sslcipher->algorithm2);
615             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
616                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
617                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
618                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
619                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
620                 EVP_MD_CTX_free(mdctx);
621                 goto err;
622             }
623             hashlen = hashlenui;
624             EVP_MD_CTX_free(mdctx);
625
626             if (!tls13_hkdf_expand(s, md, insecret,
627                                    early_exporter_master_secret,
628                                    sizeof(early_exporter_master_secret) - 1,
629                                    hashval, hashlen,
630                                    s->early_exporter_master_secret, hashlen,
631                                    1)) {
632                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
633                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
634                 goto err;
635             }
636
637             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
638                                 s->early_exporter_master_secret, hashlen)) {
639                 /* SSLfatal() already called */
640                 goto err;
641             }
642         } else if (which & SSL3_CC_HANDSHAKE) {
643             insecret = s->handshake_secret;
644             finsecret = s->client_finished_secret;
645             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
646             label = client_handshake_traffic;
647             labellen = sizeof(client_handshake_traffic) - 1;
648             log_label = CLIENT_HANDSHAKE_LABEL;
649             /*
650              * The handshake hash used for the server read/client write handshake
651              * traffic secret is the same as the hash for the server
652              * write/client read handshake traffic secret. However, if we
653              * processed early data then we delay changing the server
654              * read/client write cipher state until later, and the handshake
655              * hashes have moved on. Therefore we use the value saved earlier
656              * when we did the server write/client read change cipher state.
657              */
658             hash = s->handshake_traffic_hash;
659         } else {
660             insecret = s->master_secret;
661             label = client_application_traffic;
662             labellen = sizeof(client_application_traffic) - 1;
663             log_label = CLIENT_APPLICATION_LABEL;
664             /*
665              * For this we only use the handshake hashes up until the server
666              * Finished hash. We do not include the client's Finished, which is
667              * what ssl_handshake_hash() would give us. Instead we use the
668              * previously saved value.
669              */
670             hash = s->server_finished_hash;
671         }
672     } else {
673         /* Early data never applies to client-read/server-write */
674         if (which & SSL3_CC_HANDSHAKE) {
675             insecret = s->handshake_secret;
676             finsecret = s->server_finished_secret;
677             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
678             label = server_handshake_traffic;
679             labellen = sizeof(server_handshake_traffic) - 1;
680             log_label = SERVER_HANDSHAKE_LABEL;
681         } else {
682             insecret = s->master_secret;
683             label = server_application_traffic;
684             labellen = sizeof(server_application_traffic) - 1;
685             log_label = SERVER_APPLICATION_LABEL;
686         }
687     }
688
689     if (!(which & SSL3_CC_EARLY)) {
690         md = ssl_handshake_md(s);
691         cipher = s->s3.tmp.new_sym_enc;
692         if (!ssl3_digest_cached_records(s, 1)
693                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
694             /* SSLfatal() already called */;
695             goto err;
696         }
697     }
698
699     /*
700      * Save the hash of handshakes up to now for use when we calculate the
701      * client application traffic secret
702      */
703     if (label == server_application_traffic)
704         memcpy(s->server_finished_hash, hashval, hashlen);
705
706     if (label == server_handshake_traffic)
707         memcpy(s->handshake_traffic_hash, hashval, hashlen);
708
709     if (label == client_application_traffic) {
710         /*
711          * We also create the resumption master secret, but this time use the
712          * hash for the whole handshake including the Client Finished
713          */
714         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
715                                resumption_master_secret,
716                                sizeof(resumption_master_secret) - 1,
717                                hashval, hashlen, s->resumption_master_secret,
718                                hashlen, 1)) {
719             /* SSLfatal() already called */
720             goto err;
721         }
722     }
723
724     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
725                                   insecret, hash, label, labellen, secret, iv,
726                                   ciph_ctx)) {
727         /* SSLfatal() already called */
728         goto err;
729     }
730
731     if (label == server_application_traffic) {
732         memcpy(s->server_app_traffic_secret, secret, hashlen);
733         /* Now we create the exporter master secret */
734         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
735                                exporter_master_secret,
736                                sizeof(exporter_master_secret) - 1,
737                                hash, hashlen, s->exporter_master_secret,
738                                hashlen, 1)) {
739             /* SSLfatal() already called */
740             goto err;
741         }
742
743         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
744                             hashlen)) {
745             /* SSLfatal() already called */
746             goto err;
747         }
748     } else if (label == client_application_traffic)
749         memcpy(s->client_app_traffic_secret, secret, hashlen);
750
751     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
752         /* SSLfatal() already called */
753         goto err;
754     }
755
756     if (finsecret != NULL
757             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
758                                          finsecret, finsecretlen)) {
759         /* SSLfatal() already called */
760         goto err;
761     }
762
763     if (!s->server && label == client_early_traffic)
764         s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
765     else
766         s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
767     ret = 1;
768  err:
769     if ((which & SSL3_CC_EARLY) != 0) {
770         /* We up-refed this so now we need to down ref */
771         ssl_evp_cipher_free(cipher);
772     }
773     OPENSSL_cleanse(secret, sizeof(secret));
774     return ret;
775 }
776
777 int tls13_update_key(SSL *s, int sending)
778 {
779 #ifdef CHARSET_EBCDIC
780   static const unsigned char application_traffic[] = { 0x74, 0x72 ,0x61 ,0x66 ,0x66 ,0x69 ,0x63 ,0x20 ,0x75 ,0x70 ,0x64, 0x00};
781 #else
782   static const unsigned char application_traffic[] = "traffic upd";
783 #endif
784     const EVP_MD *md = ssl_handshake_md(s);
785     size_t hashlen = EVP_MD_size(md);
786     unsigned char *insecret, *iv;
787     unsigned char secret[EVP_MAX_MD_SIZE];
788     EVP_CIPHER_CTX *ciph_ctx;
789     int ret = 0;
790
791     if (s->server == sending)
792         insecret = s->server_app_traffic_secret;
793     else
794         insecret = s->client_app_traffic_secret;
795
796     if (sending) {
797         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
798         iv = s->write_iv;
799         ciph_ctx = s->enc_write_ctx;
800         RECORD_LAYER_reset_write_sequence(&s->rlayer);
801     } else {
802         iv = s->read_iv;
803         ciph_ctx = s->enc_read_ctx;
804         RECORD_LAYER_reset_read_sequence(&s->rlayer);
805     }
806
807     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
808                                   s->s3.tmp.new_sym_enc, insecret, NULL,
809                                   application_traffic,
810                                   sizeof(application_traffic) - 1, secret, iv,
811                                   ciph_ctx)) {
812         /* SSLfatal() already called */
813         goto err;
814     }
815
816     memcpy(insecret, secret, hashlen);
817
818     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
819     ret = 1;
820  err:
821     OPENSSL_cleanse(secret, sizeof(secret));
822     return ret;
823 }
824
825 int tls13_alert_code(int code)
826 {
827     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
828     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
829         return code;
830
831     return tls1_alert_code(code);
832 }
833
834 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
835                                  const char *label, size_t llen,
836                                  const unsigned char *context,
837                                  size_t contextlen, int use_context)
838 {
839     unsigned char exportsecret[EVP_MAX_MD_SIZE];
840 #ifdef CHARSET_EBCDIC
841     static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
842 #else
843     static const unsigned char exporterlabel[] = "exporter";
844 #endif
845     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
846     const EVP_MD *md = ssl_handshake_md(s);
847     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
848     unsigned int hashsize, datalen;
849     int ret = 0;
850
851     if (ctx == NULL || !ossl_statem_export_allowed(s))
852         goto err;
853
854     if (!use_context)
855         contextlen = 0;
856
857     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
858             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
859             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
860             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
861             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
862             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
863                                   (const unsigned char *)label, llen,
864                                   data, datalen, exportsecret, hashsize, 0)
865             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
866                                   sizeof(exporterlabel) - 1, hash, hashsize,
867                                   out, olen, 0))
868         goto err;
869
870     ret = 1;
871  err:
872     EVP_MD_CTX_free(ctx);
873     return ret;
874 }
875
876 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
877                                        const char *label, size_t llen,
878                                        const unsigned char *context,
879                                        size_t contextlen)
880 {
881 #ifdef CHARSET_EBCDIC
882   static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
883 #else
884   static const unsigned char exporterlabel[] = "exporter";
885 #endif
886     unsigned char exportsecret[EVP_MAX_MD_SIZE];
887     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
888     const EVP_MD *md;
889     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
890     unsigned int hashsize, datalen;
891     int ret = 0;
892     const SSL_CIPHER *sslcipher;
893
894     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
895         goto err;
896
897     if (!s->server && s->max_early_data > 0
898             && s->session->ext.max_early_data == 0)
899         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
900     else
901         sslcipher = SSL_SESSION_get0_cipher(s->session);
902
903     md = ssl_md(s->ctx, sslcipher->algorithm2);
904
905     /*
906      * Calculate the hash value and store it in |data|. The reason why
907      * the empty string is used is that the definition of TLS-Exporter
908      * is like so:
909      *
910      * TLS-Exporter(label, context_value, key_length) =
911      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
912      *                       "exporter", Hash(context_value), key_length)
913      *
914      * Derive-Secret(Secret, Label, Messages) =
915      *       HKDF-Expand-Label(Secret, Label,
916      *                         Transcript-Hash(Messages), Hash.length)
917      *
918      * Here Transcript-Hash is the cipher suite hash algorithm.
919      */
920     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
921             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
922             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
923             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
924             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
925             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
926                                   (const unsigned char *)label, llen,
927                                   data, datalen, exportsecret, hashsize, 0)
928             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
929                                   sizeof(exporterlabel) - 1, hash, hashsize,
930                                   out, olen, 0))
931         goto err;
932
933     ret = 1;
934  err:
935     EVP_MD_CTX_free(ctx);
936     return ret;
937 }