/* * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include #include "ssl_locl.h" #include "internal/cryptlib.h" #include #include #define TLS13_MAX_LABEL_LEN 249 /* Always filled with zeros */ static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; /* * Given a |secret|; a |label| of length |labellen|; and |data| of length * |datalen| (e.g. typically a hash of the handshake messages), derive a new * secret |outlen| bytes long and store it in the location pointed to be |out|. * The |data| value may be zero length. Any errors will be treated as fatal if * |fatal| is set. Returns 1 on success 0 on failure. */ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, const unsigned char *label, size_t labellen, const unsigned char *data, size_t datalen, unsigned char *out, size_t outlen, int fatal) { static const unsigned char label_prefix[] = "tls13 "; EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); int ret; size_t hkdflabellen; size_t hashlen; /* * 2 bytes for length of derived secret + 1 byte for length of combined * prefix and label + bytes for the label itself + 1 byte length of hash * + bytes for the hash itself */ unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) + + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN + 1 + EVP_MAX_MD_SIZE]; WPACKET pkt; if (pctx == NULL) return 0; if (labellen > TLS13_MAX_LABEL_LEN) { if (fatal) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); } else { /* * Probably we have been called from SSL_export_keying_material(), * or SSL_export_keying_material_early(). */ SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL); } EVP_PKEY_CTX_free(pctx); return 0; } hashlen = EVP_MD_size(md); if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0) || !WPACKET_put_bytes_u16(&pkt, outlen) || !WPACKET_start_sub_packet_u8(&pkt) || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1) || !WPACKET_memcpy(&pkt, label, labellen) || !WPACKET_close(&pkt) || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen) || !WPACKET_get_total_written(&pkt, &hkdflabellen) || !WPACKET_finish(&pkt)) { EVP_PKEY_CTX_free(pctx); WPACKET_cleanup(&pkt); if (fatal) SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); else SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); return 0; } ret = EVP_PKEY_derive_init(pctx) <= 0 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY) <= 0 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0 || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0 || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0 || EVP_PKEY_derive(pctx, out, &outlen) <= 0; EVP_PKEY_CTX_free(pctx); if (ret != 0) { if (fatal) SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); else SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); } return ret == 0; } /* * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on * success 0 on failure. */ int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret, unsigned char *key, size_t keylen) { static const unsigned char keylabel[] = "key"; return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1, NULL, 0, key, keylen, 1); } /* * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on * success 0 on failure. */ int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret, unsigned char *iv, size_t ivlen) { static const unsigned char ivlabel[] = "iv"; return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1, NULL, 0, iv, ivlen, 1); } int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, const unsigned char *secret, unsigned char *fin, size_t finlen) { static const unsigned char finishedlabel[] = "finished"; return tls13_hkdf_expand(s, md, secret, finishedlabel, sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1); } /* * Given the previous secret |prevsecret| and a new input secret |insecret| of * length |insecretlen|, generate a new secret and store it in the location * pointed to by |outsecret|. Returns 1 on success 0 on failure. */ int tls13_generate_secret(SSL *s, const EVP_MD *md, const unsigned char *prevsecret, const unsigned char *insecret, size_t insecretlen, unsigned char *outsecret) { size_t mdlen, prevsecretlen; int mdleni; int ret; EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); static const char derived_secret_label[] = "derived"; unsigned char preextractsec[EVP_MAX_MD_SIZE]; if (pctx == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, ERR_R_INTERNAL_ERROR); return 0; } mdleni = EVP_MD_size(md); /* Ensure cast to size_t is safe */ if (!ossl_assert(mdleni >= 0)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, ERR_R_INTERNAL_ERROR); return 0; } mdlen = (size_t)mdleni; if (insecret == NULL) { insecret = default_zeros; insecretlen = mdlen; } if (prevsecret == NULL) { prevsecret = default_zeros; prevsecretlen = 0; } else { EVP_MD_CTX *mctx = EVP_MD_CTX_new(); unsigned char hash[EVP_MAX_MD_SIZE]; /* The pre-extract derive step uses a hash of no messages */ if (mctx == NULL || EVP_DigestInit_ex(mctx, md, NULL) <= 0 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, ERR_R_INTERNAL_ERROR); EVP_MD_CTX_free(mctx); EVP_PKEY_CTX_free(pctx); return 0; } EVP_MD_CTX_free(mctx); /* Generate the pre-extract secret */ if (!tls13_hkdf_expand(s, md, prevsecret, (unsigned char *)derived_secret_label, sizeof(derived_secret_label) - 1, hash, mdlen, preextractsec, mdlen, 1)) { /* SSLfatal() already called */ EVP_PKEY_CTX_free(pctx); return 0; } prevsecret = preextractsec; prevsecretlen = mdlen; } ret = EVP_PKEY_derive_init(pctx) <= 0 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY) <= 0 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0 || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0 || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen) <= 0 || EVP_PKEY_derive(pctx, outsecret, &mdlen) <= 0; if (ret != 0) SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, ERR_R_INTERNAL_ERROR); EVP_PKEY_CTX_free(pctx); if (prevsecret == preextractsec) OPENSSL_cleanse(preextractsec, mdlen); return ret == 0; } /* * Given an input secret |insecret| of length |insecretlen| generate the * handshake secret. This requires the early secret to already have been * generated. Returns 1 on success 0 on failure. */ int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret, size_t insecretlen) { /* Calls SSLfatal() if required */ return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret, insecret, insecretlen, (unsigned char *)&s->handshake_secret); } /* * Given the handshake secret |prev| of length |prevlen| generate the master * secret and store its length in |*secret_size|. Returns 1 on success 0 on * failure. */ int tls13_generate_master_secret(SSL *s, unsigned char *out, unsigned char *prev, size_t prevlen, size_t *secret_size) { const EVP_MD *md = ssl_handshake_md(s); *secret_size = EVP_MD_size(md); /* Calls SSLfatal() if required */ return tls13_generate_secret(s, md, prev, NULL, 0, out); } /* * Generates the mac for the Finished message. Returns the length of the MAC or * 0 on error. */ size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen, unsigned char *out) { const EVP_MD *md = ssl_handshake_md(s); unsigned char hash[EVP_MAX_MD_SIZE]; size_t hashlen, ret = 0; EVP_PKEY *key = NULL; EVP_MD_CTX *ctx = EVP_MD_CTX_new(); if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) { /* SSLfatal() already called */ goto err; } if (str == s->method->ssl3_enc->server_finished_label) { key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, s->server_finished_secret, hashlen); } else if (SSL_IS_FIRST_HANDSHAKE(s)) { key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, s->client_finished_secret, hashlen); } else { unsigned char finsecret[EVP_MAX_MD_SIZE]; if (!tls13_derive_finishedkey(s, ssl_handshake_md(s), s->client_app_traffic_secret, finsecret, hashlen)) goto err; key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finsecret, hashlen); OPENSSL_cleanse(finsecret, sizeof(finsecret)); } if (key == NULL || ctx == NULL || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0 || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0 || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC, ERR_R_INTERNAL_ERROR); goto err; } ret = hashlen; err: EVP_PKEY_free(key); EVP_MD_CTX_free(ctx); return ret; } /* * There isn't really a key block in TLSv1.3, but we still need this function * for initialising the cipher and hash. Returns 1 on success or 0 on failure. */ int tls13_setup_key_block(SSL *s) { const EVP_CIPHER *c; const EVP_MD *hash; s->session->cipher = s->s3->tmp.new_cipher; if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL, NULL, 0)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK, SSL_R_CIPHER_OR_HASH_UNAVAILABLE); return 0; } s->s3->tmp.new_sym_enc = c; s->s3->tmp.new_hash = hash; return 1; } static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md, const EVP_CIPHER *ciph, const unsigned char *insecret, const unsigned char *hash, const unsigned char *label, size_t labellen, unsigned char *secret, unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx) { unsigned char key[EVP_MAX_KEY_LENGTH]; size_t ivlen, keylen, taglen; int hashleni = EVP_MD_size(md); size_t hashlen; /* Ensure cast to size_t is safe */ if (!ossl_assert(hashleni >= 0)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_EVP_LIB); goto err; } hashlen = (size_t)hashleni; if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen, secret, hashlen, 1)) { /* SSLfatal() already called */ goto err; } /* TODO(size_t): convert me */ keylen = EVP_CIPHER_key_length(ciph); if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) { uint32_t algenc; ivlen = EVP_CCM_TLS_IV_LEN; if (s->s3->tmp.new_cipher == NULL) { /* We've not selected a cipher yet - we must be doing early data */ algenc = s->session->cipher->algorithm_enc; } else { algenc = s->s3->tmp.new_cipher->algorithm_enc; } if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8)) taglen = EVP_CCM8_TLS_TAG_LEN; else taglen = EVP_CCM_TLS_TAG_LEN; } else { ivlen = EVP_CIPHER_iv_length(ciph); taglen = 0; } if (!tls13_derive_key(s, md, secret, key, keylen) || !tls13_derive_iv(s, md, secret, iv, ivlen)) { /* SSLfatal() already called */ goto err; } if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG, taglen, NULL)) || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_EVP_LIB); goto err; } return 1; err: OPENSSL_cleanse(key, sizeof(key)); return 0; } int tls13_change_cipher_state(SSL *s, int which) { static const unsigned char client_early_traffic[] = "c e traffic"; static const unsigned char client_handshake_traffic[] = "c hs traffic"; static const unsigned char client_application_traffic[] = "c ap traffic"; static const unsigned char server_handshake_traffic[] = "s hs traffic"; static const unsigned char server_application_traffic[] = "s ap traffic"; static const unsigned char exporter_master_secret[] = "exp master"; static const unsigned char resumption_master_secret[] = "res master"; static const unsigned char early_exporter_master_secret[] = "e exp master"; unsigned char *iv; unsigned char secret[EVP_MAX_MD_SIZE]; unsigned char hashval[EVP_MAX_MD_SIZE]; unsigned char *hash = hashval; unsigned char *insecret; unsigned char *finsecret = NULL; const char *log_label = NULL; EVP_CIPHER_CTX *ciph_ctx; size_t finsecretlen = 0; const unsigned char *label; size_t labellen, hashlen = 0; int ret = 0; const EVP_MD *md = NULL; const EVP_CIPHER *cipher = NULL; if (which & SSL3_CC_READ) { if (s->enc_read_ctx != NULL) { EVP_CIPHER_CTX_reset(s->enc_read_ctx); } else { s->enc_read_ctx = EVP_CIPHER_CTX_new(); if (s->enc_read_ctx == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); goto err; } } ciph_ctx = s->enc_read_ctx; iv = s->read_iv; RECORD_LAYER_reset_read_sequence(&s->rlayer); } else { s->statem.enc_write_state = ENC_WRITE_STATE_INVALID; if (s->enc_write_ctx != NULL) { EVP_CIPHER_CTX_reset(s->enc_write_ctx); } else { s->enc_write_ctx = EVP_CIPHER_CTX_new(); if (s->enc_write_ctx == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); goto err; } } ciph_ctx = s->enc_write_ctx; iv = s->write_iv; RECORD_LAYER_reset_write_sequence(&s->rlayer); } if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE)) || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) { if (which & SSL3_CC_EARLY) { EVP_MD_CTX *mdctx = NULL; long handlen; void *hdata; unsigned int hashlenui; const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session); insecret = s->early_secret; label = client_early_traffic; labellen = sizeof(client_early_traffic) - 1; log_label = CLIENT_EARLY_LABEL; handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata); if (handlen <= 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_HANDSHAKE_LENGTH); goto err; } if (s->early_data_state == SSL_EARLY_DATA_CONNECTING && s->max_early_data > 0 && s->session->ext.max_early_data == 0) { /* * If we are attempting to send early data, and we've decided to * actually do it but max_early_data in s->session is 0 then we * must be using an external PSK. */ if (!ossl_assert(s->psksession != NULL && s->max_early_data == s->psksession->ext.max_early_data)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); goto err; } sslcipher = SSL_SESSION_get0_cipher(s->psksession); } if (sslcipher == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK); goto err; } /* * We need to calculate the handshake digest using the digest from * the session. We haven't yet selected our ciphersuite so we can't * use ssl_handshake_md(). */ mdctx = EVP_MD_CTX_new(); if (mdctx == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); goto err; } cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher)); md = ssl_md(sslcipher->algorithm2); if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL) || !EVP_DigestUpdate(mdctx, hdata, handlen) || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); EVP_MD_CTX_free(mdctx); goto err; } hashlen = hashlenui; EVP_MD_CTX_free(mdctx); if (!tls13_hkdf_expand(s, md, insecret, early_exporter_master_secret, sizeof(early_exporter_master_secret) - 1, hashval, hashlen, s->early_exporter_master_secret, hashlen, 1)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); goto err; } if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL, s->early_exporter_master_secret, hashlen)) { /* SSLfatal() already called */ goto err; } } else if (which & SSL3_CC_HANDSHAKE) { insecret = s->handshake_secret; finsecret = s->client_finished_secret; finsecretlen = EVP_MD_size(ssl_handshake_md(s)); label = client_handshake_traffic; labellen = sizeof(client_handshake_traffic) - 1; log_label = CLIENT_HANDSHAKE_LABEL; /* * The handshake hash used for the server read/client write handshake * traffic secret is the same as the hash for the server * write/client read handshake traffic secret. However, if we * processed early data then we delay changing the server * read/client write cipher state until later, and the handshake * hashes have moved on. Therefore we use the value saved earlier * when we did the server write/client read change cipher state. */ hash = s->handshake_traffic_hash; } else { insecret = s->master_secret; label = client_application_traffic; labellen = sizeof(client_application_traffic) - 1; log_label = CLIENT_APPLICATION_LABEL; /* * For this we only use the handshake hashes up until the server * Finished hash. We do not include the client's Finished, which is * what ssl_handshake_hash() would give us. Instead we use the * previously saved value. */ hash = s->server_finished_hash; } } else { /* Early data never applies to client-read/server-write */ if (which & SSL3_CC_HANDSHAKE) { insecret = s->handshake_secret; finsecret = s->server_finished_secret; finsecretlen = EVP_MD_size(ssl_handshake_md(s)); label = server_handshake_traffic; labellen = sizeof(server_handshake_traffic) - 1; log_label = SERVER_HANDSHAKE_LABEL; } else { insecret = s->master_secret; label = server_application_traffic; labellen = sizeof(server_application_traffic) - 1; log_label = SERVER_APPLICATION_LABEL; } } if (!(which & SSL3_CC_EARLY)) { md = ssl_handshake_md(s); cipher = s->s3->tmp.new_sym_enc; if (!ssl3_digest_cached_records(s, 1) || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) { /* SSLfatal() already called */; goto err; } } /* * Save the hash of handshakes up to now for use when we calculate the * client application traffic secret */ if (label == server_application_traffic) memcpy(s->server_finished_hash, hashval, hashlen); if (label == server_handshake_traffic) memcpy(s->handshake_traffic_hash, hashval, hashlen); if (label == client_application_traffic) { /* * We also create the resumption master secret, but this time use the * hash for the whole handshake including the Client Finished */ if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret, resumption_master_secret, sizeof(resumption_master_secret) - 1, hashval, hashlen, s->resumption_master_secret, hashlen, 1)) { /* SSLfatal() already called */ goto err; } } if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher, insecret, hash, label, labellen, secret, iv, ciph_ctx)) { /* SSLfatal() already called */ goto err; } if (label == server_application_traffic) { memcpy(s->server_app_traffic_secret, secret, hashlen); /* Now we create the exporter master secret */ if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret, exporter_master_secret, sizeof(exporter_master_secret) - 1, hash, hashlen, s->exporter_master_secret, hashlen, 1)) { /* SSLfatal() already called */ goto err; } if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret, hashlen)) { /* SSLfatal() already called */ goto err; } } else if (label == client_application_traffic) memcpy(s->client_app_traffic_secret, secret, hashlen); if (!ssl_log_secret(s, log_label, secret, hashlen)) { /* SSLfatal() already called */ goto err; } if (finsecret != NULL && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret, finsecret, finsecretlen)) { /* SSLfatal() already called */ goto err; } if (!s->server && label == client_early_traffic) s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS; else s->statem.enc_write_state = ENC_WRITE_STATE_VALID; ret = 1; err: OPENSSL_cleanse(secret, sizeof(secret)); return ret; } int tls13_update_key(SSL *s, int sending) { static const unsigned char application_traffic[] = "traffic upd"; const EVP_MD *md = ssl_handshake_md(s); size_t hashlen = EVP_MD_size(md); unsigned char *insecret, *iv; unsigned char secret[EVP_MAX_MD_SIZE]; EVP_CIPHER_CTX *ciph_ctx; int ret = 0; if (s->server == sending) insecret = s->server_app_traffic_secret; else insecret = s->client_app_traffic_secret; if (sending) { s->statem.enc_write_state = ENC_WRITE_STATE_INVALID; iv = s->write_iv; ciph_ctx = s->enc_write_ctx; RECORD_LAYER_reset_write_sequence(&s->rlayer); } else { iv = s->read_iv; ciph_ctx = s->enc_read_ctx; RECORD_LAYER_reset_read_sequence(&s->rlayer); } if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s), s->s3->tmp.new_sym_enc, insecret, NULL, application_traffic, sizeof(application_traffic) - 1, secret, iv, ciph_ctx)) { /* SSLfatal() already called */ goto err; } memcpy(insecret, secret, hashlen); s->statem.enc_write_state = ENC_WRITE_STATE_VALID; ret = 1; err: OPENSSL_cleanse(secret, sizeof(secret)); return ret; } int tls13_alert_code(int code) { /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */ if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED) return code; return tls1_alert_code(code); } int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen, const char *label, size_t llen, const unsigned char *context, size_t contextlen, int use_context) { unsigned char exportsecret[EVP_MAX_MD_SIZE]; static const unsigned char exporterlabel[] = "exporter"; unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE]; const EVP_MD *md = ssl_handshake_md(s); EVP_MD_CTX *ctx = EVP_MD_CTX_new(); unsigned int hashsize, datalen; int ret = 0; if (ctx == NULL || !ossl_statem_export_allowed(s)) goto err; if (!use_context) contextlen = 0; if (EVP_DigestInit_ex(ctx, md, NULL) <= 0 || EVP_DigestUpdate(ctx, context, contextlen) <= 0 || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0 || EVP_DigestInit_ex(ctx, md, NULL) <= 0 || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 || !tls13_hkdf_expand(s, md, s->exporter_master_secret, (const unsigned char *)label, llen, data, datalen, exportsecret, hashsize, 0) || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, sizeof(exporterlabel) - 1, hash, hashsize, out, olen, 0)) goto err; ret = 1; err: EVP_MD_CTX_free(ctx); return ret; } int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen, const char *label, size_t llen, const unsigned char *context, size_t contextlen) { static const unsigned char exporterlabel[] = "exporter"; unsigned char exportsecret[EVP_MAX_MD_SIZE]; unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE]; const EVP_MD *md; EVP_MD_CTX *ctx = EVP_MD_CTX_new(); unsigned int hashsize, datalen; int ret = 0; const SSL_CIPHER *sslcipher; if (ctx == NULL || !ossl_statem_export_early_allowed(s)) goto err; if (!s->server && s->max_early_data > 0 && s->session->ext.max_early_data == 0) sslcipher = SSL_SESSION_get0_cipher(s->psksession); else sslcipher = SSL_SESSION_get0_cipher(s->session); md = ssl_md(sslcipher->algorithm2); /* * Calculate the hash value and store it in |data|. The reason why * the empty string is used is that the definition of TLS-Exporter * is like so: * * TLS-Exporter(label, context_value, key_length) = * HKDF-Expand-Label(Derive-Secret(Secret, label, ""), * "exporter", Hash(context_value), key_length) * * Derive-Secret(Secret, Label, Messages) = * HKDF-Expand-Label(Secret, Label, * Transcript-Hash(Messages), Hash.length) * * Here Transcript-Hash is the cipher suite hash algorithm. */ if (EVP_DigestInit_ex(ctx, md, NULL) <= 0 || EVP_DigestUpdate(ctx, context, contextlen) <= 0 || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0 || EVP_DigestInit_ex(ctx, md, NULL) <= 0 || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret, (const unsigned char *)label, llen, data, datalen, exportsecret, hashsize, 0) || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, sizeof(exporterlabel) - 1, hash, hashsize, out, olen, 0)) goto err; ret = 1; err: EVP_MD_CTX_free(ctx); return ret; }