diff options
Diffstat (limited to 'ssl/tls13_enc.c')
| -rw-r--r-- | ssl/tls13_enc.c | 810 |
1 files changed, 810 insertions, 0 deletions
diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c new file mode 100644 index 000000000000..f7ab0fa47040 --- /dev/null +++ b/ssl/tls13_enc.c @@ -0,0 +1,810 @@ +/* + * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (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 <stdlib.h> +#include "ssl_locl.h" +#include "internal/cryptlib.h" +#include <openssl/evp.h> +#include <openssl/kdf.h> + +#define TLS13_MAX_LABEL_LEN 246 + +/* 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. 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) +{ + 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 whole HkdfLabel + 1 byte for length of combined + * prefix and label + bytes for the label itself + bytes for the hash + */ + unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) + + + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN + + EVP_MAX_MD_SIZE]; + WPACKET pkt; + + if (pctx == NULL) + 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); + SSLfatal(s, SSL_AD_INTERNAL_ERROR, 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) + SSLfatal(s, SSL_AD_INTERNAL_ERROR, 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); +} + +/* + * 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); +} + +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); +} + +/* + * 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)) { + /* 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; + int mac_type = NID_undef; + + s->session->cipher = s->s3->tmp.new_cipher; + if (!ssl_cipher_get_evp + (s->session, &c, &hash, &mac_type, 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)) { + /* 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)) { + 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)) { + /* 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)) { + /* 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) + || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, + sizeof(exporterlabel) - 1, hash, hashsize, + out, olen)) + 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) + || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, + sizeof(exporterlabel) - 1, hash, hashsize, + out, olen)) + goto err; + + ret = 1; + err: + EVP_MD_CTX_free(ctx); + return ret; +} |