X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=ssl%2Ftls13_enc.c;h=44d8ba9eb1bc2c4b2252f693d2a0baad2d644c4e;hp=db8de1d1ca29c64d966364d5efd00eacb860e7ff;hb=7f6b466b2cca843dd9d12fd547489100327beb3e;hpb=c117af6765928f3fc61585b01f5d722162914d80 diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c index db8de1d1ca..44d8ba9eb1 100644 --- a/ssl/tls13_enc.c +++ b/ssl/tls13_enc.c @@ -18,17 +18,17 @@ static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; /* - * Given a |secret|; a |label| of length |labellen|; and a |hash| of the - * handshake messages, derive a new secret |outlen| bytes long and store it in - * the location pointed to be |out|. The |hash| value may be NULL. Returns 1 on - * success 0 on failure. + * 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 *hash, + const unsigned char *data, size_t datalen, unsigned char *out, size_t outlen) { - const unsigned char label_prefix[] = "TLS 1.3, "; + const unsigned char label_prefix[] = "tls13 "; EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); int ret; size_t hkdflabellen; @@ -53,7 +53,7 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1) || !WPACKET_memcpy(&pkt, label, labellen) || !WPACKET_close(&pkt) - || !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen) + || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen) || !WPACKET_get_total_written(&pkt, &hkdflabellen) || !WPACKET_finish(&pkt)) { EVP_PKEY_CTX_free(pctx); @@ -84,7 +84,7 @@ int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret, static const unsigned char keylabel[] = "key"; return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1, - NULL, key, keylen); + NULL, 0, key, keylen); } /* @@ -97,7 +97,7 @@ int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret, static const unsigned char ivlabel[] = "iv"; return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1, - NULL, iv, ivlen); + NULL, 0, iv, ivlen); } int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, @@ -107,7 +107,7 @@ int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, static const unsigned char finishedlabel[] = "finished"; return tls13_hkdf_expand(s, md, secret, finishedlabel, - sizeof(finishedlabel) - 1, NULL, fin, finlen); + sizeof(finishedlabel) - 1, NULL, 0, fin, finlen); } /* @@ -124,6 +124,8 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md, size_t mdlen, prevsecretlen; 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) return 0; @@ -138,6 +140,29 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md, 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) { + 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)) { + EVP_PKEY_CTX_free(pctx); + return 0; + } + + prevsecret = preextractsec; prevsecretlen = mdlen; } @@ -152,6 +177,8 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md, <= 0; EVP_PKEY_CTX_free(pctx); + if (prevsecret == preextractsec) + OPENSSL_cleanse(preextractsec, mdlen); return ret == 0; } @@ -243,7 +270,7 @@ int tls13_setup_key_block(SSL *s) return 1; } -static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md, +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, @@ -255,8 +282,8 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md, size_t ivlen, keylen, taglen; size_t hashlen = EVP_MD_size(md); - if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, secret, - hashlen)) { + if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen, + secret, hashlen)) { SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR); goto err; } @@ -288,7 +315,7 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md, goto err; } - if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, send) <= 0 + 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)) @@ -297,20 +324,6 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md, goto err; } -#ifdef OPENSSL_SSL_TRACE_CRYPTO - if (s->msg_callback) { - int wh = send ? TLS1_RT_CRYPTO_WRITE : 0; - - if (ciph->key_len) - s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_KEY, - key, ciph->key_len, s, s->msg_callback_arg); - - wh |= TLS1_RT_CRYPTO_IV; - s->msg_callback(2, s->version, wh, iv, ivlen, s, - s->msg_callback_arg); - } -#endif - return 1; err: OPENSSL_cleanse(key, sizeof(key)); @@ -319,18 +332,13 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md, int tls13_change_cipher_state(SSL *s, int which) { - static const unsigned char client_early_traffic[] = - "client early traffic secret"; - static const unsigned char client_handshake_traffic[] = - "client handshake traffic secret"; - static const unsigned char client_application_traffic[] = - "client application traffic secret"; - static const unsigned char server_handshake_traffic[] = - "server handshake traffic secret"; - static const unsigned char server_application_traffic[] = - "server application traffic secret"; - static const unsigned char resumption_master_secret[] = - "resumption master secret"; + 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"; unsigned char *iv; unsigned char secret[EVP_MAX_MD_SIZE]; unsigned char hashval[EVP_MAX_MD_SIZE]; @@ -343,8 +351,8 @@ int tls13_change_cipher_state(SSL *s, int which) const unsigned char *label; size_t labellen, hashlen = 0; int ret = 0; - const EVP_MD *md; - const EVP_CIPHER *cipher; + const EVP_MD *md = NULL; + const EVP_CIPHER *cipher = NULL; if (which & SSL3_CC_READ) { if (s->enc_read_ctx != NULL) { @@ -430,15 +438,15 @@ int tls13_change_cipher_state(SSL *s, int which) labellen = sizeof(client_handshake_traffic) - 1; log_label = CLIENT_HANDSHAKE_LABEL; /* - * The hanshake hash used for the server read handshake traffic - * secret is the same as the hash for the server write handshake - * traffic secret. However, if we processed early data then we delay - * changing the server read cipher state until later, and the - * handshake hashes have moved on. Therefore we use the value saved - * earlier when we did the server write change cipher state. + * 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. */ - if (s->server) - hash = s->handshake_traffic_hash; + hash = s->handshake_traffic_hash; } else { insecret = s->master_secret; label = client_application_traffic; @@ -486,7 +494,7 @@ int tls13_change_cipher_state(SSL *s, int which) if (label == server_application_traffic) memcpy(s->server_finished_hash, hashval, hashlen); - if (s->server && label == server_handshake_traffic) + if (label == server_handshake_traffic) memcpy(s->handshake_traffic_hash, hashval, hashlen); if (label == client_application_traffic) { @@ -497,11 +505,22 @@ int tls13_change_cipher_state(SSL *s, int which) if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret, resumption_master_secret, sizeof(resumption_master_secret) - 1, - hashval, s->session->master_key, hashlen)) { + hashval, hashlen, s->session->master_key, + hashlen)) { SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); goto err; } s->session->master_key_length = 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)) { + SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); + goto err; + } } if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher, @@ -533,10 +552,9 @@ int tls13_change_cipher_state(SSL *s, int which) return ret; } -int tls13_update_key(SSL *s, int send) +int tls13_update_key(SSL *s, int sending) { - static const unsigned char application_traffic[] = - "application traffic secret"; + 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; @@ -544,12 +562,12 @@ int tls13_update_key(SSL *s, int send) EVP_CIPHER_CTX *ciph_ctx; int ret = 0; - if (s->server == send) + if (s->server == sending) insecret = s->server_app_traffic_secret; else insecret = s->client_app_traffic_secret; - if (send) { + if (sending) { iv = s->write_iv; ciph_ctx = s->enc_write_ctx; RECORD_LAYER_reset_write_sequence(&s->rlayer); @@ -559,7 +577,7 @@ int tls13_update_key(SSL *s, int send) RECORD_LAYER_reset_read_sequence(&s->rlayer); } - if (!derive_secret_key_and_iv(s, send, ssl_handshake_md(s), + 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, @@ -576,8 +594,44 @@ int tls13_update_key(SSL *s, int send) int tls13_alert_code(int code) { - if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_END_OF_EARLY_DATA) + if (code == SSL_AD_MISSING_EXTENSION) 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]; + const EVP_MD *md = ssl_handshake_md(s); + EVP_MD_CTX *ctx = EVP_MD_CTX_new(); + unsigned int hashsize; + int ret = 0; + + if (ctx == NULL || !SSL_is_init_finished(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 + || !tls13_hkdf_expand(s, md, s->exporter_master_secret, + (const unsigned char *)label, llen, NULL, 0, + 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; +}