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openssl/ssl/tls13_enc.c
Matt Caswell 7426cd343d Ensure that we write out alerts correctly after early_data 
If we sent early_data and then received back an HRR, the enc_write_ctx
was stale resulting in errors if an alert needed to be sent.

Thanks to Quarkslab for reporting this.

In any case it makes little sense to encrypt alerts using the
client_early_traffic_secret, so we add special handling for alerts sent
after early_data. All such alerts are sent in plaintext.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6887)
2018-08-08 10:16:58 +01:00

809 lines
30 KiB
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/*
* 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);
}
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;
}
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