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;
}
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;
}
/*
* Construct the pre_shared_key extension
*/
int tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
size_t chainidx, int *al)
{
#ifndef OPENSSL_NO_TLS1_3
uint32_t now, agesec, agems;
size_t hashsize, binderoffset, msglen;
unsigned char *binder = NULL, *msgstart = NULL;
const EVP_MD *md;
int ret = 0;
s->session->ext.tick_identity = TLSEXT_PSK_BAD_IDENTITY;
/*
* If this is an incompatible or new session then we have nothing to resume
* so don't add this extension.
*/
if (s->session->ssl_version != TLS1_3_VERSION
|| s->session->ext.ticklen == 0)
return 1;
if (s->session->cipher == NULL) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
goto err;
}
md = ssl_md(s->session->cipher->algorithm2);
if (md == NULL) {
/* Don't recognise this cipher so we can't use the session. Ignore it */
return 1;
}
/*
* Technically the C standard just says time() returns a time_t and says
* nothing about the encoding of that type. In practice most implementations
* follow POSIX which holds it as an integral type in seconds since epoch.
* We've already made the assumption that we can do this in multiple places
* in the code, so portability shouldn't be an issue.
*/
now = (uint32_t)time(NULL);
agesec = now - (uint32_t)s->session->time;
if (s->session->ext.tick_lifetime_hint < agesec) {
/* Ticket is too old. Ignore it. */
return 1;
}
/*
* Calculate age in ms. We're just doing it to nearest second. Should be
* good enough.
*/
agems = agesec * (uint32_t)1000;
if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
/*
* Overflow. Shouldn't happen unless this is a *really* old session. If
* so we just ignore it.
*/
return 1;
}
/*
* Obfuscate the age. Overflow here is fine, this addition is supposed to
* be mod 2^32.
*/
agems += s->session->ext.tick_age_add;
hashsize = EVP_MD_size(md);
/* Create the extension, but skip over the binder for now */
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
s->session->ext.ticklen)
|| !WPACKET_put_bytes_u32(pkt, agems)
|| !WPACKET_close(pkt)
|| !WPACKET_get_total_written(pkt, &binderoffset)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_sub_allocate_bytes_u8(pkt, hashsize, &binder)
|| !WPACKET_close(pkt)
|| !WPACKET_close(pkt)
|| !WPACKET_get_total_written(pkt, &msglen)
/*
* We need to fill in all the sub-packet lengths now so we can
* calculate the HMAC of the message up to the binders
*/
|| !WPACKET_fill_lengths(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
goto err;
}
msgstart = WPACKET_get_curr(pkt) - msglen;
if (tls_psk_do_binder(s, md, msgstart, binderoffset, NULL, binder,
s->session, 1) != 1) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
goto err;
}
s->session->ext.tick_identity = 0;
ret = 1;
err:
return ret;
#else
return 1;
#endif
}
int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
size_t chainidx, int *al)
{
PACKET identities, binders, binder;
size_t binderoffset, hashsize;
SSL_SESSION *sess = NULL;
unsigned int id, i, ext = 0;
const EVP_MD *md = NULL;
/*
* If we have no PSK kex mode that we recognise then we can't resume so
* ignore this extension
*/
if ((s->ext.psk_kex_mode
& (TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE)) == 0)
return 1;
if (!PACKET_get_length_prefixed_2(pkt, &identities)) {
*al = SSL_AD_DECODE_ERROR;
return 0;
}
for (id = 0; PACKET_remaining(&identities) != 0; id++) {
PACKET identity;
unsigned long ticket_agel;
if (!PACKET_get_length_prefixed_2(&identities, &identity)
|| !PACKET_get_net_4(&identities, &ticket_agel)) {
*al = SSL_AD_DECODE_ERROR;
return 0;
}
if (s->psk_find_session_cb != NULL
&& !s->psk_find_session_cb(s, PACKET_data(&identity),
PACKET_remaining(&identity),
&sess)) {
*al = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (sess != NULL) {
/* We found a PSK */
SSL_SESSION *sesstmp = ssl_session_dup(sess, 0);
if (sesstmp == NULL) {
*al = SSL_AD_INTERNAL_ERROR;
return 0;
}
SSL_SESSION_free(sess);
sess = sesstmp;
/*
* We've just been told to use this session for this context so
* make sure the sid_ctx matches up.
*/
memcpy(sess->sid_ctx, s->sid_ctx, s->sid_ctx_length);
sess->sid_ctx_length = s->sid_ctx_length;
ext = 1;
} else {
uint32_t ticket_age = 0, now, agesec, agems;
int ret = tls_decrypt_ticket(s, PACKET_data(&identity),
PACKET_remaining(&identity), NULL, 0,
&sess);
if (ret == TICKET_FATAL_ERR_MALLOC
|| ret == TICKET_FATAL_ERR_OTHER) {
*al = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (ret == TICKET_NO_DECRYPT)
continue;
ticket_age = (uint32_t)ticket_agel;
now = (uint32_t)time(NULL);
agesec = now - (uint32_t)sess->time;
agems = agesec * (uint32_t)1000;
ticket_age -= sess->ext.tick_age_add;
/*
* For simplicity we do our age calculations in seconds. If the
* client does it in ms then it could appear that their ticket age
* is longer than ours (our ticket age calculation should always be
* slightly longer than the client's due to the network latency).
* Therefore we add 1000ms to our age calculation to adjust for
* rounding errors.
*/
if (sess->timeout >= (long)agesec
&& agems / (uint32_t)1000 == agesec
&& ticket_age <= agems + 1000
&& ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
/*
* Ticket age is within tolerance and not expired. We allow it
* for early data
*/
s->ext.early_data_ok = 1;
}
}
md = ssl_md(sess->cipher->algorithm2);
if (md != ssl_md(s->s3->tmp.new_cipher->algorithm2)) {
/* The ciphersuite is not compatible with this session. */
SSL_SESSION_free(sess);
sess = NULL;
continue;
}
break;
}
if (sess == NULL)
return 1;
binderoffset = PACKET_data(pkt) - (const unsigned char *)s->init_buf->data;
hashsize = EVP_MD_size(md);
if (!PACKET_get_length_prefixed_2(pkt, &binders)) {
*al = SSL_AD_DECODE_ERROR;
goto err;
}
for (i = 0; i <= id; i++) {
if (!PACKET_get_length_prefixed_1(&binders, &binder)) {
*al = SSL_AD_DECODE_ERROR;
goto err;
}
}
if (PACKET_remaining(&binder) != hashsize
|| tls_psk_do_binder(s, md,
(const unsigned char *)s->init_buf->data,
binderoffset, PACKET_data(&binder), NULL,
sess, 0, ext) != 1) {
*al = SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
goto err;
}
sess->ext.tick_identity = id;
SSL_SESSION_free(s->session);
s->session = sess;
return 1;
err:
SSL_SESSION_free(sess);
return 0;
}
int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
size_t chainidx, int *al)
{
PACKET identities, binders, binder;
size_t binderoffset, hashsize;
SSL_SESSION *sess = NULL;
unsigned int id, i;
const EVP_MD *md = NULL;
uint32_t ticket_age = 0, now, agesec, agems;
/*
* If we have no PSK kex mode that we recognise then we can't resume so
* ignore this extension
*/
if ((s->ext.psk_kex_mode
& (TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE)) == 0)
return 1;
if (!PACKET_get_length_prefixed_2(pkt, &identities)) {
*al = SSL_AD_DECODE_ERROR;
return 0;
}
for (id = 0; PACKET_remaining(&identities) != 0; id++) {
PACKET identity;
unsigned long ticket_agel;
int ret;
if (!PACKET_get_length_prefixed_2(&identities, &identity)
|| !PACKET_get_net_4(&identities, &ticket_agel)) {
*al = SSL_AD_DECODE_ERROR;
return 0;
}
ticket_age = (uint32_t)ticket_agel;
ret = tls_decrypt_ticket(s, PACKET_data(&identity),
PACKET_remaining(&identity), NULL, 0, &sess);
if (ret == TICKET_FATAL_ERR_MALLOC || ret == TICKET_FATAL_ERR_OTHER) {
*al = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (ret == TICKET_NO_DECRYPT)
continue;
md = ssl_md(sess->cipher->algorithm2);
if (md == NULL) {
/*
* Don't recognise this cipher so we can't use the session.
* Ignore it
*/
SSL_SESSION_free(sess);
sess = NULL;
continue;
}
/*
* TODO(TLS1.3): Somehow we need to handle the case of a ticket renewal.
* Ignored for now
*/
break;
}
if (sess == NULL)
return 1;
binderoffset = PACKET_data(pkt) - (const unsigned char *)s->init_buf->data;
hashsize = EVP_MD_size(md);
if (!PACKET_get_length_prefixed_2(pkt, &binders)) {
*al = SSL_AD_DECODE_ERROR;
goto err;
}
for (i = 0; i <= id; i++) {
if (!PACKET_get_length_prefixed_1(&binders, &binder)) {
*al = SSL_AD_DECODE_ERROR;
goto err;
}
}
if (PACKET_remaining(&binder) != hashsize
|| tls_psk_do_binder(s, md,
(const unsigned char *)s->init_buf->data,
binderoffset, PACKET_data(&binder), NULL,
sess, 0) != 1) {
*al = SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
goto err;
}
sess->ext.tick_identity = id;
now = (uint32_t)time(NULL);
agesec = now - (uint32_t)sess->time;
agems = agesec * (uint32_t)1000;
ticket_age -= sess->ext.tick_age_add;
/*
* For simplicity we do our age calculations in seconds. If the client does
* it in ms then it could appear that their ticket age is longer than ours
* (our ticket age calculation should always be slightly longer than the
* client's due to the network latency). Therefore we add 1000ms to our age
* calculation to adjust for rounding errors.
*/
if (sess->timeout >= (long)agesec
&& agems / (uint32_t)1000 == agesec
&& ticket_age <= agems + 1000
&& ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
/*
* Ticket age is within tolerance and not expired. We allow it for early
* data
*/
s->ext.early_data_ok = 1;
}
SSL_SESSION_free(s->session);
s->session = sess;
return 1;
err:
SSL_SESSION_free(sess);
return 0;
}
