kris/boringssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
4eb95ccfd6
boringssl/ssl/tls13_server.c
David Benjamin 4eb95ccfd6 Parse ClientHello extensions before deciding on resumption. 
This simplifies a little code around EMS and PSK KE modes, but requires
tweaking the SNI code.

The extensions that are more tightly integrated with the handshake are
still processed inline for now. It does, however, require an extra state
in 1.2 so the asynchronous session callback does not cause extensions to
be processed twice. Tweak a test enforce this.

This and a follow-up to move cert_cb before resumption are done in
preparation for resolving the cipher suite before resumption and only
resuming on match.

Note this has caller-visible effects:

- The legacy SNI callback happens before resumption.

- The ALPN callback happens before resumption.

- Custom extension ClientHello parsing callbacks also cannot depend on
  resumption state.

- The DoS protection callback now runs after all the extension callbacks
  as it is documented to be called after the resumption decision.

BUG=116

Change-Id: I1281a3b61789b95c370314aaed4f04c1babbc65f
Reviewed-on: https://boringssl-review.googlesource.com/11845
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2016-11-16 23:58:02 +00:00

766 lines
24 KiB
C
Raw Blame History

/* Copyright (c) 2016, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/ssl.h>
#include <assert.h>
#include <string.h>
#include <openssl/aead.h>
#include <openssl/bytestring.h>
#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/rand.h>
#include <openssl/stack.h>
#include "internal.h"
enum server_hs_state_t {
state_process_client_hello = 0,
state_select_parameters,
state_send_hello_retry_request,
state_flush_hello_retry_request,
state_process_second_client_hello,
state_send_server_hello,
state_send_encrypted_extensions,
state_send_certificate_request,
state_send_server_certificate,
state_send_server_certificate_verify,
state_complete_server_certificate_verify,
state_send_server_finished,
state_flush,
state_process_client_certificate,
state_process_client_certificate_verify,
state_process_channel_id,
state_process_client_finished,
state_send_new_session_ticket,
state_flush_new_session_tickets,
state_done,
};
static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
static int resolve_ecdhe_secret(SSL *ssl, int *out_need_retry,
struct ssl_early_callback_ctx *early_ctx) {
*out_need_retry = 0;
/* We only support connections that include an ECDHE key exchange. */
CBS key_share;
if (!ssl_early_callback_get_extension(early_ctx, &key_share,
TLSEXT_TYPE_key_share)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
return 0;
}
int found_key_share;
uint8_t *dhe_secret;
size_t dhe_secret_len;
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ssl_ext_key_share_parse_clienthello(ssl, &found_key_share, &dhe_secret,
&dhe_secret_len, &alert,
&key_share)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return 0;
}
if (!found_key_share) {
*out_need_retry = 1;
return 0;
}
int ok = tls13_advance_key_schedule(ssl, dhe_secret, dhe_secret_len);
OPENSSL_free(dhe_secret);
return ok;
}
static enum ssl_hs_wait_t do_process_client_hello(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!tls13_check_message_type(ssl, SSL3_MT_CLIENT_HELLO)) {
return ssl_hs_error;
}
struct ssl_early_callback_ctx client_hello;
if (!ssl_early_callback_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
assert(ssl->s3->have_version);
/* Load the client random. */
if (client_hello.random_len != SSL3_RANDOM_SIZE) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
memcpy(ssl->s3->client_random, client_hello.random, client_hello.random_len);
/* TLS 1.3 requires the peer only advertise the null compression. */
if (client_hello.compression_methods_len != 1 ||
client_hello.compression_methods[0] != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
/* TLS extensions. */
if (!ssl_parse_clienthello_tlsext(ssl, &client_hello)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
return ssl_hs_error;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
SSL_SESSION *session = NULL;
CBS pre_shared_key, binders;
if (hs->accept_psk_mode &&
ssl_early_callback_get_extension(&client_hello, &pre_shared_key,
TLSEXT_TYPE_pre_shared_key)) {
/* Verify that the pre_shared_key extension is the last extension in
* ClientHello. */
if (CBS_data(&pre_shared_key) + CBS_len(&pre_shared_key) !=
client_hello.extensions + client_hello.extensions_len) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PRE_SHARED_KEY_MUST_BE_LAST);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (!ssl_ext_pre_shared_key_parse_clienthello(ssl, &session, &binders,
&alert, &pre_shared_key)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
}
if (session != NULL &&
!ssl_session_is_resumable(ssl, session)) {
SSL_SESSION_free(session);
session = NULL;
}
if (session == NULL) {
if (!ssl_get_new_session(ssl, 1 /* server */)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
} else {
/* Check the PSK binder. */
if (!tls13_verify_psk_binder(ssl, session, &binders)) {
SSL_SESSION_free(session);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return ssl_hs_error;
}
/* Only authentication information carries over in TLS 1.3. */
ssl->s3->new_session = SSL_SESSION_dup(session, SSL_SESSION_DUP_AUTH_ONLY);
if (ssl->s3->new_session == NULL) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
ssl->s3->session_reused = 1;
SSL_SESSION_free(session);
}
if (ssl->ctx->dos_protection_cb != NULL &&
ssl->ctx->dos_protection_cb(&client_hello) == 0) {
/* Connection rejected for DOS reasons. */
OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
hs->state = state_select_parameters;
return ssl_hs_ok;
}
static const SSL_CIPHER *choose_tls13_cipher(
const SSL *ssl, const struct ssl_early_callback_ctx *client_hello) {
if (client_hello->cipher_suites_len % 2 != 0) {
return NULL;
}
CBS cipher_suites;
CBS_init(&cipher_suites, client_hello->cipher_suites,
client_hello->cipher_suites_len);
const int aes_is_fine = EVP_has_aes_hardware();
const SSL_CIPHER *best = NULL;
while (CBS_len(&cipher_suites) > 0) {
uint16_t cipher_suite;
if (!CBS_get_u16(&cipher_suites, &cipher_suite)) {
return NULL;
}
const SSL_CIPHER *candidate = SSL_get_cipher_by_value(cipher_suite);
if (candidate == NULL || !ssl_is_valid_cipher(ssl, candidate)) {
continue;
}
/* TLS 1.3 removes legacy ciphers, so honor the client order, but prefer
* ChaCha20 if we do not have AES hardware. */
if (aes_is_fine) {
return candidate;
}
if (candidate->algorithm_enc == SSL_CHACHA20POLY1305) {
return candidate;
}
if (best == NULL) {
best = candidate;
}
}
return best;
}
static enum ssl_hs_wait_t do_select_parameters(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!ssl->s3->session_reused) {
/* Call |cert_cb| to update server certificates if required. */
if (ssl->cert->cert_cb != NULL) {
int rv = ssl->cert->cert_cb(ssl, ssl->cert->cert_cb_arg);
if (rv == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
if (rv < 0) {
hs->state = state_select_parameters;
return ssl_hs_x509_lookup;
}
}
}
struct ssl_early_callback_ctx client_hello;
if (!ssl_early_callback_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
if (ssl->s3->session_reused) {
/* Clients may not offer sessions containing unsupported ciphers. */
if (!ssl_client_cipher_list_contains_cipher(
&client_hello,
(uint16_t)SSL_CIPHER_get_id(ssl->s3->new_session->cipher))) {
OPENSSL_PUT_ERROR(SSL, SSL_R_REQUIRED_CIPHER_MISSING);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
} else {
const SSL_CIPHER *cipher = choose_tls13_cipher(ssl, &client_hello);
if (cipher == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
ssl->s3->new_session->cipher = cipher;
/* On new sessions, stash the SNI value in the session. */
if (ssl->s3->hs->hostname != NULL) {
ssl->s3->new_session->tlsext_hostname = BUF_strdup(ssl->s3->hs->hostname);
if (ssl->s3->new_session->tlsext_hostname == NULL) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
}
}
ssl->s3->tmp.new_cipher = ssl->s3->new_session->cipher;
ssl->method->received_flight(ssl);
/* Resolve ALPN after the cipher suite is selected. HTTP/2 negotiation depends
* on the cipher suite. */
uint8_t alert;
if (!ssl_negotiate_alpn(ssl, &alert, &client_hello)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
/* The PRF hash is now known. */
size_t hash_len =
EVP_MD_size(ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl)));
/* Derive resumption material. */
uint8_t psk_secret[EVP_MAX_MD_SIZE] = {0};
if (ssl->s3->session_reused) {
if (hash_len != (size_t) ssl->s3->new_session->master_key_length) {
return ssl_hs_error;
}
memcpy(psk_secret, ssl->s3->new_session->master_key, hash_len);
}
/* Set up the key schedule, hash in the ClientHello, and incorporate the PSK
* into the running secret. */
if (!tls13_init_key_schedule(ssl) ||
!tls13_advance_key_schedule(ssl, psk_secret, hash_len)) {
return ssl_hs_error;
}
/* Resolve ECDHE and incorporate it into the secret. */
int need_retry;
if (!resolve_ecdhe_secret(ssl, &need_retry, &client_hello)) {
if (need_retry) {
hs->state = state_send_hello_retry_request;
return ssl_hs_ok;
}
return ssl_hs_error;
}
hs->state = state_send_server_hello;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_hello_retry_request(SSL *ssl,
SSL_HANDSHAKE *hs) {
CBB cbb, body, extensions;
uint16_t group_id;
if (!ssl->method->init_message(ssl, &cbb, &body,
SSL3_MT_HELLO_RETRY_REQUEST) ||
!CBB_add_u16(&body, ssl->version) ||
!tls1_get_shared_group(ssl, &group_id) ||
!CBB_add_u16_length_prefixed(&body, &extensions) ||
!CBB_add_u16(&extensions, TLSEXT_TYPE_key_share) ||
!CBB_add_u16(&extensions, 2 /* length */) ||
!CBB_add_u16(&extensions, group_id) ||
!ssl_complete_message(ssl, &cbb)) {
CBB_cleanup(&cbb);
return ssl_hs_error;
}
hs->state = state_flush_hello_retry_request;
return ssl_hs_write_message;
}
static enum ssl_hs_wait_t do_flush_hello_retry_request(SSL *ssl,
SSL_HANDSHAKE *hs) {
hs->state = state_process_second_client_hello;
return ssl_hs_flush_and_read_message;
}
static enum ssl_hs_wait_t do_process_second_client_hello(SSL *ssl,
SSL_HANDSHAKE *hs) {
if (!tls13_check_message_type(ssl, SSL3_MT_CLIENT_HELLO)) {
return ssl_hs_error;
}
struct ssl_early_callback_ctx client_hello;
if (!ssl_early_callback_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_PARSE_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
int need_retry;
if (!resolve_ecdhe_secret(ssl, &need_retry, &client_hello)) {
if (need_retry) {
/* Only send one HelloRetryRequest. */
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
}
return ssl_hs_error;
}
if (!ssl_hash_current_message(ssl)) {
return ssl_hs_error;
}
ssl->method->received_flight(ssl);
hs->state = state_send_server_hello;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_server_hello(SSL *ssl, SSL_HANDSHAKE *hs) {
CBB cbb, body, extensions;
if (!ssl->method->init_message(ssl, &cbb, &body, SSL3_MT_SERVER_HELLO) ||
!CBB_add_u16(&body, ssl->version) ||
!RAND_bytes(ssl->s3->server_random, sizeof(ssl->s3->server_random)) ||
!CBB_add_bytes(&body, ssl->s3->server_random, SSL3_RANDOM_SIZE) ||
!CBB_add_u16(&body, ssl_cipher_get_value(ssl->s3->tmp.new_cipher)) ||
!CBB_add_u16_length_prefixed(&body, &extensions) ||
!ssl_ext_pre_shared_key_add_serverhello(ssl, &extensions) ||
!ssl_ext_key_share_add_serverhello(ssl, &extensions) ||
!ssl_complete_message(ssl, &cbb)) {
goto err;
}
hs->state = state_send_encrypted_extensions;
return ssl_hs_write_message;
err:
CBB_cleanup(&cbb);
return ssl_hs_error;
}
static enum ssl_hs_wait_t do_send_encrypted_extensions(SSL *ssl,
SSL_HANDSHAKE *hs) {
if (!tls13_set_handshake_traffic(ssl)) {
return ssl_hs_error;
}
CBB cbb, body;
if (!ssl->method->init_message(ssl, &cbb, &body,
SSL3_MT_ENCRYPTED_EXTENSIONS) ||
!ssl_add_serverhello_tlsext(ssl, &body) ||
!ssl_complete_message(ssl, &cbb)) {
CBB_cleanup(&cbb);
return ssl_hs_error;
}
hs->state = state_send_certificate_request;
return ssl_hs_write_message;
}
static enum ssl_hs_wait_t do_send_certificate_request(SSL *ssl,
SSL_HANDSHAKE *hs) {
/* Determine whether to request a client certificate. */
ssl->s3->hs->cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER);
/* CertificateRequest may only be sent in non-resumption handshakes. */
if (ssl->s3->session_reused) {
ssl->s3->hs->cert_request = 0;
}
if (!ssl->s3->hs->cert_request) {
/* Skip this state. */
hs->state = state_send_server_certificate;
return ssl_hs_ok;
}
CBB cbb, body, sigalgs_cbb;
if (!ssl->method->init_message(ssl, &cbb, &body,
SSL3_MT_CERTIFICATE_REQUEST) ||
!CBB_add_u8(&body, 0 /* no certificate_request_context. */)) {
goto err;
}
const uint16_t *sigalgs;
size_t num_sigalgs = tls12_get_verify_sigalgs(ssl, &sigalgs);
if (!CBB_add_u16_length_prefixed(&body, &sigalgs_cbb)) {
goto err;
}
for (size_t i = 0; i < num_sigalgs; i++) {
if (!CBB_add_u16(&sigalgs_cbb, sigalgs[i])) {
goto err;
}
}
if (!ssl_add_client_CA_list(ssl, &body) ||
!CBB_add_u16(&body, 0 /* empty certificate_extensions. */) ||
!ssl_complete_message(ssl, &cbb)) {
goto err;
}
hs->state = state_send_server_certificate;
return ssl_hs_write_message;
err:
CBB_cleanup(&cbb);
return ssl_hs_error;
}
static enum ssl_hs_wait_t do_send_server_certificate(SSL *ssl,
SSL_HANDSHAKE *hs) {
if (ssl->s3->session_reused) {
hs->state = state_send_server_finished;
return ssl_hs_ok;
}
if (!ssl_has_certificate(ssl)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
return ssl_hs_error;
}
if (!tls13_prepare_certificate(ssl)) {
return ssl_hs_error;
}
hs->state = state_send_server_certificate_verify;
return ssl_hs_write_message;
}
static enum ssl_hs_wait_t do_send_server_certificate_verify(SSL *ssl,
SSL_HANDSHAKE *hs,
int is_first_run) {
switch (tls13_prepare_certificate_verify(ssl, is_first_run)) {
case ssl_private_key_success:
hs->state = state_send_server_finished;
return ssl_hs_write_message;
case ssl_private_key_retry:
hs->state = state_complete_server_certificate_verify;
return ssl_hs_private_key_operation;
case ssl_private_key_failure:
return ssl_hs_error;
}
assert(0);
return ssl_hs_error;
}
static enum ssl_hs_wait_t do_send_server_finished(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!tls13_prepare_finished(ssl)) {
return ssl_hs_error;
}
hs->state = state_flush;
return ssl_hs_write_message;
}
static enum ssl_hs_wait_t do_flush(SSL *ssl, SSL_HANDSHAKE *hs) {
/* Update the secret to the master secret and derive traffic keys. */
if (!tls13_advance_key_schedule(ssl, kZeroes, hs->hash_len) ||
!tls13_derive_application_secrets(ssl) ||
!tls13_set_traffic_key(ssl, evp_aead_seal, hs->server_traffic_secret_0,
hs->hash_len)) {
return ssl_hs_error;
}
hs->state = state_process_client_certificate;
return ssl_hs_flush_and_read_message;
}
static enum ssl_hs_wait_t do_process_client_certificate(SSL *ssl,
SSL_HANDSHAKE *hs) {
if (!ssl->s3->hs->cert_request) {
/* OpenSSL returns X509_V_OK when no certificates are requested. This is
* classed by them as a bug, but it's assumed by at least NGINX. */
ssl->s3->new_session->verify_result = X509_V_OK;
/* Skip this state. */
hs->state = state_process_channel_id;
return ssl_hs_ok;
}
const int allow_anonymous =
(ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) == 0;
if (!tls13_check_message_type(ssl, SSL3_MT_CERTIFICATE) ||
!tls13_process_certificate(ssl, allow_anonymous) ||
!ssl_hash_current_message(ssl)) {
return ssl_hs_error;
}
/* For historical reasons, the server's copy of the chain does not include the
* leaf while the client's does. */
if (sk_X509_num(ssl->s3->new_session->x509_chain) > 0) {
X509_free(sk_X509_shift(ssl->s3->new_session->x509_chain));
}
hs->state = state_process_client_certificate_verify;
return ssl_hs_read_message;
}
static enum ssl_hs_wait_t do_process_client_certificate_verify(
SSL *ssl, SSL_HANDSHAKE *hs) {
if (ssl->s3->new_session->x509_peer == NULL) {
/* Skip this state. */
hs->state = state_process_channel_id;
return ssl_hs_ok;
}
if (!tls13_check_message_type(ssl, SSL3_MT_CERTIFICATE_VERIFY) ||
!tls13_process_certificate_verify(ssl) ||
!ssl_hash_current_message(ssl)) {
return ssl_hs_error;
}
hs->state = state_process_channel_id;
return ssl_hs_read_message;
}
static enum ssl_hs_wait_t do_process_channel_id(SSL *ssl, SSL_HANDSHAKE *hs) {
if (!ssl->s3->tlsext_channel_id_valid) {
hs->state = state_process_client_finished;
return ssl_hs_ok;
}
if (!tls13_check_message_type(ssl, SSL3_MT_CHANNEL_ID) ||
!tls1_verify_channel_id(ssl) ||
!ssl_hash_current_message(ssl)) {
return ssl_hs_error;
}
hs->state = state_process_client_finished;
return ssl_hs_read_message;
}
static enum ssl_hs_wait_t do_process_client_finished(SSL *ssl,
SSL_HANDSHAKE *hs) {
if (!tls13_check_message_type(ssl, SSL3_MT_FINISHED) ||
!tls13_process_finished(ssl) ||
!ssl_hash_current_message(ssl) ||
/* evp_aead_seal keys have already been switched. */
!tls13_set_traffic_key(ssl, evp_aead_open, hs->client_traffic_secret_0,
hs->hash_len) ||
!tls13_derive_resumption_secret(ssl)) {
return ssl_hs_error;
}
ssl->method->received_flight(ssl);
/* Refresh the session timestamp so that it is measured from ticket
* issuance. */
ssl_session_refresh_time(ssl, ssl->s3->new_session);
hs->state = state_send_new_session_ticket;
return ssl_hs_ok;
}
/* TLS 1.3 recommends single-use tickets, so issue multiple tickets in case the
* client makes several connections before getting a renewal. */
static const int kNumTickets = 2;
static enum ssl_hs_wait_t do_send_new_session_ticket(SSL *ssl,
SSL_HANDSHAKE *hs) {
/* If the client doesn't accept resumption with PSK_DHE_KE, don't send a
* session ticket. */
if (!hs->accept_psk_mode) {
hs->state = state_done;
return ssl_hs_ok;
}
SSL_SESSION *session = ssl->s3->new_session;
if (!RAND_bytes((uint8_t *)&session->ticket_age_add, 4)) {
goto err;
}
/* TODO(svaldez): Add support for sending 0RTT through TicketEarlyDataInfo
* extension. */
CBB cbb, body, ticket, extensions;
if (!ssl->method->init_message(ssl, &cbb, &body,
SSL3_MT_NEW_SESSION_TICKET) ||
!CBB_add_u32(&body, session->timeout) ||
!CBB_add_u32(&body, session->ticket_age_add) ||
!CBB_add_u16_length_prefixed(&body, &ticket) ||
!ssl_encrypt_ticket(ssl, &ticket, session) ||
!CBB_add_u16_length_prefixed(&body, &extensions)) {
goto err;
}
/* Add a fake extension. See draft-davidben-tls-grease-01. */
if (!CBB_add_u16(&extensions,
ssl_get_grease_value(ssl, ssl_grease_ticket_extension)) ||
!CBB_add_u16(&extensions, 0 /* empty */)) {
goto err;
}
if (!ssl_complete_message(ssl, &cbb)) {
goto err;
}
hs->session_tickets_sent++;
if (hs->session_tickets_sent >= kNumTickets) {
hs->state = state_flush_new_session_tickets;
} else {
hs->state = state_send_new_session_ticket;
}
return ssl_hs_write_message;
err:
CBB_cleanup(&cbb);
return ssl_hs_error;
}
static enum ssl_hs_wait_t do_flush_new_session_tickets(SSL *ssl,
SSL_HANDSHAKE *hs) {
hs->state = state_done;
return ssl_hs_flush;
}
enum ssl_hs_wait_t tls13_server_handshake(SSL *ssl) {
SSL_HANDSHAKE *hs = ssl->s3->hs;
while (hs->state != state_done) {
enum ssl_hs_wait_t ret = ssl_hs_error;
enum server_hs_state_t state = hs->state;
switch (state) {
case state_process_client_hello:
ret = do_process_client_hello(ssl, hs);
break;
case state_select_parameters:
ret = do_select_parameters(ssl, hs);
break;
case state_send_hello_retry_request:
ret = do_send_hello_retry_request(ssl, hs);
break;
case state_flush_hello_retry_request:
ret = do_flush_hello_retry_request(ssl, hs);
break;
case state_process_second_client_hello:
ret = do_process_second_client_hello(ssl, hs);
break;
case state_send_server_hello:
ret = do_send_server_hello(ssl, hs);
break;
case state_send_encrypted_extensions:
ret = do_send_encrypted_extensions(ssl, hs);
break;
case state_send_certificate_request:
ret = do_send_certificate_request(ssl, hs);
break;
case state_send_server_certificate:
ret = do_send_server_certificate(ssl, hs);
break;
case state_send_server_certificate_verify:
ret = do_send_server_certificate_verify(ssl, hs, 1 /* first run */);
break;
case state_complete_server_certificate_verify:
ret = do_send_server_certificate_verify(ssl, hs, 0 /* complete */);
break;
case state_send_server_finished:
ret = do_send_server_finished(ssl, hs);
break;
case state_flush:
ret = do_flush(ssl, hs);
break;
case state_process_client_certificate:
ret = do_process_client_certificate(ssl, hs);
break;
case state_process_client_certificate_verify:
ret = do_process_client_certificate_verify(ssl, hs);
break;
case state_process_channel_id:
ret = do_process_channel_id(ssl, hs);
break;
case state_process_client_finished:
ret = do_process_client_finished(ssl, hs);
break;
case state_send_new_session_ticket:
ret = do_send_new_session_ticket(ssl, hs);
break;
case state_flush_new_session_tickets:
ret = do_flush_new_session_tickets(ssl, hs);
break;
case state_done:
ret = ssl_hs_ok;
break;
}
if (ret != ssl_hs_ok) {
return ret;
}
}
return ssl_hs_ok;
}
Reference in New Issue View Git Blame Copy Permalink