+
+static int final_sig_algs(SSL *s, unsigned int context, int sent)
+{
+ if (!sent && SSL_IS_TLS13(s) && !s->hit) {
+ SSLfatal(s, TLS13_AD_MISSING_EXTENSION, SSL_F_FINAL_SIG_ALGS,
+ SSL_R_MISSING_SIGALGS_EXTENSION);
+ return 0;
+ }
+
+ return 1;
+}
+
+#ifndef OPENSSL_NO_EC
+static int final_key_share(SSL *s, unsigned int context, int sent)
+{
+ if (!SSL_IS_TLS13(s))
+ return 1;
+
+ /* Nothing to do for key_share in an HRR */
+ if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0)
+ return 1;
+
+ /*
+ * If
+ * we are a client
+ * AND
+ * we have no key_share
+ * AND
+ * (we are not resuming
+ * OR the kex_mode doesn't allow non key_share resumes)
+ * THEN
+ * fail;
+ */
+ if (!s->server
+ && !sent
+ && (!s->hit
+ || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
+ /* Nothing left we can do - just fail */
+ SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_FINAL_KEY_SHARE,
+ SSL_R_NO_SUITABLE_KEY_SHARE);
+ return 0;
+ }
+ /*
+ * If
+ * we are a server
+ * AND
+ * we have no key_share
+ * THEN
+ * If
+ * we didn't already send a HelloRetryRequest
+ * AND
+ * the client sent a key_share extension
+ * AND
+ * (we are not resuming
+ * OR the kex_mode allows key_share resumes)
+ * AND
+ * a shared group exists
+ * THEN
+ * send a HelloRetryRequest
+ * ELSE If
+ * we are not resuming
+ * OR
+ * the kex_mode doesn't allow non key_share resumes
+ * THEN
+ * fail;
+ */
+ if (s->server && s->s3->peer_tmp == NULL) {
+ /* No suitable share */
+ if (s->hello_retry_request == 0 && sent
+ && (!s->hit
+ || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
+ != 0)) {
+ const uint16_t *pgroups, *clntgroups;
+ size_t num_groups, clnt_num_groups, i;
+ unsigned int group_id = 0;
+
+ /* Check if a shared group exists */
+
+ /* Get the clients list of supported groups. */
+ tls1_get_peer_groups(s, &clntgroups, &clnt_num_groups);
+ tls1_get_supported_groups(s, &pgroups, &num_groups);
+
+ /* Find the first group we allow that is also in client's list */
+ for (i = 0; i < num_groups; i++) {
+ group_id = pgroups[i];
+
+ if (check_in_list(s, group_id, clntgroups, clnt_num_groups, 1))
+ break;
+ }
+
+ if (i < num_groups) {
+ /* A shared group exists so send a HelloRetryRequest */
+ s->s3->group_id = group_id;
+ s->hello_retry_request = 1;
+ return 1;
+ }
+ }
+ if (!s->hit
+ || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
+ /* Nothing left we can do - just fail */
+ SSLfatal(s,
+ sent ? SSL_AD_HANDSHAKE_FAILURE : SSL_AD_MISSING_EXTENSION,
+ SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
+ return 0;
+ }
+ }
+
+ /* We have a key_share so don't send any more HelloRetryRequest messages */
+ if (s->server)
+ s->hello_retry_request = 0;
+
+ /*
+ * For a client side resumption with no key_share we need to generate
+ * the handshake secret (otherwise this is done during key_share
+ * processing).
+ */
+ if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_KEY_SHARE,
+ ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ return 1;
+}
+#endif
+
+static int init_psk_kex_modes(SSL *s, unsigned int context)
+{
+ s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
+ return 1;
+}
+
+int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
+ size_t binderoffset, const unsigned char *binderin,
+ unsigned char *binderout, SSL_SESSION *sess, int sign,
+ int external)
+{
+ EVP_PKEY *mackey = NULL;
+ EVP_MD_CTX *mctx = NULL;
+ unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
+ unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
+ unsigned char tmppsk[EVP_MAX_MD_SIZE];
+ unsigned char *early_secret, *psk;
+ const char resumption_label[] = "res binder";
+ const char external_label[] = "ext binder";
+ const char nonce_label[] = "resumption";
+ const char *label;
+ size_t bindersize, labelsize, hashsize = EVP_MD_size(md);
+ int ret = -1;
+ int usepskfored = 0;
+
+ if (external
+ && s->early_data_state == SSL_EARLY_DATA_CONNECTING
+ && s->session->ext.max_early_data == 0
+ && sess->ext.max_early_data > 0)
+ usepskfored = 1;
+
+ if (external) {
+ label = external_label;
+ labelsize = sizeof(external_label) - 1;
+ } else {
+ label = resumption_label;
+ labelsize = sizeof(resumption_label) - 1;
+ }
+
+ if (sess->master_key_length != hashsize) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ SSL_R_BAD_PSK);
+ goto err;
+ }
+
+ if (external) {
+ psk = sess->master_key;
+ } else {
+ psk = tmppsk;
+ if (!tls13_hkdf_expand(s, md, sess->master_key,
+ (const unsigned char *)nonce_label,
+ sizeof(nonce_label) - 1, sess->ext.tick_nonce,
+ sess->ext.tick_nonce_len, psk, hashsize)) {
+ /* SSLfatal() already called */
+ goto err;
+ }
+ }
+
+ /*
+ * Generate the early_secret. On the server side we've selected a PSK to
+ * resume with (internal or external) so we always do this. On the client
+ * side we do this for a non-external (i.e. resumption) PSK or external PSK
+ * that will be used for early_data so that it is in place for sending early
+ * data. For client side external PSK not being used for early_data we
+ * generate it but store it away for later use.
+ */
+ if (s->server || !external || usepskfored)
+ early_secret = (unsigned char *)s->early_secret;
+ else
+ early_secret = (unsigned char *)sess->early_secret;
+ if (!tls13_generate_secret(s, md, NULL, psk, hashsize, early_secret)) {
+ /* SSLfatal() already called */
+ goto err;
+ }
+
+ /*
+ * Create the handshake hash for the binder key...the messages so far are
+ * empty!
+ */
+ mctx = EVP_MD_CTX_new();
+ 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_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ /* Generate the binder key */
+ if (!tls13_hkdf_expand(s, md, early_secret, (unsigned char *)label,
+ labelsize, hash, hashsize, binderkey, hashsize)) {
+ /* SSLfatal() already called */
+ goto err;
+ }
+
+ /* Generate the finished key */
+ if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
+ /* SSLfatal() already called */
+ goto err;
+ }
+
+ if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ /*
+ * Get a hash of the ClientHello up to the start of the binders. If we are
+ * following a HelloRetryRequest then this includes the hash of the first
+ * ClientHello and the HelloRetryRequest itself.
+ */
+ if (s->hello_retry_request) {
+ size_t hdatalen;
+ void *hdata;
+
+ hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
+ if (hdatalen <= 0) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ SSL_R_BAD_HANDSHAKE_LENGTH);
+ goto err;
+ }
+
+ /*
+ * For servers the handshake buffer data will include the second
+ * ClientHello - which we don't want - so we need to take that bit off.
+ */
+ if (s->server) {
+ PACKET hashprefix, msg;
+
+ /* Find how many bytes are left after the first two messages */
+ if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
+ || !PACKET_forward(&hashprefix, 1)
+ || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
+ || !PACKET_forward(&hashprefix, 1)
+ || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+ hdatalen -= PACKET_remaining(&hashprefix);
+ }
+
+ if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+ }
+
+ if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
+ || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
+ if (mackey == NULL) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ if (!sign)
+ binderout = tmpbinder;
+
+ bindersize = hashsize;
+ if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
+ || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
+ || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
+ || bindersize != hashsize) {
+ SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER,
+ ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ if (sign) {
+ ret = 1;
+ } else {
+ /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
+ ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
+ if (!ret)
+ SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PSK_DO_BINDER,
+ SSL_R_BINDER_DOES_NOT_VERIFY);
+ }
+
+ err:
+ OPENSSL_cleanse(binderkey, sizeof(binderkey));
+ OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
+ EVP_PKEY_free(mackey);
+ EVP_MD_CTX_free(mctx);
+
+ return ret;
+}
+
+static int final_early_data(SSL *s, unsigned int context, int sent)
+{
+ if (!sent)
+ return 1;
+
+ if (!s->server) {
+ if (context == SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
+ && sent
+ && !s->ext.early_data_ok) {
+ /*
+ * If we get here then the server accepted our early_data but we
+ * later realised that it shouldn't have done (e.g. inconsistent
+ * ALPN)
+ */
+ SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_FINAL_EARLY_DATA,
+ SSL_R_BAD_EARLY_DATA);
+ return 0;
+ }
+
+ return 1;
+ }
+
+ if (s->max_early_data == 0
+ || !s->hit
+ || s->session->ext.tick_identity != 0
+ || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
+ || !s->ext.early_data_ok
+ || s->hello_retry_request) {
+ s->ext.early_data = SSL_EARLY_DATA_REJECTED;
+ } else {
+ s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
+
+ if (!tls13_change_cipher_state(s,
+ SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
+ /* SSLfatal() already called */
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static int final_maxfragmentlen(SSL *s, unsigned int context, int sent)
+{
+ /*
+ * Session resumption on server-side with MFL extension active
+ * BUT MFL extension packet was not resent (i.e. sent == 0)
+ */
+ if (s->server && s->hit && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
+ && !sent ) {
+ SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_FINAL_MAXFRAGMENTLEN,
+ SSL_R_BAD_EXTENSION);
+ return 0;
+ }
+
+ /* Current SSL buffer is lower than requested MFL */
+ if (s->session && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
+ && s->max_send_fragment < GET_MAX_FRAGMENT_LENGTH(s->session))
+ /* trigger a larger buffer reallocation */
+ if (!ssl3_setup_buffers(s)) {
+ /* SSLfatal() already called */
+ return 0;
+ }
+
+ return 1;
+}