Implement support for resumption with a HelloRetryRequest
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2341)
diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
index fd050f0..563eb57 100644
--- a/ssl/statem/extensions.c
+++ b/ssl/statem/extensions.c
@@ -968,29 +968,103 @@
/*
* 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
+ * fail;
*/
- if (((s->server && s->s3->peer_tmp == NULL) || (!s->server && !sent))
+ if (!s->server
+ && !sent
&& (!s->hit
|| (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
- /* No suitable share */
- if (s->server && s->hello_retry_request == 0 && sent) {
- s->hello_retry_request = 1;
- return 1;
- }
-
/* Nothing left we can do - just fail */
*al = SSL_AD_HANDSHAKE_FAILURE;
SSLerr(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 unsigned char *pcurves, *pcurvestmp, *clntcurves;
+ size_t num_curves, clnt_num_curves, i;
+ unsigned int group_id;
- s->hello_retry_request = 0;
+ /* Check a shared group exists */
+
+ /* Get the clients list of supported groups. */
+ if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
+ *al = SSL_AD_INTERNAL_ERROR;
+ SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ /* Get our list of available groups */
+ if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
+ *al = SSL_AD_INTERNAL_ERROR;
+ SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ /* Find the first group we allow that is also in client's list */
+ for (i = 0, pcurvestmp = pcurves; i < num_curves;
+ i++, pcurvestmp += 2) {
+ group_id = pcurvestmp[0] << 8 | pcurvestmp[1];
+
+ if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
+ break;
+ }
+
+ if (i < num_curves) {
+ /* 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 */
+ *al = SSL_AD_HANDSHAKE_FAILURE;
+ SSLerr(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
@@ -1059,13 +1133,45 @@
goto err;
}
+ if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
+ SSLerr(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.
- * TODO(TLS1.3): This will need to be tweaked when we implement
- * HelloRetryRequest to include the digest of the previous messages here.
+ * 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 (EVP_DigestInit_ex(mctx, md, NULL) <= 0
- || EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
+ if (s->hello_retry_request) {
+ size_t hdatalen;
+ void *hdata;
+
+ hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
+ if (hdatalen <= 0) {
+ SSLerr(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) {
+ if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
+ SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+ hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
+ }
+
+ if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
+ SSLerr(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) {
SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
goto err;
diff --git a/ssl/statem/extensions_srvr.c b/ssl/statem/extensions_srvr.c
index f7b7990..b555d68 100644
--- a/ssl/statem/extensions_srvr.c
+++ b/ssl/statem/extensions_srvr.c
@@ -457,37 +457,6 @@
}
/*
- * Checks a list of |groups| to determine if the |group_id| is in it. If it is
- * and |checkallow| is 1 then additionally check if the group is allowed to be
- * used. Returns 1 if the group is in the list (and allowed if |checkallow| is
- * 1) or 0 otherwise.
- */
-#ifndef OPENSSL_NO_TLS1_3
-static int check_in_list(SSL *s, unsigned int group_id,
- const unsigned char *groups, size_t num_groups,
- int checkallow)
-{
- size_t i;
-
- if (groups == NULL || num_groups == 0)
- return 0;
-
- for (i = 0; i < num_groups; i++, groups += 2) {
- unsigned int share_id = (groups[0] << 8) | (groups[1]);
-
- if (group_id == share_id
- && (!checkallow
- || tls_curve_allowed(s, groups, SSL_SECOP_CURVE_CHECK))) {
- break;
- }
- }
-
- /* If i == num_groups then not in the list */
- return i < num_groups;
-}
-#endif
-
-/*
* Process a psk_kex_modes extension received in the ClientHello. |pkt| contains
* the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
* If a failure occurs then |*al| is set to an appropriate alert value.
@@ -1034,54 +1003,10 @@
if (ckey == NULL) {
/* No key_share received from client */
if (s->hello_retry_request) {
- const unsigned char *pcurves, *pcurvestmp, *clntcurves;
- size_t num_curves, clnt_num_curves, i;
-
- /* Get the clients list of supported groups. */
- if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
- *al = SSL_AD_INTERNAL_ERROR;
- SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
- ERR_R_INTERNAL_ERROR);
- return 0;
- }
-
- /* Get our list of available groups */
- if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
- SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
- ERR_R_INTERNAL_ERROR);
- return 0;
- }
-
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
- || !WPACKET_start_sub_packet_u16(pkt)) {
- SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
- ERR_R_INTERNAL_ERROR);
- return 0;
- }
-
- /* Find first group we allow that is also in client's list */
- for (i = 0, pcurvestmp = pcurves; i < num_curves;
- i++, pcurvestmp += 2) {
- unsigned int group_id = pcurvestmp[0] << 8 | pcurvestmp[1];
-
- if (check_in_list(s, group_id, clntcurves, clnt_num_curves,
- 1)) {
- if (!WPACKET_put_bytes_u16(pkt, group_id)) {
- SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
- ERR_R_INTERNAL_ERROR);
- return 0;
- }
- break;
- }
- }
- if (i == num_curves) {
- /* No common groups */
- *al = SSL_AD_HANDSHAKE_FAILURE;
- SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
- SSL_R_NO_SHARED_GROUPS);
- return 0;
- }
- if (!WPACKET_close(pkt)) {
+ || !WPACKET_start_sub_packet_u16(pkt)
+ || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)
+ || !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
ERR_R_INTERNAL_ERROR);
return 0;
diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c
index c3dd31a..d7564e6 100644
--- a/ssl/statem/statem_lib.c
+++ b/ssl/statem/statem_lib.c
@@ -1738,3 +1738,31 @@
s->client_version = ver_max;
return 0;
}
+
+/*
+ * Checks a list of |groups| to determine if the |group_id| is in it. If it is
+ * and |checkallow| is 1 then additionally check if the group is allowed to be
+ * used. Returns 1 if the group is in the list (and allowed if |checkallow| is
+ * 1) or 0 otherwise.
+ */
+int check_in_list(SSL *s, unsigned int group_id, const unsigned char *groups,
+ size_t num_groups, int checkallow)
+{
+ size_t i;
+
+ if (groups == NULL || num_groups == 0)
+ return 0;
+
+ for (i = 0; i < num_groups; i++, groups += 2) {
+ unsigned int share_id = (groups[0] << 8) | (groups[1]);
+
+ if (group_id == share_id
+ && (!checkallow
+ || tls_curve_allowed(s, groups, SSL_SECOP_CURVE_CHECK))) {
+ break;
+ }
+ }
+
+ /* If i == num_groups then not in the list */
+ return i < num_groups;
+}
diff --git a/ssl/statem/statem_locl.h b/ssl/statem/statem_locl.h
index 429d5c7..fa13a26 100644
--- a/ssl/statem/statem_locl.h
+++ b/ssl/statem/statem_locl.h
@@ -69,6 +69,9 @@
typedef int (*confunc_f) (SSL *s, WPACKET *pkt);
+int check_in_list(SSL *s, unsigned int group_id, const unsigned char *groups,
+ size_t num_groups, int checkallow);
+
/*
* TLS/DTLS client state machine functions
*/
diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index 8aba669..66743c3 100644
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -1842,13 +1842,6 @@
s->s3->tmp.new_cipher = s->session->cipher;
}
- if (!(s->verify_mode & SSL_VERIFY_PEER)) {
- if (!ssl3_digest_cached_records(s, 0)) {
- al = SSL_AD_INTERNAL_ERROR;
- goto f_err;
- }
- }
-
/*-
* we now have the following setup.
* client_random
@@ -1975,6 +1968,12 @@
goto err;
}
+ if (!(s->verify_mode & SSL_VERIFY_PEER)
+ && !ssl3_digest_cached_records(s, 0)) {
+ al = SSL_AD_INTERNAL_ERROR;
+ goto err;
+ }
+
return 1;
err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
