1 files changed, 135 insertions, 1 deletions

diff --git a/src/lib/libssl/ssl_tlsext.c b/src/lib/libssl/ssl_tlsext.c
index c050224c70..1813d46f41 100644
--- a/src/lib/libssl/ssl_tlsext.c
+++ b/src/lib/libssl/ssl_tlsext.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_tlsext.c,v 1.6 2017/08/11 20:14:13 doug Exp $ */
+/* $OpenBSD: ssl_tlsext.c,v 1.7 2017/08/12 21:17:03 doug Exp $ */
 /*
  * Copyright (c) 2016, 2017 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2017 Doug Hogan <doug@openbsd.org>
@@ -492,6 +492,131 @@ tlsext_sni_serverhello_parse(SSL *s, CBS *cbs, int *alert)
         return 1;
 }
 
+/*
+ * SessionTicket extension - RFC 5077 section 3.2
+ */
+int
+tlsext_sessionticket_clienthello_needs(SSL *s)
+{
+        /*
+         * Send session ticket extension when enabled and not overridden.
+         *
+         * When renegotiating, send an empty session ticket to indicate support.
+         */
+        if ((SSL_get_options(s) & SSL_OP_NO_TICKET) != 0)
+                return 0;
+
+        if (s->internal->new_session)
+                return 1;
+
+        if (s->internal->tlsext_session_ticket != NULL &&
+            s->internal->tlsext_session_ticket->data == NULL)
+                return 0;
+
+        return 1;
+}
+
+int
+tlsext_sessionticket_clienthello_build(SSL *s, CBB *cbb)
+{
+        /*
+         * Signal that we support session tickets by sending an empty
+         * extension when renegotiating or no session found.
+         */
+        if (s->internal->new_session || s->session == NULL)
+                return 1;
+
+        if (s->session->tlsext_tick != NULL) {
+                /* Attempt to resume with an existing session ticket */
+                if (!CBB_add_bytes(cbb, s->session->tlsext_tick,
+                    s->session->tlsext_ticklen))
+                        return 0;
+
+        } else if (s->internal->tlsext_session_ticket != NULL) {
+                /*
+                 * Attempt to resume with a custom provided session ticket set
+                 * by SSL_set_session_ticket_ext().
+                 */
+                if (s->internal->tlsext_session_ticket->length > 0) {
+                        size_t ticklen = s->internal->tlsext_session_ticket->length;
+
+                        if ((s->session->tlsext_tick = malloc(ticklen)) == NULL)
+                                return 0;
+                        memcpy(s->session->tlsext_tick,
+                            s->internal->tlsext_session_ticket->data,
+                            ticklen);
+                        s->session->tlsext_ticklen = ticklen;
+
+                        if (!CBB_add_bytes(cbb, s->session->tlsext_tick,
+                            s->session->tlsext_ticklen))
+                                return 0;
+                }
+        }
+
+        if (!CBB_flush(cbb))
+                return 0;
+
+        return 1;
+}
+
+int
+tlsext_sessionticket_clienthello_parse(SSL *s, CBS *cbs, int *alert)
+{
+        if (s->internal->tls_session_ticket_ext_cb) {
+                if (!s->internal->tls_session_ticket_ext_cb(s, CBS_data(cbs),
+                    (int)CBS_len(cbs),
+                    s->internal->tls_session_ticket_ext_cb_arg)) {
+                        *alert = TLS1_AD_INTERNAL_ERROR;
+                        return 0;
+                }
+        }
+
+        /* We need to signal that this was processed fully */
+        if (!CBS_skip(cbs, CBS_len(cbs))) {
+                *alert = TLS1_AD_INTERNAL_ERROR;
+                return 0;
+        }
+
+        return 1;
+}
+
+int
+tlsext_sessionticket_serverhello_needs(SSL *s)
+{
+        return (s->internal->tlsext_ticket_expected &&
+            !(SSL_get_options(s) & SSL_OP_NO_TICKET));
+}
+
+int
+tlsext_sessionticket_serverhello_build(SSL *s, CBB *cbb)
+{
+        /* Empty ticket */
+
+        return 1;
+}
+
+int
+tlsext_sessionticket_serverhello_parse(SSL *s, CBS *cbs, int *alert)
+{
+        if (s->internal->tls_session_ticket_ext_cb) {
+                if (!s->internal->tls_session_ticket_ext_cb(s, CBS_data(cbs),
+                    (int)CBS_len(cbs),
+                    s->internal->tls_session_ticket_ext_cb_arg)) {
+                        *alert = TLS1_AD_INTERNAL_ERROR;
+                        return 0;
+                }
+        }
+
+        if ((SSL_get_options(s) & SSL_OP_NO_TICKET) != 0 || CBS_len(cbs) > 0) {
+                *alert = TLS1_AD_UNSUPPORTED_EXTENSION;
+                return 0;
+        }
+
+        s->internal->tlsext_ticket_expected = 1;
+
+        return 1;
+}
+
 struct tls_extension {
         uint16_t type;
         int (*clienthello_needs)(SSL *s);
@@ -539,6 +664,15 @@ static struct tls_extension tls_extensions[] = {
                 .serverhello_build = tlsext_ec_serverhello_build,
                 .serverhello_parse = tlsext_ec_serverhello_parse,
         },
+        {
+                .type = TLSEXT_TYPE_session_ticket,
+                .clienthello_needs = tlsext_sessionticket_clienthello_needs,
+                .clienthello_build = tlsext_sessionticket_clienthello_build,
+                .clienthello_parse = tlsext_sessionticket_clienthello_parse,
+                .serverhello_needs = tlsext_sessionticket_serverhello_needs,
+                .serverhello_build = tlsext_sessionticket_serverhello_build,
+                .serverhello_parse = tlsext_sessionticket_serverhello_parse,
+        },
 };
 
 #define N_TLS_EXTENSIONS (sizeof(tls_extensions) / sizeof(*tls_extensions))