Provide a handshake message handling implementation for TLS 1.3.

It receives handshake messages by reading and parsing data from the record
layer. It also provides support for building and sending handshake
messages.

ok tb@

1 files changed, 188 insertions, 0 deletions

diff --git a/src/lib/libssl/tls13_handshake_msg.c b/src/lib/libssl/tls13_handshake_msg.c
new file mode 100644
index 0000000000..f85271a537
--- /dev/null
+++ b/src/lib/libssl/tls13_handshake_msg.c
@@ -0,0 +1,188 @@
+/* $OpenBSD: tls13_handshake_msg.c,v 1.1 2019/01/20 12:27:34 jsing Exp $ */
+/*
+ * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
+ *
+ * Permission to use, copy, modify, and 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 "bytestring.h"
+#include "ssl_locl.h"
+#include "tls13_internal.h"
+
+#define TLS13_HANDSHAKE_MSG_HEADER_LEN  4
+#define TLS13_HANDSHAKE_MSG_INITIAL_LEN 256
+#define TLS13_HANDSHAKE_MSG_MAX_LEN     (256 * 1024)
+
+struct tls13_handshake_msg {
+        uint8_t msg_type;
+        uint32_t msg_len;
+        uint8_t *data;
+        size_t data_len;
+
+        struct tls13_buffer *buf;
+        CBS cbs;
+        CBB cbb;
+};
+
+struct tls13_handshake_msg *
+tls13_handshake_msg_new()
+{
+        struct tls13_handshake_msg *msg = NULL;
+
+        if ((msg = calloc(1, sizeof(struct tls13_handshake_msg))) == NULL)
+                goto err;
+        if ((msg->buf = tls13_buffer_new(0)) == NULL)
+                goto err;
+
+        return msg;
+
+ err:
+        tls13_handshake_msg_free(msg);
+
+        return NULL;
+}
+
+void
+tls13_handshake_msg_free(struct tls13_handshake_msg *msg)
+{
+        if (msg == NULL)
+                return;
+
+        tls13_buffer_free(msg->buf);
+
+        CBB_cleanup(&msg->cbb);
+
+        freezero(msg->data, msg->data_len);
+        freezero(msg, sizeof(struct tls13_handshake_msg));
+}
+
+void
+tls13_handshake_msg_data(struct tls13_handshake_msg *msg, CBS *cbs)
+{
+        CBS_init(cbs, msg->data, msg->data_len);
+}
+
+uint8_t
+tls13_handshake_msg_type(struct tls13_handshake_msg *msg)
+{
+        return msg->msg_type;
+}
+
+int
+tls13_handshake_msg_content(struct tls13_handshake_msg *msg, CBS *cbs)
+{
+        tls13_handshake_msg_data(msg, cbs);
+
+        return CBS_skip(cbs, TLS13_HANDSHAKE_MSG_HEADER_LEN);
+}
+
+int
+tls13_handshake_msg_start(struct tls13_handshake_msg *msg, CBB *body,
+    uint8_t msg_type)
+{
+        if (!CBB_init(&msg->cbb, TLS13_HANDSHAKE_MSG_INITIAL_LEN))
+                return 0;
+        if (!CBB_add_u8(&msg->cbb, msg_type))
+                return 0;
+        if (!CBB_add_u24_length_prefixed(&msg->cbb, body))
+                return 0;
+
+        return 1;
+}
+
+int
+tls13_handshake_msg_finish(struct tls13_handshake_msg *msg)
+{
+        if (!CBB_finish(&msg->cbb, &msg->data, &msg->data_len))
+                return 0;
+
+        CBS_init(&msg->cbs, msg->data, msg->data_len);
+
+        return 1;
+}
+
+static ssize_t
+tls13_handshake_msg_read_cb(void *buf, size_t n, void *cb_arg)
+{
+        struct tls13_record_layer *rl = cb_arg;
+
+        return tls13_read_handshake_data(rl, buf, n);
+}
+
+int
+tls13_handshake_msg_recv(struct tls13_handshake_msg *msg,
+    struct tls13_record_layer *rl)
+{
+        uint8_t msg_type;
+        uint32_t msg_len;
+        CBS cbs;
+        int ret;
+
+        if (msg->data != NULL)
+                return TLS13_IO_FAILURE;
+
+        if (msg->msg_type == 0) {
+                if ((ret = tls13_buffer_extend(msg->buf,
+                    TLS13_HANDSHAKE_MSG_HEADER_LEN,
+                    tls13_handshake_msg_read_cb, rl)) <= 0)
+                        return ret;
+
+                tls13_buffer_cbs(msg->buf, &cbs);
+
+                if (!CBS_get_u8(&cbs, &msg_type))
+                        return TLS13_IO_FAILURE;
+                if (!CBS_get_u24(&cbs, &msg_len))
+                        return TLS13_IO_FAILURE;
+
+                /* XXX - do we want to make this variable on message type? */
+                if (msg_len > TLS13_HANDSHAKE_MSG_MAX_LEN)
+                        return TLS13_IO_FAILURE;
+
+                msg->msg_type = msg_type;
+                msg->msg_len = msg_len;
+        }
+
+        if ((ret = tls13_buffer_extend(msg->buf,
+            TLS13_HANDSHAKE_MSG_HEADER_LEN + msg->msg_len,
+            tls13_handshake_msg_read_cb, rl)) <= 0)
+                return ret;
+
+        if (!tls13_buffer_finish(msg->buf, &msg->data, &msg->data_len))
+                return TLS13_IO_FAILURE;
+
+        return TLS13_IO_SUCCESS;
+}
+
+int
+tls13_handshake_msg_send(struct tls13_handshake_msg *msg,
+    struct tls13_record_layer *rl)
+{
+        ssize_t ret;
+
+        if (msg->data == NULL)
+                return TLS13_IO_FAILURE;
+
+        if (CBS_len(&msg->cbs) == 0)
+                return TLS13_IO_FAILURE;
+
+        while (CBS_len(&msg->cbs) > 0) {
+                if ((ret = tls13_write_handshake_data(rl, CBS_data(&msg->cbs),
+                    CBS_len(&msg->cbs))) <= 0)
+                        return ret;
+
+                if (!CBS_skip(&msg->cbs, ret))
+                        return TLS13_IO_FAILURE;
+        }
+
+        return TLS13_IO_SUCCESS;
+}