1 files changed, 150 insertions, 0 deletions
diff --git a/lib/tls13/psk_ext_parser.c b/lib/tls13/psk_ext_parser.c
new file mode 100644
index 0000000000..9f4087773d
--- /dev/null
+++ b/lib/tls13/psk_ext_parser.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2017-2018 Free Software Foundation, Inc.
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Ander Juaristi, Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+#include "gnutls_int.h"
+#include "tls13/psk_ext_parser.h"
+
+/* Returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE when no identities
+ * are present, or >= 0, on success.
+ */
+int _gnutls13_psk_ext_parser_init(psk_ext_parser_st *p,
+				  const unsigned char *data, size_t _len)
+{
+	uint16_t identities_len;
+	ssize_t len = _len;
+
+	if (!p || !data || !len)
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+	memset(p, 0, sizeof(*p));
+
+	DECR_LEN(len, 2);
+	identities_len = _gnutls_read_uint16(data);
+	data += 2;
+
+	if (identities_len == 0)
+		return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
+
+	p->id_len = identities_len;
+	p->data = (unsigned char *) data;
+	p->len = len;
+
+	DECR_LEN(len, p->id_len);
+	data += p->id_len;
+
+	DECR_LEN(len, 2);
+	p->binder_len = _gnutls_read_uint16(data);
+
+	p->binder_data = p->data + p->id_len + 2;
+	DECR_LEN(len, p->binder_len);
+
+	return 0;
+}
+
+int _gnutls13_psk_ext_parser_next_psk(psk_ext_parser_st *p, struct psk_st *psk)
+{
+	if (p->id_read >= p->id_len)
+		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
+
+	/* Read a PskIdentity structure */
+	DECR_LEN(p->len, 2);
+	psk->identity.size = _gnutls_read_uint16(p->data);
+	if (psk->identity.size == 0)
+		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
+
+	p->data += 2;
+	p->id_read += 2;
+
+	psk->identity.data = (void*)p->data;
+
+	DECR_LEN(p->len, psk->identity.size);
+	p->data += psk->identity.size;
+	p->id_read += psk->identity.size;
+
+	DECR_LEN(p->len, 4);
+	psk->ob_ticket_age = _gnutls_read_uint32(p->data);
+
+	p->data += 4;
+	p->id_read += 4;
+
+	return p->next_index++;
+}
+
+/* Output is a pointer to data, which shouldn't be de-allocated. */
+int _gnutls13_psk_ext_parser_find_binder(psk_ext_parser_st *p, int psk_index,
+					 gnutls_datum_t *binder_out)
+{
+	uint8_t binder_len;
+	int cur_index = 0, binder_found = 0;
+	ssize_t len;
+	const uint8_t *data;
+	ssize_t read_data = 0;
+
+	if (p == NULL || psk_index < 0 || binder_out == NULL)
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+	if (p->id_len == 0)
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+	len = p->binder_len;
+	data = p->binder_data;
+
+	if (len == 0)
+		return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
+
+	/* Start traversing the binders */
+	while (!binder_found && len > 0) {
+		DECR_LEN(len, 1);
+		binder_len = *(data);
+
+		if (binder_len == 0)
+			return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
+
+		data++;
+		read_data++;
+
+		if (cur_index == psk_index) {
+			/* We found the binder with the supplied index */
+			DECR_LEN(len, binder_len);
+			binder_out->data = (void*)data;
+			binder_out->size = binder_len;
+
+			data += binder_len;
+			read_data += binder_len;
+
+			binder_found = 1;
+		} else {
+			/* Not our binder - continue to the next one */
+			DECR_LEN(len, binder_len);
+			data += binder_len;
+			read_data += binder_len;
+
+			cur_index++;
+		}
+	}
+
+	if (binder_found)
+		return 0;
+	else
+		return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
+}