handshake: added support for reading and sending cookie extension

That introduces an internal API to associate data to an extension.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

8 files changed, 276 insertions, 6 deletions

diff --git a/lib/Makefile.am b/lib/Makefile.am
index 1a8c82b89c..a0ac3b4c11 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -79,7 +79,8 @@ COBJECTS = range.c record.c compress.c debug.c cipher.c	handshake-tls13.c	\
 	safe-memfuncs.c system/inet_pton.c atfork.c atfork.h randomart.c \
 	system-keys.h urls.c urls.h prf.c auto-verify.c dh-session.c \
 	cert-session.c handshake-checks.c dtls-sw.c dh-primes.c openpgp_compat.c \
-	crypto-selftests.c crypto-selftests-pk.c secrets.c extv.c extv.h
+	crypto-selftests.c crypto-selftests-pk.c secrets.c extv.c extv.h \
+	hello_ext_lib.c hello_ext_lib.h
 
 if WINDOWS
 COBJECTS += system/keys-win.c
diff --git a/lib/ext/Makefile.am b/lib/ext/Makefile.am
index 211694778d..63d94760bb 100644
--- a/lib/ext/Makefile.am
+++ b/lib/ext/Makefile.am
@@ -42,7 +42,8 @@ libgnutls_ext_la_SOURCES = max_record.c \
 	status_request.h status_request.c dumbfw.c dumbfw.h \
 	ext_master_secret.c ext_master_secret.h etm.h etm.c \
 	supported_versions.c supported_versions.h \
-	post_handshake.c post_handshake.h key_share.c key_share.h
+	post_handshake.c post_handshake.h key_share.c key_share.h \
+	cookie.c cookie.h
 
 if ENABLE_ALPN
 libgnutls_ext_la_SOURCES += alpn.c alpn.h
diff --git a/lib/ext/cookie.c b/lib/ext/cookie.c
new file mode 100644
index 0000000000..c21e5c1c9d
--- /dev/null
+++ b/lib/ext/cookie.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: 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/>
+ *
+ */
+
+/* This file contains the code for the Max Record Size TLS extension.
+ */
+
+#include "gnutls_int.h"
+#include "errors.h"
+#include "num.h"
+#include "hello_ext_lib.h"
+#include <ext/cookie.h>
+
+static int cookie_recv_params(gnutls_session_t session,
+					  const uint8_t * data,
+					  size_t data_size);
+static int cookie_send_params(gnutls_session_t session,
+					  gnutls_buffer_st * extdata);
+
+const hello_ext_entry_st ext_mod_cookie = {
+	.name = "Cookie",
+	.tls_id = 44,
+	.gid = GNUTLS_EXTENSION_COOKIE,
+	.validity = GNUTLS_EXT_FLAG_CLIENT_HELLO|GNUTLS_EXT_FLAG_HRR,
+	.parse_type = GNUTLS_EXT_MANDATORY, /* force parsing prior to EXT_TLS extensions */
+
+	.recv_func = cookie_recv_params,
+	.send_func = cookie_send_params,
+	.pack_func = NULL,
+	.unpack_func = NULL,
+	.deinit_func = _gnutls_hello_ext_default_deinit,
+	.cannot_be_overriden = 0
+};
+
+/* Only client sends this extension. */
+static int
+cookie_recv_params(gnutls_session_t session,
+		   const uint8_t * data, size_t _data_size)
+{
+	ssize_t data_size = _data_size;
+	ssize_t csize;
+	int ret;
+	gnutls_datum_t tmp;
+
+	if (session->security_parameters.entity == GNUTLS_SERVER) {
+		/* we don't support it */
+		return 0;
+	} else { /* client */
+		if (_gnutls_ext_get_msg(session) == GNUTLS_EXT_FLAG_HRR) {
+			DECR_LEN(data_size, 2);
+
+			csize = _gnutls_read_uint16(data);
+			data += 2;
+
+			DECR_LEN(data_size, csize);
+
+			if (data_size != 0)
+				return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
+
+			tmp.data = (void*)data;
+			tmp.size = csize;
+
+			ret = _gnutls_hello_ext_set_datum(session, GNUTLS_EXTENSION_COOKIE, &tmp);
+			if (ret < 0)
+				return gnutls_assert_val(ret);
+
+			return 0;
+		}
+
+		return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
+	}
+
+	return 0;
+}
+
+/* returns data_size or a negative number on failure
+ */
+static int
+cookie_send_params(gnutls_session_t session,
+		   gnutls_buffer_st * extdata)
+{
+	gnutls_datum_t tmp;
+	int ret;
+
+	/* this function sends the client extension data (dnsname) */
+	if (session->security_parameters.entity == GNUTLS_CLIENT) {
+		ret = _gnutls_hello_ext_get_datum(session, GNUTLS_EXTENSION_COOKIE, &tmp);
+		if (ret < 0)
+			return 0;
+
+		ret = _gnutls_buffer_append_data_prefix(extdata, 16, tmp.data, tmp.size);
+		if (ret < 0)
+			return gnutls_assert_val(ret);
+
+		return 0;
+	}
+
+	return 0;
+}
diff --git a/lib/ext/cookie.h b/lib/ext/cookie.h
new file mode 100644
index 0000000000..d7c4048865
--- /dev/null
+++ b/lib/ext/cookie.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: 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/>
+ *
+ */
+
+#ifndef EXT_COOKIE_H
+#define EXT_COOKIE_H
+
+#include <hello_ext.h>
+
+extern const hello_ext_entry_st ext_mod_cookie;
+
+#endif
diff --git a/lib/gnutls_int.h b/lib/gnutls_int.h
index c86f303bdb..e110631d89 100644
--- a/lib/gnutls_int.h
+++ b/lib/gnutls_int.h
@@ -299,7 +299,8 @@ typedef enum extensions_t {
 	GNUTLS_EXTENSION_POST_HANDSHAKE,
 	GNUTLS_EXTENSION_SAFE_RENEGOTIATION,
 	GNUTLS_EXTENSION_SERVER_NAME,
-	GNUTLS_EXTENSION_MAX = GNUTLS_EXTENSION_SERVER_NAME
+	GNUTLS_EXTENSION_COOKIE,
+	GNUTLS_EXTENSION_MAX = GNUTLS_EXTENSION_COOKIE
 } extensions_t;
 
 #define GNUTLS_EXTENSION_MAX_VALUE 31
diff --git a/lib/hello_ext.c b/lib/hello_ext.c
index e22f72fca8..6d1927bcc5 100644
--- a/lib/hello_ext.c
+++ b/lib/hello_ext.c
@@ -47,6 +47,7 @@
 #include <ext/dumbfw.h>
 #include <ext/key_share.h>
 #include <ext/etm.h>
+#include <ext/cookie.h>
 #include "extv.h"
 #include <num.h>
 
@@ -80,6 +81,7 @@ static hello_ext_entry_st const *extfunc[MAX_EXT_TYPES+1] = {
 	&ext_mod_supported_ecc_pf,
 	&ext_mod_sig,
 	&ext_mod_key_share,
+	&ext_mod_cookie,
 #ifdef ENABLE_DTLS_SRTP
 	&ext_mod_srtp,
 #endif
@@ -622,7 +624,7 @@ _gnutls_hello_ext_set_sdata(gnutls_session_t session, extensions_t id,
 
 int
 _gnutls_hello_ext_get_sdata(gnutls_session_t session,
-			     extensions_t id, gnutls_ext_priv_data_t * data)
+			    extensions_t id, gnutls_ext_priv_data_t * data)
 {
 	int i;
 
@@ -640,8 +642,8 @@ _gnutls_hello_ext_get_sdata(gnutls_session_t session,
 
 int
 _gnutls_hello_ext_get_resumed_sdata(gnutls_session_t session,
-				     extensions_t id,
-				     gnutls_ext_priv_data_t * data)
+				    extensions_t id,
+				    gnutls_ext_priv_data_t * data)
 {
 	int i;
 
diff --git a/lib/hello_ext_lib.c b/lib/hello_ext_lib.c
new file mode 100644
index 0000000000..a9ae28caed
--- /dev/null
+++ b/lib/hello_ext_lib.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: 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/>
+ *
+ */
+
+/* Internal API functions to be used by extension handlers.
+ */
+
+#include "gnutls_int.h"
+#include "hello_ext.h"
+#include "hello_ext_lib.h"
+
+void _gnutls_hello_ext_default_deinit(gnutls_ext_priv_data_t priv)
+{
+	gnutls_free(priv);
+}
+
+/* When this is used, the deinitialization function must be set to default:
+ * _gnutls_hello_ext_default_deinit.
+ *
+ * This also prevents and errors on duplicate entries.
+ */
+int
+_gnutls_hello_ext_set_datum(gnutls_session_t session,
+			    extensions_t id, const gnutls_datum_t *data)
+{
+	gnutls_ext_priv_data_t epriv;
+
+	if (_gnutls_hello_ext_get_sdata(session, id, &epriv) >= 0)
+		return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
+
+	if (data->size >= UINT16_MAX)
+		return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
+
+	epriv = gnutls_malloc(data->size+2);
+	if (epriv == NULL)
+		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
+
+	_gnutls_write_uint16(data->size, epriv);
+	memcpy(((uint8_t*)epriv)+2, data->data, data->size);
+
+	_gnutls_hello_ext_set_sdata(session, id, epriv);
+
+	return 0;
+}
+
+int
+_gnutls_hello_ext_get_datum(gnutls_session_t session,
+			    extensions_t id, gnutls_datum_t *data /* constant contents */)
+{
+	gnutls_ext_priv_data_t epriv;
+	int ret;
+
+	ret = _gnutls_hello_ext_get_sdata(session, id, &epriv);
+	if (ret < 0 || epriv == NULL)
+		return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
+
+	data->size = _gnutls_read_uint16(epriv);
+	data->data = ((uint8_t*)epriv)+2;
+
+	return 0;
+}
+
diff --git a/lib/hello_ext_lib.h b/lib/hello_ext_lib.h
new file mode 100644
index 0000000000..6f1a5c21aa
--- /dev/null
+++ b/lib/hello_ext_lib.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: 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/>
+ *
+ */
+
+#ifndef GNUTLS_EXT_LIB_H
+#define GNUTLS_EXT_LIB_H
+
+#include <gnutls/gnutls.h>
+#include "hello_ext.h"
+
+void _gnutls_hello_ext_default_deinit(gnutls_ext_priv_data_t priv);
+
+int
+_gnutls_hello_ext_set_datum(gnutls_session_t session,
+			    extensions_t id, const gnutls_datum_t *data);
+int
+_gnutls_hello_ext_get_datum(gnutls_session_t session,
+			    extensions_t id, gnutls_datum_t *data /* constant contents */);
+
+#endif