From b0d80c7f28528c2c8857c5662b4aca779b3184bb Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Sun, 18 May 2014 21:51:42 +0200
Subject: [PATCH] Allow Cipher and Digest "none".

This is for backwards compatibility with tinc 1.0, it has no effect on
the SPTPS protocol.
---
 src/net_packet.c     |  2 +-
 src/protocol_auth.c  | 20 +++++++++++++------
 src/protocol_key.c   | 37 ++++++++++++++++++++---------------
 test/algorithms.test | 46 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+), 22 deletions(-)
 create mode 100755 test/algorithms.test

diff --git a/src/net_packet.c b/src/net_packet.c
index ecdcfe20..70b6106b 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -378,7 +378,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 		return;
 	}
 
-	if(!cipher_active(n->incipher)) {
+	if(!n->status.validkey) {
 		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
 		return;
 	}
diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index f3322c73..b8d4ee8e 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -514,14 +514,22 @@ bool metakey_h(connection_t *c, const char *request) {
 
 	/* Check and lookup cipher and digest algorithms */
 
-	if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
-		logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
-		return false;
+	if(cipher) {
+		if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
+			return false;
+		}
+	} else {
+		c->incipher = NULL;
 	}
 
-	if(!(c->indigest = digest_open_by_nid(digest, -1))) {
-		logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
-		return false;
+	if(digest) {
+		if(!(c->indigest = digest_open_by_nid(digest, -1))) {
+			logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
+			return false;
+		}
+	} else {
+		c->indigest = NULL;
 	}
 
 	c->status.decryptin = true;
diff --git a/src/protocol_key.c b/src/protocol_key.c
index b8744a95..e838f613 100644
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -260,25 +260,32 @@ bool send_ans_key(node_t *to) {
 	if(to->status.sptps)
 		abort();
 
-	size_t keylen = cipher_keylength(myself->incipher);
+	size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1;
 	char key[keylen * 2 + 1];
 
+	randomize(key, keylen);
+
 	cipher_close(to->incipher);
 	digest_close(to->indigest);
 
-	to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
-	to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
+	if(myself->incipher) {
+		to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
+		if(!to->incipher)
+			abort();
+		if(!cipher_set_key(to->incipher, key, false))
+			abort();
+	}
+
+	if(myself->indigest) {
+		to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
+		if(!to->indigest)
+			abort();
+		if(!digest_set_key(to->indigest, key, keylen))
+			abort();
+	}
+
 	to->incompression = myself->incompression;
 
-	if(!to->incipher || !to->indigest)
-		abort();
-
-	randomize(key, keylen);
-	if(!cipher_set_key(to->incipher, key, false))
-		abort();
-	if(!digest_set_key(to->indigest, key, keylen))
-		abort();
-
 	bin2hex(key, key, keylen);
 
 	// Reset sequence number and late packet window
@@ -422,16 +429,16 @@ bool ans_key_h(connection_t *c, const char *request) {
 
 	keylen = hex2bin(key, key, sizeof key);
 
-	if(keylen != cipher_keylength(from->outcipher)) {
+	if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
 		return true;
 	}
 
 	/* Update our copy of the origin's packet key */
 
-	if(!cipher_set_key(from->outcipher, key, true))
+	if(from->outcipher && !cipher_set_key(from->outcipher, key, true))
 		return false;
-	if(!digest_set_key(from->outdigest, key, keylen))
+	if(from->outdigest && !digest_set_key(from->outdigest, key, keylen))
 		return false;
 
 	from->status.validkey = true;
diff --git a/test/algorithms.test b/test/algorithms.test
new file mode 100755
index 00000000..2b79fc8a
--- /dev/null
+++ b/test/algorithms.test
@@ -0,0 +1,46 @@
+#!/bin/sh
+
+. ./testlib.sh
+
+# Initialize two nodes
+
+$tinc $c1 <<EOF
+init foo
+set DeviceType dummy
+set Port 32755
+set Address localhost
+set ExperimentalProtocol no
+EOF
+
+$tinc $c2 <<EOF
+init bar
+set DeviceType dummy
+set Port 0
+set ExperimentalProtocol no
+EOF
+
+# Exchange configuration
+
+$tinc $c1 export | $tinc $c2 exchange | $tinc $c1 import
+$tinc $c2 add ConnectTo foo
+$tinc $c1 start $r1
+
+# Test various ciphers and digests
+
+for digest in none md5 sha1 sha256 sha512; do
+	for cipher in none bf-cbc aes-128-cbc aes-256-cbc camellia-128-cbc camellia-256-cbc; do
+		echo Testing $cipher $digest
+		$tinc $c2 <<EOF
+set Digest $digest
+set Cipher $cipher
+EOF
+
+		$tinc $c2 start $r2
+		sleep 2;
+		$tinc $c1 info bar
+		$tinc $c1 info bar | grep -q 'directly with UDP'
+		$tinc $c2 stop
+	done
+done
+
+$tinc $c1 stop