Added plaintext link support

RNS/Link.py

@@ -41,7 +41,6 @@ class Link:
 			except Exception as e:
 				RNS.log("Validating link request failed", RNS.LOG_VERBOSE)
 				return None
-			
 
 		else:
 			RNS.log("Invalid link request payload size, dropping request", RNS.LOG_VERBOSE)
@@ -49,12 +48,15 @@ class Link:
 
 
 	def __init__(self, destination=None, owner=None, peer_pub_bytes = None):
+		if destination != None and destination.type != RNS.Destination.SINGLE:
+			raise TypeError("Links can only be established to the \"single\" destination type")
 		self.callbacks = LinkCallbacks()
 		self.status = Link.PENDING
 		self.type = RNS.Destination.LINK
 		self.owner = owner
 		self.destination = destination
 		self.attached_interface = None
+		self.__encryption_disabled = False
 		if self.destination == None:
 			self.initiator = False
 		else:
@@ -142,6 +144,8 @@ class Link:
 				self.callbacks.packet(plaintext, packet)
 
 	def encrypt(self, plaintext):
+		if self.__encryption_disabled:
+			return plaintext
 		try:
 			fernet = Fernet(base64.urlsafe_b64encode(self.derived_key))
 			ciphertext = base64.urlsafe_b64decode(fernet.encrypt(plaintext))
@@ -151,6 +155,8 @@ class Link:
 
 
 	def decrypt(self, ciphertext):
+		if self.__encryption_disabled:
+			return ciphertext
 		try:
 			fernet = Fernet(base64.urlsafe_b64encode(self.derived_key))
 			plaintext = fernet.decrypt(base64.urlsafe_b64encode(ciphertext))
@@ -170,5 +176,14 @@ class Link:
 	def resource_completed_callback(self, callback):
 		self.callbacks.resource_completed = callback
 
+	def disableEncryption(self):
+		if (RNS.Reticulum.should_allow_unencrypted()):
+			RNS.log("The link "+str(self)+" was downgraded to an encryptionless link", RNS.LOG_NOTICE)
+			self.__encryption_disabled = True
+		else:
+			RNS.log("Attempt to disable encryption on link, but encryptionless links are not allowed by config.", RNS.LOG_CRITICAL)
+			RNS.log("Shutting down Reticulum now!", RNS.LOG_CRITICAL)
+			RNS.panic()
+
 	def __str__(self):
 		return RNS.prettyhexrep(self.link_id)

RNS/Reticulum.py

@@ -28,6 +28,8 @@ class Reticulum:
 		Reticulum.storagepath = Reticulum.configdir+"/storage"
 		Reticulum.cachepath = Reticulum.configdir+"/storage/cache"
 
+		Reticulum.__allow_unencrypted = False
+
 		if not os.path.isdir(Reticulum.storagepath):
 			os.makedirs(Reticulum.storagepath)
 
@@ -61,6 +63,24 @@ class Reticulum:
 					if RNS.loglevel > 6:
 						RNS.loglevel = 6
 
+		if "reticulum" in self.config:
+			for option in self.config["reticulum"]:
+				value = self.config["reticulum"][option]
+				if option == "allow_unencrypted":
+					if value == "true":
+						RNS.log("", RNS.LOG_CRITICAL)
+						RNS.log("! ! !", RNS.LOG_CRITICAL)
+						RNS.log("", RNS.LOG_CRITICAL)
+						RNS.log("Danger! Encryptionless links have been allowed in the config file!", RNS.LOG_CRITICAL)
+						RNS.log("Beware of the consequences! Any data sent over a link can potentially be intercepted,", RNS.LOG_CRITICAL)
+						RNS.log("read and modified! If you are not absolutely sure that you want this,", RNS.LOG_CRITICAL)
+						RNS.log("you should exit Reticulum NOW and change your config file!", RNS.LOG_CRITICAL)
+						RNS.log("", RNS.LOG_CRITICAL)
+						RNS.log("! ! !", RNS.LOG_CRITICAL)
+						RNS.log("", RNS.LOG_CRITICAL)
+						Reticulum.__allow_unencrypted = True
+
+
 		for name in self.config["interfaces"]:
 			c = self.config["interfaces"][name]
 			try:
@@ -235,4 +255,8 @@ class Reticulum:
 		if not os.path.isdir(Reticulum.configdir):
 			os.makedirs(Reticulum.configdir)
 		self.config.write()
-		self.applyConfig()
+		self.applyConfig()
+
+	@staticmethod
+	def should_allow_unencrypted():
+		return Reticulum.__allow_unencrypted

RNS/__init__.py

@@ -1,4 +1,5 @@
 import os
+import sys
 import glob
 import time
 
@@ -73,4 +74,7 @@ def hexrep(data, delimit=True):
 def prettyhexrep(data):
 	delimiter = ""
 	hexrep = "<"+delimiter.join("{:02x}".format(ord(c)) for c in data)+">"
-	return hexrep
+	return hexrep
+
+def panic():
+	os._exit(255)