Initial plugin implementation.

LICENSE

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+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
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+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

README.md

@@ -0,0 +1,56 @@
+mallumo
+=======
+
+e2e encryption in weechat using libsodium.
+
+## Dependencies
+
+* `python-3.8` or newer.
+* [`pynacl`](https://github.com/pyca/pynacl/)
+
+N.B. I have only tested this on python3.10, but it should work with
+others too.
+
+## Installation
+
+First clone the repo and symlink the python module into your weechat
+directory:
+
+```shell
+$ git clone https://github.com/darkrenaissance/mallumo
+$ ln -s $(realpath mallumo/mallumo.py) ~/.weechat/python
+```
+
+With this method, you can receive updates seamlessly, just by issuing
+`git pull`.
+
+
+## Usage
+
+In weechat:
+
+```
+/mallumo help
+
+[python/mallumo]  /mallumo  gen
+                            kex
+                            reset
+                            status
+
+E2E encryption for private IRC messages
+
+Quick start:
+
+Add an E2E item to the status bar by adding '[mallumo]' to the config setting
+weechat.bar.status.items. This will show if your current chat is encrypted.
+
+Usage:
+/mallumo gen          [ generate a keypair ]
+/mallumo kex          [ initiate an e2e encrypted session ]
+/mallumo reset [-f]   [ unset the public key associated to the current buffer ]
+/mallumo status       [ show session status ]
+```
+
+## License
+
+GNU GPL version 3

mallumo.py

@@ -0,0 +1,540 @@
+"""E2E encryption in weechat"""
+from base64 import b64encode, b64decode
+import shlex
+import traceback
+
+from nacl.public import PrivateKey, PublicKey, Box
+import weechat as wc
+
+SCRIPT_NAME = "mallumo"
+SCRIPT_AUTHOR = "Ivan Jelincic <parazyd@dyne.org>"
+SCRIPT_LICENSE = "GPL3"
+SCRIPT_VERSION = "0.1"
+SCRIPT_DESC = "E2E encryption for private IRC messages"
+SCRIPT_HELP = f"""{SCRIPT_DESC}
+
+Quick start:
+
+Add an E2E item to the status bar by adding '[mallumo]' to the config setting
+weechat.bar.status.items. This will show if your current chat is encrypted.
+
+Usage:
+/{SCRIPT_NAME} gen          [ generate a keypair ]
+/{SCRIPT_NAME} kex          [ initiate an e2e encrypted session ]
+/{SCRIPT_NAME} reset [-f]   [ unset the public key associated to the current buffer ]
+/{SCRIPT_NAME} status       [ show session status ]
+"""
+
+# Here we'll keep all the NaCl boxes in memory for quick access.
+SODIUM_BOXES = {}
+
+# These are our weechat configuration sections
+CONFIG_SECTIONS = {}
+
+# Configuration file
+CONFIG_FILE = None
+
+# These bytes can't be in a protocol message
+IRC_SANITIZE_TABLE = dict((ord(char), None) for char in "\r\n\x00")
+
+
+def prnt(buf, msg):
+    """Print a message to a given buffer"""
+    wc.prnt(buf, f"{SCRIPT_NAME}: {msg}")
+
+
+def eprnt(buf, msg):
+    """Print an error message to a given buffer"""
+    wc.prnt(buf, f"{wc.prefix('error')}{SCRIPT_NAME}: {msg}")
+
+
+def config_prefix(option):
+    """Set up a prefix for config lookup"""
+    return f"{SCRIPT_NAME}.{option}"
+
+
+def config_get_prefixed(option):
+    """Get a config value prepended with our prefix"""
+    return wc.config_get(config_prefix(option))
+
+
+def config_string(option):
+    """Get a string config value prepended with our prefix"""
+    return wc.config_string(config_get_prefixed(option))
+
+
+def debug(msg):
+    """Debugging facility"""
+    debug_option = config_get_prefixed("general.debug")
+    if not wc.config_boolean(debug_option):
+        return
+
+    debug_buffer = wc.buffer_search("python", f"{SCRIPT_NAME} debug")
+    if not debug_buffer:
+        debug_buffer = wc.buffer_new(f"{SCRIPT_NAME} debug", "", "", "", "")
+        wc.buffer_set(debug_buffer, "title", f"{SCRIPT_NAME} debug")
+        wc.buffer_set(debug_buffer, "localvar_set_no_log", "1")
+
+    prnt(debug_buffer, f"debug:\t{msg}")
+
+
+def buffer_is_private(buf):
+    """Check whether given buffer is a private chat"""
+    return wc.buffer_get_string(buf, "localvar_type") == "private"
+
+
+def irc_user(nick, server):
+    """Format an identifier given nickname and server"""
+    return f"{nick.lower()}@{server}"
+
+
+def e2e_statusbar_cb(data, item, window):
+    """Callback for statusbar item changes"""
+    if window:
+        buf = wc.window_get_pointer(window, "buffer")
+    else:
+        # If the bar item is in a root bar that is not in a window, window
+        # will be empty.
+        buf = wc.current_buffer()
+
+    if not buffer_is_private(buf):
+        return ""
+
+    peer = irc_user(
+        wc.buffer_get_string(buf, "localvar_channel"),
+        wc.buffer_get_string(buf, "localvar_server"),
+    )
+
+    bar_parts = []
+
+    box = SODIUM_BOXES.get(peer)
+
+    if box:
+        bar_parts.append("".join(
+            [wc.color("green"), "SEC",
+             wc.color("default")]))
+    else:
+        bar_parts.append("".join(
+            [wc.color("lightred"), "!SEC",
+             wc.color("default")]))
+
+    result = "".join(bar_parts)
+    if result:
+        result = f"{wc.color('default')}E2E:{result}"
+
+    if box:
+        wc.buffer_set(buf, "localvar_set_e2e_encrypted", "true")
+    else:
+        wc.buffer_set(buf, "localvar_set_e2e_encrypted", "false")
+
+    return result
+
+
+def isupport_value(server, feature):
+    """Check server supports features"""
+    args = f"{server},{feature}"
+    return wc.info_get("irc_server_isupport_value", args)
+
+
+def is_a_channel(channel, server):
+    """Check if we're in a channel"""
+    prefixes = \
+        tuple(isupport_value(server, "CHANTYPES")) + \
+        tuple(isupport_value(server, "STATUSMSG"))
+
+    if not prefixes:
+        prefixes = ("#", "&", "+", "!", "@")
+
+    return channel.startswith(prefixes)
+
+
+class PrivmsgParseException(Exception):
+    """Pass exception if we fail to parse a privmsg"""
+
+
+def parse_privmsg(message, server):
+    """Parse a privmsg"""
+    wc_result = wc.info_get_hashtable("irc_message_parse",
+                                      dict(message=message))
+
+    if wc_result["command"].upper() == "PRIVMSG":
+        target, text = wc_result["arguments"].split(" ", 1)
+        if text.startswith(":"):
+            text = text[1:]
+
+        result = {
+            "from": wc_result["host"],
+            "to": target,
+            "text": text,
+        }
+
+        if wc_result["host"]:
+            result["from_nick"] = wc_result["nick"]
+        else:
+            result["from_nick"] = ""
+
+        if is_a_channel(target, server):
+            result["to_channel"] = target
+            result["to_nick"] = None
+        else:
+            result["to_channel"] = None
+            result["to_nick"] = target
+
+        return result
+
+    raise PrivmsgParseException(message)
+
+
+def command(buf, command_str):
+    """Wrapper around weechat.command"""
+    debug(command_str)
+    wc.command(buf, command_str)
+
+
+def irc_sanitize(msg):
+    """Sanitize IRC input"""
+    return str(msg).translate(IRC_SANITIZE_TABLE)
+
+
+def privmsg(server, nick, message):
+    """Send privmsgs"""
+    for line in message.splitlines():
+        srv = irc_sanitize(server)
+        nik = irc_sanitize(nick)
+        lin = irc_sanitize(line)
+        command("", f"/quote -server {srv} PRIVMSG {nik} :{lin}")
+
+
+def msg_is_kex(msg):
+    """Check if message is for key exchange"""
+    return (msg.startswith("?e2e_kexreq:") or msg.startswith("?e2e_kexrep:")
+            ) and msg.endswith("?") and len(msg) == 57
+
+
+def message_in_cb(data, modifier, modifier_data, string):
+    """Incoming messages callback"""
+    debug(("message_in_cb", data, modifier, modifier_data, string))
+
+    parsed = parse_privmsg(string, modifier_data)
+    debug(("parsed message", parsed))
+
+    # If we're in a channel, do nothing more
+    if parsed["to_channel"]:
+        return string
+
+    server = modifier_data
+
+    # Here we implement commands that might come to us.
+    msg = parsed["text"]
+
+    # Key exchange request/reply
+    if msg_is_kex(msg):
+        encoded_pubkey = msg[12:-1]
+        # Try parsing the public key
+        try:
+            their_pubkey = PublicKey(b64decode(encoded_pubkey))
+        except:
+            # Just do nothing
+            return string
+
+        # At this point we got a valid pubkey. Let's write it down, in case
+        # we didn't have it already.
+        nick = irc_user(parsed["from_nick"], server)
+        if not wc.config_is_set_plugin(f"pubkey_{nick}"):
+            wc.config_set_plugin(f"pubkey_{nick}", encoded_pubkey)
+
+        # If we didn't set up our keypair, we'll also stay silent.
+        encoded_secret = config_string("general.secret")
+        if encoded_secret == "":
+            eprnt("", "You have not created an e2e keypair. Try /mallumo gen")
+            return string
+
+        our_secret = PrivateKey(b64decode(encoded_secret))
+        our_pubkey = b64encode(our_secret.public_key.encode()).decode()
+
+        # Otherwise, reply with our pubkey to complete the key exchange.
+        if msg.startswith("?e2e_kexreq:"):
+            privmsg(server, parsed["from_nick"], f"?e2e_kexrep:{our_pubkey}?")
+
+        # And finally, set up a Box.
+        SODIUM_BOXES[nick] = Box(our_secret, their_pubkey)
+
+        # Make it green!
+        wc.bar_item_update(SCRIPT_NAME)
+        return string
+
+    if msg.startswith("?e2e_msg:") and msg.endswith("?"):
+        # An encrypted message, let's try to decrypt it.
+        encoded_text = msg[9:-1]
+
+        # Do we have a box?
+        nick = irc_user(parsed["from_nick"], server)
+        box = SODIUM_BOXES.get(nick)
+        if not box:
+            if not wc.config_is_set_plugin(f"pubkey_{nick}"):
+                eprnt("", f"{nick} tried to send you an encrypted message")
+                eprnt("", "But we could not find their public key.")
+                eprnt("", "Try to do key exchange first with /mallumo kex")
+                return string
+
+            encoded_pubkey = wc.config_get_plugin(f"pubkey_{nick}")
+            their_pubkey = PublicKey(b64decode(encoded_pubkey))
+
+            encoded_secret = config_string("general.secret")
+            if encoded_secret == "":
+                eprnt("", f"{nick} tried to send you an encrypted message")
+                eprnt("", "But we don't have a secret key set up!")
+                eprnt("", "You have to set up a secret key with /mallumo gen")
+                return string
+
+            our_secret = PrivateKey(b64decode(encoded_secret))
+            SODIUM_BOXES[nick] = Box(our_secret, their_pubkey)
+            box = SODIUM_BOXES.get(nick)
+
+        # Try to decrypt the message
+        try:
+            plaintext = box.decrypt(b64decode(encoded_text))
+        except:
+            eprnt("", f"Failed decrypting message from {nick}")
+            return string
+
+        return string.replace(msg, plaintext.decode())
+
+    nick = irc_user(parsed["from_nick"], server)
+    if SODIUM_BOXES.get(nick):
+        # Prepend a warning if we have an initialized box, but got an
+        # unencrypted message.
+        return string.replace(msg, f"[!SEC] {msg}")
+
+    return string
+
+
+def message_out_cb(data, modifier, modifier_data, string):
+    """Outgoing messages callback"""
+    result = ""
+
+    # If any exception is raised in this function, weechat will not send
+    # the outgoing message, which could be something that the user intended
+    # to be encrypted. This paranoid exception handling ensures that the
+    # system fails closed and not open.
+    try:
+        debug(("message_out_cb", data, modifier, modifier_data, string))
+
+        parsed = parse_privmsg(string, modifier_data)
+        debug(("parsed_message", parsed))
+
+        if parsed["to_channel"]:
+            return string
+
+        # Try encrypting the message
+        server = modifier_data
+
+        # Do we have a box?
+        nick = irc_user(parsed["to"], server)
+        box = SODIUM_BOXES.get(nick)
+        if not box:
+            if not wc.config_is_set_plugin(f"pubkey_{nick}"):
+                eprnt("", f"{nick} tried to send you an encrypted message")
+                eprnt("", "But we could not find their public key.")
+                eprnt("", "Try to do key exchange first with /mallumo kex")
+                return string
+
+            encoded_pubkey = wc.config_get_plugin(f"pubkey_{nick}")
+            their_pubkey = PublicKey(b64decode(encoded_pubkey))
+
+            encoded_secret = config_string("general.secret")
+            if encoded_secret == "":
+                eprnt("", f"{nick} tried to send you an encrypted message")
+                eprnt("", "But we don't have a secret key set up!")
+                eprnt("", "You have to set up a secret key with /mallumo gen")
+                return string
+
+            our_secret = PrivateKey(b64decode(encoded_secret))
+            SODIUM_BOXES[nick] = Box(our_secret, their_pubkey)
+            box = SODIUM_BOXES.get(nick)
+
+        # In case we're replying to kex
+        if parsed["text"].startswith("?e2e_kexrep:"):
+            return string
+
+        encrypted = box.encrypt(parsed["text"].encode())
+        encrypted_encoded = b64encode(encrypted).decode()
+        privmsg(server, parsed["to"], f"?e2e_msg:{encrypted_encoded}?")
+
+    except:
+        try:
+            eprnt("", traceback.format_exc())
+        except:
+            pass
+
+    return result
+
+
+def command_cb(data, buf, args):
+    """mallumo commands"""
+    result = wc.WEECHAT_RC_ERROR
+
+    if not buffer_is_private(buf):
+        eprnt(buf, "These commands can only be ran in a private buffer")
+        return result
+
+    arg_parts = shlex.split(args)
+
+    if arg_parts[0] == "gen":
+        prnt(buf, "========================================================")
+        prnt(buf, "Generating a keypair...")
+        secret = PrivateKey.generate()
+        public = secret.public_key
+        secret_e = b64encode(secret.encode()).decode()
+        public_e = b64encode(public.encode()).decode()
+        prnt(buf, f"Secret: {secret_e}")
+        prnt(buf, f"Public: {public_e}")
+        prnt(buf, "")
+        prnt(buf, "Set this secret key with the following command:")
+        prnt(buf, f'/set {SCRIPT_NAME}.general.secret "{secret_e}"')
+        prnt(buf, "========================================================")
+        return wc.WEECHAT_RC_OK
+
+    if arg_parts[0] == "kex":
+        encoded_secret = config_string("general.secret")
+        if encoded_secret == "":
+            eprnt(buf, "You do not have a keypair set up.")
+            eprnt(buf, f'Run "/{SCRIPT_NAME} gen" to create one')
+            return result
+
+        nick, server = (wc.buffer_get_string(buf, "localvar_channel"),
+                        wc.buffer_get_string(buf, "localvar_server"))
+        user = irc_user(nick, server)
+
+        encoded_pubkey = wc.config_get_plugin(f"pubkey_{user}")
+        if encoded_pubkey != "":
+            eprnt(buf, "This user already has a key set up.")
+            eprnt(buf, "If you want to change it, you have to unset it first:")
+            eprnt(buf, f"/{SCRIPT_NAME} reset")
+            return result
+
+        secret = PrivateKey(b64decode(encoded_secret))
+        public = b64encode(secret.public_key.encode()).decode()
+
+        privmsg(server, nick, f"?e2e_kexreq:{public}?")
+        return wc.WEECHAT_RC_OK
+
+    if arg_parts[0] == "reset":
+        if len(arg_parts) < 2 or arg_parts[1] != "-f":
+            eprnt(buf, f"Use `/{SCRIPT_NAME} reset -f` to actually do this.")
+            return result
+
+        nick = irc_user(wc.buffer_get_string(buf, "localvar_channel"),
+                        wc.buffer_get_string(buf, "localvar_server"))
+
+        command("", f"/unset plugins.var.python.{SCRIPT_NAME}.pubkey_{nick}")
+        prnt(buf, f"Public key for {nick} has been unset.")
+        return wc.WEECHAT_RC_OK
+
+    if arg_parts[0] == "status":
+        nick = irc_user(wc.buffer_get_string(buf, "localvar_channel"),
+                        wc.buffer_get_string(buf, "localvar_server"))
+
+        status = {
+            "initialized": False,
+            "has_pubkey": False,
+            "has_secret": False,
+        }
+
+        encoded_secret = config_string("general.secret")
+        if encoded_secret != "":
+            status["has_secret"] = True
+
+        encoded_pubkey = wc.config_get_plugin(f"pubkey_{nick}")
+        if encoded_pubkey != "":
+            status["has_pubkey"] = True
+
+        box = SODIUM_BOXES.get(nick)
+        if box:
+            status["initialized"] = True
+
+        prnt(buf, "====================================================")
+        prnt(buf, "E2E Status:")
+        if status["initialized"]:
+            prnt(buf, f"{wc.color('green')}Initialized{wc.color('default')}")
+            prnt(buf, f"Box secret: {b64encode(box.shared_key()).decode()}")
+        else:
+            eprnt(buf, f"{wc.color('red')}Uninitialized{wc.color('default')}")
+            prnt(buf, "Box secret: Not initialized")
+
+        if status["has_pubkey"]:
+            prnt(buf, f"{nick} pubkey: {encoded_pubkey}")
+        else:
+            eprnt(buf, f"{nick} pubkey: Not found")
+
+        if status["has_secret"]:
+            secret = PrivateKey(b64decode(encoded_secret))
+            pubkey = b64encode(secret.public_key.encode()).decode()
+            prnt(buf, f"own pubkey: {pubkey}")
+        else:
+            eprnt(buf, "own pubkey: Not initialized")
+
+        prnt(buf, "====================================================")
+
+        if not status["initialized"] and (status["has_pubkey"] and \
+            status["has_secret"]):
+            # However we have enough things to initiate the encryption.
+            pubkey = PublicKey(b64decode(encoded_pubkey))
+            box = Box(secret, pubkey)
+            SODIUM_BOXES[nick] = box
+            prnt(buf, "We managed to instantiate a box now...")
+            prnt(buf, "Further messages should be e2e encrypted")
+            wc.bar_item_update(SCRIPT_NAME)
+
+    return result
+
+
+def free_all_config():
+    """Free config items that were set"""
+    for section in CONFIG_SECTIONS.values():
+        wc.config_section_free_options(section)
+        wc.config_section_free(section)
+
+    wc.config_free(CONFIG_FILE)
+
+
+def shutdown():
+    """Teardown"""
+    wc.config_write(CONFIG_FILE)
+    free_all_config()
+    wc.bar_item_remove(E2E_STATUSBAR)
+    return wc.WEECHAT_RC_OK
+
+
+if wc.register(SCRIPT_NAME, SCRIPT_AUTHOR, SCRIPT_VERSION, SCRIPT_LICENSE,
+               SCRIPT_DESC, "shutdown", ""):
+    prnt("", "Plugin registered successfully!")
+
+    CONFIG_FILE = wc.config_new(SCRIPT_NAME, "", "")
+
+    CONFIG_SECTIONS["general"] = wc.config_new_section(CONFIG_FILE, "general",
+                                                       0, 0, "", "", "", "",
+                                                       "", "", "", "", "", "")
+
+    for opt, typ, description, default in [
+        ("debug", "boolean", "script debugging", "on"),
+        ("secret", "string", "secret key (base64)", ""),
+    ]:
+        wc.config_new_option(CONFIG_FILE, CONFIG_SECTIONS["general"], opt, typ,
+                             description, "", 0, 0, default, default, 0, "",
+                             "", "", "", "", "")
+
+    wc.config_read(CONFIG_FILE)
+
+    wc.hook_modifier("irc_in_privmsg", "message_in_cb", "")
+    wc.hook_modifier("irc_out_privmsg", "message_out_cb", "")
+
+    wc.hook_command(SCRIPT_NAME, SCRIPT_HELP, "gen ||"
+                    "kex ||"
+                    "reset ||"
+                    "status ||", "", "", "command_cb", "")
+
+    E2E_STATUSBAR = wc.bar_item_new(SCRIPT_NAME, "e2e_statusbar_cb", "")
+    wc.bar_item_update(SCRIPT_NAME)
+
+    prnt("", "Plugin initialized successfully!")