Fix #2448 (SMP in the OTR plugin)

Add a /otrsmp <abort|ask|answer> command.

also improve usability a bit, and mention the trust status in the info
bar.

1 files changed, 228 insertions, 52 deletions

diff --git a/plugins/otr.py b/plugins/otr.py
index 7488ed46..fcb1640f 100644
--- a/plugins/otr.py
+++ b/plugins/otr.py
@@ -71,6 +71,14 @@ Command added to Conversation Tabs and Private Tabs:
             *NOT* with multiple rewrites in a secure manner, you should do that
             yourself if you want to be sure.
 
+    /otrsmp
+        **Usage:** ``/otrsmp <ask|answer|abort> [question] [secret]``
+
+        Verify the identify of your contact by using a pre-defined secret.
+
+        - The ``abort`` command aborts an ongoing verification
+        - The ``ask`` command start a verification, with a question or not
+        - The ``answer`` command answers a verification and ends the smp session
 
 To use OTR, make sure the plugin is loaded (if not, then do ``/load otr``).
 
@@ -198,12 +206,14 @@ import curses
 from potr.context import NotEncryptedError, UnencryptedMessage, ErrorReceived, NotOTRMessage,\
         STATE_ENCRYPTED, STATE_PLAINTEXT, STATE_FINISHED, Context, Account, crypt
 
+import common
 import xhtml
 from common import safeJID
 from config import config
 from plugin import BasePlugin
 from tabs import ConversationTab, DynamicConversationTab, PrivateTab
 from theming import get_theme, dump_tuple
+from decorators import command_args_parser
 
 OTR_DIR = os.path.join(os.getenv('XDG_DATA_HOME') or
         '~/.local/share', 'poezio', 'otr')
@@ -220,6 +230,22 @@ POLICY_FLAGS = {
 log = logging.getLogger(__name__)
 
 
+OTR_TUTORIAL = _(
+"""%(info)sThis contact has not yet been verified.
+You have several methods of authentication available:
+
+1) Verify each other's fingerprints using a secure (and different) channel:
+Your fingerprint: %(normal)s%(our_fpr)s%(info)s
+%(jid_c)s%(jid)s%(info)s's fingerprint: %(normal)s%(remote_fpr)s%(info)s
+Then use the command: /otr trust
+
+2) SMP pre-shared secret you both know:
+/otrsmp ask <secret>
+
+3) SMP pre-shared secret you both know with a question:
+/otrsmp ask <question> <secret>
+""")
+
 def hl(tab):
     if tab.state != 'current':
         tab.state = 'private'
@@ -236,6 +262,8 @@ class PoezioContext(Context):
         self.core = core
         self.flags = {}
         self.trustName = safeJID(peer).bare
+        self.in_smp = False
+        self.smp_own = False
 
     def getPolicy(self, key):
         if key in self.flags:
@@ -243,6 +271,10 @@ class PoezioContext(Context):
         else:
             return False
 
+    def reset_smp(self):
+        self.in_smp = False
+        self.smp_own = False
+
     def inject(self, msg, appdata=None):
         message = self.xmpp.make_message(mto=self.peer,
                                          mbody=msg.decode('ascii'),
@@ -253,6 +285,7 @@ class PoezioContext(Context):
     def setState(self, newstate):
         color_jid = '\x19%s}' % dump_tuple(get_theme().COLOR_MUC_JID)
         color_info = '\x19%s}' % dump_tuple(get_theme().COLOR_INFORMATION_TEXT)
+        color_normal = '\x19%s}' % dump_tuple(get_theme().COLOR_NORMAL_TEXT)
 
         tab = self.core.get_tab_by_name(self.peer)
         if not tab:
@@ -261,28 +294,27 @@ class PoezioContext(Context):
             if tab and not tab.locked_resource == safeJID(self.peer).resource:
                 tab = None
         if self.state == STATE_ENCRYPTED:
-            if newstate == STATE_ENCRYPTED:
+            if newstate == STATE_ENCRYPTED and tab:
                 log.debug('OTR conversation with %s refreshed', self.peer)
-                if tab:
-                    if self.getCurrentTrust():
-                        msg = _('%(info)sRefreshed \x19btrusted\x19o%(info)s'
-                                ' OTR conversation with %(jid_c)s%(jid)s') % {
-                                        'info': color_info,
-                                        'jid_c': color_jid,
-                                        'jid': self.peer
-                                        }
-                        tab.add_message(msg, typ=self.log)
-                    else:
-                        msg = _('%(info)sRefreshed \x19buntrusted\x19o%(info)s'
-                                ' OTR conversation with %(jid_c)s%(jid)s'
-                                '%(info)s, key: \x19o%(key)s') % {
-                                   'jid': self.peer,
-                                   'key': self.getCurrentKey(),
-                                   'info': color_info,
-                                   'jid_c': color_jid}
-
-                        tab.add_message(msg, typ=self.log)
-                    hl(tab)
+                if self.getCurrentTrust():
+                    msg = _('%(info)sRefreshed \x19btrusted\x19o%(info)s'
+                            ' OTR conversation with %(jid_c)s%(jid)s') % {
+                                    'info': color_info,
+                                    'jid_c': color_jid,
+                                    'jid': self.peer
+                                    }
+                    tab.add_message(msg, typ=self.log)
+                else:
+                    msg = _('%(info)sRefreshed \x19buntrusted\x19o%(info)s'
+                            ' OTR conversation with %(jid_c)s%(jid)s'
+                            '%(info)s, key: \x19o%(key)s') % {
+                               'jid': self.peer,
+                               'key': self.getCurrentKey(),
+                               'info': color_info,
+                               'jid_c': color_jid}
+
+                    tab.add_message(msg, typ=self.log)
+                hl(tab)
             elif newstate == STATE_FINISHED or newstate == STATE_PLAINTEXT:
                 log.debug('OTR conversation with %s finished', self.peer)
                 if tab:
@@ -290,26 +322,32 @@ class PoezioContext(Context):
                                         color_info, color_jid, self.peer),
                                     typ=self.log)
                     hl(tab)
-        else:
-            if newstate == STATE_ENCRYPTED:
-                if tab:
-                    if self.getCurrentTrust():
-                        msg = _('%(info)sStarted a \x19btrusted\x19o%(info)s '
-                                'OTR conversation with %(jid_c)s%(jid)s') % {
-                                        'jid': self.peer,
-                                        'info': color_info,
-                                        'jid_c': color_jid}
-                        tab.add_message(msg, typ=self.log)
-                    else:
-                        msg = _('%(info)sStarted an \x19buntrusted\x19o%(info)s'
-                                ' OTR conversation with %(jid_c)s%(jid)s'
-                                '%(info)s, key: \x19o%(key)s') % {
-                                        'jid': self.peer,
-                                        'key': self.getCurrentKey(),
-                                        'info': color_info,
-                                        'jid_c': color_jid}
-                        tab.add_message(msg, typ=self.log)
-                    hl(tab)
+        elif newstate == STATE_ENCRYPTED and tab:
+            if self.getCurrentTrust():
+                msg = _('%(info)sStarted a \x19btrusted\x19o%(info)s '
+                        'OTR conversation with %(jid_c)s%(jid)s') % {
+                                'jid': self.peer,
+                                'info': color_info,
+                                'jid_c': color_jid}
+                tab.add_message(msg, typ=self.log)
+            else:
+                tab.add_message(OTR_TUTORIAL % {
+                    'jid': safeJID(self.peer).bare,
+                    'remote_fpr': self.getCurrentKey(),
+                    'our_fpr': self.user.getPrivkey(),
+                    'info': color_info,
+                    'normal': color_normal,
+                    'jid_c': color_jid},
+                    typ=0)
+                msg = _('%(info)sStarted an \x19buntrusted\x19o%(info)s'
+                        ' OTR conversation with %(jid_c)s%(jid)s'
+                        '%(info)s, key: \x19o%(key)s') % {
+                                'jid': self.peer,
+                                'key': self.getCurrentKey(),
+                                'info': color_info,
+                                'jid_c': color_jid}
+                tab.add_message(msg, typ=self.log)
+            hl(tab)
 
         log.debug('Set encryption state of %s to %s', self.peer, states[newstate])
         super(PoezioContext, self).setState(newstate)
@@ -414,7 +452,7 @@ class Plugin(BasePlugin):
         self.account = PoezioAccount(self.core.xmpp.boundjid.bare, OTR_DIR)
         self.account.load_trusts()
         self.contexts = {}
-        usage = '[start|refresh|end|fpr|ourfpr|drop|trust|untrust]'
+        usage = '<start|refresh|end|fpr|ourfpr|drop|trust|untrust>'
         shortdesc = 'Manage an OTR conversation'
         desc = ('Manage an OTR conversation.\n'
                 'start/refresh: Start or refresh a conversation\n'
@@ -424,6 +462,24 @@ class Plugin(BasePlugin):
                 'drop: Remove the current key (FOREVER)\n'
                 'trust: Set this key for this contact as trusted\n'
                 'untrust: Remove the trust for the key of this contact\n')
+        smp_usage = '<abort|ask|answer> [question] [answer]'
+        smp_short = 'Identify a contact'
+        smp_desc = ('Verify the identify of your contact by using a pre-defined secret.\n'
+                    'abort: Abort an ongoing verification\n'
+                    'ask: Start a verification, with a question or not\n'
+                    'answer: Finish a verification\n')
+
+        self.api.add_tab_command(ConversationTab, 'otrsmp', self.command_smp,
+                help=smp_desc,
+                usage=smp_usage,
+                short=smp_short,
+                completion=self.completion_smp)
+        self.api.add_tab_command(PrivateTab, 'otrsmp', self.command_smp,
+                help=smp_desc,
+                usage=smp_usage,
+                short=smp_short,
+                completion=self.completion_smp)
+
         self.api.add_tab_command(ConversationTab, 'otr', self.command_otr,
                 help=desc,
                 usage=usage,
@@ -463,6 +519,63 @@ class Plugin(BasePlugin):
         try:
             ctx = self.get_context(msg['from'])
             txt, tlvs = ctx.receiveMessage(msg["body"].encode('utf-8'))
+
+            if tlvs:
+                smp1q = get_tlv(tlvs, potr.proto.SMP1QTLV)
+                smp1 = get_tlv(tlvs, potr.proto.SMP1TLV)
+                smp2 = get_tlv(tlvs, potr.proto.SMP2TLV)
+                smp3 = get_tlv(tlvs, potr.proto.SMP3TLV)
+                smp4 = get_tlv(tlvs, potr.proto.SMP4TLV)
+                abort = get_tlv(tlvs, potr.proto.SMPABORTTLV)
+                if abort:
+                    ctx.reset_smp()
+                    tab.add_message('%sSMP aborted by peer.' % color_info, typ=0)
+                elif ctx.in_smp and not ctx.smpIsValid():
+                    ctx.reset_smp()
+                    tab.add_message('%sSMP aborted.' % color_info, typ=0)
+                elif smp1 or smp1q:
+                    if smp1q:
+                        try:
+                            question = ' with question: \x19o' + smp1q.msg.decode('utf-8')
+                        except UnicodeDecodeError:
+                            self.api.information('The peer sent a question but it had a wrong encoding', 'Error')
+                            question = ''
+                    else:
+                        question = ''
+                    ctx.in_smp = True
+                    ctx.smp_own = False
+                    tab.add_message('%(info)sPeer %(jid_c)s%(jid)s%(info)s has '
+                                    'requested SMP verification%(q)s%(info)s.\n'
+                                    'Answer with: /otrsmp answer <secret>' % {
+                                        'q': question,
+                                        'info': color_info,
+                                        'jid': tab.name,
+                                        'jid_c': color_jid}, typ=0)
+                elif smp2:
+                    if not ctx.in_smp:
+                        ctx.reset_smp()
+                    else:
+                        tab.add_message('%sSMP progressing.' % color_info, typ=0)
+                elif smp3 or smp4:
+                    if ctx.smpIsSuccess():
+                        if not ctx.getCurrentTrust():
+                            tab.add_message('%sYou may want to authenticate '
+                                            'your peer by asking your own '
+                                            'question: /otrsmp ask [question]'
+                                            ' <secret>' % color_info,
+                                            typ=0)
+                        ctx.reset_smp()
+                        tab.add_message('%sSMP Verification \x19bsucceeded' % color_info,
+                                        typ=0)
+                        #self.smp_finish('SMP verification succeeded.', 'success')
+                    else:
+                        ctx.reset_smp()
+                        tab.add_message('%sSMP Verification \x19bfailed' % color_info,
+                                        typ=0)
+                        #self.smp_finish('SMP verification failed.', 'error')
+                self.core.refresh_window()
+
+
         except UnencryptedMessage as err:
             # received an unencrypted message inside an OTR session
             text = _('%(info)sThe following message from %(jid_c)s%(jid)s'
@@ -632,13 +745,18 @@ class Plugin(BasePlugin):
             if ctx:
                 context = ctx
         state = states[context.state]
-        return ' OTR: %s' % state
+        trust = 'trusted' if context.getCurrentTrust() else 'untrusted'
+
+        return ' OTR: %s (%s)' % (state, trust)
 
     def command_otr(self, arg):
         """
         /otr [start|refresh|end|fpr|ourfpr]
         """
-        arg = arg.strip()
+        args = common.shell_split(arg)
+        if not args:
+            return self.api.core.command_help('otr')
+        action = args.pop(0)
         tab = self.api.current_tab()
         name = tab.name
         color_jid = '\x19%s}' % dump_tuple(get_theme().COLOR_MUC_JID)
@@ -648,14 +766,13 @@ class Plugin(BasePlugin):
             name = safeJID(tab.name)
             name.resource = tab.locked_resource
             name = name.full
-        if arg == 'end': # close the session
+        if action == 'end': # close the session
             context = self.get_context(name)
             context.disconnect()
             if isinstance(tab, DynamicConversationTab) and not tab.locked_resource:
                 ctx = self.find_encrypted_context_with_matching(safeJID(name).bare)
                 ctx.disconnect()
-
-        elif arg == 'start' or arg == 'refresh':
+        elif action == 'start' or action == 'refresh':
             otr = self.get_context(name)
             secs = self.config.get('timeout', 3)
             if isinstance(tab, DynamicConversationTab) and tab.locked_resource:
@@ -689,7 +806,7 @@ class Plugin(BasePlugin):
                          'info': color_info,
                          'jid_c': color_jid}
             tab.add_message(text, typ=0)
-        elif arg == 'ourfpr':
+        elif action == 'ourfpr':
             fpr = self.account.getPrivkey()
             text = _('%(info)sYour OTR key fingerprint is %(norm)s%(fpr)s.') % {
                          'jid': tab.name,
@@ -697,7 +814,7 @@ class Plugin(BasePlugin):
                          'norm': color_normal,
                          'fpr': fpr}
             tab.add_message(text, typ=0)
-        elif arg == 'fpr':
+        elif action == 'fpr':
             if name in self.contexts:
                 ctx = self.contexts[name]
                 if ctx.getCurrentKey() is not None:
@@ -716,14 +833,14 @@ class Plugin(BasePlugin):
                                  'info': color_info,
                                  'jid_c': color_jid}
                     tab.add_message(text, typ=0)
-        elif arg == 'drop':
+        elif action == 'drop':
             # drop the privkey (and obviously, end the current conversations before that)
             for context in self.contexts.values():
                 if context.state not in (STATE_FINISHED, STATE_PLAINTEXT):
                     context.disconnect()
             self.account.drop_privkey()
             tab.add_message('%sPrivate key dropped.' % color_info, typ=0)
-        elif arg == 'trust':
+        elif action == 'trust':
             ctx = self.get_context(name)
             key = ctx.getCurrentKey()
             if key:
@@ -740,7 +857,7 @@ class Plugin(BasePlugin):
                                  'info': color_info,
                                  'jid_c': color_jid}
                 tab.add_message(text, typ=0)
-        elif arg == 'untrust':
+        elif action == 'untrust':
             ctx = self.get_context(name)
             key = ctx.getCurrentKey()
             if key:
@@ -764,3 +881,62 @@ class Plugin(BasePlugin):
         comp = ['start', 'fpr', 'ourfpr', 'refresh', 'end', 'trust', 'untrust']
         return the_input.new_completion(comp, 1, quotify=False)
 
+    @command_args_parser.quoted(1, 2)
+    def command_smp(self, args):
+        """
+        /otrsmp <ask|answer|abort> [question] [secret]
+        """
+        if args is None or not args:
+            return self.core.command_help('otrsmp')
+        color_jid = '\x19%s}' % dump_tuple(get_theme().COLOR_MUC_JID)
+        color_info = '\x19%s}' % dump_tuple(get_theme().COLOR_INFORMATION_TEXT)
+        length = len(args)
+        action = args.pop(0)
+        if length == 2:
+            question = None
+            secret = args.pop(0).encode('utf-8')
+        elif length == 3:
+            question = args.pop(0).encode('utf-8')
+            secret = args.pop(0).encode('utf-8')
+        else:
+            question = secret = None
+
+        tab = self.api.current_tab()
+        name = tab.name
+        if isinstance(tab, DynamicConversationTab) and tab.locked_resource:
+            name = safeJID(tab.name)
+            name.resource = tab.locked_resource
+            name = name.full
+
+        ctx = self.get_context(name)
+        if ctx.state != STATE_ENCRYPTED:
+            return self.api.information('The current conversation is not encrypted', 'Error')
+
+        if action == 'ask':
+            ctx.in_smp = True
+            ctx.smp_own = True
+            if question:
+                ctx.smpInit(secret, question)
+            else:
+                ctx.smpInit(secret)
+            tab.add_message('%(info)sInitiated SMP request with %(jid_c)s'
+                            '%(jid)s%(info)s.' % {
+                                'info': color_info,
+                                'jid': name,
+                                'jid_c': color_jid}, typ=0)
+        elif action == 'answer':
+            ctx.smpGotSecret(secret)
+        elif action == 'abort':
+            if ctx.in_smp:
+                ctx.smpAbort()
+                tab.add_message('%sSMP aborted.' % color_info, typ=0)
+        self.core.refresh_window()
+
+    def completion_smp(self, the_input):
+        if the_input.get_argument_position() == 1:
+            return the_input.new_completion(['ask', 'answer', 'abort'], 1, quotify=False)
+
+def get_tlv(tlvs, cls):
+    for tlv in tlvs:
+        if isinstance(tlv, cls):
+            return tlv