From 4cfd56a69bfd8d112a3b59863ba529092b7bf3df Mon Sep 17 00:00:00 2001
From: Yann Leboulanger <asterix@lagaule.org>
Date: Thu, 1 Oct 2009 22:17:19 +0200
Subject: [PATCH] add a workarround for backward compatibility about esession.
 see #4396

---
 src/common/stanza_session.py | 32 +++++++++++++++++++++++++-------
 src/common/xmpp/c14n.py      |  6 +++---
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/src/common/stanza_session.py b/src/common/stanza_session.py
index 91282e046..3d4770827 100644
--- a/src/common/stanza_session.py
+++ b/src/common/stanza_session.py
@@ -215,6 +215,18 @@ class EncryptedStanzaSession(StanzaSession):
 		# has the remote contact's identity ever been verified?
 		self.verified_identity = False
 
+	def _get_contact(self):
+		c = gajim.contacts.get_contact(self.conn.name, self.jid, self.resource)
+		if not c:
+			c = gajim.contacts.get_contact(self.conn.name, self.jid)
+		return c
+
+	def _is_buggy_gajim(self):
+		c = self._get_contact()
+		if gajim.capscache.is_supported(c, xmpp.NS_ROSTERX):
+			return False
+		return True
+
 	def set_kc_s(self, value):
 		'''
 		keep the encrypter updated with my latest cipher key
@@ -376,7 +388,8 @@ class EncryptedStanzaSession(StanzaSession):
 	def c7lize_mac_id(self, form):
 		kids = form.getChildren()
 		macable = [x for x in kids if x.getVar() not in ('mac', 'identity')]
-		return ''.join(xmpp.c14n.c14n(el) for el in macable)
+		return ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for el in \
+			macable)
 
 	def verify_identity(self, form, dh_i, sigmai, i_o):
 		m_o = base64.b64decode(form['mac'])
@@ -409,7 +422,7 @@ class EncryptedStanzaSession(StanzaSession):
 						keyvalue.getTagData(x))) for x in ('Modulus', 'Exponent'))
 					eir_pubkey = RSA.construct((n,long(e)))
 
-					pubkey_o = xmpp.c14n.c14n(keyvalue)
+					pubkey_o = xmpp.c14n.c14n(keyvalue, self._is_buggy_gajim())
 				else:
 					# FIXME DSA, etc.
 					raise NotImplementedError()
@@ -459,7 +472,8 @@ class EncryptedStanzaSession(StanzaSession):
 		else:
 			pubkey_s = ''
 
-		form_s2 = ''.join(xmpp.c14n.c14n(el) for el in form.getChildren())
+		form_s2 = ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for el in \
+			form.getChildren())
 
 		old_c_s = self.c_s
 		content = self.n_o + self.n_s + crypto.encode_mpi(dh_i) + pubkey_s + \
@@ -560,7 +574,8 @@ class EncryptedStanzaSession(StanzaSession):
 		x.addChild(node=self.make_dhfield(modp_options, sigmai))
 		self.sigmai = sigmai
 
-		self.form_s = ''.join(xmpp.c14n.c14n(el) for el in x.getChildren())
+		self.form_s = ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for el \
+			in x.getChildren())
 
 		feature.addChild(node=x)
 
@@ -689,8 +704,10 @@ class EncryptedStanzaSession(StanzaSession):
 			b64ed = base64.b64encode(to_add[name])
 			x.addChild(node=xmpp.DataField(name=name, value=b64ed))
 
-		self.form_o = ''.join(xmpp.c14n.c14n(el) for el in form.getChildren())
-		self.form_s = ''.join(xmpp.c14n.c14n(el) for el in x.getChildren())
+		self.form_o = ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for el \
+			in form.getChildren())
+		self.form_s = ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for el \
+			in x.getChildren())
 
 		self.status = 'responded-e2e'
 
@@ -792,7 +809,8 @@ class EncryptedStanzaSession(StanzaSession):
 			result.addChild(node=xmpp.DataField(name='dhkeys',
 				value=base64.b64encode(crypto.encode_mpi(e))))
 
-			self.form_o = ''.join(xmpp.c14n.c14n(el) for el in form.getChildren())
+			self.form_o = ''.join(xmpp.c14n.c14n(el, self._is_buggy_gajim()) for \
+				el in form.getChildren())
 
 		# MUST securely destroy K unless it will be used later to generate the
 		# final shared secret
diff --git a/src/common/xmpp/c14n.py b/src/common/xmpp/c14n.py
index b21129a22..bccce8155 100644
--- a/src/common/xmpp/c14n.py
+++ b/src/common/xmpp/c14n.py
@@ -21,7 +21,7 @@
 ''' XML canonicalisation methods (for XEP-0116) '''
 from simplexml import ustr
 
-def c14n(node):
+def c14n(node, is_buggy):
 	s = "<" + node.name
 	if node.namespace:
 		if not node.parent or node.parent.namespace != node.namespace:
@@ -29,7 +29,7 @@ def c14n(node):
 
 	sorted_attrs = sorted(node.attrs.keys())
 	for key in sorted_attrs:
-		if key == 'xmlns':
+		if not is_buggy and key == 'xmlns':
 			continue
 		val = ustr(node.attrs[key])
 		# like XMLescape() but with whitespace and without &gt;
@@ -40,7 +40,7 @@ def c14n(node):
 		for a in node.kids:
 			if (len(node.data)-1) >= cnt:
 				s = s + normalise_text(node.data[cnt])
-			s = s + c14n(a)
+			s = s + c14n(a, is_buggy)
 			cnt=cnt+1
 	if (len(node.data)-1) >= cnt: s = s + normalise_text(node.data[cnt])
 	if not node.kids and s.endswith('>'):