Include a horrible custom DER/RSA implementation

I'm sorry, but I'm also not sorry.

lib/msf/core/payload/python/meterpreter_loader.rb

@@ -145,13 +145,19 @@ module Payload::Python::MeterpreterLoader
   end
 
   def python_encryptor_loader
-    encryptor = Rex::Text.encode_base64(python_encryptor_source)
+    aes_encryptor = Rex::Text.encode_base64(python_aes_source)
+    rsa_encryptor = Rex::Text.encode_base64(python_rsa_source)
     %Q?
 import codecs,imp,base64
 met_aes = imp.new_module('met_aes')
-exec(compile(base64.b64decode(codecs.getencoder('utf-8')('#{encryptor}')[0]),'<string>','exec'), met_aes.__dict__)
+met_rsa = imp.new_module('met_rsa')
+exec(compile(base64.b64decode(codecs.getencoder('utf-8')('#{aes_encryptor}')[0]),'<string>','exec'), met_aes.__dict__)
+exec(compile(base64.b64decode(codecs.getencoder('utf-8')('#{rsa_encryptor}')[0]),'<string>','exec'), met_rsa.__dict__)
 sys.modules['met_aes'] = met_aes
-import met_aes
+sys.modules['met_rsa'] = met_rsa
+import met_rsa, met_aes
+def met_rsa_encrypt(der, msg):
+  return met_rsa.rsa_enc(der, msg)
 def met_aes_encrypt(key, iv, pt):
 	return met_aes.AESCBC(key).encrypt(iv, pt)
 def met_aes_decrypt(key, iv, pt):
@@ -159,7 +165,68 @@ def met_aes_decrypt(key, iv, pt):
     ?
   end
 
-  def python_encryptor_source
+  def python_rsa_source
+    %Q?
+import struct as s, base64 as b, sys, math, random, binascii, os
+is2 = sys.version_info[0] < 3
+def bt(b):
+	if is2:
+		return b
+	return ord(b)
+def b2i(b):
+	if is2:
+		return int(b.encode('hex'), 16)
+	return int.from_bytes(b, byteorder='big')
+def i2b(i):
+	h='{0:x}'.format(i)
+	if len(h)%2==1:
+		h = '0'+h
+	return binascii.unhexlify(h)
+def rs(a, o):
+	if a[o] == bt(b'\\x81'):
+		return (s.unpack('B', a[o+1])[0], 2 + o)
+	elif a[o] == bt(b'\\x82'):
+		return (s.unpack('>H', a[o+1:o+3])[0], 3 + o)
+def ri(b, o):
+	i, o = rs(b, o)
+	return (b[o:o+i], o+i)
+def b2me(b):
+	if b[0] != bt(b'\\x30'):
+		return (None, None)
+	_, o = rs(b, 1)
+	if b[o] != bt(b'\\x02'):
+		return (None, None)
+	(m, o) = ri(b, o + 1)
+	if b[o] != bt(b'\\x02'):
+		return (None, None)
+	e = b[o+2:]
+	return (b2i(m), b2i(e))
+def der2me(d):
+	if d[0] != bt(b'\\x30'):
+		return (None, None)
+	_, o = rs(d, 1)
+	while o < len(d):
+		if d[o] == bt(b'\\x30'):
+			o += s.unpack('B', d[o+1:o+2])[0]
+		elif d[o] == bt(b'\\x05'):
+			o += 2
+		elif d[o] == bt(b'\\x03'):
+			_, o = rs(d, o + 1)
+			return b2me(d[o + 1:])
+		else:
+			return (None, None)
+def rsa_enc(der, msg):
+	m, e = der2me(der)
+	h=b'\\x00\\x02'
+	d=b'\\00'
+	#p=os.urandom(256-len(h)-len(msg)-len(d))
+	l=256-len(h)-len(msg)-len(d)
+	p=os.urandom(512).replace(b'\\x00',b'')
+	return i2b(pow(b2i(h+p[:l]+d+msg), e, m))
+?
+  end
+
+  def python_aes_source
     %Q?
 import copy,struct,sys
 def chunks(lst, n):
@@ -282,7 +349,7 @@ class AESCBC(object):
 			raise ValueError('ciphertext block must be 16 bytes')
 		cb=_s2b(ct);pt=[(p^l)for(p,l)in zip(self.dec_in(cb),self._lcb)];self._lcb=cb
 		return _b2s(pt)
-    ?
+?
   end
 
 end