Use HKDF from Pypi, not local copy

setup.py

@@ -24,7 +24,7 @@ setup(name="magic-wormhole",
                      "wormhole-server = wormhole_server.runner:entry",
                      ]},
       install_requires=["spake2==0.3", "pynacl", "requests", "argparse",
-                        "six", "twisted >= 16.1.0"],
+                        "six", "twisted >= 16.1.0", "hkdf"],
       extras_require={"tor": ["txtorcon", "ipaddr"]},
       test_suite="wormhole.test",
       cmdclass=commands,

src/txwormhole/transcribe.py

@@ -18,9 +18,12 @@ from wormhole import __version__
 from wormhole import codes
 from wormhole.errors import ServerError, Timeout, WrongPasswordError, UsageError
 from wormhole.timing import DebugTiming
-from wormhole.hkdf import HKDF
+from hkdf import Hkdf
 from wormhole.channel_monitor import monitor
 
+def HKDF(skm, outlen, salt=None, CTXinfo=b""):
+    return Hkdf(salt, skm).expand(CTXinfo, outlen)
+
 CONFMSG_NONCE_LENGTH = 128//8
 CONFMSG_MAC_LENGTH = 256//8
 def make_confmsg(confkey, nonce):

src/txwormhole/transit.py

@@ -8,11 +8,14 @@ from twisted.internet import (reactor, interfaces, defer, protocol,
 from twisted.internet.defer import inlineCallbacks, returnValue
 from twisted.protocols import policies
 from nacl.secret import SecretBox
-from wormhole.hkdf import HKDF
+from hkdf import Hkdf
 from wormhole.errors import UsageError
 from wormhole.timing import DebugTiming
 from . import ipaddrs
 
+def HKDF(skm, outlen, salt=None, CTXinfo=b""):
+    return Hkdf(salt, skm).expand(CTXinfo, outlen)
+
 def debug(msg):
     if False:
         print(msg)

src/wormhole/blocking/transcribe.py

@@ -11,9 +11,12 @@ from .. import __version__
 from .. import codes
 from ..errors import ServerError, Timeout, WrongPasswordError, UsageError
 from ..timing import DebugTiming
-from ..hkdf import HKDF
+from hkdf import Hkdf
 from ..channel_monitor import monitor
 
+def HKDF(skm, outlen, salt=None, CTXinfo=b""):
+    return Hkdf(salt, skm).expand(CTXinfo, outlen)
+
 SECOND = 1
 MINUTE = 60*SECOND
 

src/wormhole/hkdf.py

@@ -1,161 +0,0 @@
-from hashlib import sha256, sha1
-import hmac
-import six
-
-def HKDF(SKM, dkLen, XTS=None, CTXinfo=b"", digest=sha256,
-         _test_expected_PRK=None):
-    assert isinstance(SKM, six.binary_type), type(SKM)
-    assert isinstance(XTS, (six.binary_type,type(None))), type(XTS)
-    assert isinstance(CTXinfo, six.binary_type), type(CTXinfo)
-    hlen = len(digest(b"").digest())
-    assert dkLen <= hlen*255
-    if XTS is None:
-        XTS = b"\x00"*hlen
-    # extract
-    PRK = hmac.new(XTS, SKM, digest).digest()
-    if _test_expected_PRK and _test_expected_PRK != PRK:
-        raise ValueError("test failed")
-    # expand
-    blocks = []
-    counter = 1
-    t = b""
-    while hlen*len(blocks) < dkLen:
-        t = hmac.new(PRK, t+CTXinfo+six.int2byte(counter), digest).digest()
-        blocks.append(t)
-        counter += 1
-    return b"".join(blocks)[:dkLen]
-
-def power_on_self_test():
-    from binascii import hexlify, unhexlify
-
-    def _test(IKM, salt, info, L, PRK, OKM, digest=sha256):
-        def remove_prefix(prefix, s):
-            assert s.startswith(prefix)
-            return s[len(prefix):]
-        ikm = unhexlify(remove_prefix("0x", IKM))
-        salt = unhexlify(remove_prefix("0x", salt))
-        info = unhexlify(remove_prefix("0x", info))
-        prk = unhexlify(remove_prefix("0x", PRK))
-        okm = unhexlify(remove_prefix("0x", OKM))
-        if digest is None:
-            out = HKDF(ikm, L, salt, info, _test_expected_PRK=prk)
-        else:
-            out = HKDF(ikm, L, salt, info, digest=digest,
-                       _test_expected_PRK=prk)
-        if okm != out:
-            raise ValueError("got %s, expected %s" % (hexlify(out), hexlify(okm)))
-
-    # test vectors from RFC5869
-    _test(IKM="0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
-          salt="0x000102030405060708090a0b0c",
-          info="0xf0f1f2f3f4f5f6f7f8f9",
-          L=42,
-          PRK=("0x077709362c2e32df0ddc3f0dc47bba63"
-               "90b6c73bb50f9c3122ec844ad7c2b3e5"),
-          OKM=("0x3cb25f25faacd57a90434f64d0362f2a"
-               "2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
-               "34007208d5b887185865"))
-
-    _test(IKM=("0x000102030405060708090a0b0c0d0e0f"
-               "101112131415161718191a1b1c1d1e1f"
-               "202122232425262728292a2b2c2d2e2f"
-               "303132333435363738393a3b3c3d3e3f"
-               "404142434445464748494a4b4c4d4e4f"),
-          salt=("0x606162636465666768696a6b6c6d6e6f"
-                "707172737475767778797a7b7c7d7e7f"
-                "808182838485868788898a8b8c8d8e8f"
-                "909192939495969798999a9b9c9d9e9f"
-                "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"),
-          info=("0xb0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
-                "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
-                "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
-                "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
-                "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff"),
-          L=82,
-          PRK=("0x06a6b88c5853361a06104c9ceb35b45c"
-               "ef760014904671014a193f40c15fc244"),
-          OKM=("0xb11e398dc80327a1c8e7f78c596a4934"
-               "4f012eda2d4efad8a050cc4c19afa97c"
-               "59045a99cac7827271cb41c65e590e09"
-               "da3275600c2f09b8367793a9aca3db71"
-               "cc30c58179ec3e87c14c01d5c1f3434f"
-               "1d87"))
-
-    _test(IKM="0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
-          salt="0x",
-          info="0x",
-          L=42,
-          PRK=("0x19ef24a32c717b167f33a91d6f648bdf"
-               "96596776afdb6377ac434c1c293ccb04"),
-          OKM=("0x8da4e775a563c18f715f802a063c5a31"
-               "b8a11f5c5ee1879ec3454e5f3c738d2d"
-               "9d201395faa4b61a96c8"))
-
-    _test(digest=sha1,
-          IKM="0x0b0b0b0b0b0b0b0b0b0b0b",
-          salt="0x000102030405060708090a0b0c",
-          info="0xf0f1f2f3f4f5f6f7f8f9",
-          L=42,
-          PRK="0x9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
-          OKM=("0x085a01ea1b10f36933068b56efa5ad81"
-               "a4f14b822f5b091568a9cdd4f155fda2"
-               "c22e422478d305f3f896"))
-    _test(digest=sha1,
-       IKM=("0x000102030405060708090a0b0c0d0e0f"
-            "101112131415161718191a1b1c1d1e1f"
-            "202122232425262728292a2b2c2d2e2f"
-            "303132333435363738393a3b3c3d3e3f"
-            "404142434445464748494a4b4c4d4e4f"),
-       salt=("0x606162636465666768696a6b6c6d6e6f"
-             "707172737475767778797a7b7c7d7e7f"
-             "808182838485868788898a8b8c8d8e8f"
-             "909192939495969798999a9b9c9d9e9f"
-             "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"),
-       info=("0xb0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
-             "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
-             "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
-             "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
-             "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff"),
-       L=82,
-       PRK="0x8adae09a2a307059478d309b26c4115a224cfaf6",
-       OKM=("0x0bd770a74d1160f7c9f12cd5912a06eb"
-            "ff6adcae899d92191fe4305673ba2ffe"
-            "8fa3f1a4e5ad79f3f334b3b202b2173c"
-            "486ea37ce3d397ed034c7f9dfeb15c5e"
-            "927336d0441f4c4300e2cff0d0900b52"
-            "d3b4"))
-    _test(digest=sha1,
-          IKM="0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
-          salt="0x",
-          info="0x",
-          L=42,
-          PRK="0xda8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
-          OKM=("0x0ac1af7002b3d761d1e55298da9d0506"
-               "b9ae52057220a306e07b6b87e8df21d0"
-               "ea00033de03984d34918"))
-
-    _test(digest=sha1,
-          IKM="0x0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
-          salt="0x",
-          info="0x",
-          L=42,
-          PRK="0x2adccada18779e7c2077ad2eb19d3f3e731385dd",
-          OKM=("0x2c91117204d745f3500d636a62f64f0a"
-               "b3bae548aa53d423b0d1f27ebba6f5e5"
-               "673a081d70cce7acfc48"))
-
-    # finally test that HKDF() without a digest= uses SHA256
-
-    _test(digest=None,
-          IKM="0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
-          salt="0x",
-          info="0x",
-          L=42,
-          PRK=("0x19ef24a32c717b167f33a91d6f648bdf"
-               "96596776afdb6377ac434c1c293ccb04"),
-          OKM=("0x8da4e775a563c18f715f802a063c5a31"
-               "b8a11f5c5ee1879ec3454e5f3c738d2d"
-               "9d201395faa4b61a96c8"))
-    #print "all test passed"
-
-power_on_self_test()

tests/test_hkdf.py

@@ -0,0 +1,45 @@
+from __future__ import print_function
+import unittest
+from binascii import unhexlify #, hexlify
+from hkdf import Hkdf
+
+#def generate_KAT():
+#    print("KAT = [")
+#    for salt in (b"", b"salt"):
+#        for context in (b"", b"context"):
+#            skm = b"secret"
+#            out = HKDF(skm, 64, XTS=salt, CTXinfo=context)
+#            hexout = "  '%s' +\n  '%s'" % (hexlify(out[:32]),
+#                                           hexlify(out[32:]))
+#            print(" (%r, %r, %r,\n%s)," % (salt, context, skm, hexout))
+#    print("]")
+
+KAT = [
+ ('', '', 'secret',
+  '2f34e5ff91ec85d53ca9b543683174d0cf550b60d5f52b24c97b386cfcf6cbbf' +
+  '9cfd42fd37e1e5a214d15f03058d7fee63dc28f564b7b9fe3da514f80daad4bf'),
+ ('', 'context', 'secret',
+  'c24c303a1adfb4c3e2b092e6254ed481c41d8955ba8ec3f6a1473493a60c957b' +
+  '31b723018ca75557214d3d5c61c0c7a5315b103b21ff00cb03ebe023dc347a47'),
+ ('salt', '', 'secret',
+  'f1156507c39b0e326159e778696253122de430899a8df2484040a85a5f95ceb1' +
+  'dfca555d4cc603bdf7153ed1560de8cbc3234b27a6d2be8e8ca202d90649679a'),
+ ('salt', 'context', 'secret',
+  '61a4f201a867bcc12381ddb180d27074408d03ee9d5750855e5a12d967fa060f' +
+  '10336ead9370927eaabb0d60b259346ee5f57eb7ceba8c72f1ed3f2932b1bf19'),
+]
+
+class TestKAT(unittest.TestCase):
+    # note: this uses SHA256
+    def test_kat(self):
+        for (salt, context, skm, expected_hexout) in KAT:
+            expected_out = unhexlify(expected_hexout)
+            for outlen in range(0, len(expected_out)):
+                out = Hkdf(salt.encode("ascii"),
+                           skm.encode("ascii")).expand(context.encode("ascii"),
+                                                       outlen)
+                self.assertEqual(out, expected_out[:outlen])
+
+#if __name__ == '__main__':
+#    generate_KAT()
+