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Add support for SRP authentication to the manager #312

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235 changes: 235 additions & 0 deletions labrad/crypto.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
import logging
import os
import re
from collections import namedtuple


try:
Expand Down Expand Up @@ -143,3 +144,237 @@ def grouped(s, n=2):
s = s[n:]

return ':'.join(g.upper() for g in grouped(digest, 2))


def hexstr_to_int(s):
"""Convert a string of hex digits to an int after stripping whitespace."""
return int(re.sub(r'\s', '', s), 16)


def int_to_bytes(n):
"""Convert the given int to a byte string in big-endian byte order."""
bs = []
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@jayich jayich Jan 19, 2017

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bs -> byte_string

while n > 0:
b, n = n & 0xFF, n >> 8
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@kunalq kunalq Jan 30, 2017

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For readability, I'd break apart the parallel assignment here--

   b = n & 0xFF
   n = n >> 8

bs.insert(0, chr(b))
return b''.join(bs)


def bytes_to_int(bs):
"""Convert a big-endian byte string to an int."""
n = 0
for b in bs:
n = (n << 8) + ord(b)
return n


def hash_all(hash_class, *args):
"""Concatenate and hash the given args using the given hash function.

hash_class: a callable that returns a hash algorithm with the same
interface as the hash algorithms defined in hashlib.

args: Each arg can be given as a byte string or an int. Integer args are
converted to bytes using int_to_bytes, while byte strings are left
untouched.
"""
m = hash_class()
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m -> hash

for a in args:
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@jayich jayich Jan 19, 2017

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a -> argument, or a -> arg

if isinstance(a, (int, long)):
a = int_to_bytes(a)
m.update(a)
return m.digest()


# SRP (Secure Remote Password) protocol support.
# For details see RFC 5054 (https://tools.ietf.org/html/rfc5054)

SrpGroup = namedtuple('SrpGroup', ['N', 'g'])

SrpGroup1024 = SrpGroup(
N = hexstr_to_int("""
EEAF0AB9 ADB38DD6 9C33F80A FA8FC5E8 60726187 75FF3C0B 9EA2314C
9C256576 D674DF74 96EA81D3 383B4813 D692C6E0 E0D5D8E2 50B98BE4
8E495C1D 6089DAD1 5DC7D7B4 6154D6B6 CE8EF4AD 69B15D49 82559B29
7BCF1885 C529F566 660E57EC 68EDBC3C 05726CC0 2FD4CBF4 976EAA9A
FD5138FE 8376435B 9FC61D2F C0EB06E3
"""),
g = 2
)

SrpGroup1536 = SrpGroup(
N = hexstr_to_int("""
9DEF3CAF B939277A B1F12A86 17A47BBB DBA51DF4 99AC4C80 BEEEA961
4B19CC4D 5F4F5F55 6E27CBDE 51C6A94B E4607A29 1558903B A0D0F843
80B655BB 9A22E8DC DF028A7C EC67F0D0 8134B1C8 B9798914 9B609E0B
E3BAB63D 47548381 DBC5B1FC 764E3F4B 53DD9DA1 158BFD3E 2B9C8CF5
6EDF0195 39349627 DB2FD53D 24B7C486 65772E43 7D6C7F8C E442734A
F7CCB7AE 837C264A E3A9BEB8 7F8A2FE9 B8B5292E 5A021FFF 5E91479E
8CE7A28C 2442C6F3 15180F93 499A234D CF76E3FE D135F9BB
"""),
g = 2
)

SrpGroup2048 = SrpGroup(
N = hexstr_to_int("""
AC6BDB41 324A9A9B F166DE5E 1389582F AF72B665 1987EE07 FC319294
3DB56050 A37329CB B4A099ED 8193E075 7767A13D D52312AB 4B03310D
CD7F48A9 DA04FD50 E8083969 EDB767B0 CF609517 9A163AB3 661A05FB
D5FAAAE8 2918A996 2F0B93B8 55F97993 EC975EEA A80D740A DBF4FF74
7359D041 D5C33EA7 1D281E44 6B14773B CA97B43A 23FB8016 76BD207A
436C6481 F1D2B907 8717461A 5B9D32E6 88F87748 544523B5 24B0D57D
5EA77A27 75D2ECFA 032CFBDB F52FB378 61602790 04E57AE6 AF874E73
03CE5329 9CCC041C 7BC308D8 2A5698F3 A8D0C382 71AE35F8 E9DBFBB6
94B5C803 D89F7AE4 35DE236D 525F5475 9B65E372 FCD68EF2 0FA7111F
9E4AFF73
"""),
g = 2
)

SrpGroup4096 = SrpGroup(
N = hexstr_to_int("""
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08
8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B
302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9
A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6
49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8
FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C
180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718
3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D
04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D
B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226
1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C
BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC
E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26
99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB
04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2
233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127
D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34063199
FFFFFFFF FFFFFFFF
"""),
g = 5
)

SrpGroup8192 = SrpGroup(
N = hexstr_to_int("""
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08
8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B
302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9
A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6
49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8
FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C
180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718
3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D
04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D
B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226
1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C
BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC
E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26
99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB
04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2
233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127
D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492
36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD F8FF9406
AD9E530E E5DB382F 413001AE B06A53ED 9027D831 179727B0 865A8918
DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B DB7F1447 E6CC254B 33205151
2BD7AF42 6FB8F401 378CD2BF 5983CA01 C64B92EC F032EA15 D1721D03
F482D7CE 6E74FEF6 D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F
BEC7E8F3 23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA
CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328 06A1D58B
B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C DA56C9EC 2EF29632
387FE8D7 6E3C0468 043E8F66 3F4860EE 12BF2D5B 0B7474D6 E694F91E
6DBE1159 74A3926F 12FEE5E4 38777CB6 A932DF8C D8BEC4D0 73B931BA
3BC832B6 8D9DD300 741FA7BF 8AFC47ED 2576F693 6BA42466 3AAB639C
5AE4F568 3423B474 2BF1C978 238F16CB E39D652D E3FDB8BE FC848AD9
22222E04 A4037C07 13EB57A8 1A23F0C7 3473FC64 6CEA306B 4BCBC886
2F8385DD FA9D4B7F A2C087E8 79683303 ED5BDD3A 062B3CF5 B3A278A6
6D2A13F8 3F44F82D DF310EE0 74AB6A36 4597E899 A0255DC1 64F31CC5
0846851D F9AB4819 5DED7EA1 B1D510BD 7EE74D73 FAF36BC3 1ECFA268
359046F4 EB879F92 4009438B 481C6CD7 889A002E D5EE382B C9190DA6
FC026E47 9558E447 5677E9AA 9E3050E2 765694DF C81F56E8 80B96E71
60C980DD 98EDD3DF FFFFFFFF FFFFFFFF
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@kunalq kunalq Jan 30, 2017

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Likewise here, I think we can have a common file that can be read in to store these numbers. Then both Scala & python can read them in.

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And, actually, we can use MoultingYAML in Scala and Python's YAML format to stuff these into a YAML file keyed on the bit size.

"""),
g = 19
)

srp_groups = {
"1024": SrpGroup1024,
"1536": SrpGroup1536,
"2048": SrpGroup2048,
"4096": SrpGroup4096,
"8192": SrpGroup8192
}


class SRP(object):
"""Secure Remote Password (SRP) protocol implementation.

For details of the algorithm, see https://tools.ietf.org/html/rfc5054
"""
def __init__(self, identity, password, group=SrpGroup1024,
hash_class=hashlib.sha1):
"""Initialize an SRP instance.

Args:
identity (str): username
password (str): password
group (SrpGroup | str): Group parameters to use in the SRP protocol
or name of a group to use.
hash_class (callable): Called with no args and should return a hash
algorithm with the same interface as those defined in hashlib.
"""
if isinstance(group, str):
group = srp_groups[group]

def generator():
N, g = group.N, group.g
N_bytes = int_to_bytes(N)

def H(*args):
return hash_all(hash_class, *args)

def PAD(x):
return int_to_bytes(x).rjust(len(N_bytes), chr(0))
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I would suggest renaming PAD -> pad to keep naming consistent (even though this looks like it's mimicking a C macro)


# send identity. get back salt and server B
salt, B_bytes = yield

a = bytes_to_int(os.urandom(32))
A = pow(g, a, N)

B = bytes_to_int(B_bytes)
if B % N == 0:
raise Exception("auth failed: invalid challenge from server")

x = bytes_to_int(H(salt, H(identity, ':', password)))
k = bytes_to_int(H(N, PAD(g)))
u = bytes_to_int(H(PAD(A), PAD(B)))
if u == 0:
raise Exception("auth failed: incompatible server and client "
"challenges")
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I recommend making an AuthException class and raising that instead, in case we need it in the future (or using the existing LoginFailedError exception)...


S = pow(B - k * pow(g, x, N), a + u * x, N)

M1 = bytes_to_int(H(PAD(A), PAD(B), PAD(S)))
M2 = bytes_to_int(H(PAD(A), PAD(M1), PAD(S)))

# send client confirmation M1, get back server confirmation M2
M2_server_bytes = yield int_to_bytes(A), int_to_bytes(M1)
M2_server = bytes_to_int(M2_server_bytes)

# authentication succeeded if the server M2 matched ours
yield M2_server == M2

self._generator = generator()
self._generator.next()

def process_server_challenge(self, salt, B_bytes):
A_bytes, M1_bytes = self._generator.send((salt, B_bytes))
return A_bytes, M1_bytes

def process_server_confirmation(self, M2_server_bytes):
success = self._generator.send(M2_server_bytes)
if not success:
raise Exception("auth failed: unable to confirm server message")
58 changes: 36 additions & 22 deletions labrad/protocol.py
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Original file line number Diff line number Diff line change
Expand Up @@ -387,7 +387,6 @@ def require_secure_connection(auth_type):
'username+password auth. Cannot log in '
'as user {}.'.format(username))
credential = auth.Password(username, password)

else:
# Have neither username nor password.
# Check manager-supported auth methods; use OAuth if available.
Expand Down Expand Up @@ -416,20 +415,34 @@ def require_secure_connection(auth_type):

if isinstance(credential, auth.Password):
if not credential.username:
# send login packet to get password challenge
challenge = yield self._sendManagerRequest()

# send password response
m = hashlib.md5()
m.update(challenge)
if isinstance(credential.password, bytes):
m.update(credential.password)
if 'srp' in self.manager_features:
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@jayich jayich Jan 19, 2017

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what does "srp" stand for?

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@kunalq kunalq Jan 30, 2017

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@jayich Secure Random Password -- see https://tools.ietf.org/html/rfc5054

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@jayich jayich Jan 30, 2017

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@kunalq , thank you.

@maffoo , space permitting consider srp -> secure_random_password, or secure_rnd_passwd.

# send identity
group, salt, B_bytes = yield self._sendManagerRequest(10, username)

# send password response
srp = crypto.SRP(identity=username, group=group,
password=credential.password)
A_bytes, M1 = srp.process_server_challenge(salt, B_bytes)
try:
resp, M2 = yield self._sendManagerRequest(11, (A_bytes, M1))
except Exception:
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I realize that labrad will propagate the stack trace to the client, which should hopefully explain where the exception is being raised, but I'm still hesitant to use this outside of generic code. Any chance we can be more specific in this exception? My experience with except Exception is that it can cause serious debugging issues trying to isolate root causes.

raise errors.LoginFailedError('Incorrect password.')
srp.process_server_confirmation(M2)
else:
m.update(credential.password.encode('UTF-8'))
try:
resp = yield self._sendManagerRequest(0, m.digest())
except Exception:
raise errors.LoginFailedError('Incorrect password.')
# send login packet to get password challenge
challenge = yield self._sendManagerRequest()

# send password response
m = hashlib.md5()
m.update(challenge)
if isinstance(credential.password, bytes):
m.update(credential.password)
else:
m.update(credential.password.encode('UTF-8'))
try:
resp = yield self._sendManagerRequest(0, m.digest())
except Exception:
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Ditto here

raise errors.LoginFailedError('Incorrect password.')
else:
method = 'username+password'
require_secure_connection(method)
Expand Down Expand Up @@ -543,14 +556,6 @@ def connect(host=C.MANAGER_HOST, port=None, tls_mode=C.MANAGER_TLS,
def authenticate(p):
yield p.authenticate(username, password, headless)

if tls_mode == 'on':
tls_options = crypto.tls_options(host)
p = yield _factory.connectSSL(host, port, tls_options, timeout=C.TIMEOUT)
p.set_address(host, port)
p.spawn_kw = spawn_kw
yield authenticate(p)
returnValue(p)

@inlineCallbacks
def do_connect():
p = yield _factory.connectTCP(host, port, timeout=C.TIMEOUT)
Expand Down Expand Up @@ -580,6 +585,15 @@ def ping(p):
manager_features = set()
returnValue(manager_features)

if tls_mode == 'on':
tls_options = crypto.tls_options(host)
p = yield _factory.connectSSL(host, port, tls_options, timeout=C.TIMEOUT)
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p is a port? possibly p -> port

p.set_address(host, port)
p.spawn_kw = spawn_kw
p.manager_features = yield ping(p)
yield authenticate(p)
returnValue(p)

p = yield do_connect()
is_local_connection = util.is_local_connection(p.transport)
if ((tls_mode == 'starttls-force') or
Expand Down