1# Authors:
2#   Trevor Perrin
3#   Dave Baggett (Arcode Corporation) - MD5 support for MAC_SSL
4#   Yngve Pettersen (ported by Paul Sokolovsky) - TLS 1.2
5#
6# See the LICENSE file for legal information regarding use of this file.
7
8"""Miscellaneous helper functions."""
9
10from .utils.compat import *
11from .utils.cryptomath import *
12
13import hmac
14
15#1024, 1536, 2048, 3072, 4096, 6144, and 8192 bit groups]
16goodGroupParameters = [(2,0xEEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE48E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B297BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9AFD5138FE8376435B9FC61D2FC0EB06E3),\
17                       (2,0x9DEF3CAFB939277AB1F12A8617A47BBBDBA51DF499AC4C80BEEEA9614B19CC4D5F4F5F556E27CBDE51C6A94BE4607A291558903BA0D0F84380B655BB9A22E8DCDF028A7CEC67F0D08134B1C8B97989149B609E0BE3BAB63D47548381DBC5B1FC764E3F4B53DD9DA1158BFD3E2B9C8CF56EDF019539349627DB2FD53D24B7C48665772E437D6C7F8CE442734AF7CCB7AE837C264AE3A9BEB87F8A2FE9B8B5292E5A021FFF5E91479E8CE7A28C2442C6F315180F93499A234DCF76E3FED135F9BB),\
18                       (2,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
19                       (2,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
20                       (5,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
21                       (5,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
22                       (5,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
23
24def P_hash(macFunc, secret, seed, length):
25    bytes = bytearray(length)
26    A = seed
27    index = 0
28    while 1:
29        A = macFunc(secret, A)
30        output = macFunc(secret, A + seed)
31        for c in output:
32            if index >= length:
33                return bytes
34            bytes[index] = c
35            index += 1
36    return bytes
37
38def PRF(secret, label, seed, length):
39    #Split the secret into left and right halves
40    # which may share a byte if len is odd
41    S1 = secret[ : int(math.ceil(len(secret)/2.0))]
42    S2 = secret[ int(math.floor(len(secret)/2.0)) : ]
43
44    #Run the left half through P_MD5 and the right half through P_SHA1
45    p_md5 = P_hash(HMAC_MD5, S1, label + seed, length)
46    p_sha1 = P_hash(HMAC_SHA1, S2, label + seed, length)
47
48    #XOR the output values and return the result
49    for x in range(length):
50        p_md5[x] ^= p_sha1[x]
51    return p_md5
52
53def PRF_1_2(secret, label, seed, length):
54    return P_hash(HMAC_SHA256, secret, label + seed, length)
55
56def PRF_SSL(secret, seed, length):
57    bytes = bytearray(length)
58    index = 0
59    for x in range(26):
60        A = bytearray([ord('A')+x] * (x+1)) # 'A', 'BB', 'CCC', etc..
61        input = secret + SHA1(A + secret + seed)
62        output = MD5(input)
63        for c in output:
64            if index >= length:
65                return bytes
66            bytes[index] = c
67            index += 1
68    return bytes
69
70def calcMasterSecret(version, premasterSecret, clientRandom, serverRandom):
71    if version == (3,0):
72        masterSecret = PRF_SSL(premasterSecret,
73                            clientRandom + serverRandom, 48)
74    elif version in ((3,1), (3,2)):
75        masterSecret = PRF(premasterSecret, b"master secret",
76                            clientRandom + serverRandom, 48)
77    elif version == (3,3):
78        masterSecret = PRF_1_2(premasterSecret, b"master secret",
79                            clientRandom + serverRandom, 48)
80    else:
81        raise AssertionError()
82    return masterSecret
83
84
85def makeX(salt, username, password):
86    if len(username)>=256:
87        raise ValueError("username too long")
88    if len(salt)>=256:
89        raise ValueError("salt too long")
90    innerHashResult = SHA1(username + bytearray(b":") + password)
91    outerHashResult = SHA1(salt + innerHashResult)
92    return bytesToNumber(outerHashResult)
93
94#This function is used by VerifierDB.makeVerifier
95def makeVerifier(username, password, bits):
96    bitsIndex = {1024:0, 1536:1, 2048:2, 3072:3, 4096:4, 6144:5, 8192:6}[bits]
97    g,N = goodGroupParameters[bitsIndex]
98    salt = getRandomBytes(16)
99    x = makeX(salt, username, password)
100    verifier = powMod(g, x, N)
101    return N, g, salt, verifier
102
103def PAD(n, x):
104    nLength = len(numberToByteArray(n))
105    b = numberToByteArray(x)
106    if len(b) < nLength:
107        b = (b"\0" * (nLength-len(b))) + b
108    return b
109
110def makeU(N, A, B):
111  return bytesToNumber(SHA1(PAD(N, A) + PAD(N, B)))
112
113def makeK(N, g):
114  return bytesToNumber(SHA1(numberToByteArray(N) + PAD(N, g)))
115
116def createHMAC(k, digestmod=hashlib.sha1):
117    return hmac.HMAC(k, digestmod=digestmod)
118
119def createMAC_SSL(k, digestmod=None):
120    mac = MAC_SSL()
121    mac.create(k, digestmod=digestmod)
122    return mac
123
124
125class MAC_SSL(object):
126    def create(self, k, digestmod=None):
127        self.digestmod = digestmod or hashlib.sha1
128        # Repeat pad bytes 48 times for MD5; 40 times for other hash functions.
129        self.digest_size = 16 if (self.digestmod is hashlib.md5) else 20
130        repeat = 40 if self.digest_size == 20 else 48
131        opad = b"\x5C" * repeat
132        ipad = b"\x36" * repeat
133
134        self.ohash = self.digestmod(k + opad)
135        self.ihash = self.digestmod(k + ipad)
136
137    def update(self, m):
138        self.ihash.update(m)
139
140    def copy(self):
141        new = MAC_SSL()
142        new.ihash = self.ihash.copy()
143        new.ohash = self.ohash.copy()
144        new.digestmod = self.digestmod
145        new.digest_size = self.digest_size
146        return new
147
148    def digest(self):
149        ohash2 = self.ohash.copy()
150        ohash2.update(self.ihash.digest())
151        return bytearray(ohash2.digest())
152