1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
local crypto = require "prosody.util.crypto";
local json = require "prosody.util.json";
local hashes = require "prosody.util.hashes";
local base64_encode = require "prosody.util.encodings".base64.encode;
local base64_decode = require "prosody.util.encodings".base64.decode;
local secure_equals = require "prosody.util.hashes".equals;
local bit = require "prosody.util.bitcompat";
local hex = require "prosody.util.hex";
local rand = require "prosody.util.random";
local s_pack = require "prosody.util.struct".pack;
local s_gsub = string.gsub;
local v4_public = {};
local b64url_rep = { ["+"] = "-", ["/"] = "_", ["="] = "", ["-"] = "+", ["_"] = "/" };
local function b64url(data)
return (s_gsub(base64_encode(data), "[+/=]", b64url_rep));
end
local valid_tails = {
nil; -- Always invalid
"^.[AQgw]$"; -- b??????00
"^..[AQgwEUk0IYo4Mcs8]$"; -- b????0000
}
local function unb64url(data)
local rem = #data%4;
if data:sub(-1,-1) == "=" or rem == 1 or (rem > 1 and not data:sub(-rem):match(valid_tails[rem])) then
return nil;
end
return base64_decode(s_gsub(data, "[-_]", b64url_rep).."==");
end
local function le64(n)
return s_pack("<I8", bit.band(n, 0x7F));
end
local function pae(parts)
if type(parts) ~= "table" then
error("bad argument #1 to 'pae' (table expected, got "..type(parts)..")");
end
local o = { le64(#parts) };
for _, part in ipairs(parts) do
table.insert(o, le64(#part)..part);
end
return table.concat(o);
end
function v4_public.sign(m, sk, f, i)
if type(m) ~= "table" then
return nil, "PASETO payloads must be a table";
end
m = json.encode(m);
local h = "v4.public.";
local m2 = pae({ h, m, f or "", i or "" });
local sig = crypto.ed25519_sign(sk, m2);
if not f or f == "" then
return h..b64url(m..sig);
else
return h..b64url(m..sig).."."..b64url(f);
end
end
function v4_public.verify(tok, pk, expected_f, i)
local h, sm, f = tok:match("^(v4%.public%.)([^%.]+)%.?(.*)$");
if not h then
return nil, "invalid-token-format";
end
f = f and unb64url(f) or nil;
if expected_f then
if not f or not secure_equals(expected_f, f) then
return nil, "invalid-footer";
end
end
local raw_sm = unb64url(sm);
if not raw_sm or #raw_sm <= 64 then
return nil, "invalid-token-format";
end
local s, m = raw_sm:sub(-64), raw_sm:sub(1, -65);
local m2 = pae({ h, m, f or "", i or "" });
local ok = crypto.ed25519_verify(pk, m2, s);
if not ok then
return nil, "invalid-token";
end
local payload, err = json.decode(m);
if err ~= nil or type(payload) ~= "table" then
return nil, "json-decode-error";
end
return payload;
end
v4_public.import_private_key = crypto.import_private_pem;
v4_public.import_public_key = crypto.import_public_pem;
function v4_public.new_keypair()
return crypto.generate_ed25519_keypair();
end
function v4_public.init(private_key_pem, public_key_pem, options)
local sign, verify = v4_public.sign, v4_public.verify;
local public_key = public_key_pem and v4_public.import_public_key(public_key_pem);
local private_key = private_key_pem and v4_public.import_private_key(private_key_pem);
local default_footer = options and options.default_footer;
local default_assertion = options and options.default_implicit_assertion;
return private_key and function (token, token_footer, token_assertion)
return sign(token, private_key, token_footer or default_footer, token_assertion or default_assertion);
end, public_key and function (token, expected_footer, token_assertion)
return verify(token, public_key, expected_footer or default_footer, token_assertion or default_assertion);
end;
end
function v4_public.new_signer(private_key_pem, options)
return (v4_public.init(private_key_pem, nil, options));
end
function v4_public.new_verifier(public_key_pem, options)
return (select(2, v4_public.init(nil, public_key_pem, options)));
end
local v3_local = { _key_mt = {} };
local function v3_local_derive_keys(k, n)
local tmp = hashes.hkdf_hmac_sha384(48, k, nil, "paseto-encryption-key"..n);
local Ek = tmp:sub(1, 32);
local n2 = tmp:sub(33);
local Ak = hashes.hkdf_hmac_sha384(48, k, nil, "paseto-auth-key-for-aead"..n);
return Ek, Ak, n2;
end
function v3_local.encrypt(m, k, f, i)
assert(#k == 32)
if type(m) ~= "table" then
return nil, "PASETO payloads must be a table";
end
m = json.encode(m);
local h = "v3.local.";
local n = rand.bytes(32);
local Ek, Ak, n2 = v3_local_derive_keys(k, n);
local c = crypto.aes_256_ctr_encrypt(Ek, n2, m);
local m2 = pae({ h, n, c, f or "", i or "" });
local t = hashes.hmac_sha384(Ak, m2);
if not f or f == "" then
return h..b64url(n..c..t);
else
return h..b64url(n..c..t).."."..b64url(f);
end
end
function v3_local.decrypt(tok, k, expected_f, i)
assert(#k == 32)
local h, sm, f = tok:match("^(v3%.local%.)([^%.]+)%.?(.*)$");
if not h then
return nil, "invalid-token-format";
end
f = f and unb64url(f) or nil;
if expected_f then
if not f or not secure_equals(expected_f, f) then
return nil, "invalid-footer";
end
end
local m = unb64url(sm);
if not m or #m <= 80 then
return nil, "invalid-token-format";
end
local n, c, t = m:sub(1, 32), m:sub(33, -49), m:sub(-48);
local Ek, Ak, n2 = v3_local_derive_keys(k, n);
local preAuth = pae({ h, n, c, f or "", i or "" });
local t2 = hashes.hmac_sha384(Ak, preAuth);
if not secure_equals(t, t2) then
return nil, "invalid-token";
end
local m2 = crypto.aes_256_ctr_decrypt(Ek, n2, c);
if not m2 then
return nil, "invalid-token";
end
local payload, err = json.decode(m2);
if err ~= nil or type(payload) ~= "table" then
return nil, "json-decode-error";
end
return payload;
end
function v3_local.new_key()
return "secret-token:paseto.v3.local:"..hex.encode(rand.bytes(32));
end
function v3_local.init(key, options)
local encoded_key = key:match("^secret%-token:paseto%.v3%.local:(%x+)$");
if not encoded_key or #encoded_key ~= 64 then
return error("invalid key for v3.local");
end
local raw_key = hex.decode(encoded_key);
local default_footer = options and options.default_footer;
local default_assertion = options and options.default_implicit_assertion;
return function (token, token_footer, token_assertion)
return v3_local.encrypt(token, raw_key, token_footer or default_footer, token_assertion or default_assertion);
end, function (token, token_footer, token_assertion)
return v3_local.decrypt(token, raw_key, token_footer or default_footer, token_assertion or default_assertion);
end;
end
function v3_local.new_signer(key, options)
return (v3_local.init(key, options));
end
function v3_local.new_verifier(key, options)
return (select(2, v3_local.init(key, options)));
end
return {
pae = pae;
v3_local = v3_local;
v4_public = v4_public;
};
|
