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util/sasl/scram.lua @ 362:d8c3e94d765d
util.sasl.scram: Correctly verify that the server added its own nonce
| author | Kim Alvefur <zash@zash.se> |
|---|---|
| date | Tue, 30 Sep 2014 11:59:52 +0200 |
| parent | 359:a7aa761a436d |
| child | 363:056ccefa6acf |
| rev | line source |
|---|---|
| 355 | 1 |
| 2 local base64, unbase64 = require "mime".b64, require"mime".unb64; | |
| 3 local crypto = require"crypto"; | |
| 4 local bit = require"bit"; | |
| 5 | |
| 6 local tonumber = tonumber; | |
| 7 local char, byte = string.char, string.byte; | |
| 8 local gsub = string.gsub; | |
| 9 local xor = bit.bxor; | |
| 10 | |
|
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
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11 local function XOR(a, b) |
| 355 | 12 return (gsub(a, "()(.)", function(i, c) |
| 13 return char(xor(byte(c), byte(b, i))) | |
| 14 end)); | |
| 15 end | |
| 16 | |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
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17 local function H(str) |
| 355 | 18 return crypto.digest("sha1", str, true); |
| 19 end | |
| 20 | |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
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21 local function HMAC(key, str) |
| 355 | 22 return crypto.hmac.digest("sha1", str, key, true); |
| 23 end | |
| 24 | |
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358
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
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25 local function Hi(str, salt, i) |
| 355 | 26 local U = HMAC(str, salt .. "\0\0\0\1"); |
| 27 local ret = U; | |
| 28 for _ = 2, i do | |
| 29 U = HMAC(str, U); | |
| 30 ret = XOR(ret, U); | |
| 31 end | |
| 32 return ret; | |
| 33 end | |
| 34 | |
| 35 local function Normalize(str) | |
| 36 return str; -- TODO | |
| 37 end | |
| 38 | |
| 39 local function value_safe(str) | |
| 40 return (gsub(str, "[,=]", { [","] = "=2C", ["="] = "=3D" })); | |
| 41 end | |
| 42 | |
| 43 local function scram(stream, name) | |
| 44 local username = "n=" .. value_safe(stream.username); | |
| 45 local c_nonce = base64(crypto.rand.bytes(15)); | |
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util.sasl.scram: Correctly verify that the server added its own nonce
Kim Alvefur <zash@zash.se>
parents:
359
diff
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46 local our_nonce = "r=" .. c_nonce; |
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d8c3e94d765d
util.sasl.scram: Correctly verify that the server added its own nonce
Kim Alvefur <zash@zash.se>
parents:
359
diff
changeset
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47 local client_first_message_bare = username .. "," .. our_nonce; |
| 355 | 48 local cbind_data = ""; |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
Kim Alvefur <zash@zash.se>
parents:
355
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changeset
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49 local gs2_cbind_flag = "y"; |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
Kim Alvefur <zash@zash.se>
parents:
355
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50 if name == "SCRAM-SHA-1-PLUS" then |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
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parents:
355
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51 cbind_data = stream.conn:socket():getfinished(); |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
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parents:
355
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52 gs2_cbind_flag = "p=tls-unique"; |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
Kim Alvefur <zash@zash.se>
parents:
355
diff
changeset
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53 end |
| 355 | 54 local gs2_header = gs2_cbind_flag .. ",,"; |
| 55 local client_first_message = gs2_header .. client_first_message_bare; | |
| 56 local cont, server_first_message = coroutine.yield(client_first_message); | |
| 57 if cont ~= "challenge" then return false end | |
| 58 | |
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362
d8c3e94d765d
util.sasl.scram: Correctly verify that the server added its own nonce
Kim Alvefur <zash@zash.se>
parents:
359
diff
changeset
|
59 local nonce, salt, iteration_count = server_first_message:match("(r=[^,]+),s=([^,]*),i=(%d+)"); |
| 355 | 60 local i = tonumber(iteration_count); |
| 61 salt = unbase64(salt); | |
| 62 if not nonce or not salt or not i then | |
| 63 return false, "Could not parse server_first_message"; | |
| 64 elseif nonce:find(c_nonce, 3, true) ~= 3 then | |
| 65 return false, "nonce sent by server does not match our nonce"; | |
|
362
d8c3e94d765d
util.sasl.scram: Correctly verify that the server added its own nonce
Kim Alvefur <zash@zash.se>
parents:
359
diff
changeset
|
66 elseif nonce == our_nonce then |
| 355 | 67 return false, "server did not append s-nonce to nonce"; |
| 68 end | |
| 69 | |
| 70 local cbind_input = gs2_header .. cbind_data; | |
| 71 local channel_binding = "c=" .. base64(cbind_input); | |
| 72 local client_final_message_without_proof = channel_binding .. "," .. nonce; | |
| 73 | |
| 74 local SaltedPassword = Hi(Normalize(stream.password), salt, i); | |
| 75 local ClientKey = HMAC(SaltedPassword, "Client Key"); | |
| 76 local StoredKey = H(ClientKey); | |
| 77 local AuthMessage = client_first_message_bare .. "," .. server_first_message .. "," .. client_final_message_without_proof; | |
| 78 local ClientSignature = HMAC(StoredKey, AuthMessage); | |
| 79 local ClientProof = XOR(ClientKey, ClientSignature); | |
| 80 local ServerKey = HMAC(SaltedPassword, "Server Key"); | |
| 81 local ServerSignature = HMAC(ServerKey, AuthMessage); | |
| 82 | |
| 83 local proof = "p=" .. base64(ClientProof); | |
| 84 local client_final_message = client_final_message_without_proof .. "," .. proof; | |
| 85 | |
| 86 local ok, server_final_message = coroutine.yield(client_final_message); | |
| 87 if ok ~= "success" then return false, "success-expected" end | |
| 88 | |
| 89 local verifier = server_final_message:match("v=([^,]+)"); | |
| 90 if unbase64(verifier) ~= ServerSignature then | |
| 91 return false, "server signature did not match"; | |
| 92 end | |
| 93 return true; | |
| 94 end | |
| 95 | |
|
358
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
96 return function (stream, name) |
| 355 | 97 if stream.username and (stream.password or (stream.client_key or stream.server_key)) then |
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358
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
98 if name == "SCRAM-SHA-1" then |
|
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
99 return scram, 99; |
| 359 | 100 elseif name == "SCRAM-SHA-1-PLUS" then |
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358
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
101 local sock = stream.conn:ssl() and stream.conn:socket(); |
|
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
102 if sock and sock.getfinished then |
|
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
103 return scram, 100; |
|
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
104 end |
|
356
f95e797895ee
SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
Kim Alvefur <zash@zash.se>
parents:
355
diff
changeset
|
105 end |
| 355 | 106 end |
| 107 end | |
|
358
a8f6fd6a70ed
plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
Kim Alvefur <zash@zash.se>
parents:
356
diff
changeset
|
108 |
