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util/sasl/scram.lua @ 453:e60c776b7760
util.sasl.scram: Refactor channel binding
This will ease support for new channel binding methods.
| author | Kim Alvefur <zash@zash.se> |
|---|---|
| date | Wed, 03 Aug 2022 03:04:17 +0200 |
| parent | 407:c99db5172309 |
| child | 454:9f27a2075e9e |
| rev | line source |
|---|---|
| 355 | 1 |
| 2 local base64, unbase64 = require "mime".b64, require"mime".unb64; | |
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util.sasl.scram: Use the new util.hashes and util.random
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3 local hashes = require"util.hashes"; |
| 355 | 4 local bit = require"bit"; |
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5 local random = require"util.random"; |
| 355 | 6 |
| 7 local tonumber = tonumber; | |
| 8 local char, byte = string.char, string.byte; | |
| 9 local gsub = string.gsub; | |
| 10 local xor = bit.bxor; | |
| 11 | |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
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12 local function XOR(a, b) |
| 355 | 13 return (gsub(a, "()(.)", function(i, c) |
| 14 return char(xor(byte(c), byte(b, i))) | |
| 15 end)); | |
| 16 end | |
| 17 | |
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util.sasl.scram: Use the new util.hashes and util.random
Kim Alvefur <zash@zash.se>
parents:
365
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18 local H, HMAC = hashes.sha1, hashes.hmac_sha1; |
| 355 | 19 |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
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parents:
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20 local function Hi(str, salt, i) |
| 355 | 21 local U = HMAC(str, salt .. "\0\0\0\1"); |
| 22 local ret = U; | |
| 23 for _ = 2, i do | |
| 24 U = HMAC(str, U); | |
| 25 ret = XOR(ret, U); | |
| 26 end | |
| 27 return ret; | |
| 28 end | |
| 29 | |
| 30 local function Normalize(str) | |
| 31 return str; -- TODO | |
| 32 end | |
| 33 | |
| 34 local function value_safe(str) | |
| 35 return (gsub(str, "[,=]", { [","] = "=2C", ["="] = "=3D" })); | |
| 36 end | |
| 37 | |
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38 local function cb(conn) |
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39 if conn:ssl() then |
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40 if sock.getfinished then |
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41 return "p=tls-unique", sock:getfinished(); |
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42 end |
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43 end |
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44 end |
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45 |
| 355 | 46 local function scram(stream, name) |
| 47 local username = "n=" .. value_safe(stream.username); | |
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48 local c_nonce = base64(random.bytes(15)); |
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util.sasl.scram: Correctly verify that the server added its own nonce
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49 local our_nonce = "r=" .. c_nonce; |
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util.sasl.scram: Correctly verify that the server added its own nonce
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50 local client_first_message_bare = username .. "," .. our_nonce; |
| 355 | 51 local cbind_data = ""; |
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52 local gs2_cbind_flag = "n"; |
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SCRAM: Add channel binding support (SCRAM-SHA-1-PLUS)
Kim Alvefur <zash@zash.se>
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53 if name == "SCRAM-SHA-1-PLUS" then |
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util.sasl.scram: Refactor channel binding
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parents:
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54 gs2_cbind_flag, cbind_data = cb(stream.conn); |
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parents:
407
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55 elseif cb(stream.conn) then |
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util.sasl.scram: Refactor channel binding
Kim Alvefur <zash@zash.se>
parents:
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56 gs2_cbind_flag = "y"; |
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57 end |
| 355 | 58 local gs2_header = gs2_cbind_flag .. ",,"; |
| 59 local client_first_message = gs2_header .. client_first_message_bare; | |
| 60 local cont, server_first_message = coroutine.yield(client_first_message); | |
| 61 if cont ~= "challenge" then return false end | |
| 62 | |
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util.sasl.scram: Correctly verify that the server added its own nonce
Kim Alvefur <zash@zash.se>
parents:
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63 local nonce, salt, iteration_count = server_first_message:match("(r=[^,]+),s=([^,]*),i=(%d+)"); |
| 355 | 64 local i = tonumber(iteration_count); |
| 65 salt = unbase64(salt); | |
| 66 if not nonce or not salt or not i then | |
| 67 return false, "Could not parse server_first_message"; | |
| 68 elseif nonce:find(c_nonce, 3, true) ~= 3 then | |
| 69 return false, "nonce sent by server does not match our nonce"; | |
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util.sasl.scram: Correctly verify that the server added its own nonce
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parents:
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70 elseif nonce == our_nonce then |
| 355 | 71 return false, "server did not append s-nonce to nonce"; |
| 72 end | |
| 73 | |
| 74 local cbind_input = gs2_header .. cbind_data; | |
| 75 local channel_binding = "c=" .. base64(cbind_input); | |
| 76 local client_final_message_without_proof = channel_binding .. "," .. nonce; | |
| 77 | |
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util.sasl.scram: Add support for authenticating with pre-hashed password
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parents:
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78 local SaltedPassword; |
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79 local ClientKey; |
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80 local ServerKey; |
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81 |
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82 if stream.client_key and stream.server_key then |
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parents:
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83 ClientKey = stream.client_key; |
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84 ServerKey = stream.server_key; |
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parents:
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85 else |
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86 if stream.salted_password then |
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87 SaltedPassword = stream.salted_password; |
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88 elseif stream.password then |
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parents:
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89 SaltedPassword = Hi(Normalize(stream.password), salt, i); |
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90 end |
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91 ServerKey = HMAC(SaltedPassword, "Server Key"); |
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92 ClientKey = HMAC(SaltedPassword, "Client Key"); |
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93 end |
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94 |
| 355 | 95 local StoredKey = H(ClientKey); |
| 96 local AuthMessage = client_first_message_bare .. "," .. server_first_message .. "," .. client_final_message_without_proof; | |
| 97 local ClientSignature = HMAC(StoredKey, AuthMessage); | |
| 98 local ClientProof = XOR(ClientKey, ClientSignature); | |
| 99 local ServerSignature = HMAC(ServerKey, AuthMessage); | |
| 100 | |
| 101 local proof = "p=" .. base64(ClientProof); | |
| 102 local client_final_message = client_final_message_without_proof .. "," .. proof; | |
| 103 | |
| 104 local ok, server_final_message = coroutine.yield(client_final_message); | |
| 105 if ok ~= "success" then return false, "success-expected" end | |
| 106 | |
| 107 local verifier = server_final_message:match("v=([^,]+)"); | |
| 108 if unbase64(verifier) ~= ServerSignature then | |
| 109 return false, "server signature did not match"; | |
| 110 end | |
| 111 return true; | |
| 112 end | |
| 113 | |
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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
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114 return function (stream, name) |
| 355 | 115 if stream.username and (stream.password or (stream.client_key or stream.server_key)) then |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
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parents:
356
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116 if name == "SCRAM-SHA-1" then |
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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
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117 return scram, 99; |
| 359 | 118 elseif name == "SCRAM-SHA-1-PLUS" then |
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util.sasl.scram: Refactor channel binding
Kim Alvefur <zash@zash.se>
parents:
407
diff
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119 if cb(stream.conn) then |
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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
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120 return scram, 100; |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
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parents:
356
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121 end |
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122 end |
| 355 | 123 end |
| 124 end | |
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plugins.sasl: Alter mechanism loading and pass name of loaded mechanism. Fixes attempting SCRAM-PLUS when only SCRAM is offered
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125 |
