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util/jwt.lua @ 12594:29685403be32
mod_saslauth: Implement RFC 9266 'tls-exporter' channel binding (#1760)
Brings back SCRAM-SHA-*-PLUS from its hiatus brought on by the earlier
channel binding method being undefined for TLS 1.3, and the increasing
deployment of TLS 1.3.
See 1bfd238e05ad and #1542
Requires future version of LuaSec, once support for this key material
export method is merged.
See https://github.com/brunoos/luasec/pull/187
author | Kim Alvefur <zash@zash.se> |
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date | Wed, 01 Jun 2022 15:06:59 +0200 |
parent | 11561:d2f33b8fdc96 |
child | 12696:27a72982e331 |
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local s_gsub = string.gsub; local json = require "util.json"; local hashes = require "util.hashes"; local base64_encode = require "util.encodings".base64.encode; local base64_decode = require "util.encodings".base64.decode; local secure_equals = require "util.hashes".equals; local b64url_rep = { ["+"] = "-", ["/"] = "_", ["="] = "", ["-"] = "+", ["_"] = "/" }; local function b64url(data) return (s_gsub(base64_encode(data), "[+/=]", b64url_rep)); end local function unb64url(data) return base64_decode(s_gsub(data, "[-_]", b64url_rep).."=="); end local static_header = b64url('{"alg":"HS256","typ":"JWT"}') .. '.'; local function sign(key, payload) local encoded_payload = json.encode(payload); local signed = static_header .. b64url(encoded_payload); local signature = hashes.hmac_sha256(key, signed); return signed .. "." .. b64url(signature); end local jwt_pattern = "^(([A-Za-z0-9-_]+)%.([A-Za-z0-9-_]+))%.([A-Za-z0-9-_]+)$" local function verify(key, blob) local signed, bheader, bpayload, signature = string.match(blob, jwt_pattern); if not signed then return nil, "invalid-encoding"; end local header = json.decode(unb64url(bheader)); if not header or type(header) ~= "table" then return nil, "invalid-header"; elseif header.alg ~= "HS256" then return nil, "unsupported-algorithm"; end if not secure_equals(b64url(hashes.hmac_sha256(key, signed)), signature) then return false, "signature-mismatch"; end local payload, err = json.decode(unb64url(bpayload)); if err ~= nil then return nil, "json-decode-error"; end return true, payload; end return { sign = sign; verify = verify; };