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util/jwt.lua @ 13029:8ad432953300
mod_debug_reset: Remove now unused import of util.time (thanks luacheck)
author | Matthew Wild <mwild1@gmail.com> |
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date | Thu, 06 Apr 2023 14:49:11 +0100 (21 months ago) |
parent | 12975:d10957394a3c |
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local s_gsub = string.gsub; 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 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 jwt_pattern = "^(([A-Za-z0-9-_]+)%.([A-Za-z0-9-_]+))%.([A-Za-z0-9-_]+)$" local function decode_jwt(blob, expected_alg) 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 ~= expected_alg then return nil, "unsupported-algorithm"; end return signed, signature, bpayload; end local function new_static_header(algorithm_name) return b64url('{"alg":"'..algorithm_name..'","typ":"JWT"}') .. '.'; end local function decode_raw_payload(raw_payload) local payload, err = json.decode(unb64url(raw_payload)); if err ~= nil then return nil, "json-decode-error"; elseif type(payload) ~= "table" then return nil, "invalid-payload-type"; end return true, payload; end -- HS*** family local function new_hmac_algorithm(name) local static_header = new_static_header(name); local hmac = hashes["hmac_sha"..name:sub(-3)]; local function sign(key, payload) local encoded_payload = json.encode(payload); local signed = static_header .. b64url(encoded_payload); local signature = hmac(key, signed); return signed .. "." .. b64url(signature); end local function verify(key, blob) local signed, signature, raw_payload = decode_jwt(blob, name); if not signed then return nil, signature; end -- nil, err if not secure_equals(b64url(hmac(key, signed)), signature) then return false, "signature-mismatch"; end return decode_raw_payload(raw_payload); end local function load_key(key) assert(type(key) == "string", "key must be string (long, random, secure)"); return key; end return { sign = sign, verify = verify, load_key = load_key }; end local function new_crypto_algorithm(name, key_type, c_sign, c_verify, sig_encode, sig_decode) local static_header = new_static_header(name); return { sign = function (private_key, payload) local encoded_payload = json.encode(payload); local signed = static_header .. b64url(encoded_payload); local signature = c_sign(private_key, signed); if sig_encode then signature = sig_encode(signature); end return signed.."."..b64url(signature); end; verify = function (public_key, blob) local signed, signature, raw_payload = decode_jwt(blob, name); if not signed then return nil, signature; end -- nil, err signature = unb64url(signature); if sig_decode and signature then signature = sig_decode(signature); end if not signature then return false, "signature-mismatch"; end local verify_ok = c_verify(public_key, signed, signature); if not verify_ok then return false, "signature-mismatch"; end return decode_raw_payload(raw_payload); end; load_public_key = function (public_key_pem) local key = assert(crypto.import_public_pem(public_key_pem)); assert(key:get_type() == key_type, "incorrect key type"); return key; end; load_private_key = function (private_key_pem) local key = assert(crypto.import_private_pem(private_key_pem)); assert(key:get_type() == key_type, "incorrect key type"); return key; end; }; end -- RS***, PS*** local rsa_sign_algos = { RS = "rsassa_pkcs1", PS = "rsassa_pss" }; local function new_rsa_algorithm(name) local family, digest_bits = name:match("^(..)(...)$"); local c_sign = crypto[rsa_sign_algos[family].."_sha"..digest_bits.."_sign"]; local c_verify = crypto[rsa_sign_algos[family].."_sha"..digest_bits.."_verify"]; return new_crypto_algorithm(name, "rsaEncryption", c_sign, c_verify); end -- ES*** local function new_ecdsa_algorithm(name, c_sign, c_verify, sig_bytes) local function encode_ecdsa_sig(der_sig) local r, s = crypto.parse_ecdsa_signature(der_sig, sig_bytes); return r..s; end local expected_sig_length = sig_bytes*2; local function decode_ecdsa_sig(jwk_sig) if #jwk_sig ~= expected_sig_length then return nil; end return crypto.build_ecdsa_signature(jwk_sig:sub(1, sig_bytes), jwk_sig:sub(sig_bytes+1)); end return new_crypto_algorithm(name, "id-ecPublicKey", c_sign, c_verify, encode_ecdsa_sig, decode_ecdsa_sig); end local algorithms = { HS256 = new_hmac_algorithm("HS256"), HS384 = new_hmac_algorithm("HS384"), HS512 = new_hmac_algorithm("HS512"); ES256 = new_ecdsa_algorithm("ES256", crypto.ecdsa_sha256_sign, crypto.ecdsa_sha256_verify, 32); ES512 = new_ecdsa_algorithm("ES512", crypto.ecdsa_sha512_sign, crypto.ecdsa_sha512_verify, 66); RS256 = new_rsa_algorithm("RS256"), RS384 = new_rsa_algorithm("RS384"), RS512 = new_rsa_algorithm("RS512"); PS256 = new_rsa_algorithm("PS256"), PS384 = new_rsa_algorithm("PS384"), PS512 = new_rsa_algorithm("PS512"); }; local function new_signer(algorithm, key_input, options) local impl = assert(algorithms[algorithm], "Unknown JWT algorithm: "..algorithm); local key = (impl.load_private_key or impl.load_key)(key_input); local sign = impl.sign; local default_ttl = (options and options.default_ttl) or 3600; return function (payload) local issued_at; if not payload.iat then issued_at = os.time(); payload.iat = issued_at; end if not payload.exp then payload.exp = (issued_at or os.time()) + default_ttl; end return sign(key, payload); end end local function new_verifier(algorithm, key_input, options) local impl = assert(algorithms[algorithm], "Unknown JWT algorithm: "..algorithm); local key = (impl.load_public_key or impl.load_key)(key_input); local verify = impl.verify; local check_expiry = not (options and options.accept_expired); local claim_verifier = options and options.claim_verifier; return function (token) local ok, payload = verify(key, token); if ok then local expires_at = check_expiry and payload.exp; if expires_at then if type(expires_at) ~= "number" then return nil, "invalid-expiry"; elseif expires_at < os.time() then return nil, "token-expired"; end end if claim_verifier and not claim_verifier(payload) then return nil, "incorrect-claims"; end end return ok, payload; end end local function init(algorithm, private_key, public_key, options) return new_signer(algorithm, private_key, options), new_verifier(algorithm, public_key or private_key, options); end return { init = init; new_signer = new_signer; new_verifier = new_verifier; -- Exported mainly for tests _algorithms = algorithms; -- Deprecated sign = algorithms.HS256.sign; verify = algorithms.HS256.verify; };