121 lines
3.3 KiB
JavaScript
121 lines
3.3 KiB
JavaScript
/* eslint no-bitwise: 0 */
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/* global base64urlDecode */
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function arrayToString(a) {
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return String.fromCharCode.apply(null, a);
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}
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function stringToArray(s) {
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return s.split("").map(c => c.charCodeAt());
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}
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function base64urlToArray(s) {
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return stringToArray(base64urlDecode(s));
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}
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function pemToArray(pem) {
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return stringToArray(window.atob(pem));
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}
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function arrayToPem(a) {
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return window.btoa(a.map(c => String.fromCharCode(c)).join(""));
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}
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function arrayToLen(a) {
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let result = 0;
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for (let i = 0; i < a.length; i += 1) {
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result = result * 256 + a[i];
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}
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return result;
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}
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function integerToOctet(n) {
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const result = [];
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for (let i = n; i > 0; i >>= 8) {
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result.push(i & 0xff);
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}
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return result.reverse();
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}
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function lenToArray(n) {
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const oct = integerToOctet(n);
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let i;
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for (i = oct.length; i < 4; i += 1) {
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oct.unshift(0);
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}
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return oct;
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}
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function decodePublicKey(s) {
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const split = s.split(" ");
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const prefix = split[0];
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if (prefix !== "ssh-rsa") {
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throw new Error(`Unknown prefix: ${prefix}`);
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}
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const buffer = pemToArray(split[1]);
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const nameLen = arrayToLen(buffer.splice(0, 4));
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const type = arrayToString(buffer.splice(0, nameLen));
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if (type !== "ssh-rsa") {
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throw new Error(`Unknown key type: ${type}`);
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}
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const exponentLen = arrayToLen(buffer.splice(0, 4));
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const exponent = buffer.splice(0, exponentLen);
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const keyLen = arrayToLen(buffer.splice(0, 4));
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const key = buffer.splice(0, keyLen);
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return { type, exponent, key, name: split[2] };
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}
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function checkHighestBit(v) {
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if (v[0] >> 7 === 1) {
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// add leading zero if first bit is set
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v.unshift(0);
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}
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return v;
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}
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function jwkToInternal(jwk) {
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return {
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type: "ssh-rsa",
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exponent: checkHighestBit(stringToArray(base64urlDecode(jwk.e))),
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name: "name",
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key: checkHighestBit(stringToArray(base64urlDecode(jwk.n))),
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};
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}
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function encodePublicKey(jwk, name) {
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const k = jwkToInternal(jwk);
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k.name = name;
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const keyLenA = lenToArray(k.key.length);
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const exponentLenA = lenToArray(k.exponent.length);
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const typeLenA = lenToArray(k.type.length);
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const array = [].concat(typeLenA, stringToArray(k.type), exponentLenA, k.exponent, keyLenA, k.key);
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const encoding = arrayToPem(array);
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return `${k.type} ${encoding} ${k.name}`;
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}
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function asnEncodeLen(n) {
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let result = [];
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if (n >> 7) {
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result = integerToOctet(n);
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result.unshift(0x80 + result.length);
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} else {
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result.push(n);
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}
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return result;
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}
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function encodePrivateKey(jwk) {
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const order = ["n", "e", "d", "p", "q", "dp", "dq", "qi"];
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const list = order.map(prop => {
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const v = checkHighestBit(stringToArray(base64urlDecode(jwk[prop])));
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const len = asnEncodeLen(v.length);
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return [0x02].concat(len, v); // int tag is 0x02
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});
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let seq = [0x02, 0x01, 0x00]; // extra seq for SSH
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seq = seq.concat(...list);
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const len = asnEncodeLen(seq.length);
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const a = [0x30].concat(len, seq); // seq is 0x30
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return arrayToPem(a);
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}
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module.exports = { base64urlToArray, decodePublicKey, encodePublicKey, encodePrivateKey }; |