103 lines
2.6 KiB
JavaScript
103 lines
2.6 KiB
JavaScript
/* eslint no-bitwise: 0 */
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function wrap(text, len) {
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const length = len || 72;
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let result = "";
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for (let i = 0; i < text.length; i += length) {
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result += text.slice(i, i + length);
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result += "\n";
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}
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return result;
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}
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function pemPublicKey(key) {
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return `---- BEGIN RSA PUBLIC KEY ----\n${wrap(key, 65)}---- END RSA PUBLIC KEY ----`;
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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 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 checkHighestBit(v) {
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if (v[0] >> 7 === 1) {
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v.unshift(0); // add leading zero if first bit is set
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}
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return v;
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}
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function asn1Int(int) {
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const v = checkHighestBit(int);
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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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function asn1Seq(seq) {
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const len = asnEncodeLen(seq.length);
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return [0x30].concat(len, seq); // seq tag is 0x30
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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 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 pemToArray(pem) {
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return stringToArray(window.atob(pem));
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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 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 publicSshToPem(publicKey) {
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const { key, exponent } = decodePublicKey(publicKey);
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const seq = [key, exponent].map(asn1Int).reduce((acc, a) => acc.concat(a));
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return pemPublicKey(arrayToPem(asn1Seq(seq)));
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}
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module.exports = { publicSshToPem }; |