diff --git a/src/core/operations/ParseSSHHostKey.mjs b/src/core/operations/ParseSSHHostKey.mjs new file mode 100644 index 00000000..811f33c8 --- /dev/null +++ b/src/core/operations/ParseSSHHostKey.mjs @@ -0,0 +1,143 @@ +/** + * @author j433866 [j433866@gmail.com] + * @copyright Crown Copyright 2019 + * @license Apache-2.0 + */ + +import Operation from "../Operation"; +import OperationError from "../errors/OperationError"; +import Utils from "../Utils"; +import { fromBase64 } from "../lib/Base64"; +import { fromHex, toHexFast } from "../lib/Hex"; + +/** + * Parse SSH Host Key operation + */ +class ParseSSHHostKey extends Operation { + + /** + * ParseSSHHostKey constructor + */ + constructor() { + super(); + + this.name = "Parse SSH Host Key"; + this.module = "Default"; + this.description = "Parses a SSH host key. The key can be in either Hex or Base64."; + this.infoURL = "https://wikipedia.org/wiki/Secure_Shell"; + this.inputType = "string"; + this.outputType = "string"; + this.args = [ + { + name: "Input Format", + type: "option", + value: [ + "Auto", + "Base64", + "Hex" + ] + } + ]; + } + + /** + * @param {string} input + * @param {Object[]} args + * @returns {string} + */ + run(input, args) { + const [inputFormat] = args, + inputKey = this.convertKeyToBinary(input.trim(), inputFormat), + fields = this.parseKey(inputKey), + keyType = Utils.byteArrayToChars(fromHex(fields[0]), ""); + + let output = `Key type: ${keyType}`; + + if (keyType === "ssh-rsa") { + output += `\nExponent: 0x${fields[1]}`; + output += `\nModulus: 0x${fields[2]}`; + } else if (keyType === "ssh-dss") { + output += `\np: 0x${fields[1]}`; + output += `\nq: 0x${fields[2]}`; + output += `\ng: 0x${fields[3]}`; + output += `\ny: 0x${fields[4]}`; + } else if (keyType.startsWith("ecdsa-sha2")) { + output += `\nCurve: ${Utils.byteArrayToChars(fromHex(fields[0]))}`; + output += `\nPoint: 0x${fields.slice(2)}`; + } else { + output += "\nUnsupported key type."; + output += `\nParameters: ${fields.slice(1)}`; + } + + return output; + } + + /** + * Converts the key to binary format from either hex or base64 + * + * @param {string} inputKey + * @param {string} inputFormat + * @returns {byteArray} + */ + convertKeyToBinary(inputKey, inputFormat) { + if (inputFormat === "Auto") { + inputFormat = this.detectKeyFormat(inputKey); + } + if (inputFormat === "Hex") { + return fromHex(inputKey); + } else if (inputFormat === "Base64") { + return fromBase64(inputKey, null, "byteArray"); + } else { + throw new OperationError("Invalid input format."); + } + } + + + /** + * Detects if the key is base64 or hex encoded + * + * @param {string} inputKey + * @returns {string} + */ + detectKeyFormat(inputKey) { + const hexPattern = new RegExp(/^(?:[\dA-Fa-f]{2}[ ,;:]?)+$/); + const b64Pattern = new RegExp(/^\s*(?:[A-Za-z\d+/]{4})+(?:[A-Za-z\d+/]{2}==|[A-Za-z\d+/]{3}=)?\s*$/); + + if (hexPattern.test(inputKey)) { + return "Hex"; + } else if (b64Pattern.test(inputKey)) { + return "Base64"; + } else { + throw new OperationError("Unable to detect input key format."); + } + } + + + /** + * Parses fields from the key + * + * @param {byteArray} key + */ + parseKey(key) { + const fields = []; + while (key.length > 0) { + const lengthField = key.slice(0, 4); + let decodedLength = 0; + for (let i = 0; i < lengthField.length; i++) { + decodedLength += lengthField[i]; + decodedLength = decodedLength << 8; + } + decodedLength = decodedLength >> 8; + // Break if length wasn't decoded correctly + if (decodedLength <= 0) break; + + fields.push(toHexFast(key.slice(4, 4 + decodedLength))); + key = key.slice(4 + decodedLength); + } + + return fields; + } + +} + +export default ParseSSHHostKey;