Current File : //lib/node_modules/npm/node_modules/sshpk/lib/formats/openssh-cert.js
// Copyright 2017 Joyent, Inc.
module.exports = {
read: read,
verify: verify,
sign: sign,
signAsync: signAsync,
write: write,
/* Internal private API */
fromBuffer: fromBuffer,
toBuffer: toBuffer
};
var assert = require('assert-plus');
var SSHBuffer = require('../ssh-buffer');
var crypto = require('crypto');
var Buffer = require('safer-buffer').Buffer;
var algs = require('../algs');
var Key = require('../key');
var PrivateKey = require('../private-key');
var Identity = require('../identity');
var rfc4253 = require('./rfc4253');
var Signature = require('../signature');
var utils = require('../utils');
var Certificate = require('../certificate');
function verify(cert, key) {
/*
* We always give an issuerKey, so if our verify() is being called then
* there was no signature. Return false.
*/
return (false);
}
var TYPES = {
'user': 1,
'host': 2
};
Object.keys(TYPES).forEach(function (k) { TYPES[TYPES[k]] = k; });
var ECDSA_ALGO = /^ecdsa-sha2-([^@-]+)-cert-v01@openssh.com$/;
function read(buf, options) {
if (Buffer.isBuffer(buf))
buf = buf.toString('ascii');
var parts = buf.trim().split(/[ \t\n]+/g);
if (parts.length < 2 || parts.length > 3)
throw (new Error('Not a valid SSH certificate line'));
var algo = parts[0];
var data = parts[1];
data = Buffer.from(data, 'base64');
return (fromBuffer(data, algo));
}
function fromBuffer(data, algo, partial) {
var sshbuf = new SSHBuffer({ buffer: data });
var innerAlgo = sshbuf.readString();
if (algo !== undefined && innerAlgo !== algo)
throw (new Error('SSH certificate algorithm mismatch'));
if (algo === undefined)
algo = innerAlgo;
var cert = {};
cert.signatures = {};
cert.signatures.openssh = {};
cert.signatures.openssh.nonce = sshbuf.readBuffer();
var key = {};
var parts = (key.parts = []);
key.type = getAlg(algo);
var partCount = algs.info[key.type].parts.length;
while (parts.length < partCount)
parts.push(sshbuf.readPart());
assert.ok(parts.length >= 1, 'key must have at least one part');
var algInfo = algs.info[key.type];
if (key.type === 'ecdsa') {
var res = ECDSA_ALGO.exec(algo);
assert.ok(res !== null);
assert.strictEqual(res[1], parts[0].data.toString());
}
for (var i = 0; i < algInfo.parts.length; ++i) {
parts[i].name = algInfo.parts[i];
if (parts[i].name !== 'curve' &&
algInfo.normalize !== false) {
var p = parts[i];
p.data = utils.mpNormalize(p.data);
}
}
cert.subjectKey = new Key(key);
cert.serial = sshbuf.readInt64();
var type = TYPES[sshbuf.readInt()];
assert.string(type, 'valid cert type');
cert.signatures.openssh.keyId = sshbuf.readString();
var principals = [];
var pbuf = sshbuf.readBuffer();
var psshbuf = new SSHBuffer({ buffer: pbuf });
while (!psshbuf.atEnd())
principals.push(psshbuf.readString());
if (principals.length === 0)
principals = ['*'];
cert.subjects = principals.map(function (pr) {
if (type === 'user')
return (Identity.forUser(pr));
else if (type === 'host')
return (Identity.forHost(pr));
throw (new Error('Unknown identity type ' + type));
});
cert.validFrom = int64ToDate(sshbuf.readInt64());
cert.validUntil = int64ToDate(sshbuf.readInt64());
cert.signatures.openssh.critical = sshbuf.readBuffer();
cert.signatures.openssh.exts = sshbuf.readBuffer();
/* reserved */
sshbuf.readBuffer();
var signingKeyBuf = sshbuf.readBuffer();
cert.issuerKey = rfc4253.read(signingKeyBuf);
/*
* OpenSSH certs don't give the identity of the issuer, just their
* public key. So, we use an Identity that matches anything. The
* isSignedBy() function will later tell you if the key matches.
*/
cert.issuer = Identity.forHost('**');
var sigBuf = sshbuf.readBuffer();
cert.signatures.openssh.signature =
Signature.parse(sigBuf, cert.issuerKey.type, 'ssh');
if (partial !== undefined) {
partial.remainder = sshbuf.remainder();
partial.consumed = sshbuf._offset;
}
return (new Certificate(cert));
}
function int64ToDate(buf) {
var i = buf.readUInt32BE(0) * 4294967296;
i += buf.readUInt32BE(4);
var d = new Date();
d.setTime(i * 1000);
d.sourceInt64 = buf;
return (d);
}
function dateToInt64(date) {
if (date.sourceInt64 !== undefined)
return (date.sourceInt64);
var i = Math.round(date.getTime() / 1000);
var upper = Math.floor(i / 4294967296);
var lower = Math.floor(i % 4294967296);
var buf = Buffer.alloc(8);
buf.writeUInt32BE(upper, 0);
buf.writeUInt32BE(lower, 4);
return (buf);
}
function sign(cert, key) {
if (cert.signatures.openssh === undefined)
cert.signatures.openssh = {};
try {
var blob = toBuffer(cert, true);
} catch (e) {
delete (cert.signatures.openssh);
return (false);
}
var sig = cert.signatures.openssh;
var hashAlgo = undefined;
if (key.type === 'rsa' || key.type === 'dsa')
hashAlgo = 'sha1';
var signer = key.createSign(hashAlgo);
signer.write(blob);
sig.signature = signer.sign();
return (true);
}
function signAsync(cert, signer, done) {
if (cert.signatures.openssh === undefined)
cert.signatures.openssh = {};
try {
var blob = toBuffer(cert, true);
} catch (e) {
delete (cert.signatures.openssh);
done(e);
return;
}
var sig = cert.signatures.openssh;
signer(blob, function (err, signature) {
if (err) {
done(err);
return;
}
try {
/*
* This will throw if the signature isn't of a
* type/algo that can be used for SSH.
*/
signature.toBuffer('ssh');
} catch (e) {
done(e);
return;
}
sig.signature = signature;
done();
});
}
function write(cert, options) {
if (options === undefined)
options = {};
var blob = toBuffer(cert);
var out = getCertType(cert.subjectKey) + ' ' + blob.toString('base64');
if (options.comment)
out = out + ' ' + options.comment;
return (out);
}
function toBuffer(cert, noSig) {
assert.object(cert.signatures.openssh, 'signature for openssh format');
var sig = cert.signatures.openssh;
if (sig.nonce === undefined)
sig.nonce = crypto.randomBytes(16);
var buf = new SSHBuffer({});
buf.writeString(getCertType(cert.subjectKey));
buf.writeBuffer(sig.nonce);
var key = cert.subjectKey;
var algInfo = algs.info[key.type];
algInfo.parts.forEach(function (part) {
buf.writePart(key.part[part]);
});
buf.writeInt64(cert.serial);
var type = cert.subjects[0].type;
assert.notStrictEqual(type, 'unknown');
cert.subjects.forEach(function (id) {
assert.strictEqual(id.type, type);
});
type = TYPES[type];
buf.writeInt(type);
if (sig.keyId === undefined) {
sig.keyId = cert.subjects[0].type + '_' +
(cert.subjects[0].uid || cert.subjects[0].hostname);
}
buf.writeString(sig.keyId);
var sub = new SSHBuffer({});
cert.subjects.forEach(function (id) {
if (type === TYPES.host)
sub.writeString(id.hostname);
else if (type === TYPES.user)
sub.writeString(id.uid);
});
buf.writeBuffer(sub.toBuffer());
buf.writeInt64(dateToInt64(cert.validFrom));
buf.writeInt64(dateToInt64(cert.validUntil));
if (sig.critical === undefined)
sig.critical = Buffer.alloc(0);
buf.writeBuffer(sig.critical);
if (sig.exts === undefined)
sig.exts = Buffer.alloc(0);
buf.writeBuffer(sig.exts);
/* reserved */
buf.writeBuffer(Buffer.alloc(0));
sub = rfc4253.write(cert.issuerKey);
buf.writeBuffer(sub);
if (!noSig)
buf.writeBuffer(sig.signature.toBuffer('ssh'));
return (buf.toBuffer());
}
function getAlg(certType) {
if (certType === 'ssh-rsa-cert-v01@openssh.com')
return ('rsa');
if (certType === 'ssh-dss-cert-v01@openssh.com')
return ('dsa');
if (certType.match(ECDSA_ALGO))
return ('ecdsa');
if (certType === 'ssh-ed25519-cert-v01@openssh.com')
return ('ed25519');
throw (new Error('Unsupported cert type ' + certType));
}
function getCertType(key) {
if (key.type === 'rsa')
return ('ssh-rsa-cert-v01@openssh.com');
if (key.type === 'dsa')
return ('ssh-dss-cert-v01@openssh.com');
if (key.type === 'ecdsa')
return ('ecdsa-sha2-' + key.curve + '-cert-v01@openssh.com');
if (key.type === 'ed25519')
return ('ssh-ed25519-cert-v01@openssh.com');
throw (new Error('Unsupported key type ' + key.type));
}
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