TritonDataCenter/node-sshpk-agent#10 add support for rsa-sha2-256 sig…

…natures

Reviewed by: Brittany Wald <brittany.wald@joyent.com>
Reviewed by: Cody Peter Mello <cody.mello@joyent.com>

lib/formats/openssh-cert.js

@@ -206,10 +206,14 @@ function signAsync(cert, signer, done) {
 			done(err);
 			return;
 		}
-		if ((signature.type === 'rsa' || signature.type === 'dsa') &&
-		    signature.hashAlgorithm !== 'sha1') {
-			done(new Error('RSA/DSA keys can only sign with ' +
-			    'SHA-1 for OpenSSH certificates'));
+		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;

lib/key.js

@@ -171,6 +171,7 @@ Key.prototype.createVerify = function (hashAlgo) {
 	assert.ok(v, 'failed to create verifier');
 	var oldVerify = v.verify.bind(v);
 	var key = this.toBuffer('pkcs8');
+	var curve = this.curve;
 	var self = this;
 	v.verify = function (signature, fmt) {
 		if (Signature.isSignature(signature, [2, 0])) {
@@ -179,6 +180,9 @@ Key.prototype.createVerify = function (hashAlgo) {
 			if (signature.hashAlgorithm &&
 			    signature.hashAlgorithm !== hashAlgo)
 				return (false);
+			if (signature.curve && self.type === 'ecdsa' &&
+			    signature.curve !== curve)
+				return (false);
 			return (oldVerify(key, signature.toBuffer('asn1')));
 
 		} else if (typeof (signature) === 'string' ||

lib/private-key.js

@@ -166,12 +166,14 @@ PrivateKey.prototype.createSign = function (hashAlgo) {
 	var oldSign = v.sign.bind(v);
 	var key = this.toBuffer('pkcs1');
 	var type = this.type;
+	var curve = this.curve;
 	v.sign = function () {
 		var sig = oldSign(key);
 		if (typeof (sig) === 'string')
 			sig = new Buffer(sig, 'binary');
 		sig = Signature.parse(sig, type, 'asn1');
 		sig.hashAlgorithm = hashAlgo;
+		sig.curve = curve;
 		return (sig);
 	};
 	return (v);

lib/signature.js

@@ -26,6 +26,7 @@ function Signature(opts) {
 
 	this.type = opts.type;
 	this.hashAlgorithm = opts.hashAlgo;
+	this.curve = opts.curve;
 	this.parts = opts.parts;
 	this.part = partLookup;
 }
@@ -36,18 +37,45 @@ Signature.prototype.toBuffer = function (format) {
 	assert.string(format, 'format');
 
 	var buf;
+	var stype = 'ssh-' + this.type;
 
 	switch (this.type) {
 	case 'rsa':
+		switch (this.hashAlgorithm) {
+		case 'sha256':
+			stype = 'rsa-sha2-256';
+			break;
+		case 'sha512':
+			stype = 'rsa-sha2-512';
+			break;
+		case 'sha1':
+		case undefined:
+			break;
+		default:
+			throw (new Error('SSH signature ' +
+			    'format does not support hash ' +
+			    'algorithm ' + this.hashAlgorithm));
+		}
+		if (format === 'ssh') {
+			buf = new SSHBuffer({});
+			buf.writeString(stype);
+			buf.writePart(this.part.sig);
+			return (buf.toBuffer());
+		} else {
+			return (this.part.sig.data);
+		}
+		break;
+
 	case 'ed25519':
 		if (format === 'ssh') {
 			buf = new SSHBuffer({});
-			buf.writeString('ssh-' + this.type);
+			buf.writeString(stype);
 			buf.writePart(this.part.sig);
 			return (buf.toBuffer());
 		} else {
 			return (this.part.sig.data);
 		}
+		break;
 
 	case 'dsa':
 	case 'ecdsa':
@@ -126,11 +154,9 @@ Signature.parse = function (data, type, format) {
 		assert.ok(data.length > 0, 'signature must not be empty');
 		switch (opts.type) {
 		case 'rsa':
-			return (parseOneNum(data, type, format, opts,
-			    'ssh-rsa'));
+			return (parseOneNum(data, type, format, opts));
 		case 'ed25519':
-			return (parseOneNum(data, type, format, opts,
-			    'ssh-ed25519'));
+			return (parseOneNum(data, type, format, opts));
 
 		case 'dsa':
 		case 'ecdsa':
@@ -152,15 +178,38 @@ Signature.parse = function (data, type, format) {
 	}
 };
 
-function parseOneNum(data, type, format, opts, headType) {
+function parseOneNum(data, type, format, opts) {
 	if (format === 'ssh') {
 		try {
 			var buf = new SSHBuffer({buffer: data});
 			var head = buf.readString();
 		} catch (e) {
 			/* fall through */
 		}
-		if (head === headType) {
+		if (buf !== undefined) {
+			var msg = 'SSH signature does not match expected ' +
+			    'type (expected ' + type + ', got ' + head + ')';
+			switch (head) {
+			case 'ssh-rsa':
+				assert.strictEqual(type, 'rsa', msg);
+				opts.hashAlgo = 'sha1';
+				break;
+			case 'rsa-sha2-256':
+				assert.strictEqual(type, 'rsa', msg);
+				opts.hashAlgo = 'sha256';
+				break;
+			case 'rsa-sha2-512':
+				assert.strictEqual(type, 'rsa', msg);
+				opts.hashAlgo = 'sha512';
+				break;
+			case 'ssh-ed25519':
+				assert.strictEqual(type, 'ed25519', msg);
+				opts.hashAlgo = 'sha512';
+				break;
+			default:
+				throw (new Error('Unknown SSH signature ' +
+				    'type: ' + head));
+			}
 			var sig = buf.readPart();
 			assert.ok(buf.atEnd(), 'extra trailing bytes');
 			sig.name = 'sig';
@@ -204,7 +253,26 @@ function parseECDSA(data, type, format, opts) {
 
 	var r, s;
 	var inner = buf.readBuffer();
-	if (inner.toString('ascii').match(/^ecdsa-/)) {
+	var stype = inner.toString('ascii');
+	if (stype.slice(0, 6) === 'ecdsa-') {
+		var parts = stype.split('-');
+		assert.strictEqual(parts[0], 'ecdsa');
+		assert.strictEqual(parts[1], 'sha2');
+		opts.curve = parts[2];
+		switch (opts.curve) {
+		case 'nistp256':
+			opts.hashAlgo = 'sha256';
+			break;
+		case 'nistp384':
+			opts.hashAlgo = 'sha384';
+			break;
+		case 'nistp521':
+			opts.hashAlgo = 'sha512';
+			break;
+		default:
+			throw (new Error('Unsupported ECDSA curve: ' +
+			    opts.curve));
+		}
 		inner = buf.readBuffer();
 		assert.ok(buf.atEnd(), 'extra trailing bytes on outer');
 		buf = new SSHBuffer({buffer: inner});

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sshpk",
-  "version": "1.12.0",
+  "version": "1.13.0",
   "description": "A library for finding and using SSH public keys",
   "main": "lib/index.js",
   "scripts": {

test/assets/openssh-rsa256.pub

@@ -0,0 +1 @@
+ssh-rsa-cert-v01@openssh.com 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

test/certs.js

@@ -331,3 +331,14 @@ test('example cert: lots of SAN (x509)', function (t) {
 	}));
 	t.end();
 });
+
+test('example cert: openssh rsa with sha256 (7.0p1+)', function (t) {
+	var cert = sshpk.parseCertificate(
+	    fs.readFileSync(path.join(testDir, 'openssh-rsa256.pub')),
+	    'openssh');
+	t.strictEqual(cert.subjectKey.type, 'rsa');
+	t.ok(cert.isSignedByKey(cert.subjectKey));
+	t.strictEqual(cert.signatures.openssh.signature.hashAlgorithm,
+	    'sha256');
+	t.end();
+});