sshpk - npm Package Compare versions

Comparing version 1.10.2 to 1.11.0

lib/certificate.js

@@ -42,2 +42,4 @@ // Copyright 2016 Joyent, Inc.
 
+	assert.optionalArrayOfString(opts.purposes, 'options.purposes');
+
 	this._hashCache = {};
@@ -53,2 +55,3 @@
 	this.validUntil = opts.validUntil;
+	this.purposes = opts.purposes;
 }
@@ -113,2 +116,6 @@
 		return (false);
+	if (this.issuer.purposes && this.issuer.purposes.length > 0 &&
+	    this.issuer.purposes.indexOf('ca') === -1) {
+		return (false);
+	}
 
@@ -186,2 +193,43 @@ return (this.isSignedByKey(issuerCert.subjectKey));
 
+	var purposes = options.purposes;
+	if (purposes === undefined)
+		purposes = [];
+
+	if (purposes.indexOf('signature') === -1)
+		purposes.push('signature');
+
+	/* Self-signed certs are always CAs. */
+	if (purposes.indexOf('ca') === -1)
+		purposes.push('ca');
+	if (purposes.indexOf('crl') === -1)
+		purposes.push('crl');
+
+	/*
+	 * If we weren't explicitly given any other purposes, do the sensible
+	 * thing and add some basic ones depending on the subject type.
+	 */
+	if (purposes.length <= 3) {
+		var hostSubjects = subjects.filter(function (subject) {
+			return (subject.type === 'host');
+		});
+		var userSubjects = subjects.filter(function (subject) {
+			return (subject.type === 'user');
+		});
+		if (hostSubjects.length > 0) {
+			if (purposes.indexOf('serverAuth') === -1)
+				purposes.push('serverAuth');
+		}
+		if (userSubjects.length > 0) {
+			if (purposes.indexOf('clientAuth') === -1)
+				purposes.push('clientAuth');
+		}
+		if (userSubjects.length > 0 || hostSubjects.length > 0) {
+			if (purposes.indexOf('keyAgreement') === -1)
+				purposes.push('keyAgreement');
+			if (key.type === 'rsa' &&
+			    purposes.indexOf('encryption') === -1)
+				purposes.push('encryption');
+		}
+	}
+
 	var cert = new Certificate({
@@ -195,3 +243,4 @@ subjects: subjects,
 		validFrom: validFrom,
-		validUntil: validUntil
+		validUntil: validUntil,
+		purposes: purposes
 	});
@@ -244,2 +293,38 @@ cert.signWith(key);
 
+	var purposes = options.purposes;
+	if (purposes === undefined)
+		purposes = [];
+
+	if (purposes.indexOf('signature') === -1)
+		purposes.push('signature');
+
+	if (options.ca === true) {
+		if (purposes.indexOf('ca') === -1)
+			purposes.push('ca');
+		if (purposes.indexOf('crl') === -1)
+			purposes.push('crl');
+	}
+
+	var hostSubjects = subjects.filter(function (subject) {
+		return (subject.type === 'host');
+	});
+	var userSubjects = subjects.filter(function (subject) {
+		return (subject.type === 'user');
+	});
+	if (hostSubjects.length > 0) {
+		if (purposes.indexOf('serverAuth') === -1)
+			purposes.push('serverAuth');
+	}
+	if (userSubjects.length > 0) {
+		if (purposes.indexOf('clientAuth') === -1)
+			purposes.push('clientAuth');
+	}
+	if (userSubjects.length > 0 || hostSubjects.length > 0) {
+		if (purposes.indexOf('keyAgreement') === -1)
+			purposes.push('keyAgreement');
+		if (key.type === 'rsa' &&
+		    purposes.indexOf('encryption') === -1)
+			purposes.push('encryption');
+	}
+
 	var cert = new Certificate({
@@ -253,3 +338,4 @@ subjects: subjects,
 		validFrom: validFrom,
-		validUntil: validUntil
+		validUntil: validUntil,
+		purposes: purposes
 	});
@@ -256,0 +342,0 @@ cert.signWith(issuerKey);

lib/formats/x509.js

@@ -82,3 +82,6 @@ // Copyright 2016 Joyent, Inc.
 	'issuerKeyId': '2.5.29.35',
-	'altName': '2.5.29.17'
+	'altName': '2.5.29.17',
+	'basicConstraints': '2.5.29.19',
+	'keyUsage': '2.5.29.15',
+	'extKeyUsage': '2.5.29.37'
 };
@@ -214,2 +217,22 @@
 
+/* RFC5280, section 4.2.1.12 (KeyPurposeId) */
+var EXTPURPOSE = {
+	'serverAuth': '1.3.6.1.5.5.7.3.1',
+	'clientAuth': '1.3.6.1.5.5.7.3.2',
+	'codeSigning': '1.3.6.1.5.5.7.3.3',
+
+	/* See https://github.com/joyent/oid-docs/blob/master/root.md */
+	'joyentDocker': '1.3.6.1.4.1.38678.1.4.1',
+	'joyentCmon': '1.3.6.1.4.1.38678.1.4.2'
+};
+var EXTPURPOSE_REV = {};
+Object.keys(EXTPURPOSE).forEach(function (k) {
+	EXTPURPOSE_REV[EXTPURPOSE[k]] = k;
+});
+
+var KEYUSEBITS = [
+	'signature', 'identity', 'keyEncryption',
+	'encryption', 'keyAgreement', 'ca', 'crl'
+];
+
 function readExtension(cert, buf, der) {
@@ -228,2 +251,77 @@ der.readSequence();
 	switch (extId) {
+	case (EXTS.basicConstraints):
+		der.readSequence(asn1.Ber.OctetString);
+		der.readSequence();
+		var bcEnd = der.offset + der.length;
+		var ca = false;
+		if (der.peek() === asn1.Ber.Boolean)
+			ca = der.readBoolean();
+		if (cert.purposes === undefined)
+			cert.purposes = [];
+		if (ca === true)
+			cert.purposes.push('ca');
+		var bc = { oid: extId, critical: critical };
+		if (der.offset < bcEnd && der.peek() === asn1.Ber.Integer)
+			bc.pathLen = der.readInt();
+		sig.extras.exts.push(bc);
+		break;
+	case (EXTS.extKeyUsage):
+		der.readSequence(asn1.Ber.OctetString);
+		der.readSequence();
+		if (cert.purposes === undefined)
+			cert.purposes = [];
+		var ekEnd = der.offset + der.length;
+		while (der.offset < ekEnd) {
+			var oid = der.readOID();
+			cert.purposes.push(EXTPURPOSE_REV[oid] || oid);
+		}
+		/*
+		 * This is a bit of a hack: in the case where we have a cert
+		 * that's only allowed to do serverAuth or clientAuth (and not
+		 * the other), we want to make sure all our Subjects are of
+		 * the right type. But we already parsed our Subjects and
+		 * decided if they were hosts or users earlier (since it appears
+		 * first in the cert).
+		 *
+		 * So we go through and mutate them into the right kind here if
+		 * it doesn't match. This might not be hugely beneficial, as it
+		 * seems that single-purpose certs are not often seen in the
+		 * wild.
+		 */
+		if (cert.purposes.indexOf('serverAuth') !== -1 &&
+		    cert.purposes.indexOf('clientAuth') === -1) {
+			cert.subjects.forEach(function (ide) {
+				if (ide.type !== 'host') {
+					ide.type = 'host';
+					ide.hostname = ide.uid ||
+					    ide.email ||
+					    ide.components[0].value;
+				}
+			});
+		} else if (cert.purposes.indexOf('clientAuth') !== -1 &&
+		    cert.purposes.indexOf('serverAuth') === -1) {
+			cert.subjects.forEach(function (ide) {
+				if (ide.type !== 'user') {
+					ide.type = 'user';
+					ide.uid = ide.hostname ||
+					    ide.email ||
+					    ide.components[0].value;
+				}
+			});
+		}
+		sig.extras.exts.push({ oid: extId, critical: critical });
+		break;
+	case (EXTS.keyUsage):
+		der.readSequence(asn1.Ber.OctetString);
+		var bits = der.readString(asn1.Ber.BitString, true);
+		var setBits = readBitField(bits, KEYUSEBITS);
+		setBits.forEach(function (bit) {
+			if (cert.purposes === undefined)
+				cert.purposes = [];
+			if (cert.purposes.indexOf(bit) === -1)
+				cert.purposes.push(bit);
+		});
+		sig.extras.exts.push({ oid: extId, critical: critical,
+		    bits: bits });
+		break;
 	case (EXTS.altName):
@@ -427,2 +525,3 @@ der.readSequence(asn1.Ber.OctetString);
 	if (altNames.length > 0 || subject.type === 'host' ||
+	    (cert.purposes !== undefined && cert.purposes.length > 0) ||
 	    (sig.extras && sig.extras.exts)) {
@@ -432,5 +531,18 @@ der.startSequence(Local(3));
 
-		var exts = [
-			{ oid: EXTS.altName }
-		];
+		var exts = [];
+		if (cert.purposes !== undefined && cert.purposes.length > 0) {
+			exts.push({
+				oid: EXTS.basicConstraints,
+				critical: true
+			});
+			exts.push({
+				oid: EXTS.keyUsage,
+				critical: true
+			});
+			exts.push({
+				oid: EXTS.extKeyUsage,
+				critical: true
+			});
+		}
+		exts.push({ oid: EXTS.altName });
 		if (sig.extras && sig.extras.exts)
@@ -476,2 +588,50 @@ exts = sig.extras.exts;
 				der.endSequence();
+			} else if (exts[i].oid === EXTS.basicConstraints) {
+				der.startSequence(asn1.Ber.OctetString);
+				der.startSequence();
+				var ca = (cert.purposes.indexOf('ca') !== -1);
+				var pathLen = exts[i].pathLen;
+				der.writeBoolean(ca);
+				if (pathLen !== undefined)
+					der.writeInt(pathLen);
+				der.endSequence();
+				der.endSequence();
+			} else if (exts[i].oid === EXTS.extKeyUsage) {
+				der.startSequence(asn1.Ber.OctetString);
+				der.startSequence();
+				cert.purposes.forEach(function (purpose) {
+					if (purpose === 'ca')
+						return;
+					if (KEYUSEBITS.indexOf(purpose) !== -1)
+						return;
+					var oid = purpose;
+					if (EXTPURPOSE[purpose] !== undefined)
+						oid = EXTPURPOSE[purpose];
+					der.writeOID(oid);
+				});
+				der.endSequence();
+				der.endSequence();
+			} else if (exts[i].oid === EXTS.keyUsage) {
+				der.startSequence(asn1.Ber.OctetString);
+				/*
+				 * If we parsed this certificate from a byte
+				 * stream (i.e. we didn't generate it in sshpk)
+				 * then we'll have a ".bits" property on the
+				 * ext with the original raw byte contents.
+				 *
+				 * If we have this, use it here instead of
+				 * regenerating it. This guarantees we output
+				 * the same data we parsed, so signatures still
+				 * validate.
+				 */
+				if (exts[i].bits !== undefined) {
+					der.writeBuffer(exts[i].bits,
+					    asn1.Ber.BitString);
+				} else {
+					var bits = writeBitField(cert.purposes,
+					    KEYUSEBITS);
+					der.writeBuffer(bits,
+					    asn1.Ber.BitString);
+				}
+				der.endSequence();
 			} else {
@@ -491,1 +651,56 @@ der.writeBuffer(exts[i].data,
 }
+
+/*
+ * Reads an ASN.1 BER bitfield out of the Buffer produced by doing
+ * `BerReader#readString(asn1.Ber.BitString)`. That function gives us the raw
+ * contents of the BitString tag, which is a count of unused bits followed by
+ * the bits as a right-padded byte string.
+ *
+ * `bits` is the Buffer, `bitIndex` should contain an array of string names
+ * for the bits in the string, ordered starting with bit #0 in the ASN.1 spec.
+ *
+ * Returns an array of Strings, the names of the bits that were set to 1.
+ */
+function readBitField(bits, bitIndex) {
+	var bitLen = 8 * (bits.length - 1) - bits[0];
+	var setBits = {};
+	for (var i = 0; i < bitLen; ++i) {
+		var byteN = 1 + Math.floor(i / 8);
+		var bit = 7 - (i % 8);
+		var mask = 1 << bit;
+		var bitVal = ((bits[byteN] & mask) !== 0);
+		var name = bitIndex[i];
+		if (bitVal && typeof (name) === 'string') {
+			setBits[name] = true;
+		}
+	}
+	return (Object.keys(setBits));
+}
+
+/*
+ * `setBits` is an array of strings, containing the names for each bit that
+ * sould be set to 1. `bitIndex` is same as in `readBitField()`.
+ *
+ * Returns a Buffer, ready to be written out with `BerWriter#writeString()`.
+ */
+function writeBitField(setBits, bitIndex) {
+	var bitLen = bitIndex.length;
+	var blen = Math.ceil(bitLen / 8);
+	var unused = blen * 8 - bitLen;
+	var bits = new Buffer(1 + blen);
+	bits.fill(0);
+	bits[0] = unused;
+	for (var i = 0; i < bitLen; ++i) {
+		var byteN = 1 + Math.floor(i / 8);
+		var bit = 7 - (i % 8);
+		var mask = 1 << bit;
+		var name = bitIndex[i];
+		if (name === undefined)
+			continue;
+		var bitVal = (setBits.indexOf(name) !== -1);
+		if (bitVal) {
+			bits[byteN] |= mask;
+		}
+	}
+	return (bits);
+}

package.json

 {
   "name": "sshpk",
-  "version": "1.10.2",
+  "version": "1.11.0",
   "description": "A library for finding and using SSH public keys",
@@ -5,0 +5,0 @@ "main": "lib/index.js",

README.md

@@ -411,6 +411,6 @@ sshpk
 
-Notably, there is no implementation of CA chain-of-trust verification, and no
-support for key usage restrictions (or other kinds of restrictions). Please do
-the security world a favour, and DO NOT use this code for certificate
-verification in the traditional X.509 CA chain style.
+Notably, there is no implementation of CA chain-of-trust verification, and only
+very minimal support for key usage restrictions. Please do the security world
+a favour, and DO NOT use this code for certificate verification in the
+traditional X.509 CA chain style.
 
@@ -440,2 +440,3 @@ ### `parseCertificate(data, format)`
    - `serial` -- optional Buffer, the serial number of the certificate
+   - `purposes` -- optional Array of String, X.509 key usage restrictions
 
@@ -457,2 +458,3 @@ ### `createCertificate(subject, key, issuer, issuerKey[, options])`
    - `serial` -- optional Buffer, the serial number of the certificate
+   - `purposes` -- optional Array of String, X.509 key usage restrictions
 
@@ -481,2 +483,19 @@ ### `Certificate#subjects`
 
+### `Certificate#purposes`
+
+Array of Strings indicating the X.509 key usage purposes that this certificate
+is valid for. The possible strings at the moment are:
+
+ * `'signature'` -- key can be used for digital signatures
+ * `'identity'` -- key can be used to attest about the identity of the signer
+                   (X.509 calls this `nonRepudiation`)
+ * `'codeSigning'` -- key can be used to sign executable code
+ * `'keyEncryption'` -- key can be used to encrypt other keys
+ * `'encryption'` -- key can be used to encrypt data (only applies for RSA)
+ * `'keyAgreement'` -- key can be used for key exchange protocols such as
+                       Diffie-Hellman
+ * `'ca'` -- key can be used to sign other certificates (is a Certificate
+             Authority)
+ * `'crl'` -- key can be used to sign Certificate Revocation Lists (CRLs)
+
 ### `Certificate#isExpired([when])`
@@ -483,0 +502,0 @@

No alert changes

Improved metrics

Total package byte prevSize

183817

increased by5.79%

Lines of code

4632

increased by6.61%

Number of lines in readme file

686

increased by2.85%

No dependency changes