v1.2.0: add support for ssh private keys (EC and RSA)

README.md

@@ -12,6 +12,9 @@ Features
 
 * [x] SSH Public Keys
   * fingerprint
+* [x] SSH EC Private Keys
+* [ ] SSH RSA Private Keys
+  * `dp` and `dq` values are unavailable
 * [x] RSA Public Keys
 * [x] EC Public Keys
   * P-256 (prime256v1, secp256r1)
@@ -29,9 +32,14 @@ Try one of these:
 
 ### Need SSH Private Keys?
 
-SSH private keys are just normal PEM files,
+Many SSH private keys are just normal PEM files,
 so you can use Eckles or Rasha, as mentioned above.
 
+As for the [OpenSSH-specific Private Keys](https://coolaj86.com/articles/the-openssh-private-key-format/),
+EC is **fully supported**, but RSA has only partial support.
+
+For more information see the "SSH Private Keys" section at the end of this file.
+
 # CLI
 
 You can install `ssh-to-jwk` and use it from command line:
@@ -73,6 +81,25 @@ sshtojwk.fingerprint({ pub: pub }).then(function (fingerprint) {
 });
 ```
 
+# SSH Private Keys
+
+As mentioned above, EC private keys are fully supported,
+and RSA private keys are partially supported.
+
+It's unlikely that we'll support full SSH-to-JWK conversion for private RSA keys
+because OpenSSH omits the `dp` and `dq` values.
+
+Although they are "optional" (they can be computed from the available values),
+to compute them in JavaScript would require a large and expensive BigInt library -
+and including (or writing) such a library would require contradicting the
+"lightweight" and/or "zero dependency" goals for this library.
+
+That said, for someone willing to include a BigInt library in their code
+it should be trivial to perform the operations to derive `dp` and `dq`.
+
+If that's you please open an issue because I am interested in creating
+a `ssh-to-jwk-bigint` library... I just don't have a use case for it right now.
+
 # Legal
 
 [ssh-to-jwk.js](https://git.coolaj86.com/coolaj86/ssh-to-jwk.js) |

fixtures/privkey-ec-p256.openssh.pem

@@ -0,0 +1,9 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAaAAAABNlY2RzYS
+1zaGEyLW5pc3RwMjU2AAAACG5pc3RwMjU2AAAAQQR9WZPeBSvixkhjQOh9yCXXlEx5CN9M
+yh94CJJ1rigf8693gc90HmahIR5oMGHwlqMoS7kKrRw+4KpxqsF7LGvxAAAAqJZtgRuWbY
+EbAAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBH1Zk94FK+LGSGNA
+6H3IJdeUTHkI30zKH3gIknWuKB/zr3eBz3QeZqEhHmgwYfCWoyhLuQqtHD7gqnGqwXssa/
+EAAAAgBzKpRmMyXZ4jnSt3ARz0ul6R79AXAr5gQqDAmoFeEKwAAAAOYWpAYm93aWUubG9j
+YWwBAg==
+-----END OPENSSH PRIVATE KEY-----

fixtures/privkey-ec-p384.openssh.pem

@@ -0,0 +1,10 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAiAAAABNlY2RzYS
+1zaGEyLW5pc3RwMzg0AAAACG5pc3RwMzg0AAAAYQTDNcLzjWUqG5H+grU/Z+RNOsvqH4V5
+qU1UlkUzqTImYvm7ClYgYtXqbReCzLn1E+DOQw1N1f5E/YjPNduLlklsEv3q55k7BDTTiN
+k5c15CpCbIV4eWeLRSFSJBGQHlv+sAAADYZYs6wGWLOsAAAAATZWNkc2Etc2hhMi1uaXN0
+cDM4NAAAAAhuaXN0cDM4NAAAAGEEwzXC841lKhuR/oK1P2fkTTrL6h+FealNVJZFM6kyJm
+L5uwpWIGLV6m0Xgsy59RPgzkMNTdX+RP2IzzXbi5ZJbBL96ueZOwQ004jZOXNeQqQmyFeH
+lni0UhUiQRkB5b/rAAAAMQDbyZ7XRFtCCvdmdYJPkPuMzQBO5VJ1g/9eeFjI2ZLyIhtPh3
+tvrki2EjEi8X4iLroAAAAOYWpAYm93aWUubG9jYWwB
+-----END OPENSSH PRIVATE KEY-----

fixtures/privkey-rsa-2048.openssh.pem

@@ -0,0 +1,27 @@
+-----BEGIN OPENSSH PRIVATE KEY-----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+-----END OPENSSH PRIVATE KEY-----

fixtures/pub-ec-p256.ssh.pub

@@ -0,0 +1 @@
+ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBH1Zk94FK+LGSGNA6H3IJdeUTHkI30zKH3gIknWuKB/zr3eBz3QeZqEhHmgwYfCWoyhLuQqtHD7gqnGqwXssa/E= aj@bowie.local

fixtures/pub-ec-p384.ssh.pub

@@ -0,0 +1 @@
+ecdsa-sha2-nistp384 AAAAE2VjZHNhLXNoYTItbmlzdHAzODQAAAAIbmlzdHAzODQAAABhBMM1wvONZSobkf6CtT9n5E06y+ofhXmpTVSWRTOpMiZi+bsKViBi1eptF4LMufUT4M5DDU3V/kT9iM8124uWSWwS/ernmTsENNOI2TlzXkKkJshXh5Z4tFIVIkEZAeW/6w== aj@bowie.local

fixtures/pub-rsa-2048.ssh.pub

@@ -0,0 +1 @@
+ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDTNGUXvKQQ2sbdXdILzeI7u60ziBDHqCbrYxUkdro0LA8SqimkQexHKd9SBVvrxNm3l1LsCRmeIgrxlhwuptsygK80rRX5Jit2DCRP62tyMBIEIqLxAksMEW1z6M3XIdIj2jWkL6ei6Qver03JWt4TfxZG94axSPxPaHYf6Psb+lZnMfYrWXtVD9hJA6vQjKNqmpUo1I2dWq6e6F3Oepejfu9Cz1yMnEsNJG3COubJSXUkEdsJYSrW3wfUnMPBrlnjs8uP4NBTik+5SHmpb+pU3+2DjgC4tsnTIkiusaLIp/qJmS+X18pFzRCMy2jfX1QeHMPsXnBSvdfyIdZfIVs5 aj@bowie.local

lib/pem.js

@@ -0,0 +1,28 @@
+'use strict';
+
+var PEM = module.exports;
+var Enc = require('./encoding.js');
+
+PEM.parseBlock = function pemToDer(pem) {
+  var lines = pem.trim().split(/\n/);
+  var end = lines.length - 1;
+  var head = lines[0].match(/-----BEGIN (.*)-----/);
+  var foot = lines[end].match(/-----END (.*)-----/);
+
+  if (head) {
+    lines = lines.slice(1, end);
+    head = head[1];
+    if (head !== foot[1]) {
+      throw new Error("headers and footers do not match");
+    }
+  }
+
+  return { type: head, bytes: Enc.base64ToBuf(lines.join('')) };
+};
+
+PEM.packBlock = function (opts) {
+  return '-----BEGIN ' + opts.type + '-----\n'
+    + Enc.bufToBase64(opts.bytes).match(/.{1,64}/g).join('\n') + '\n'
+    + '-----END ' + opts.type + '-----'
+  ;
+};

lib/ssh-parser.js

@@ -2,11 +2,20 @@
 
 var SSH = module.exports;
 var Enc = require('./encoding.js');
+var PEM = require('./pem.js');
 
 SSH.parse = function (opts) {
   var pub = opts.pub || opts;
   var ssh = SSH.parseBlock(pub);
-  ssh = SSH.parseElements(ssh);
+  if ('OPENSSH PRIVATE KEY' === ssh.type) {
+    ssh = SSH.parsePrivateElements(ssh);
+    if (opts.public) {
+      ssh.elements = ssh.elements.slice(0, 3);
+    }
+  } else {
+    ssh.elements = SSH.parseElements(ssh.bytes);
+  }
+
   //delete ssh.bytes;
   return SSH.parsePublicKey(ssh);
 };
@@ -27,6 +36,9 @@ SSH.fingerprint = function (opts) {
 };
 
 SSH.parseBlock = function (ssh) {
+  if (/^-----BEGIN OPENSSH PRIVATE KEY-----/.test(ssh)) {
+    return PEM.parseBlock(ssh);
+  }
   ssh = ssh.split(/\s+/g);
 
   return {
@@ -36,10 +48,69 @@ SSH.parseBlock = function (ssh) {
   };
 };
 
-SSH.parseElements = function (ssh) {
+SSH.parsePrivateElements = function (ssh) {
+  // https://coolaj86.com/articles/the-openssh-private-key-format/
   var buf = ssh.bytes;
   var fulllen = buf.byteLength || buf.length;
   var offset = (buf.byteOffset || 0);
+  var dv = new DataView(buf.buffer.slice(offset, offset + fulllen));
+  var index = 0;
+  var padlen = 0;
+  var len;
+
+  // The last byte will be either
+  //   * a non-printable pad character
+  //   * a printable comment character
+  function lastByteIsPad() {
+    var n = ssh.bytes[(ssh.bytes.bytesLength || ssh.bytes.length) - 1];
+    return n >= 0x01 && n <= 0x07;
+  }
+  while (lastByteIsPad()) {
+    padlen += 1;
+    len = (ssh.bytes.bytesLength || ssh.bytes.length);
+    ssh.bytes = ssh.bytes.slice(0, len - 1);
+  }
+
+  //  o  p  e  n  s  s  h  -  k  e  y  -  v  1  NULL
+  // 6f 70 65 6e 73 73 68 2d 6b 65 79 2d 76 31 00
+  // 15 characters
+  // 4-byte len, "none" (encryption)
+  // 4-byte len, "none" (kdfname)
+  if ('none' !== Enc.bufToBin(ssh.bytes.slice(15 + 8 + 4, 15 + 8 + 8))) {
+    throw new Error("Key is either encrypted (not yet supported), corrupt, or not openssh-key-v1");
+  }
+  if (padlen >= 8) {
+    throw new Error("Padding length should be between 0 and 7, not '" + padlen + "'."
+      + " Probably not an ssh private key.");
+  }
+  // 4-byte len, nil (kdf)
+  // 4-byte number of keys
+  index += 15 + 8 + 8 + 4 + 4;
+
+  // length of public key
+  len = dv.getUint32(index, false);
+  // throw away public key (it's in the private key)
+  index += 4 + len;
+
+  // length of dummy checksum + private key + padding
+  len = dv.getUint32(index, false) - padlen;
+  // throw away dummy checksum
+  index += 4 + 8;
+
+  ssh.elements = SSH.parseElements(ssh.bytes.slice(index, index + (len - 8)));
+  index += Array.prototype.reduce.call(ssh.elements, function (el, sum) {
+    // 32-bit len + element len
+    return 4 + (el.byteLength || el.length) + sum;
+  }, 0);
+
+  // comment will exist, even if it's an empty string
+  ssh.comment = Enc.bufToBin(ssh.elements.pop());
+  return ssh;
+};
+SSH.parseElements = function (buf) {
+  var fulllen = buf.byteLength || buf.length;
+  // Note: node has weird offsets
+  var offset = (buf.byteOffset || 0);
   var i = 0;
   var index = 0;
   // using dataview to be browser-compatible (I do want _some_ code reuse)
@@ -53,6 +124,7 @@ SSH.parseElements = function (ssh) {
     if (i > 15) { throw new Error("15+ elements, probably not a public ssh key"); }
     len = dv.getUint32(index, false);
     index += 4;
+    if (0 === len) { continue; }
     el = buf.slice(index, index + len);
     // remove BigUInt '00' prefix
     if (0x00 === el[0]) {
@@ -67,8 +139,7 @@ SSH.parseElements = function (ssh) {
     }).join('\n'));
   }
 
-  ssh.elements = els;
-  return ssh;
+  return els;
 };
 
 SSH.parsePublicKey = function (ssh) {
@@ -78,11 +149,26 @@ SSH.parsePublicKey = function (ssh) {
 
   // RSA keys are all the same
   if (SSH.types.rsa === typ) {
-    ssh.jwk = {
-      kty: 'RSA'
-    , n: Enc.bufToUrlBase64(els[2])
-    , e: Enc.bufToUrlBase64(els[1])
-    };
+    if (3 === els.length) {
+      ssh.jwk = {
+        kty: 'RSA'
+      , n: Enc.bufToUrlBase64(els[2])
+      , e: Enc.bufToUrlBase64(els[1])
+      };
+    } else {
+      console.log('len:', els.length);
+      ssh.jwk = {
+        kty: 'RSA'
+      , n: Enc.bufToUrlBase64(els[2])
+      , e: Enc.bufToUrlBase64(els[1])
+      , d: Enc.bufToUrlBase64(els[3])
+      , p: Enc.bufToUrlBase64(els[5])
+      , q: Enc.bufToUrlBase64(els[6])
+      //, dp: Enc.bufToUrlBase64(els[x])
+      //, dq: Enc.bufToUrlBase64(els[x])
+      , qi: Enc.bufToUrlBase64(els[4])
+      };
+    }
     return ssh;
   }
 
@@ -101,11 +187,15 @@ SSH.parsePublicKey = function (ssh) {
   // els[1] is just a repeat of a subset of els[0]
   var x = els[2].slice(1, 1 + len);
   var y = els[2].slice(1 + len, 1 + len + len);
+  var d;
 
   // I don't think EC keys use 0x00 padding, but just in case
   while (0x00 === x[0]) { x = x.slice(1); }
   while (0x00 === y[0]) { y = y.slice(1); }
 
+  if (els[3]) {
+    ssh.jwk.d = Enc.bufToUrlBase64(els[3]);
+  }
   ssh.jwk.x = Enc.bufToUrlBase64(x);
   ssh.jwk.y = Enc.bufToUrlBase64(y);
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ssh-to-jwk",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "💯 SSH to JWK in a lightweight, zero-dependency library.",
   "homepage": "https://git.coolaj86.com/coolaj86/ssh-to-jwk.js",
   "main": "index.js",