crypto: add sign/verify support for RSASSA-PSS

Adds support for the PSS padding scheme. Until now, the sign/verify
functions used the old EVP_Sign*/EVP_Verify* OpenSSL API, making it
impossible to change the padding scheme. Fixed by first computing the
message digest and then signing/verifying with a custom EVP_PKEY_CTX,
allowing us to specify options such as the padding scheme and the PSS
salt length.

Fixes: nodejs#1127
PR-URL: nodejs#11705
Reviewed-By: Shigeki Ohtsu <ohtsu@ohtsu.org>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

doc/api/crypto.md

@@ -896,17 +896,32 @@ console.log(sign.sign(privateKey).toString('hex'));
 ### sign.sign(private_key[, output_format])
 <!-- YAML
 added: v0.1.92
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/11705
+    description: Support for RSASSA-PSS and additional options was added.
 -->
 
 Calculates the signature on all the data passed through using either
 [`sign.update()`][] or [`sign.write()`][stream-writable-write].
 
 The `private_key` argument can be an object or a string. If `private_key` is a
 string, it is treated as a raw key with no passphrase. If `private_key` is an
-object, it is interpreted as a hash containing two properties:
+object, it must contain one or more of the following properties:
 
-* `key`: {string} - PEM encoded private key
+* `key`: {string} - PEM encoded private key (required)
 * `passphrase`: {string} - passphrase for the private key
+* `padding`: {integer} - Optional padding value for RSA, one of the following:
+  * `crypto.constants.RSA_PKCS1_PADDING` (default)
+  * `crypto.constants.RSA_PKCS1_PSS_PADDING`
+
+  Note that `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function
+  used to sign the message as specified in section 3.1 of [RFC 4055][].
+* `saltLength`: {integer} - salt length for when padding is
+  `RSA_PKCS1_PSS_PADDING`. The special value
+  `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest
+  size, `crypto.constants.RSA_PSS_SALTLEN_MAX_SIGN` (default) sets it to the
+  maximum permissible value.
 
 The `output_format` can specify one of `'latin1'`, `'hex'` or `'base64'`. If
 `output_format` is provided a string is returned; otherwise a [`Buffer`][] is
@@ -989,11 +1004,33 @@ This can be called many times with new data as it is streamed.
 ### verifier.verify(object, signature[, signature_format])
 <!-- YAML
 added: v0.1.92
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/11705
+    description: Support for RSASSA-PSS and additional options was added.
 -->
+- `object` {string | Object}
+- `signature` {string | Buffer | Uint8Array}
+- `signature_format` {string}
 
 Verifies the provided data using the given `object` and `signature`.
-The `object` argument is a string containing a PEM encoded object, which can be
-one an RSA public key, a DSA public key, or an X.509 certificate.
+The `object` argument can be either a string containing a PEM encoded object,
+which can be an RSA public key, a DSA public key, or an X.509 certificate,
+or an object with one or more of the following properties:
+
+* `key`: {string} - PEM encoded public key (required)
+* `padding`: {integer} - Optional padding value for RSA, one of the following:
+  * `crypto.constants.RSA_PKCS1_PADDING` (default)
+  * `crypto.constants.RSA_PKCS1_PSS_PADDING`
+
+  Note that `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function
+  used to verify the message as specified in section 3.1 of [RFC 4055][].
+* `saltLength`: {integer} - salt length for when padding is
+  `RSA_PKCS1_PSS_PADDING`. The special value
+  `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest
+  size, `crypto.constants.RSA_PSS_SALTLEN_AUTO` (default) causes it to be
+  determined automatically.
+
 The `signature` argument is the previously calculated signature for the data, in
 the `signature_format` which can be `'latin1'`, `'hex'` or `'base64'`.
 If a `signature_format` is specified, the `signature` is expected to be a
@@ -1900,6 +1937,21 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
     <td><code>RSA_PKCS1_PSS_PADDING</code></td>
     <td></td>
   </tr>
+  <tr>
+    <td><code>RSA_PSS_SALTLEN_DIGEST</code></td>
+    <td>Sets the salt length for `RSA_PKCS1_PSS_PADDING` to the digest size
+        when signing or verifying.</td>
+  </tr>
+  <tr>
+    <td><code>RSA_PSS_SALTLEN_MAX_SIGN</code></td>
+    <td>Sets the salt length for `RSA_PKCS1_PSS_PADDING` to the maximum
+        permissible value when signing data.</td>
+  </tr>
+  <tr>
+    <td><code>RSA_PSS_SALTLEN_AUTO</code></td>
+    <td>Causes the salt length for `RSA_PKCS1_PSS_PADDING` to be determined
+        automatically when verifying a signature.</td>
+  </tr>
   <tr>
     <td><code>POINT_CONVERSION_COMPRESSED</code></td>
     <td></td>
@@ -1975,6 +2027,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
 [publicly trusted list of CAs]: https://mxr.mozilla.org/mozilla/source/security/nss/lib/ckfw/builtins/certdata.txt
 [RFC 2412]: https://www.rfc-editor.org/rfc/rfc2412.txt
 [RFC 3526]: https://www.rfc-editor.org/rfc/rfc3526.txt
+[RFC 4055]: https://www.rfc-editor.org/rfc/rfc4055.txt
 [stream]: stream.html
 [stream-writable-write]: stream.html#stream_writable_write_chunk_encoding_callback
 [Crypto Constants]: #crypto_crypto_constants_1

lib/crypto.js

@@ -283,7 +283,28 @@ Sign.prototype.sign = function sign(options, encoding) {
 
   var key = options.key || options;
   var passphrase = options.passphrase || null;
-  var ret = this._handle.sign(toBuf(key), null, passphrase);
+
+  // Options specific to RSA
+  var rsaPadding = constants.RSA_PKCS1_PADDING;
+  if (options.hasOwnProperty('padding')) {
+    if (options.padding === options.padding >> 0) {
+      rsaPadding = options.padding;
+    } else {
+      throw new TypeError('padding must be an integer');
+    }
+  }
+
+  var pssSaltLength = constants.RSA_PSS_SALTLEN_AUTO;
+  if (options.hasOwnProperty('saltLength')) {
+    if (options.saltLength === options.saltLength >> 0) {
+      pssSaltLength = options.saltLength;
+    } else {
+      throw new TypeError('saltLength must be an integer');
+    }
+  }
+
+  var ret = this._handle.sign(toBuf(key), null, passphrase, rsaPadding,
+                              pssSaltLength);
 
   encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding && encoding !== 'buffer')
@@ -309,9 +330,31 @@ util.inherits(Verify, stream.Writable);
 Verify.prototype._write = Sign.prototype._write;
 Verify.prototype.update = Sign.prototype.update;
 
-Verify.prototype.verify = function verify(object, signature, sigEncoding) {
+Verify.prototype.verify = function verify(options, signature, sigEncoding) {
+  var key = options.key || options;
   sigEncoding = sigEncoding || exports.DEFAULT_ENCODING;
-  return this._handle.verify(toBuf(object), toBuf(signature, sigEncoding));
+
+  // Options specific to RSA
+  var rsaPadding = constants.RSA_PKCS1_PADDING;
+  if (options.hasOwnProperty('padding')) {
+    if (options.padding === options.padding >> 0) {
+      rsaPadding = options.padding;
+    } else {
+      throw new TypeError('padding must be an integer');
+    }
+  }
+
+  var pssSaltLength = constants.RSA_PSS_SALTLEN_AUTO;
+  if (options.hasOwnProperty('saltLength')) {
+    if (options.saltLength === options.saltLength >> 0) {
+      pssSaltLength = options.saltLength;
+    } else {
+      throw new TypeError('saltLength must be an integer');
+    }
+  }
+
+  return this._handle.verify(toBuf(key), toBuf(signature, sigEncoding), null,
+                             rsaPadding, pssSaltLength);
 };
 
 function rsaPublic(method, defaultPadding) {

src/node_constants.cc

@@ -974,6 +974,18 @@ void DefineOpenSSLConstants(Local<Object> target) {
     NODE_DEFINE_CONSTANT(target, RSA_PKCS1_PSS_PADDING);
 #endif
 
+#ifdef RSA_PSS_SALTLEN_DIGEST
+    NODE_DEFINE_CONSTANT(target, RSA_PSS_SALTLEN_DIGEST);
+#endif
+
+#ifdef RSA_PSS_SALTLEN_MAX_SIGN
+    NODE_DEFINE_CONSTANT(target, RSA_PSS_SALTLEN_MAX_SIGN);
+#endif
+
+#ifdef RSA_PSS_SALTLEN_AUTO
+    NODE_DEFINE_CONSTANT(target, RSA_PSS_SALTLEN_AUTO);
+#endif
+
 #if HAVE_OPENSSL
   // NOTE: These are not defines
   NODE_DEFINE_CONSTANT(target, POINT_CONVERSION_COMPRESSED);

src/node_constants.h

@@ -7,6 +7,19 @@
 #include "v8.h"
 
 #if HAVE_OPENSSL
+
+#ifndef RSA_PSS_SALTLEN_DIGEST
+#define RSA_PSS_SALTLEN_DIGEST -1
+#endif
+
+#ifndef RSA_PSS_SALTLEN_MAX_SIGN
+#define RSA_PSS_SALTLEN_MAX_SIGN -2
+#endif
+
+#ifndef RSA_PSS_SALTLEN_AUTO
+#define RSA_PSS_SALTLEN_AUTO -2
+#endif
+
 #define DEFAULT_CIPHER_LIST_CORE "ECDHE-RSA-AES128-GCM-SHA256:"     \
                                  "ECDHE-ECDSA-AES128-GCM-SHA256:"   \
                                  "ECDHE-RSA-AES256-GCM-SHA384:"     \