crypto: add createCipher/WithIV functions

This commit extracts the common code from the Cipher/Cipheriv and
Decipher/Decipheriv constructors into a separate function to avoid
code duplication.

Backport-PR-URL: #20706
PR-URL: #20164
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>

Author: danbev

lib/internal/crypto/cipher.js

@@ -73,10 +73,21 @@ function getUIntOption(options, key) {
   return -1;
 }
 
-function Cipher(cipher, password, options) {
-  if (!(this instanceof Cipher))
-    return new Cipher(cipher, password, options);
+function createCipherBase(cipher, credential, options, decipher, iv) {
+  const authTagLength = getUIntOption(options, 'authTagLength');
+
+  this._handle = new CipherBase(decipher);
+  if (iv === undefined) {
+    this._handle.init(cipher, credential, authTagLength);
+  } else {
+    this._handle.initiv(cipher, credential, iv, authTagLength);
+  }
+  this._decoder = null;
 
+  LazyTransform.call(this, options);
+}
+
+function createCipher(cipher, password, options, decipher) {
   if (typeof cipher !== 'string')
     throw new ERR_INVALID_ARG_TYPE('cipher', 'string', cipher);
 
@@ -89,14 +100,38 @@ function Cipher(cipher, password, options) {
     );
   }
 
-  const authTagLength = getUIntOption(options, 'authTagLength');
+  createCipherBase.call(this, cipher, password, options, decipher);
+}
 
-  this._handle = new CipherBase(true);
+function createCipherWithIV(cipher, key, options, decipher, iv) {
+  if (typeof cipher !== 'string')
+    throw new ERR_INVALID_ARG_TYPE('cipher', 'string', cipher);
 
-  this._handle.init(cipher, password, authTagLength);
-  this._decoder = null;
+  key = toBuf(key);
+  if (!isArrayBufferView(key)) {
+    throw new ERR_INVALID_ARG_TYPE(
+      'key',
+      ['string', 'Buffer', 'TypedArray', 'DataView'],
+      key
+    );
+  }
 
-  LazyTransform.call(this, options);
+  iv = toBuf(iv);
+  if (iv !== null && !isArrayBufferView(iv)) {
+    throw new ERR_INVALID_ARG_TYPE(
+      'iv',
+      ['string', 'Buffer', 'TypedArray', 'DataView'],
+      iv
+    );
+  }
+  createCipherBase.call(this, cipher, key, options, decipher, iv);
+}
+
+function Cipher(cipher, password, options) {
+  if (!(this instanceof Cipher))
+    return new Cipher(cipher, password, options);
+
+  createCipher.call(this, cipher, password, options, true);
 }
 
 inherits(Cipher, LazyTransform);
@@ -198,34 +233,7 @@ function Cipheriv(cipher, key, iv, options) {
   if (!(this instanceof Cipheriv))
     return new Cipheriv(cipher, key, iv, options);
 
-  if (typeof cipher !== 'string')
-    throw new ERR_INVALID_ARG_TYPE('cipher', 'string', cipher);
-
-  key = toBuf(key);
-  if (!isArrayBufferView(key)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'key',
-      ['string', 'Buffer', 'TypedArray', 'DataView'],
-      key
-    );
-  }
-
-  iv = toBuf(iv);
-  if (iv !== null && !isArrayBufferView(iv)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'iv',
-      ['string', 'Buffer', 'TypedArray', 'DataView'],
-      iv
-    );
-  }
-
-  const authTagLength = getUIntOption(options, 'authTagLength');
-
-  this._handle = new CipherBase(true);
-  this._handle.initiv(cipher, key, iv, authTagLength);
-  this._decoder = null;
-
-  LazyTransform.call(this, options);
+  createCipherWithIV.call(this, cipher, key, options, true, iv);
 }
 
 inherits(Cipheriv, LazyTransform);
@@ -248,25 +256,7 @@ function Decipher(cipher, password, options) {
   if (!(this instanceof Decipher))
     return new Decipher(cipher, password, options);
 
-  if (typeof cipher !== 'string')
-    throw new ERR_INVALID_ARG_TYPE('cipher', 'string', cipher);
-
-  password = toBuf(password);
-  if (!isArrayBufferView(password)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'password',
-      ['string', 'Buffer', 'TypedArray', 'DataView'],
-      password
-    );
-  }
-
-  const authTagLength = getUIntOption(options, 'authTagLength');
-
-  this._handle = new CipherBase(false);
-  this._handle.init(cipher, password, authTagLength);
-  this._decoder = null;
-
-  LazyTransform.call(this, options);
+  createCipher.call(this, cipher, password, options, false);
 }
 
 inherits(Decipher, LazyTransform);
@@ -286,34 +276,7 @@ function Decipheriv(cipher, key, iv, options) {
   if (!(this instanceof Decipheriv))
     return new Decipheriv(cipher, key, iv, options);
 
-  if (typeof cipher !== 'string')
-    throw new ERR_INVALID_ARG_TYPE('cipher', 'string', cipher);
-
-  key = toBuf(key);
-  if (!isArrayBufferView(key)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'key',
-      ['string', 'Buffer', 'TypedArray', 'DataView'],
-      key
-    );
-  }
-
-  iv = toBuf(iv);
-  if (iv !== null && !isArrayBufferView(iv)) {
-    throw new ERR_INVALID_ARG_TYPE(
-      'iv',
-      ['string', 'Buffer', 'TypedArray', 'DataView'],
-      iv
-    );
-  }
-
-  const authTagLength = getUIntOption(options, 'authTagLength');
-
-  this._handle = new CipherBase(false);
-  this._handle.initiv(cipher, key, iv, authTagLength);
-  this._decoder = null;
-
-  LazyTransform.call(this, options);
+  createCipherWithIV.call(this, cipher, key, options, false, iv);
 }
 
 inherits(Decipheriv, LazyTransform);