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 <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: danbev

lib/internal/crypto/cipher.js

@@ -73,10 +73,21 @@ function getUIntOption(options, key) {
 return-1;
 }
 
-functionCipher(cipher,password,options){
-if(!(thisinstanceofCipher))
-returnnewCipher(cipher,password,options);
+functioncreateCipherBase(cipher,credential,options,decipher,iv){
+constauthTagLength=getUIntOption(options,'authTagLength');
+
+this._handle=newCipherBase(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);
+}
+
+functioncreateCipher(cipher,password,options,decipher){
 if(typeofcipher!=='string')
 thrownewERR_INVALID_ARG_TYPE('cipher','string',cipher);
 
@@ -89,14 +100,38 @@ function Cipher(cipher, password, options) {
 );
 }
 
-constauthTagLength=getUIntOption(options,'authTagLength');
+createCipherBase.call(this,cipher,password,options,decipher);
+}
 
-this._handle=newCipherBase(true);
+functioncreateCipherWithIV(cipher,key,options,decipher,iv){
+if(typeofcipher!=='string')
+thrownewERR_INVALID_ARG_TYPE('cipher','string',cipher);
 
-this._handle.init(cipher,password,authTagLength);
-this._decoder=null;
+key=toBuf(key);
+if(!isArrayBufferView(key)){
+thrownewERR_INVALID_ARG_TYPE(
+'key',
+['string','Buffer','TypedArray','DataView'],
+key
+);
+}
 
-LazyTransform.call(this,options);
+iv=toBuf(iv);
+if(iv!==null&&!isArrayBufferView(iv)){
+thrownewERR_INVALID_ARG_TYPE(
+'iv',
+['string','Buffer','TypedArray','DataView'],
+iv
+);
+}
+createCipherBase.call(this,cipher,key,options,decipher,iv);
+}
+
+functionCipher(cipher,password,options){
+if(!(thisinstanceofCipher))
+returnnewCipher(cipher,password,options);
+
+createCipher.call(this,cipher,password,options,true);
 }
 
 inherits(Cipher,LazyTransform);
@@ -198,34 +233,7 @@ function Cipheriv(cipher, key, iv, options) {
 if(!(thisinstanceofCipheriv))
 returnnewCipheriv(cipher,key,iv,options);
 
-if(typeofcipher!=='string')
-thrownewERR_INVALID_ARG_TYPE('cipher','string',cipher);
-
-key=toBuf(key);
-if(!isArrayBufferView(key)){
-thrownewERR_INVALID_ARG_TYPE(
-'key',
-['string','Buffer','TypedArray','DataView'],
-key
-);
-}
-
-iv=toBuf(iv);
-if(iv!==null&&!isArrayBufferView(iv)){
-thrownewERR_INVALID_ARG_TYPE(
-'iv',
-['string','Buffer','TypedArray','DataView'],
-iv
-);
-}
-
-constauthTagLength=getUIntOption(options,'authTagLength');
-
-this._handle=newCipherBase(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(!(thisinstanceofDecipher))
 returnnewDecipher(cipher,password,options);
 
-if(typeofcipher!=='string')
-thrownewERR_INVALID_ARG_TYPE('cipher','string',cipher);
-
-password=toBuf(password);
-if(!isArrayBufferView(password)){
-thrownewERR_INVALID_ARG_TYPE(
-'password',
-['string','Buffer','TypedArray','DataView'],
-password
-);
-}
-
-constauthTagLength=getUIntOption(options,'authTagLength');
-
-this._handle=newCipherBase(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(!(thisinstanceofDecipheriv))
 returnnewDecipheriv(cipher,key,iv,options);
 
-if(typeofcipher!=='string')
-thrownewERR_INVALID_ARG_TYPE('cipher','string',cipher);
-
-key=toBuf(key);
-if(!isArrayBufferView(key)){
-thrownewERR_INVALID_ARG_TYPE(
-'key',
-['string','Buffer','TypedArray','DataView'],
-key
-);
-}
-
-iv=toBuf(iv);
-if(iv!==null&&!isArrayBufferView(iv)){
-thrownewERR_INVALID_ARG_TYPE(
-'iv',
-['string','Buffer','TypedArray','DataView'],
-iv
-);
-}
-
-constauthTagLength=getUIntOption(options,'authTagLength');
-
-this._handle=newCipherBase(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);