From 16edf0b1f7401df07e0d2f96c8b97516e50cffd9 Mon Sep 17 00:00:00 2001
From: Joe Kyo <xunianzu@gmail.com>
Date: Wed, 6 Sep 2017 10:31:03 +0100
Subject: [PATCH] crypto/cipher: panic when IV length does not equal block size
 in NewOFB

Functions like NewCBCDecrypter, NewCBCEncrypter, NewCFBDecrypter,
NewCFBEncrypter and NewCTR all panic when IV length does not equal block size.
This commit changes NewOFB to panic too, instead of returning nil silently.

Change-Id: Ic4d3ebfad79bb0cf4759fa1c1a400c1a8d043490
Reviewed-on: https://go-review.googlesource.com/61850
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Run-TryBot: Filippo Valsorda <hi@filippo.io>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---
 src/crypto/cipher/ofb.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/crypto/cipher/ofb.go b/src/crypto/cipher/ofb.go
index e86ebcb237e..7b35f8995c8 100644
--- a/src/crypto/cipher/ofb.go
+++ b/src/crypto/cipher/ofb.go
@@ -19,7 +19,7 @@ type ofb struct {
 func NewOFB(b Block, iv []byte) Stream {
 	blockSize := b.BlockSize()
 	if len(iv) != blockSize {
-		return nil
+		panic("cipher.NewOFB: IV length must equal block size")
 	}
 	bufSize := streamBufferSize
 	if bufSize < blockSize {