From 9225bbfc0c6559aa4002ea8f35696cd74475429d Mon Sep 17 00:00:00 2001
From: Adam Langley <agl@golang.org>
Date: Tue, 29 Mar 2011 15:47:35 -0400
Subject: [PATCH] crypto/cipher: bad CTR IV length now triggers panic

R=rsc
CC=golang-dev
https://golang.org/cl/4326042
---
 src/pkg/crypto/cipher/ctr.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/pkg/crypto/cipher/ctr.go b/src/pkg/crypto/cipher/ctr.go
index 04436ec23b0..147b74fc2fd 100644
--- a/src/pkg/crypto/cipher/ctr.go
+++ b/src/pkg/crypto/cipher/ctr.go
@@ -22,6 +22,10 @@ type ctr struct {
 // NewCTR returns a Stream which encrypts/decrypts using the given Block in
 // counter mode. The length of iv must be the same as the Block's block size.
 func NewCTR(block Block, iv []byte) Stream {
+	if len(iv) != block.BlockSize() {
+		panic("cipher.NewCTR: iv length must equal block size")
+	}
+
 	return &ctr{
 		b:       block,
 		ctr:     dup(iv),