From 081464fa142ce908d0606417e5f576263cb29584 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Wed, 28 Jul 2010 11:03:09 +0000
Subject: [PATCH] Make ctr mode behaviour consistent with other modes.

---
 crypto/evp/e_aes.c   | 16 +++-------------
 crypto/evp/evp.h     |  1 +
 crypto/evp/evp_enc.c |  5 ++++-
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/crypto/evp/e_aes.c b/crypto/evp/e_aes.c
index 3dc85762a2..a7fbba3689 100644
--- a/crypto/evp/e_aes.c
+++ b/crypto/evp/e_aes.c
@@ -122,7 +122,7 @@ static int aes_counter (EVP_CIPHER_CTX *ctx, unsigned char *out,
 static const EVP_CIPHER aes_128_ctr_cipher=
 	{
 	NID_aes_128_ctr,1,16,16,
-	EVP_CIPH_CUSTOM_IV,
+	EVP_CIPH_CTR_MODE,
 	aes_init_key,
 	aes_counter,
 	NULL,
@@ -139,7 +139,7 @@ const EVP_CIPHER *EVP_aes_128_ctr (void)
 static const EVP_CIPHER aes_192_ctr_cipher=
 	{
 	NID_aes_192_ctr,1,24,16,
-	EVP_CIPH_CUSTOM_IV,
+	EVP_CIPH_CTR_MODE,
 	aes_init_key,
 	aes_counter,
 	NULL,
@@ -156,7 +156,7 @@ const EVP_CIPHER *EVP_aes_192_ctr (void)
 static const EVP_CIPHER aes_256_ctr_cipher=
 	{
 	NID_aes_256_ctr,1,32,16,
-	EVP_CIPH_CUSTOM_IV,
+	EVP_CIPH_CTR_MODE,
 	aes_init_key,
 	aes_counter,
 	NULL,
@@ -188,16 +188,6 @@ static int aes_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 		return 0;
 		}
 
-	if (ctx->cipher->flags&EVP_CIPH_CUSTOM_IV)
-		{
-		if (iv!=NULL)
-			memcpy (ctx->iv,iv,ctx->cipher->iv_len);
-		else	{
-			EVPerr(EVP_F_AES_INIT_KEY,EVP_R_AES_IV_SETUP_FAILED);
-			return 0;
-			}
-		}
-
 	return 1;
 	}
 
diff --git a/crypto/evp/evp.h b/crypto/evp/evp.h
index 037f14be23..b5f847857f 100644
--- a/crypto/evp/evp.h
+++ b/crypto/evp/evp.h
@@ -326,6 +326,7 @@ struct evp_cipher_st
 #define		EVP_CIPH_CBC_MODE		0x2
 #define		EVP_CIPH_CFB_MODE		0x3
 #define		EVP_CIPH_OFB_MODE		0x4
+#define		EVP_CIPH_CTR_MODE		0x5
 #define 	EVP_CIPH_MODE			0xF0007
 /* Set if variable length cipher */
 #define 	EVP_CIPH_VARIABLE_LENGTH	0x8
diff --git a/crypto/evp/evp_enc.c b/crypto/evp/evp_enc.c
index bead6a2170..a35621a2ec 100644
--- a/crypto/evp/evp_enc.c
+++ b/crypto/evp/evp_enc.c
@@ -206,11 +206,14 @@ skip_to_init:
 			ctx->num = 0;
 
 			case EVP_CIPH_CBC_MODE:
+			case EVP_CIPH_CTR_MODE:
 
 			OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) <=
 					(int)sizeof(ctx->iv));
 			if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
-			memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
+			/* Don't reuse IV for CTR mode */
+			if (EVP_CIPHER_CTX_mode(ctx) != EVP_CIPH_CTR_MODE)
+				memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 			break;
 
 			default:
-- 
2.25.1