From b4b734e882d792bb94cd912660c7fa48a3598fc2 Mon Sep 17 00:00:00 2001
From: mikeb <mikeb@openbsd.org>
Date: Tue, 27 Oct 2015 11:13:06 +0000
Subject: [PATCH] Sync chacha_ivsetup to the version in ssh so that we could
 specify custom counter value when setting up Chacha context.

ok reyk djm
---
 sys/crypto/chacha_private.h |  8 ++++----
 sys/dev/rnd.c               | 10 +++++-----
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/sys/crypto/chacha_private.h b/sys/crypto/chacha_private.h
index 66b57c59d7b..662c074de4e 100644
--- a/sys/crypto/chacha_private.h
+++ b/sys/crypto/chacha_private.h
@@ -50,7 +50,7 @@ static const char sigma[16] = "expand 32-byte k";
 static const char tau[16] = "expand 16-byte k";
 
 static void
-chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits,u32 ivbits)
+chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits)
 {
   const char *constants;
 
@@ -75,10 +75,10 @@ chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits,u32 ivbits)
 }
 
 static void
-chacha_ivsetup(chacha_ctx *x,const u8 *iv)
+chacha_ivsetup(chacha_ctx *x, const u8 *iv, const u8 *counter)
 {
-  x->input[12] = 0;
-  x->input[13] = 0;
+  x->input[12] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 0);
+  x->input[13] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 4);
   x->input[14] = U8TO32_LITTLE(iv + 0);
   x->input[15] = U8TO32_LITTLE(iv + 4);
 }
diff --git a/sys/dev/rnd.c b/sys/dev/rnd.c
index 58f12eda783..ed84f239cfb 100644
--- a/sys/dev/rnd.c
+++ b/sys/dev/rnd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rnd.c,v 1.175 2015/05/25 03:07:07 deraadt Exp $	*/
+/*	$OpenBSD: rnd.c,v 1.176 2015/10/27 11:13:06 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2011 Theo de Raadt.
@@ -568,8 +568,8 @@ static inline void
 _rs_init(u_char *buf, size_t n)
 {
 	KASSERT(n >= KEYSZ + IVSZ);
-	chacha_keysetup(&rs, buf, KEYSZ * 8, 0);
-	chacha_ivsetup(&rs, buf + KEYSZ);
+	chacha_keysetup(&rs, buf, KEYSZ * 8);
+	chacha_ivsetup(&rs, buf + KEYSZ, NULL);
 }
 
 static void
@@ -833,8 +833,8 @@ randomread(dev_t dev, struct uio *uio, int ioflag)
 	buf = malloc(POOLBYTES, M_TEMP, M_WAITOK);
 	if (total > ARC4_MAIN_MAX_BYTES) {
 		arc4random_buf(lbuf, sizeof(lbuf));
-		chacha_keysetup(&lctx, lbuf, KEYSZ * 8, 0);
-		chacha_ivsetup(&lctx, lbuf + KEYSZ);
+		chacha_keysetup(&lctx, lbuf, KEYSZ * 8);
+		chacha_ivsetup(&lctx, lbuf + KEYSZ, NULL);
 		explicit_bzero(lbuf, sizeof(lbuf));
 		myctx = 1;
 	}
-- 
2.20.1