From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37298 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751762AbcKQIgv (ORCPT ); Thu, 17 Nov 2016 03:36:51 -0500 Subject: Patch "hwrng: core - Don't use a stack buffer in add_early_randomness()" has been added to the 4.4-stable tree To: luto@kernel.org, gregkh@linuxfoundation.org, herbert@gondor.apana.org.au, mmullins@mmlx.us Cc: , From: Date: Thu, 17 Nov 2016 09:36:52 +0100 Message-ID: <1479371812101225@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled hwrng: core - Don't use a stack buffer in add_early_randomness() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hwrng-core-don-t-use-a-stack-buffer-in-add_early_randomness.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 Mon Sep 17 00:00:00 2001 From: Andrew Lutomirski Date: Mon, 17 Oct 2016 10:06:27 -0700 Subject: hwrng: core - Don't use a stack buffer in add_early_randomness() From: Andrew Lutomirski commit 6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 upstream. hw_random carefully avoids using a stack buffer except in add_early_randomness(). This causes a crash in virtio_rng if CONFIG_VMAP_STACK=y. Reported-by: Matt Mullins Tested-by: Matt Mullins Fixes: d3cc7996473a ("hwrng: fetch randomness only after device init") Signed-off-by: Andy Lutomirski Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/char/hw_random/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -84,14 +84,14 @@ static size_t rng_buffer_size(void) static void add_early_randomness(struct hwrng *rng) { - unsigned char bytes[16]; int bytes_read; + size_t size = min_t(size_t, 16, rng_buffer_size()); mutex_lock(&reading_mutex); - bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + bytes_read = rng_get_data(rng, rng_buffer, size, 1); mutex_unlock(&reading_mutex); if (bytes_read > 0) - add_device_randomness(bytes, bytes_read); + add_device_randomness(rng_buffer, bytes_read); } static inline void cleanup_rng(struct kref *kref) Patches currently in stable-queue which might be from luto@kernel.org are queue-4.4/hwrng-core-don-t-use-a-stack-buffer-in-add_early_randomness.patch