From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:47440 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728570AbeJIB7N (ORCPT ); Mon, 8 Oct 2018 21:59:13 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jinbum Park , Johannes Berg , Sasha Levin Subject: [PATCH 4.18 018/168] mac80211_hwsim: Fix possible Spectre-v1 for hwsim_world_regdom_custom Date: Mon, 8 Oct 2018 20:29:58 +0200 Message-Id: <20181008175620.744522583@linuxfoundation.org> In-Reply-To: <20181008175620.043587728@linuxfoundation.org> References: <20181008175620.043587728@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jinbum Park [ Upstream commit 3a2af7cccbbaf2362db9053a946a6084e12bfa73 ] User controls @idx which to be used as index of hwsim_world_regdom_custom. So, It can be exploited via Spectre-like attack. (speculative execution) This kind of attack leaks address of hwsim_world_regdom_custom, It leads an attacker to bypass security mechanism such as KASLR. So sanitize @idx before using it to prevent attack. I leveraged strategy [1] to find and exploit this gadget. [1] https://github.com/jinb-park/linux-exploit/tree/master/exploit-remaining-spectre-gadget/ Signed-off-by: Jinbum Park [johannes: unwrap URL] Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/mac80211_hwsim.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -33,6 +33,7 @@ #include #include #include +#include #include "mac80211_hwsim.h" #define WARN_QUEUE 100 @@ -3229,6 +3230,9 @@ static int hwsim_new_radio_nl(struct sk_ kfree(hwname); return -EINVAL; } + + idx = array_index_nospec(idx, + ARRAY_SIZE(hwsim_world_regdom_custom)); param.regd = hwsim_world_regdom_custom[idx]; }