From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:38232 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727468AbeKIHo4 (ORCPT ); Fri, 9 Nov 2018 02:44:56 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Doug Ledford Subject: [PATCH 4.9 162/171] IB/ucm: Fix Spectre v1 vulnerability Date: Thu, 8 Nov 2018 13:52:12 -0800 Message-Id: <20181108215138.652601648@linuxfoundation.org> In-Reply-To: <20181108215127.257643509@linuxfoundation.org> References: <20181108215127.257643509@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: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva commit 0295e39595e1146522f2722715dba7f7fba42217 upstream. hdr.cmd can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/infiniband/core/ucm.c:1127 ib_ucm_write() warn: potential spectre issue 'ucm_cmd_table' [r] (local cap) Fix this by sanitizing hdr.cmd before using it to index ucm_cmd_table. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Signed-off-by: Doug Ledford Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/ucm.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/infiniband/core/ucm.c +++ b/drivers/infiniband/core/ucm.c @@ -46,6 +46,8 @@ #include #include +#include + #include #include @@ -1115,6 +1117,7 @@ static ssize_t ib_ucm_write(struct file if (hdr.cmd >= ARRAY_SIZE(ucm_cmd_table)) return -EINVAL; + hdr.cmd = array_index_nospec(hdr.cmd, ARRAY_SIZE(ucm_cmd_table)); if (hdr.in + sizeof(hdr) > len) return -EINVAL;