From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46624 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728232AbeHWLsu (ORCPT ); Thu, 23 Aug 2018 07:48:50 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Garry , Tejun Heo , Sasha Levin Subject: [PATCH 4.14 043/217] libahci: Fix possible Spectre-v1 pmp indexing in ahci_led_store() Date: Thu, 23 Aug 2018 09:52:36 +0200 Message-Id: <20180823075507.463449517@linuxfoundation.org> In-Reply-To: <20180823075505.090246914@linuxfoundation.org> References: <20180823075505.090246914@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: John Garry [ Upstream commit fae2a63737e5973f1426bc139935a0f42e232844 ] Currently smatch warns of possible Spectre-V1 issue in ahci_led_store(): drivers/ata/libahci.c:1150 ahci_led_store() warn: potential spectre issue 'pp->em_priv' (local cap) Userspace controls @pmp from following callchain: em_message->store() ->ata_scsi_em_message_store() -->ap->ops->em_store() --->ahci_led_store() After the mask+shift @pmp is effectively an 8b value, which is used to index into an array of length 8, so sanitize the array index. Signed-off-by: John Garry Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/ata/libahci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -1135,10 +1136,12 @@ static ssize_t ahci_led_store(struct ata /* get the slot number from the message */ pmp = (state & EM_MSG_LED_PMP_SLOT) >> 8; - if (pmp < EM_MAX_SLOTS) + if (pmp < EM_MAX_SLOTS) { + pmp = array_index_nospec(pmp, EM_MAX_SLOTS); emp = &pp->em_priv[pmp]; - else + } else { return -EINVAL; + } /* mask off the activity bits if we are in sw_activity * mode, user should turn off sw_activity before setting