From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934049AbdKAVWc (ORCPT ); Wed, 1 Nov 2017 17:22:32 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:35105 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934022AbdKAVW2 (ORCPT ); Wed, 1 Nov 2017 17:22:28 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Dan Carpenter , Tejun Heo , Willy Tarreau Subject: [PATCH 3.10 039/139] libata: array underflow in ata_find_dev() Date: Wed, 1 Nov 2017 22:17:39 +0100 Message-Id: <1509571159-4405-40-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1509571159-4405-1-git-send-email-w@1wt.eu> References: <1509571159-4405-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Carpenter commit 59a5e266c3f5c1567508888dd61a45b86daed0fa upstream. My static checker complains that "devno" can be negative, meaning that we read before the start of the loop. I've looked at the code, and I think the warning is right. This come from /proc so it's root only or it would be quite a quite a serious bug. The call tree looks like this: proc_scsi_write() <- gets id and channel from simple_strtoul() -> scsi_add_single_device() <- calls shost->transportt->user_scan() -> ata_scsi_user_scan() -> ata_find_dev() Signed-off-by: Dan Carpenter Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org Signed-off-by: Willy Tarreau --- drivers/ata/libata-scsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index f3f0801..aa4e36b 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2794,10 +2794,12 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc) static struct ata_device *ata_find_dev(struct ata_port *ap, int devno) { if (!sata_pmp_attached(ap)) { - if (likely(devno < ata_link_max_devices(&ap->link))) + if (likely(devno >= 0 && + devno < ata_link_max_devices(&ap->link))) return &ap->link.device[devno]; } else { - if (likely(devno < ap->nr_pmp_links)) + if (likely(devno >= 0 && + devno < ap->nr_pmp_links)) return &ap->pmp_link[devno].device[0]; } -- 2.8.0.rc2.1.gbe9624a