Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S942096AbdDTHB5 (ORCPT ); Thu, 20 Apr 2017 03:01:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46072 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S942036AbdDTGiS (ORCPT ); Thu, 20 Apr 2017 02:38:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kefeng Wang , "Martin K. Petersen" Subject: [PATCH 3.18 008/124] scsi: sr: Sanity check returned mode data Date: Thu, 20 Apr 2017 08:34:43 +0200 Message-Id: <20170420063557.339023690@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170420063557.021306233@linuxfoundation.org> References: <20170420063557.021306233@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1639 Lines: 46 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin K. Petersen commit a00a7862513089f17209b732f230922f1942e0b9 upstream. Kefeng Wang discovered that old versions of the QEMU CD driver would return mangled mode data causing us to walk off the end of the buffer in an attempt to parse it. Sanity check the returned mode sense data. Reported-by: Kefeng Wang Tested-by: Kefeng Wang Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/sr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -839,6 +839,7 @@ static void get_capabilities(struct scsi unsigned char *buffer; struct scsi_mode_data data; struct scsi_sense_hdr sshdr; + unsigned int ms_len = 128; int rc, n; static const char *loadmech[] = @@ -865,10 +866,11 @@ static void get_capabilities(struct scsi scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr); /* ask for mode page 0x2a */ - rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128, + rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len, SR_TIMEOUT, 3, &data, NULL); - if (!scsi_status_is_good(rc)) { + if (!scsi_status_is_good(rc) || data.length > ms_len || + data.header_length + data.block_descriptor_length > data.length) { /* failed, drive doesn't have capabilities mode page */ cd->cdi.speed = 1; cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |