Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751466AbdGZUTn (ORCPT ); Wed, 26 Jul 2017 16:19:43 -0400 Received: from mx2.math.uh.edu ([129.7.128.33]:47688 "EHLO mx2.math.uh.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750970AbdGZUTl (ORCPT ); Wed, 26 Jul 2017 16:19:41 -0400 From: Jason L Tibbitts III To: Johannes Thumshirn Cc: Doug Gilbert , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, dvyukov@google.com, hare@suse.com, hch@lst.de, martin.petersen@oracle.com Subject: Re: [REGRESSION] 28676d869bbb (scsi: sg: check for valid direction before starting the request) breaks mtx tape library control References: <20170718073747.GD4875@linux-x5ow.site> <20170719070335.GC4151@linux-x5ow.site> <20170719083654.GE4151@linux-x5ow.site> <20170721164343.GA4086@linux-x5ow.site> <20170725071852.GA3750@linux-x5ow.site> <20170726073934.GC4039@linux-x5ow.site> Date: Wed, 26 Jul 2017 15:19:31 -0500 In-Reply-To: <20170726073934.GC4039@linux-x5ow.site> (Johannes Thumshirn's message of "Wed, 26 Jul 2017 09:39:34 +0200") Message-ID: User-Agent: Gnus/5.130014 (Ma Gnus v0.14) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: -2.9 (--) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1667 Lines: 59 >>>>> "JT" == Johannes Thumshirn writes: JT> It's probably best to just check for dxfer_len <= 2^28 to be valid JT> as Doug suggested: I can verify that patch on top of git head (as of a few hours ago) does function properly. It didn't apply directly on top of 4.12 but even I can handle fixing that up. The result (just deleting the function and changing the call to a check for hp->dxfer_len >= SZ_256M) works fine and is at the end. So thanks. If this goes in, please CC to stable. - J< diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 82c33a6..aa6f1de 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -751,29 +751,6 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf, return count; } -static bool sg_is_valid_dxfer(sg_io_hdr_t *hp) -{ - switch (hp->dxfer_direction) { - case SG_DXFER_NONE: - if (hp->dxferp || hp->dxfer_len > 0) - return false; - return true; - case SG_DXFER_TO_DEV: - case SG_DXFER_FROM_DEV: - case SG_DXFER_TO_FROM_DEV: - if (!hp->dxferp || hp->dxfer_len == 0) - return false; - return true; - case SG_DXFER_UNKNOWN: - if ((!hp->dxferp && hp->dxfer_len) || - (hp->dxferp && hp->dxfer_len == 0)) - return false; - return true; - default: - return false; - } -} - static int sg_common_write(Sg_fd * sfp, Sg_request * srp, unsigned char *cmnd, int timeout, int blocking) @@ -794,7 +771,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, "sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) cmnd[0], (int) hp->cmd_len)); - if (!sg_is_valid_dxfer(hp)) + if (hp->dxfer_len >= SZ_256M) return -EINVAL; k = sg_start_req(srp, cmnd);