From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3A11C47404 for ; Sat, 12 Oct 2019 03:18:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B352221835 for ; Sat, 12 Oct 2019 03:18:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727072AbfJLDSH (ORCPT ); Fri, 11 Oct 2019 23:18:07 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:54768 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727014AbfJLDSH (ORCPT ); Fri, 11 Oct 2019 23:18:07 -0400 Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 134F739EEE64CA84714C; Sat, 12 Oct 2019 11:18:05 +0800 (CST) Received: from huawei.com (10.90.53.225) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.439.0; Sat, 12 Oct 2019 11:17:55 +0800 From: zhengbin To: , , , CC: , Subject: [PATCH v3] scsi: core: fix uninit-value access of variable sshdr Date: Sat, 12 Oct 2019 11:25:06 +0800 Message-ID: <1570850706-12063-1-git-send-email-zhengbin13@huawei.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.90.53.225] X-CFilter-Loop: Reflected Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org kmsan report a warning in 5.1-rc4: BUG: KMSAN: uninit-value in sr_get_events drivers/scsi/sr.c:207 [inline] BUG: KMSAN: uninit-value in sr_check_events+0x2cf/0x1090 drivers/scsi/sr.c:243 CPU: 1 PID: 13858 Comm: syz-executor.0 Tainted: G B 5.1.0-rc4+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x131/0x2a0 mm/kmsan/kmsan.c:619 __msan_warning+0x7a/0xf0 mm/kmsan/kmsan_instr.c:310 sr_get_events drivers/scsi/sr.c:207 [inline] sr_check_events+0x2cf/0x1090 drivers/scsi/sr.c:243 The reason is as follows: sr_get_events struct scsi_sense_hdr sshdr; -->uninit scsi_execute_req -->If fail, will not set sshdr scsi_sense_valid(&sshdr) -->access sshdr We can init sshdr in sr_get_events, but there have many callers of scsi_execute, scsi_execute_req, we have to troubleshoot all callers, the simpler way is init sshdr in __scsi_execute. BTW: sr_do_ioctl should check whether sshdr is valid, fix this Signed-off-by: zhengbin --- v1->v2: modify the comments suggested by Bart v2->v3: fix bug in sr_do_ioctl drivers/scsi/scsi_lib.c | 7 +++++++ drivers/scsi/sr_ioctl.c | 5 +++++ 2 files changed, 12 insertions(+) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 5447738..d5e29c5 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -255,6 +255,13 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, struct scsi_request *rq; int ret = DRIVER_ERROR << 24; + /* + * Zero-initialize sshdr for those callers that check the *sshdr + * contents even if no sense data is available. + */ + if (sshdr) + memset(sshdr, 0, sizeof(struct scsi_sense_hdr)); + req = blk_get_request(sdev->request_queue, data_direction == DMA_TO_DEVICE ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT); diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c index ffcf902..335cfdd 100644 --- a/drivers/scsi/sr_ioctl.c +++ b/drivers/scsi/sr_ioctl.c @@ -206,6 +206,11 @@ int sr_do_ioctl(Scsi_CD *cd, struct packet_command *cgc) /* Minimal error checking. Ignore cases we know about, and report the rest. */ if (driver_byte(result) != 0) { + if (!scsi_sense_valid(sshdr)) { + err = -EIO; + goto out; + } + switch (sshdr->sense_key) { case UNIT_ATTENTION: SDev->changed = 1; -- 2.7.4