Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 063BBC433F5 for ; Tue, 16 Nov 2021 02:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D940760E0C for ; Tue, 16 Nov 2021 02:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349576AbhKPCW0 (ORCPT ); Mon, 15 Nov 2021 21:22:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:52662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238457AbhKORiS (ORCPT ); Mon, 15 Nov 2021 12:38:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 414496322D; Mon, 15 Nov 2021 17:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636997153; bh=7SncVSBCItQeD44StCjNdZhJa3WwhhsJupE2RG51Lvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dR7S1WNa3CMzXrDOIqsugufR83BqG6dwhWOzVSpxkK1bwve4t7ob8youx0ACGPDIk xXcmiLhr7evyNkxWv6sElhmPeteNS+DQFt2vLcD8vdhwQJxoASC0PdV41DR+Bv/y3E HCxYHCyO5JnN+Zc8vg4IBlBEHlZKeEIJm+yNSWcg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bart Van Assche , Christoph Hellwig , "James E.J. Bottomley" , "Martin K. Petersen" , linux-scsi@vger.kernel.org, syzbot+5516b30f5401d4dcbcae@syzkaller.appspotmail.com, Tadeusz Struk Subject: [PATCH 5.10 011/575] scsi: core: Remove command size deduction from scsi_setup_scsi_cmnd() Date: Mon, 15 Nov 2021 17:55:36 +0100 Message-Id: <20211115165343.996963128@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165343.579890274@linuxfoundation.org> References: <20211115165343.579890274@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tadeusz Struk commit 703535e6ae1e94c89a9c1396b4c7b6b41160ef0c upstream. No need to deduce command size in scsi_setup_scsi_cmnd() anymore as appropriate checks have been added to scsi_fill_sghdr_rq() function and the cmd_len should never be zero here. The code to do that wasn't correct anyway, as it used uninitialized cmd->cmnd, which caused a null-ptr-deref if the command size was zero as in the trace below. Fix this by removing the unneeded code. KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 1822 Comm: repro Not tainted 5.15.0 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014 Call Trace: blk_mq_dispatch_rq_list+0x7c7/0x12d0 __blk_mq_sched_dispatch_requests+0x244/0x380 blk_mq_sched_dispatch_requests+0xf0/0x160 __blk_mq_run_hw_queue+0xe8/0x160 __blk_mq_delay_run_hw_queue+0x252/0x5d0 blk_mq_run_hw_queue+0x1dd/0x3b0 blk_mq_sched_insert_request+0x1ff/0x3e0 blk_execute_rq_nowait+0x173/0x1e0 blk_execute_rq+0x15c/0x540 sg_io+0x97c/0x1370 scsi_ioctl+0xe16/0x28e0 sd_ioctl+0x134/0x170 blkdev_ioctl+0x362/0x6e0 block_ioctl+0xb0/0xf0 vfs_ioctl+0xa7/0xf0 do_syscall_64+0x3d/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae ---[ end trace 8b086e334adef6d2 ]--- Kernel panic - not syncing: Fatal exception Link: https://lore.kernel.org/r/20211103170659.22151-2-tadeusz.struk@linaro.org Fixes: 2ceda20f0a99 ("scsi: core: Move command size detection out of the fast path") Cc: Bart Van Assche Cc: Christoph Hellwig Cc: James E.J. Bottomley Cc: Martin K. Petersen Cc: Cc: Cc: # 5.15, 5.14, 5.10 Reported-by: syzbot+5516b30f5401d4dcbcae@syzkaller.appspotmail.com Reviewed-by: Bart Van Assche Reviewed-by: Christoph Hellwig Signed-off-by: Tadeusz Struk Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/scsi_lib.c | 2 -- 1 file changed, 2 deletions(-) --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1193,8 +1193,6 @@ static blk_status_t scsi_setup_scsi_cmnd } cmd->cmd_len = scsi_req(req)->cmd_len; - if (cmd->cmd_len == 0) - cmd->cmd_len = scsi_command_size(cmd->cmnd); cmd->cmnd = scsi_req(req)->cmd; cmd->transfersize = blk_rq_bytes(req); cmd->allowed = scsi_req(req)->retries;