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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 77D99C433FF for ; Mon, 29 Jul 2019 19:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46732217D7 for ; Mon, 29 Jul 2019 19:29:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428547; bh=YHh7Ki8cG3PLKbuJicjYSL7b+d/UKNTDJG7wmwaq3HM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZrAPJBg1WfwS21qWQJ00W9DlbmNjwqWOelQFRlgEo1K8b3Ep/bXPsq+G/y/3Ll7tM dibGDl+4O1uFeU5V4jH8FvDd3mjjNY1qPn6WhkgAwC2TZJaw/iAfgOYIY4mOzdgMhx dXYO/K7FWemGYQysO/kqJp4IXYBDsHy41r1SICac= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730066AbfG2T3G (ORCPT ); Mon, 29 Jul 2019 15:29:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:41718 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730048AbfG2T3A (ORCPT ); Mon, 29 Jul 2019 15:29:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 782FD2070B; Mon, 29 Jul 2019 19:28:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428539; bh=YHh7Ki8cG3PLKbuJicjYSL7b+d/UKNTDJG7wmwaq3HM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c6zVSKTvHBdO9GEVnCe7YbG5NlTYxlPEf4xB4WigyHCIYI/oIOva4WyI+uT73HAAb 7WfsH7fyXKYWB9UhjHIUtA0QuFtUIo/WKHX3ETUxiEyG9iFgIra5ERTXYYZgbjZwrz mAvM2yiXmWOILgGmCu2YtZWFd1JxqQCGqV0kRf70= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Denis Efremov , Willy Tarreau , Linus Torvalds , Sasha Levin Subject: [PATCH 4.14 109/293] floppy: fix invalid pointer dereference in drive_name Date: Mon, 29 Jul 2019 21:20:00 +0200 Message-Id: <20190729190832.999899592@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 9b04609b784027968348796a18f601aed9db3789 ] This fixes the invalid pointer dereference in the drive_name function of the floppy driver. The native_format field of the struct floppy_drive_params is used as floppy_type array index in the drive_name function. Thus, the field should be checked the same way as the autodetect field. To trigger the bug, one could use a value out of range and set the drive parameters with the FDSETDRVPRM ioctl. Next, FDGETDRVTYP ioctl should be used to call the drive_name. A floppy disk is not required to be inserted. CAP_SYS_ADMIN is required to call FDSETDRVPRM. The patch adds the check for a value of the native_format field to be in the '0 <= x < ARRAY_SIZE(floppy_type)' range of the floppy_type array indices. The bug was found by syzkaller. Signed-off-by: Denis Efremov Tested-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- drivers/block/floppy.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index a4f630ef2b75..b4051e251041 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3386,7 +3386,8 @@ static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo) return 0; } -static bool valid_floppy_drive_params(const short autodetect[8]) +static bool valid_floppy_drive_params(const short autodetect[8], + int native_format) { size_t floppy_type_size = ARRAY_SIZE(floppy_type); size_t i = 0; @@ -3397,6 +3398,9 @@ static bool valid_floppy_drive_params(const short autodetect[8]) return false; } + if (native_format < 0 || native_format >= floppy_type_size) + return false; + return true; } @@ -3526,7 +3530,8 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode, unsigned int SUPBOUND(size, strlen((const char *)outparam) + 1); break; case FDSETDRVPRM: - if (!valid_floppy_drive_params(inparam.dp.autodetect)) + if (!valid_floppy_drive_params(inparam.dp.autodetect, + inparam.dp.native_format)) return -EINVAL; *UDP = inparam.dp; break; @@ -3725,7 +3730,7 @@ static int compat_setdrvprm(int drive, return -EPERM; if (copy_from_user(&v, arg, sizeof(struct compat_floppy_drive_params))) return -EFAULT; - if (!valid_floppy_drive_params(v.autodetect)) + if (!valid_floppy_drive_params(v.autodetect, v.native_format)) return -EINVAL; mutex_lock(&floppy_mutex); UDP->cmos = v.cmos; -- 2.20.1