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=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 0D6A4C76186 for ; Wed, 24 Jul 2019 19:34:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8F1E229FA for ; Wed, 24 Jul 2019 19:34:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563996891; bh=SYxnJyk4RjHZkdvp/bc8OP9PAli/rQDxIMRvvTDJe2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TAO11SGqr/I/rcfu1rpHEbK4XqHYcq42R0LihLNtTnFGSB7qBkRkfe7yXSqeDYM7L 69g6//YZyKW3xWqMfmSp7R+5XKaquR2JK14TJuiK+L7DyjKR9/T63AZKGtWGneUocK 88waabKcGBMNjKN15VZkACsPFSq6j8+56+9Bokq8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389127AbfGXTet (ORCPT ); Wed, 24 Jul 2019 15:34:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:57484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389115AbfGXTes (ORCPT ); Wed, 24 Jul 2019 15:34:48 -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 2310C2238C; Wed, 24 Jul 2019 19:34:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563996887; bh=SYxnJyk4RjHZkdvp/bc8OP9PAli/rQDxIMRvvTDJe2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1GNwiMa3mSFf3f3FAvb5kJlylOEqa/ccbzFZAnarxern3wwCJwZks8RHZ72SD/qNd SEEdHBBlEgH46A92ZaNb4QZCrysaZ+JoKZzlXjkYPdjafgBHGTPAo2DobJqyXdET9o O4zr53dwz5rBN36TvTO8HtCwlRxYpBnK6xbInLRA= 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 5.2 249/413] floppy: fix out-of-bounds read in next_valid_format Date: Wed, 24 Jul 2019 21:19:00 +0200 Message-Id: <20190724191753.446996167@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191735.096702571@linuxfoundation.org> References: <20190724191735.096702571@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 5635f897ed83fd539df78e98ba69ee91592f9bb8 ] This fixes a global out-of-bounds read access in the next_valid_format function of the floppy driver. The values from autodetect field of the struct floppy_drive_params are used as indices for the floppy_type array in the next_valid_format function 'floppy_type[DP->autodetect[probed_format]].sect'. To trigger the bug, one could use a value out of range and set the drive parameters with the FDSETDRVPRM ioctl. A floppy disk is not required to be inserted. CAP_SYS_ADMIN is required to call FDSETDRVPRM. The patch adds the check for values of the autodetect 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 | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 51246bc9709a..b70d6e103a57 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3380,6 +3380,20 @@ static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo) return 0; } +static bool valid_floppy_drive_params(const short autodetect[8]) +{ + size_t floppy_type_size = ARRAY_SIZE(floppy_type); + size_t i = 0; + + for (i = 0; i < 8; ++i) { + if (autodetect[i] < 0 || + autodetect[i] >= floppy_type_size) + return false; + } + + return true; +} + static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long param) { @@ -3506,6 +3520,8 @@ 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)) + return -EINVAL; *UDP = inparam.dp; break; case FDGETDRVPRM: @@ -3703,6 +3719,8 @@ 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)) + return -EINVAL; mutex_lock(&floppy_mutex); UDP->cmos = v.cmos; UDP->max_dtr = v.max_dtr; -- 2.20.1