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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 3E8DEC433E0 for ; Thu, 4 Jun 2020 23:50:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F3278206DC for ; Thu, 4 Jun 2020 23:50:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="zmIpj3BM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3278206DC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9E0E328005B; Thu, 4 Jun 2020 19:50:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 943D1280005; Thu, 4 Jun 2020 19:50:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BF0528005B; Thu, 4 Jun 2020 19:50:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0068.hostedemail.com [216.40.44.68]) by kanga.kvack.org (Postfix) with ESMTP id 5F65F280005 for ; Thu, 4 Jun 2020 19:50:58 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 2D2FC376F for ; Thu, 4 Jun 2020 23:50:58 +0000 (UTC) X-FDA: 76893177396.25.fork09_5d0f14726d9b Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 0E8D31804E3A1 for ; Thu, 4 Jun 2020 23:50:58 +0000 (UTC) X-HE-Tag: fork09_5d0f14726d9b X-Filterd-Recvd-Size: 2426 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf16.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Jun 2020 23:50:57 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 BFA44208B8; Thu, 4 Jun 2020 23:50:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591314657; bh=u8xP0OKnchFttDQ67ScPkf5fFPYI87jxkZOC6iHME2E=; h=Date:From:To:Subject:In-Reply-To:From; b=zmIpj3BMBy7cdj4kqi/Rmnt64+ulDAw8l4qMAdGkVkLRx0VkiEFDL0fi/c4qgwNyY O4PTgbl48Rwtuz0WmzHxnw/F5mqbXDbxDqtuexCQs1aD69Jh/0qwpKLB8mnDOxYMnS xixGd/1IPeBBEQ4TzR1UlBSeryb5c/0dMunGssEs= Date: Thu, 04 Jun 2020 16:50:56 -0700 From: Andrew Morton To: akpm@linux-foundation.org, dvyukov@google.com, elver@google.com, hirofumi@mail.parknet.co.jp, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 090/127] fat: don't allow to mount if the FAT length == 0 Message-ID: <20200604235056.ras4DFMTz%akpm@linux-foundation.org> In-Reply-To: <20200604164523.e15f3177f4b69dcb4f2534a1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 0E8D31804E3A1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: OGAWA Hirofumi Subject: fat: don't allow to mount if the FAT length == 0 If FAT length == 0, the image doesn't have any data. And it can be the cause of overlapping the root dir and FAT entries. Also Windows treats it as invalid format. Link: http://lkml.kernel.org/r/87r1wz8mrd.fsf@mail.parknet.co.jp Reported-by: syzbot+6f1624f937d9d6911e2d@syzkaller.appspotmail.com Signed-off-by: OGAWA Hirofumi Cc: Marco Elver Cc: Dmitry Vyukov Signed-off-by: Andrew Morton --- fs/fat/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/fat/inode.c~fat-dont-allow-to-mount-if-the-fat-length-==-0 +++ a/fs/fat/inode.c @@ -1519,6 +1519,12 @@ static int fat_read_bpb(struct super_blo goto out; } + if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) { + if (!silent) + fat_msg(sb, KERN_ERR, "bogus number of FAT sectors"); + goto out; + } + error = 0; out: _