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=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 8787FC433E4 for ; Mon, 17 Aug 2020 18:42:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B0C720578 for ; Mon, 17 Aug 2020 18:42:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597689749; bh=tu5BHVgGfCYGAiaqVkbBFErksR4pdIG1CSJuZ8WnQyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KuQ1PtO6s5MgalcnRPbqDTKza9vqBN81VwlgDWgJrA6uaMbwlVFFt0la5xE+jYBRy 6m08Ixb163BJf/YZhC4V7ikC8lthkZQ3HhvIHoYZRpKc73m3QLnZEz9w/R++ANspke edSIVsyQy9LmCliPVGZDuhN9yPN2bmk4whTss8vw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731667AbgHQSmQ (ORCPT ); Mon, 17 Aug 2020 14:42:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:43538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387519AbgHQP5Q (ORCPT ); Mon, 17 Aug 2020 11:57:16 -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 A149120729; Mon, 17 Aug 2020 15:57:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597679835; bh=tu5BHVgGfCYGAiaqVkbBFErksR4pdIG1CSJuZ8WnQyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mySpNKUzApYfNDfaJ0f8FtJAR3hY8XSYzRhtBG35PaHESB7u9H4XHS8ADYmt6RwKY OGIcYqBkNzEqh/rClkgbm8BdRCWtPP38u8fLHVe9rH+bbUl38boR4T+LamJITSW/dD YjUhnpq7od/zCIqr5MWAh59RVRDGMGuhLnxyuD0A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+c7d9ec7a1a7272dd71b3@syzkaller.appspotmail.com, syzbot+3b7b03a0c28948054fb5@syzkaller.appspotmail.com, syzbot+6e056ee473568865f3e6@syzkaller.appspotmail.com, Eric Biggers , Andrew Morton , Alexander Viro , Qiujun Huang , Linus Torvalds Subject: [PATCH 5.7 349/393] fs/minix: reject too-large maximum file size Date: Mon, 17 Aug 2020 17:16:39 +0200 Message-Id: <20200817143836.530703027@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143819.579311991@linuxfoundation.org> References: <20200817143819.579311991@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Biggers commit 270ef41094e9fa95273f288d7d785313ceab2ff3 upstream. If the minix filesystem tries to map a very large logical block number to its on-disk location, block_to_path() can return offsets that are too large, causing out-of-bounds memory accesses when accessing indirect index blocks. This should be prevented by the check against the maximum file size, but this doesn't work because the maximum file size is read directly from the on-disk superblock and isn't validated itself. Fix this by validating the maximum file size at mount time. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+c7d9ec7a1a7272dd71b3@syzkaller.appspotmail.com Reported-by: syzbot+3b7b03a0c28948054fb5@syzkaller.appspotmail.com Reported-by: syzbot+6e056ee473568865f3e6@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Qiujun Huang Cc: Link: http://lkml.kernel.org/r/20200628060846.682158-4-ebiggers@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/minix/inode.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) --- a/fs/minix/inode.c +++ b/fs/minix/inode.c @@ -150,6 +150,23 @@ static int minix_remount (struct super_b return 0; } +static bool minix_check_superblock(struct minix_sb_info *sbi) +{ + if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0) + return false; + + /* + * s_max_size must not exceed the block mapping limitation. This check + * is only needed for V1 filesystems, since V2/V3 support an extra level + * of indirect blocks which places the limit well above U32_MAX. + */ + if (sbi->s_version == MINIX_V1 && + sbi->s_max_size > (7 + 512 + 512*512) * BLOCK_SIZE) + return false; + + return true; +} + static int minix_fill_super(struct super_block *s, void *data, int silent) { struct buffer_head *bh; @@ -228,11 +245,12 @@ static int minix_fill_super(struct super } else goto out_no_fs; + if (!minix_check_superblock(sbi)) + goto out_illegal_sb; + /* * Allocate the buffer map to keep the superblock small. */ - if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0) - goto out_illegal_sb; i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh); map = kzalloc(i, GFP_KERNEL); if (!map)