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 B4839C433DF for ; Mon, 17 Aug 2020 17:54:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8791E2063A for ; Mon, 17 Aug 2020 17:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597686895; bh=tu5BHVgGfCYGAiaqVkbBFErksR4pdIG1CSJuZ8WnQyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BjDjN02ZZMLm3/7nP0R6w6FgByKA1R043Q3JfWSUlmyujUWUaZR+lOQ0vsI5C6y+d GUrw6C511R+NKVrrCH0IrrOA9VHh7tHpw5CvIT+vM7dcb+ps9D5nnzBLw49yRzWZYm MkI2ALZD37pCZ00Q7uJajnNcxpN5+p8c95XBuGN4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731710AbgHQRyx (ORCPT ); Mon, 17 Aug 2020 13:54:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:38394 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388582AbgHQQLA (ORCPT ); Mon, 17 Aug 2020 12:11:00 -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 03C9520578; Mon, 17 Aug 2020 16:10:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597680659; bh=tu5BHVgGfCYGAiaqVkbBFErksR4pdIG1CSJuZ8WnQyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sBvOYRb5WXgXynZujJM2nV0LK71Z51BAJa8qlFUekRbGG/6XcKsiAPK8+StmuhSH3 m53ECa26UQmAyJ2HitqjqSkgSvSv1Mi1WO96tPoV1uvCUOm0ZDLeT4uR4u/S9G/T5r yRstnDB1jNBeYMhkz2i1AxaOfonGYoGmDGQOIoaY= 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 5.4 264/270] fs/minix: reject too-large maximum file size Date: Mon, 17 Aug 2020 17:17:45 +0200 Message-Id: <20200817143808.966403367@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143755.807583758@linuxfoundation.org> References: <20200817143755.807583758@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 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)