From patchwork Thu Jan 2 22:07:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 234611 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=-6.8 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,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 71BA4C3276C for ; Thu, 2 Jan 2020 22:46:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43F4E222C3 for ; Thu, 2 Jan 2020 22:46:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578005180; bh=Z4v0fY047Fr8jxw/FMskSquTJGFpuTPUuJw95HPMS2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UBmfTHkggqXhtsSVsnHkhqEf1+LTZVXRYQ9UWoSV0weDcZNufgx2p24hm2qLms7At BcYAa61f6sUpdj/ijgbXDpT2YsEPeNKcojqgo8Y55jEFT5Dk2hBmKaBThezyqVMvRG SkGirFLIyPh8pJAaQf3XLkyjv7BwYSm6PAqINI9E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730235AbgABWbE (ORCPT ); Thu, 2 Jan 2020 17:31:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:35730 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729815AbgABWbD (ORCPT ); Thu, 2 Jan 2020 17:31:03 -0500 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 7D58A20863; Thu, 2 Jan 2020 22:31:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004263; bh=Z4v0fY047Fr8jxw/FMskSquTJGFpuTPUuJw95HPMS2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KfPaEhiFE1PNzFwUdlmsZh53i1jI00krf50a5zdtAP3H7XAP1rGpaaFG/tZW8Xhnc Ei/4UKcFpwwLeCWi28hTleyO7wa0YT3cQiEK2RK1JJ1owm+9JjmEGH8+QVFi0L8eij L2m3r2ImjY4mqhzJcR5QojEa7c1xnlRqFxblO93A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Theodore Tso Subject: [PATCH 4.9 106/171] ext4: fix ext4_empty_dir() for directories with holes Date: Thu, 2 Jan 2020 23:07:17 +0100 Message-Id: <20200102220601.890579715@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220546.960200039@linuxfoundation.org> References: <20200102220546.960200039@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kara commit 64d4ce892383b2ad6d782e080d25502f91bf2a38 upstream. Function ext4_empty_dir() doesn't correctly handle directories with holes and crashes on bh->b_data dereference when bh is NULL. Reorganize the loop to use 'offset' variable all the times instead of comparing pointers to current direntry with bh->b_data pointer. Also add more strict checking of '.' and '..' directory entries to avoid entering loop in possibly invalid state on corrupted filesystems. CC: stable@vger.kernel.org Fixes: 4e19d6b65fb4 ("ext4: allow directory holes") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20191202170213.4761-2-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2721,7 +2721,7 @@ bool ext4_empty_dir(struct inode *inode) { unsigned int offset; struct buffer_head *bh; - struct ext4_dir_entry_2 *de, *de1; + struct ext4_dir_entry_2 *de; struct super_block *sb; if (ext4_has_inline_data(inode)) { @@ -2746,19 +2746,25 @@ bool ext4_empty_dir(struct inode *inode) return true; de = (struct ext4_dir_entry_2 *) bh->b_data; - de1 = ext4_next_entry(de, sb->s_blocksize); - if (le32_to_cpu(de->inode) != inode->i_ino || - le32_to_cpu(de1->inode) == 0 || - strcmp(".", de->name) || strcmp("..", de1->name)) { - ext4_warning_inode(inode, "directory missing '.' and/or '..'"); + if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size, + 0) || + le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) { + ext4_warning_inode(inode, "directory missing '.'"); brelse(bh); return true; } - offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) + - ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize); - de = ext4_next_entry(de1, sb->s_blocksize); + offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize); + de = ext4_next_entry(de, sb->s_blocksize); + if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size, + offset) || + le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) { + ext4_warning_inode(inode, "directory missing '..'"); + brelse(bh); + return true; + } + offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize); while (offset < inode->i_size) { - if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) { + if (!(offset & (sb->s_blocksize - 1))) { unsigned int lblock; brelse(bh); lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb); @@ -2769,12 +2775,11 @@ bool ext4_empty_dir(struct inode *inode) } if (IS_ERR(bh)) return true; - de = (struct ext4_dir_entry_2 *) bh->b_data; } + de = (struct ext4_dir_entry_2 *) (bh->b_data + + (offset & (sb->s_blocksize - 1))); if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size, offset)) { - de = (struct ext4_dir_entry_2 *)(bh->b_data + - sb->s_blocksize); offset = (offset | (sb->s_blocksize - 1)) + 1; continue; } @@ -2783,7 +2788,6 @@ bool ext4_empty_dir(struct inode *inode) return false; } offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize); - de = ext4_next_entry(de, sb->s_blocksize); } brelse(bh); return true;