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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABD9ECCA47C for ; Tue, 7 Jun 2022 14:11:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245187AbiFGOLk (ORCPT ); Tue, 7 Jun 2022 10:11:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245156AbiFGOLf (ORCPT ); Tue, 7 Jun 2022 10:11:35 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id AF869A5029 for ; Tue, 7 Jun 2022 07:11:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654611092; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SoSZK5Fdg2O/rluBKwwyKA4eybAvHOSFBw/HkVVeuhM=; b=E9fC0hBUCBCt1yZLrY1ZPNnTMxUr+F4N3zmE6QLPbpa+60qfjezZxlYD6LRE8GFtGIrvTJ fZ4dBcfK758eaUjDPJv6q+62PZ0JirwQ00Co+HqxszSphXjZa1XEX+KYWuPGQ1Eg5nUv9N YinyO+3Z6a0qalvre+6KF+TJGC0GhAg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-484-e0npgYDeOriiVThidcw_lQ-1; Tue, 07 Jun 2022 10:11:29 -0400 X-MC-Unique: e0npgYDeOriiVThidcw_lQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F30F811E75; Tue, 7 Jun 2022 14:11:29 +0000 (UTC) Received: from fedora (unknown [10.40.193.176]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5B38F404754D; Tue, 7 Jun 2022 14:11:28 +0000 (UTC) Date: Tue, 7 Jun 2022 16:11:26 +0200 From: Lukas Czerner To: Theodore Ts'o Cc: Ext4 Developers List , Nils Bars , Moritz =?utf-8?B?U2NobMO2Z2Vs?= , Nico Schiller Subject: Re: [PATCH 6/7] libext2fs: check for cyclic loops in the extent tree Message-ID: <20220607141126.qnn6o3zkqydxyfpj@fedora> References: <20220607042444.1798015-1-tytso@mit.edu> <20220607042444.1798015-7-tytso@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220607042444.1798015-7-tytso@mit.edu> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Jun 07, 2022 at 12:24:43AM -0400, Theodore Ts'o wrote: > In the extent tree handling code in libext2fs, when we go move down > the extent tree, if a cyclic loop is detected, return an error. Looks good. Reviewed-by: Lukas Czerner > > Reported-by: Nils Bars > Reported-by: Moritz Schlögel > Reported-by: Nico Schiller > Signed-off-by: Theodore Ts'o > --- > lib/ext2fs/ext2_err.et.in | 3 +++ > lib/ext2fs/extent.c | 11 +++++++++-- > 2 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in > index cf0e00ea..bb1dcf14 100644 > --- a/lib/ext2fs/ext2_err.et.in > +++ b/lib/ext2fs/ext2_err.et.in > @@ -551,4 +551,7 @@ ec EXT2_ET_NO_GDESC, > ec EXT2_FILSYS_CORRUPTED, > "The internal ext2_filsys data structure appears to be corrupted" > > +ec EXT2_ET_EXTENT_CYCLE, > + "Found cyclic loop in extent tree" > + > end > diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c > index 1a206a16..82e75ccd 100644 > --- a/lib/ext2fs/extent.c > +++ b/lib/ext2fs/extent.c > @@ -47,6 +47,7 @@ struct extent_path { > int visit_num; > int flags; > blk64_t end_blk; > + blk64_t blk; > void *curr; > }; > > @@ -286,6 +287,7 @@ errcode_t ext2fs_extent_open2(ext2_filsys fs, ext2_ino_t ino, > handle->path[0].end_blk = > (EXT2_I_SIZE(handle->inode) + fs->blocksize - 1) >> > EXT2_BLOCK_SIZE_BITS(fs->super); > + handle->path[0].blk = 0; > handle->path[0].visit_num = 1; > handle->level = 0; > handle->magic = EXT2_ET_MAGIC_EXTENT_HANDLE; > @@ -305,14 +307,14 @@ errout: > errcode_t ext2fs_extent_get(ext2_extent_handle_t handle, > int flags, struct ext2fs_extent *extent) > { > - struct extent_path *path, *newpath; > + struct extent_path *path, *newpath, *tp; > struct ext3_extent_header *eh; > struct ext3_extent_idx *ix = 0; > struct ext3_extent *ex; > errcode_t retval; > blk64_t blk; > blk64_t end_blk; > - int orig_op, op; > + int orig_op, op, l; > int failed_csum = 0; > > EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE); > @@ -467,6 +469,11 @@ retry: > } > blk = ext2fs_le32_to_cpu(ix->ei_leaf) + > ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32); > + for (l = handle->level, tp = path; l > 0; l--, tp--) { > + if (blk == tp->blk) > + return EXT2_ET_EXTENT_CYCLE; > + } > + newpath->blk = blk; > if ((handle->fs->flags & EXT2_FLAG_IMAGE_FILE) && > (handle->fs->io != handle->fs->image_io)) > memset(newpath->buf, 0, handle->fs->blocksize); > -- > 2.31.0 >