From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0DC8225779 for ; Sun, 21 Dec 2025 11:25:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766316360; cv=none; b=rc7ptSSS+6mIq16f7NPOJOk1xHHgN2qOBT9BKJJcihkmCeHSNMgRcH2pgwF/XfOA8PABVV8CRhRYiNeGPyza6uuIjeqa/mGn+nGQ0LRxRLeFv7uJ3BJ4qtXtVx7AZs0FQ9eqHRgV+hJqdcuzxQqp0rZMH62td1DruOJ+jICqQTs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766316360; c=relaxed/simple; bh=Pl3L/iYStqADtYbqQj+rW26cq4qgINpm5Xm7v2pGpvg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IWrJ8BGQEUaMfs30vjX4nEIBZPHc/Sg90aGkoxxac0RcQbo5ZASi0QwSWmIhQIPMD+JxXPOMeEqlXId3agjTBib56p3buxciRstb1OLaPVbfrcu5BlJ6ScCJKmjVddrJQwkLOVdI0za/i6wW+cuLQymdU6/DcW5InY/ghqLtN7Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=HrmfjBvb; arc=none smtp.client-ip=115.124.30.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="HrmfjBvb" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766316349; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=jlnOinxV0hU70dSI+0Hpl0Zst97d6HfeNUIxfGlixA4=; b=HrmfjBvb15CpV9oone8FLISGw9lP92/8vmKRleOgRAuK7gKqmAgBdSnO6QEekHEn64+sOD7ExjPEeph8p6FE5WEv0NdH404eGxDAZAb7uLqcI4ZHBYt5UV71cUQAouC0p3kIyfLTd+T2v2xzIaD7MRyiNllPCRhy90v0Ssb/QRE= Received: from 30.41.143.132(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0WvIhz1V_1766316348 cluster:ay36) by smtp.aliyun-inc.com; Sun, 21 Dec 2025 19:25:48 +0800 Message-ID: <18466382-29d3-4896-8297-bead3baa8c5e@linux.alibaba.com> Date: Sun, 21 Dec 2025 19:25:47 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4] ocfs2: fix oob in __ocfs2_find_path To: Heming Zhao , Edward Adam Davis , akpm Cc: eadavis@qq.org, jlbec@evilplan.org, linux-kernel@vger.kernel.org, mark@fasheh.com, ocfs2-devel@lists.linux.dev, syzkaller-bugs@googlegroups.com References: <2v5rwkwevjoy2i3kwcb6s3zvyutp5zdcwwdnqbgukxn35aeu2z@abmakzczn45z> From: Joseph Qi In-Reply-To: <2v5rwkwevjoy2i3kwcb6s3zvyutp5zdcwwdnqbgukxn35aeu2z@abmakzczn45z> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/12/19 18:07, Heming Zhao wrote: > On Fri, Dec 19, 2025 at 04:31:52PM +0800, Edward Adam Davis wrote: >> syzbot constructed a corrupted image, which resulted in el->l_count >> from the b-tree extent block being 0. Since the length of the l_recs >> array depends on l_count, reading its member e_blkno triggered the >> out-of-bounds access reported by syzbot in [1]. >> >> The loop terminates when l_count is 0, similar to when next_free is 0. >> >> [1] >> UBSAN: array-index-out-of-bounds in fs/ocfs2/alloc.c:1838:11 >> index 0 is out of range for type 'struct ocfs2_extent_rec[] __counted_by(l_count)' (aka 'struct ocfs2_extent_rec[]') >> Call Trace: >> __ocfs2_find_path+0x606/0xa40 fs/ocfs2/alloc.c:1838 >> ocfs2_find_leaf+0xab/0x1c0 fs/ocfs2/alloc.c:1946 >> ocfs2_get_clusters_nocache+0x172/0xc60 fs/ocfs2/extent_map.c:418 >> ocfs2_get_clusters+0x505/0xa70 fs/ocfs2/extent_map.c:631 >> ocfs2_extent_map_get_blocks+0x202/0x6a0 fs/ocfs2/extent_map.c:678 >> ocfs2_read_virt_blocks+0x286/0x930 fs/ocfs2/extent_map.c:1001 >> ocfs2_read_dir_block fs/ocfs2/dir.c:521 [inline] >> ocfs2_find_entry_el fs/ocfs2/dir.c:728 [inline] >> ocfs2_find_entry+0x3e4/0x2090 fs/ocfs2/dir.c:1120 >> ocfs2_find_files_on_disk+0xdf/0x310 fs/ocfs2/dir.c:2023 >> ocfs2_lookup_ino_from_name+0x52/0x100 fs/ocfs2/dir.c:2045 >> _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline] >> ocfs2_get_system_file_inode+0x326/0x770 fs/ocfs2/sysfile.c:112 >> ocfs2_init_global_system_inodes+0x319/0x660 fs/ocfs2/super.c:461 >> ocfs2_initialize_super fs/ocfs2/super.c:2196 [inline] >> ocfs2_fill_super+0x4432/0x65b0 fs/ocfs2/super.c:993 >> get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 >> vfs_get_tree+0x92/0x2a0 fs/super.c:1751 >> fc_mount fs/namespace.c:1199 [inline] >> >> Reported-by: syzbot+151afab124dfbc5f15e6@syzkaller.appspotmail.com >> Closes: https://syzkaller.appspot.com/bug?extid=151afab124dfbc5f15e6 >> Signed-off-by: Edward Adam Davis > > LGTM. > Reviewed-by: Heming Zhao Acked-by: Joseph Qi >> --- >> v3 -> v4: update comments >> v2 -> v3: remove le16 and Fix tag and update comments >> v1 -> v2: check l_count and update comments >> >> fs/ocfs2/alloc.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c >> index 58bf58b68955..b7db177d17d6 100644 >> --- a/fs/ocfs2/alloc.c >> +++ b/fs/ocfs2/alloc.c >> @@ -1812,14 +1812,15 @@ static int __ocfs2_find_path(struct ocfs2_caching_info *ci, >> ret = -EROFS; >> goto out; >> } >> - if (le16_to_cpu(el->l_next_free_rec) == 0) { >> + if (!el->l_next_free_rec || !el->l_count) { >> ocfs2_error(ocfs2_metadata_cache_get_super(ci), >> - "Owner %llu has empty extent list at depth %u\n", >> + "Owner %llu has empty extent list at depth %u\n" >> + "(next free=%u count=%u)\n", >> (unsigned long long)ocfs2_metadata_cache_owner(ci), >> - le16_to_cpu(el->l_tree_depth)); >> + le16_to_cpu(el->l_tree_depth), >> + le16_to_cpu(el->l_next_free_rec), le16_to_cpu(el->l_count)); >> ret = -EROFS; >> goto out; >> - >> } >> >> for(i = 0; i < le16_to_cpu(el->l_next_free_rec) - 1; i++) { >> -- >> 2.43.0 >>