From: "Colin Walters" <walters@verbum.org>
To: "Gao Xiang" <hsiangkao@linux.alibaba.com>, linux-erofs@lists.ozlabs.org
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] erofs: fix incorrect symlink detection in fast symlink
Date: Mon, 09 Sep 2024 09:58:16 -0400 [thread overview]
Message-ID: <21ddadb7-407d-48b6-9c1b-845ead2eefb4@app.fastmail.com> (raw)
In-Reply-To: <25f0356d-d949-483c-8e59-ddc9cace61f6@linux.alibaba.com>
On Mon, Sep 9, 2024, at 9:21 AM, Gao Xiang wrote:
>
> It can be bigger.
>
> Like ext4, EROFS supports PAGE_SIZE symlink via page_get_link()
> (non-fastsymlink cases), but mostly consider this as 4KiB though
> regardless of on-disk block sizes.
But symlink targets can't be bigger than PATH_MAX which has always been 4KiB right? (Does Linux support systems with sub-4KiB pages?)
I guess let me ask it a different way: Since we're removing a sanity check here I just want to be sure that the constraints are still handled.
Hmm, skimming through the vfs code from vfs_readlink() I'm not seeing anything constraining the userspace buffer length which seems surprising.
Ah interesting, XFS has
#define XFS_SYMLINK_MAXLEN 1024
and always constrains even its kmalloc invocation to that.
next prev parent reply other threads:[~2024-09-09 13:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-09 2:28 [PATCH] " Gao Xiang
2024-09-09 2:37 ` Gao Xiang
2024-09-09 3:19 ` [PATCH v2] " Gao Xiang
2024-09-09 12:48 ` Colin Walters
2024-09-09 13:21 ` Gao Xiang
2024-09-09 13:58 ` Colin Walters [this message]
2024-09-09 14:14 ` Gao Xiang
2024-09-09 14:46 ` Colin Walters
2024-09-09 15:40 ` Gao Xiang
2024-09-10 0:12 ` Colin Walters
2024-09-10 2:18 ` Gao Xiang
2024-09-10 20:51 ` Colin Walters
2024-09-11 2:27 ` Gao Xiang
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