From: Dominique Martinet <asmadeus@codewreck.org>
To: Hui Peng <benquike@gmail.com>
Cc: ericvh@kernel.org, lucho@ionkov.net, linux_oss@crudebyte.com,
v9fs@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 9p: reject RERROR/RLERROR with zero errcode and guard 0-link drop_nlink()
Date: Tue, 22 Sep 2026 17:47:37 +0900 [thread overview]
Message-ID: <arJAqVPrm1XfL1w-@codewreck.org> (raw)
In-Reply-To: <20260919221734.3708000-1-benquike@gmail.com>
Hui Peng wrote on Sat, Sep 19, 2026 at 10:17:34PM +0000:
> Fix two issues in 9p client and VFS inode handling:
Please split this in two commits.
> 1. In p9_check_errors() (net/9p/client.c), a malicious or buggy 9p
> server returning P9_RERROR or P9_RLERROR with ecode == 0 causes
> p9_check_errors() to return 0 (success) while leaving the unparsed
> response payload as if the expected reply message type succeeded. Map
> ecode == 0 on RERROR / RLERROR to -EPROTO.
Sure
> 2. In v9fs_dec_count() (fs/9p/vfs_inode.c), only call drop_nlink() when
> inode->i_nlink > 0 so unlinking an inode whose server-reported nlink
> was already 0 does not underflow i_nlink and trigger
> WARN_ON(inode->i_nlink == 0).
I'm pretty sure this is racy but the dir case already is anyway, so meh,
why not, ok.
--
Dominique Martinet | Asmadeus
prev parent reply other threads:[~2026-09-22 8:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-19 22:17 Hui Peng
2026-09-22 8:47 ` Dominique Martinet [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=arJAqVPrm1XfL1w-@codewreck.org \
--to=asmadeus@codewreck.org \
--cc=benquike@gmail.com \
--cc=ericvh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux_oss@crudebyte.com \
--cc=lucho@ionkov.net \
--cc=v9fs@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®