From: JP Kobryn <inwardvessel@gmail.com>
To: Dominique Martinet <asmadeus@codewreck.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Christian Schoenebeck <linux_oss@crudebyte.com>,
ericvh@kernel.org, lucho@ionkov.net, mhiramat@kernel.org,
mathieu.desnoyers@efficios.com, v9fs@lists.linux.dev,
linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH] 9p: prevent read overrun in protocol dump tracepoint
Date: Mon, 4 Dec 2023 08:20:37 -0800 [thread overview]
Message-ID: <ZW38VTs2L4vbcJLO@localhost.localdomain> (raw)
In-Reply-To: <ZWwS3_DGmqc73dxm@codewreck.org>
On Sun, Dec 03, 2023 at 02:32:15PM +0900, Dominique Martinet wrote:
> Steven Rostedt wrote on Sat, Dec 02, 2023 at 11:15:24PM -0500:
> > > Also, for custom tracepoints e.g. bpftrace the program needs to know how
> > > many bytes can be read safely even if it's just for dumping -- unless
> > > dynamic_array is a "fat pointer" that conveys its own size?
> > > (Sorry didn't take the time to check)
> >
> > Yes, there's also a __get_dynamic_array_len(line) that will return the
> > allocated length of the line. Is that what you need?
>
> Yes, thanks! So the lower two bytes of the field are its position in
> the entry and the higher two bytes its size; ok.
> It doesn't look like bpftrace has any helper for it but that can
> probably be sorted out if someone wants to dump data there.
>
>
> Let's update the event to use a dynamic array and have printk fomrat to
> use %*ph with that length.
>
> JP Kobryn, does that sound good to you? I'm not sure what you were
> trying to do in the first place.
> Do you want to send a v2 or shall I?
Sounds good. I'll send out a v2. Thanks Steve for recommending the
dynamic array macros.
JP
>
> --
> Dominique Martinet | Asmadeus
prev parent reply other threads:[~2023-12-04 16:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-02 3:04 [PATCH] 9p: prevent read overrun in protocol dump tracepoint JP Kobryn
2023-12-02 4:35 ` asmadeus
2023-12-02 7:19 ` asmadeus
2023-12-02 13:05 ` Christian Schoenebeck
2023-12-03 1:14 ` Steven Rostedt
2023-12-03 1:33 ` Dominique Martinet
2023-12-03 4:15 ` Steven Rostedt
2023-12-03 5:32 ` Dominique Martinet
2023-12-04 16:20 ` JP Kobryn [this message]
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