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From: "Andrew Jeffery" <andrew@aj.id.au>
To: "Kees Cook" <keescook@chromium.org>
Cc: linux-arm-kernel@lists.infradead.org,
	"Russell King" <linux@armlinux.org.uk>,
	mhiramat@kernel.org, labbott@redhat.com,
	mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: kprobes: Avoid fortify_panic() when copying optprobe template
Date: Mon, 18 May 2020 10:19:45 +0930	[thread overview]
Message-ID: <8a30fb45-779d-4459-984b-f7792858c92e@www.fastmail.com> (raw)
In-Reply-To: <202005171447.00CFE0C@keescook>



On Mon, 18 May 2020, at 07:18, Kees Cook wrote:
> On Mon, May 18, 2020 at 01:09:59AM +0930, Andrew Jeffery wrote:
> > As mentioned, a couple of attempts have been made to address the issue
> > by casting a pointer to optprobe_template_entry before providing it to
> > memcpy(), however gccs such as Ubuntu 20.04's arm-linux-gnueabi-gcc
> > 9.3.0 (Ubuntu 9.3.0-10ubuntu1) see through these efforts.
> 
> Ah, dang. :P
> 
> How about converting them all to unsized arrays, which would also allow
> the code to drop the "&" everywhere, I think. This is untested:

Looks better than my hack. Took it for a spin under qemu and it works for me.

Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Andrew Jeffery <andrew@aj.id.au>

Thanks Kees!

Andrew

WARNING: multiple messages have this Message-ID (diff)
From: "Andrew Jeffery" <andrew@aj.id.au>
To: "Kees Cook" <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org,
	Russell King <linux@armlinux.org.uk>,
	mathieu.desnoyers@efficios.com, mhiramat@kernel.org,
	labbott@redhat.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: kprobes: Avoid fortify_panic() when copying optprobe template
Date: Mon, 18 May 2020 10:19:45 +0930	[thread overview]
Message-ID: <8a30fb45-779d-4459-984b-f7792858c92e@www.fastmail.com> (raw)
In-Reply-To: <202005171447.00CFE0C@keescook>



On Mon, 18 May 2020, at 07:18, Kees Cook wrote:
> On Mon, May 18, 2020 at 01:09:59AM +0930, Andrew Jeffery wrote:
> > As mentioned, a couple of attempts have been made to address the issue
> > by casting a pointer to optprobe_template_entry before providing it to
> > memcpy(), however gccs such as Ubuntu 20.04's arm-linux-gnueabi-gcc
> > 9.3.0 (Ubuntu 9.3.0-10ubuntu1) see through these efforts.
> 
> Ah, dang. :P
> 
> How about converting them all to unsized arrays, which would also allow
> the code to drop the "&" everywhere, I think. This is untested:

Looks better than my hack. Took it for a spin under qemu and it works for me.

Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Andrew Jeffery <andrew@aj.id.au>

Thanks Kees!

Andrew

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  reply	other threads:[~2020-05-18  0:50 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-17 15:39 [PATCH] ARM: kprobes: Avoid fortify_panic() when copying optprobe template Andrew Jeffery
2020-05-17 15:39 ` Andrew Jeffery
2020-05-17 16:02 ` Russell King - ARM Linux admin
2020-05-17 16:02   ` Russell King - ARM Linux admin
2020-05-18  8:10   ` Andrew Jeffery
2020-05-18  8:10     ` Andrew Jeffery
2020-05-17 21:48 ` Kees Cook
2020-05-17 21:48   ` Kees Cook
2020-05-18  0:49   ` Andrew Jeffery [this message]
2020-05-18  0:49     ` Andrew Jeffery
2020-05-18  2:20   ` Masami Hiramatsu
2020-05-18  2:20     ` Masami Hiramatsu
2020-05-19  0:22     ` Andrew Jeffery
2020-05-19  0:22       ` Andrew Jeffery

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