Re: process '/usr/bin/rsync' started with executable stack

From: Kees Cook <keescook@chromium.org>
To: Christian Kujau <lists@nerdbynature.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Willy Tarreau <w@1wt.eu>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: Re: process '/usr/bin/rsync' started with executable stack
Date: Tue, 23 Jun 2020 11:32:44 -0700	[thread overview]
Message-ID: <202006231131.AD0A7F5F@keescook> (raw)
In-Reply-To: <alpine.DEB.2.22.1.446.2006231023390.3892@trent.utfs.org>

On Tue, Jun 23, 2020 at 10:39:26AM -0700, Christian Kujau wrote:
> Hi,
> 
> exactly this[0] happened today, on a 5.6.5 kernel:
> 
>   process '/usr/bin/rsync' started with executable stack
> 
> But I can't reproduce this message, and rsync (v3.2.0, not exactly 
> abandonware) runs several times a day, so to repeat Andrew's questions[0] 
> from last year:
> 
>   > What are poor users supposed to do if this message comes out? 
>   > Hopefully google the message and end up at this thread.  What do you
>   > want to tell them?
> 
> Also, the PID is missing from that message. I had some long running rsync 
> processes running earlier, maybe the RWE status would have been visible in 
> /proc/$PID/map, or somewhere else maybe?
> 
> Please advise? :-)
> 
> Thanks,
> Christian.
> 
> [0] https://lore.kernel.org/patchwork/patch/1164047/#1362722
> 
> 
> $ checksec --format=json --extended --file=`which rsync` | jq
> {
>   "/usr/bin/rsync": {
>     "relro": "full",
>     "canary": "yes",
>     "nx": "no",
^^^^^^^^^^^^^^^^^^

It is, indeed, marked executable, it seems. What distro is this?

-Kees

>     "pie": "yes",
>     "clangcfi": "no",
>     "safestack": "no",
>     "rpath": "no",
>     "runpath": "no",
>     "symbols": "no",
>     "fortify_source": "yes",
>     "fortified": "10",
>     "fortify-able": "19"
>   }
> }
> 
> -- 
> BOFH excuse #244:
> 
> Your cat tried to eat the mouse.

-- 
Kees Cook