From: Andrew Morton <akpm@linux-foundation.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: linux-kernel@vger.kernel.org, stable@kernel.org,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH] CPU online file permission
Date: Mon, 30 Jul 2007 16:57:20 -0700 [thread overview]
Message-ID: <20070730165720.37780cc6.akpm@linux-foundation.org> (raw)
In-Reply-To: <200707300056.l6U0ukUe021931@devserv.devel.redhat.com>
On Sun, 29 Jul 2007 20:56:46 -0400
Ulrich Drepper <drepper@redhat.com> wrote:
> Is there a reason why the "online" file in the subdirectories for the CPUs
> in /sys/devices/system isn't world-readable?
No sane one which I can think of. It seems that it originally sprang forth
from Rusty's keyboard in that form.
> I cannot imagine it to be
> security relevant especially now that a getcpu() syscall can be used to
> determine what CPUa thread runs on.
>
> The file is useful to correctly implement the sysconf() function to return
> the number of online CPUs. In the presence of hotplug we currently cannot
> provide this information. The patch below should to it.
>
>
> Signed-off-by: Ulrich Drepper <drepper@redhat.com>
>
> --- drivers/base/cpu.c 2007-02-20 12:01:31.000000000 -0800
> +++ drivers/base/cpu.c-new 2007-07-29 17:52:58.000000000 -0700
> @@ -53,7 +53,7 @@
> ret = count;
> return ret;
> }
> -static SYSDEV_ATTR(online, 0600, show_online, store_online);
> +static SYSDEV_ATTR(online, 0644, show_online, store_online);
>
> static void __devinit register_cpu_control(struct cpu *cpu)
> {
I'll pass this by the -stable guys too - I assume we'd like it fixed in
2.6.22 (or earlier) as well..
next prev parent reply other threads:[~2007-07-30 23:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-30 0:56 [PATCH] CPU online file permission Ulrich Drepper
2007-07-30 23:57 ` Andrew Morton [this message]
2007-07-31 7:38 ` Rusty Russell
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