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From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Linus Torvalds
	<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Konstantin Khlebnikov
	<khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
	Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Linux Kernel Mailing List
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Roman Gushchin <klamm-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
	Nikita Vetoshkin
	<nekto0n-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
	Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Subject: Re: [PATCH 2/2] kernel/fork: handle put_user errors for CLONE_PARENT_SETTID
Date: Fri, 6 Feb 2015 22:07:38 +0100	[thread overview]
Message-ID: <20150206210738.GA18332@redhat.com> (raw)
In-Reply-To: <CA+55aFxBuf-0UkoYCrwH_vNsWFnUkFOz5c9O_Mswe_w0BTkqbQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

I am not sure about these changes too, but

On 02/06, Linus Torvalds wrote:
>
> What's the upside? If somebody passes in a bad pointer, it's their
> problem.

Yes. But unless I am totally confused (quite possible) this put_user()
can fail even if the pointer is valid.

So at least I think Konstantin has found a real problem. Which (I think)
shoud be fixed, and this is not connected to fork.

> insane with the whole "readable vs writable" thing.

Agreed, this part doesn't look nice in any case.

Oleg.

WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
	Linux API <linux-api@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Roman Gushchin <klamm@yandex-team.ru>,
	Nikita Vetoshkin <nekto0n@yandex-team.ru>,
	Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [PATCH 2/2] kernel/fork: handle put_user errors for CLONE_PARENT_SETTID
Date: Fri, 6 Feb 2015 22:07:38 +0100	[thread overview]
Message-ID: <20150206210738.GA18332@redhat.com> (raw)
In-Reply-To: <CA+55aFxBuf-0UkoYCrwH_vNsWFnUkFOz5c9O_Mswe_w0BTkqbQ@mail.gmail.com>

I am not sure about these changes too, but

On 02/06, Linus Torvalds wrote:
>
> What's the upside? If somebody passes in a bad pointer, it's their
> problem.

Yes. But unless I am totally confused (quite possible) this put_user()
can fail even if the pointer is valid.

So at least I think Konstantin has found a real problem. Which (I think)
shoud be fixed, and this is not connected to fork.

> insane with the whole "readable vs writable" thing.

Agreed, this part doesn't look nice in any case.

Oleg.


  parent reply	other threads:[~2015-02-06 21:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-06 16:23 [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID Konstantin Khlebnikov
2015-02-06 16:23 ` [PATCH 2/2] kernel/fork: handle put_user errors for CLONE_PARENT_SETTID Konstantin Khlebnikov
2015-02-06 16:23   ` Konstantin Khlebnikov
2015-02-06 20:49   ` Linus Torvalds
2015-02-06 20:49     ` Linus Torvalds
     [not found]     ` <CA+55aFxBuf-0UkoYCrwH_vNsWFnUkFOz5c9O_Mswe_w0BTkqbQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-02-06 21:07       ` Oleg Nesterov [this message]
2015-02-06 21:07         ` Oleg Nesterov
2015-02-06 21:13     ` Konstantin Khlebnikov
2015-02-06 21:55       ` Andy Lutomirski
     [not found]       ` <CALYGNiMv021=WC2uXsjo5zT8JwewweZUDdk0x8FGHh9V5j6bFQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-02-06 22:10         ` Linus Torvalds
2015-02-06 22:10           ` Linus Torvalds
2015-02-06 19:44 ` [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID Oleg Nesterov
2015-02-06 19:44   ` Oleg Nesterov
     [not found]   ` <20150206194405.GA13960-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-06 19:55     ` Oleg Nesterov
2015-02-06 19:55       ` Oleg Nesterov
     [not found]       ` <20150206195529.GA15517-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-06 20:27         ` Konstantin Khlebnikov
2015-02-06 20:27           ` Konstantin Khlebnikov
2015-02-06 20:32         ` memcg && uaccess (Was: [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID) Oleg Nesterov
2015-02-06 20:32           ` Oleg Nesterov
     [not found]           ` <20150206203246.GA16924-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-10 16:19             ` Johannes Weiner
2015-02-10 16:19               ` Johannes Weiner
2015-02-10 19:47               ` Oleg Nesterov

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