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From: Solar Designer <solar@openwall.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Sergey Vlasov <vsu@altlinux.ru>,
	vendor-sec@lst.de, linux-kernel@vger.kernel.org,
	security@linux.kernel.org
Subject: Re: PID reuse safety for userspace apps (Re: [linux-usb-devel] Re: [Security] [vendor-sec] [BUG/PATCH/RFC] Oops while completing async USB via usbdevio)
Date: Wed, 28 Sep 2005 01:16:24 +0400	[thread overview]
Message-ID: <20050927211624.GA4947@openwall.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0509271335530.3308@g5.osdl.org>

On Tue, Sep 27, 2005 at 01:42:44PM -0700, Linus Torvalds wrote:
> Note that for at least signal sending, the security aspect is _not_ about 
> whether the pid has been re-used, but about whether the _user_ matches.

That's true.  And, changing topic to userspace apps, killall(1)
currently has no race-free way to check whether the user still matches.

There's also the reliability aspect: killing one's own process, but
other than the intended one, is a reliability issue.

What I have proposed is a way to deal with both of these.

killall is just an example.  A GUI point-and-click task manager would
have the same problem and the same solution would work for it.

-- 
Alexander

  reply	other threads:[~2005-09-27 21:17 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-25 15:13 [BUG/PATCH/RFC] Oops while completing async USB via usbdevio Harald Welte
2005-09-27  8:04 ` [vendor-sec] " Greg KH
2005-09-27  9:13   ` Greg KH
     [not found]     ` <20050927110319.GD1980@piware.de>
2005-09-27 12:22       ` [vendor-sec] " Greg KH
2005-09-27 12:48   ` [vendor-sec] " Christoph Hellwig
2005-09-27 12:57     ` Greg KH
2005-09-27 12:59       ` Christoph Hellwig
2005-09-27 13:09         ` Greg KH
2005-09-27 15:27           ` David Brownell
2005-09-27 14:53 ` [Security] " Linus Torvalds
2005-09-27 16:00   ` [linux-usb-devel] " Sergey Vlasov
2005-09-27 16:09     ` Linus Torvalds
2005-09-27 16:52       ` Sergey Vlasov
2005-09-27 17:02         ` Linus Torvalds
2005-09-30 10:47           ` Harald Welte
2005-09-30 14:56             ` Linus Torvalds
2005-09-30 18:44               ` Chris Wright
2005-09-30 19:27                 ` Linus Torvalds
2005-09-30 20:38                   ` Chris Wright
2005-09-30 22:08                   ` Harald Welte
2005-09-30 22:16                     ` Linus Torvalds
2005-10-10 17:44                       ` Harald Welte
2005-10-10 18:07                         ` Chris Wright
2005-10-11  9:45                           ` Harald Welte
2005-10-11 23:10                             ` [vendor-sec] " Greg KH
2005-10-11 23:44                               ` Linus Torvalds
2005-10-12  7:24                                 ` Harald Welte
2005-10-13  5:51                             ` Horms
2005-10-11 13:57                           ` Bernd Petrovitsch
2005-10-10 18:19                         ` Linus Torvalds
2005-10-10 22:47                           ` Chris Wright
2005-10-10 20:03                         ` [linux-usb-devel] " Alan Stern
2005-10-11  8:28                           ` Harald Welte
2005-10-11 17:37                           ` Paul Jackson
2005-10-11 17:58                             ` linux-os (Dick Johnson)
2005-10-11 19:13                               ` Alan Stern
2005-10-11 20:02                                 ` [Security] " Alan Cox
2005-09-27 17:20         ` PID reuse safety for userspace apps (Re: [linux-usb-devel] Re: [Security] [vendor-sec] [BUG/PATCH/RFC] Oops while completing async USB via usbdevio) Solar Designer
2005-09-27 20:34           ` Alan Cox
2005-09-27 20:42             ` Linus Torvalds
2005-09-27 21:16               ` Solar Designer [this message]
2005-09-27 21:03             ` Solar Designer
2005-09-27 16:58       ` [linux-usb-devel] Re: [Security] [vendor-sec] [BUG/PATCH/RFC] Oops while completing async USB via usbdevio Alan Cox
2005-09-27 16:59         ` Linus Torvalds
2005-09-27 20:35           ` Alan Cox
2005-10-13 23:00         ` Pete Zaitcev
2005-10-13 23:16           ` Linus Torvalds
2005-10-13 23:56             ` Pete Zaitcev

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