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From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: Cyrill Gorcunov <gorcunov@gmail.com>,
	Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>,
	peterz@infradead.org, mingo@redhat.com, mhocko@suse.com,
	keescook@chromium.org, linux-kernel@vger.kernel.org,
	mguzik@redhat.com, bsegall@google.com, john.stultz@linaro.org,
	oleg@redhat.com, matthltc@us.ibm.com, akpm@linux-foundation.org,
	luto@amacapital.net, vbabka@suse.cz, xemul@virtuozzo.com
Subject: Re: [PATCH] prctl: remove one-shot limitation for changing exe link
Date: Mon, 18 Jul 2016 21:11:55 +0100	[thread overview]
Message-ID: <20160718211155.393aca3c@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <87inwa2406.fsf@x220.int.ebiederm.org>

> >> 1) Attach to process via ptrace (protected by CAP_SYS_PTRACE)
> >> 2) Unmap all the process file mappings, related to "exe" file.
> >> 3) Change exe link (protected by CAP_SYS_RESOURCE).
> >> 
> >> IOW, some other process already has an access to process internals (and thus
> >> it's already compromised), and can inject fork and use the child of the
> >> compromised program to masquerade.
> >> Which means this limitation doesn't solve the problem it was aimed to.

IFF it is the same uid or root (in which case you already lost). In the
case of cross uid activity this is not true.

Alan

  parent reply	other threads:[~2016-07-18 20:14 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12 15:30 [PATCH] prctl: remove one-shot limitation for changing exe link Stanislav Kinsburskiy
2016-07-12 16:42 ` Oleg Nesterov
2016-07-12 16:52   ` Stanislav Kinsburskiy
2016-07-12 17:01     ` Oleg Nesterov
2016-07-12 16:48 ` Cyrill Gorcunov
2016-07-12 16:52   ` Eric W. Biederman
2016-07-12 17:29     ` Cyrill Gorcunov
2016-07-12 21:42       ` Cyrill Gorcunov
2016-07-13 10:47     ` Stanislav Kinsburskiy
2016-07-18 20:11     ` One Thousand Gnomes [this message]
2016-07-20 11:30       ` Stanislav Kinsburskiy
     [not found] ` <8a863273-c571-63d6-c0c3-637dff5645a3@virtuozzo.com>
2016-07-25 18:21   ` Eric W. Biederman
2016-07-25 19:22     ` Cyrill Gorcunov
2016-07-25 19:56       ` Eric W. Biederman
2016-07-26  8:34         ` Cyrill Gorcunov
2016-07-30 17:31           ` Eric W. Biederman
2016-07-30 20:28             ` Mateusz Guzik
2016-07-31 18:45               ` Eric W. Biederman
2016-07-31 18:45               ` Eric W. Biederman
2016-08-22 15:40                 ` Richard Guy Briggs
2016-07-31 22:43             ` Cyrill Gorcunov
2016-07-31 22:49               ` Andy Lutomirski
2016-08-01  9:04             ` Cyrill Gorcunov
2016-08-10 10:48             ` Stanislav Kinsburskiy
2016-07-26 10:21     ` Stanislav Kinsburskiy
2016-07-12 15:42 Stanislav Kinsburskiy
     [not found] <1d254efe-5410-40c4-af4b-9e898682d0b3@email.android.com>
2016-07-13 10:15 ` Oleg Nesterov

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