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Message-ID: <m1pr6dwgsh.fsf@fess.ebiederm.org>
Date: Thu, 17 Dec 2009 11:18:22 -0800
From: ebiederm@...ssion.com (Eric W. Biederman)
To: Michael Stone <michael@...top.org>
Cc: Ulrich Drepper <drepper@...il.com>, linux-kernel@...r.kernel.org,
netdev@...r.kernel.org, linux-security-module@...r.kernel.org,
"Andi Kleen" <andi@...stfloor.org>, "David Lang" <david@...g.hm>,
"Oliver Hartkopp" <socketcan@...tkopp.net>,
"Alan Cox" <alan@...rguk.ukuu.org.uk>,
"Herbert Xu" <herbert@...dor.apana.org.au>,
"Valdis Kletnieks" <Valdis.Kletnieks@...edu>,
"Bryan Donlan" <bdonlan@...il.com>,
"Evgeniy Polyakov" <zbr@...emap.net>,
"C. Scott Ananian" <cscott@...ott.net>,
"James Morris" <jmorris@...ei.org>,
"Bernie Innocenti" <bernie@...ewiz.org>,
"Mark Seaborn" <mrs@...hic-beasts.com>
Subject: Re: [PATCH] Security: Implement prctl(PR_SET_NETWORK, PR_NETWORK_OFF) semantics.
Michael Stone <michael@...top.org> writes:
> diff --git a/kernel/ptrace.c b/kernel/ptrace.c
> index 23bd09c..5b38db0 100644
> --- a/kernel/ptrace.c
> +++ b/kernel/ptrace.c
> @@ -151,6 +151,8 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
> dumpable = get_dumpable(task->mm);
> if (!dumpable && !capable(CAP_SYS_PTRACE))
> return -EPERM;
> + if (current->network)
> + return -EPERM;
The principle should be: you gain no privileges by ptracing.
Therefore this check should be:
if (current->network && !task->network)
return -EPERM;
Which keeps the ptrace logic from being a larger hammer than it needs
to be.
Eric
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