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Date:   Wed, 15 Apr 2020 14:38:15 +0200
From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Eugene Syromiatnikov <esyr@redhat.com>
Cc:     linux-kernel@vger.kernel.org,
        Christian Brauner <christian@brauner.io>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Li Zefan <lizefan@huawei.com>,
        Peter Zijlstra <peterz@infradead.org>, cgroups@vger.kernel.org,
        "Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH] clone3: fix cgroup argument sanity check
Message-ID: <20200415123815.qrc7m2ddboh645uo@wittgenstein>
References: <20200412202533.GA29554@asgard.redhat.com>
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On Sun, Apr 12, 2020 at 10:25:33PM +0200, Eugene Syromiatnikov wrote:
> Checking that cgroup field value of struct clone_args is less than 0
> is useless, as it is defined as unsigned 64-bit integer.  Moreover,
> it doesn't catch the situations where its higher bits are lost during
> the assignment to the cgroup field of the cgroup field of the internal
> struct kernel_clone_args (where it is declared as signed 32-bit
> integer), so it is still possible to pass garbage there.  A check
> against INT_MAX solves both these issues.
> 
> Fixes: ef2c41cf38a7559b ("clone3: allow spawning processes into cgroups")
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Applied, thanks!
Christian