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Date:   Fri, 9 Oct 2020 13:50:14 +0200
From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Aleksa Sarai <cyphar@cyphar.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Shuah Khan <shuah@kernel.org>,
        containers@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] openat2: reject RESOLVE_BENEATH|RESOLVE_IN_ROOT
Message-ID: <20201009115014.ft7kjyejhqvommnv@wittgenstein>
References: <20201007103608.17349-1-cyphar@cyphar.com>
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On Wed, Oct 07, 2020 at 09:36:08PM +1100, Aleksa Sarai wrote:
> This was an oversight in the original implementation, as it makes no
> sense to specify both scoping flags to the same openat2(2) invocation
> (before this patch, the result of such an invocation was equivalent to
> RESOLVE_IN_ROOT being ignored).
> 
> This is a userspace-visible ABI change, but the only user of openat2(2)
> at the moment is LXC which doesn't specify both flags and so no
> userspace programs will break as a result.

Indeed!

> 
> Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall")
> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> Cc: <stable@vger.kernel.org> # v5.6+
> ---

Thanks! This is a good fix imho.
Christian