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Date:   Tue, 19 Jan 2021 09:33:24 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Christian Brauner <christian.brauner@ubuntu.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        linux-fsdevel@vger.kernel.org,
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        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v5 19/42] namei: handle idmapped mounts in may_*() helpers
Message-ID: <20210119093324.GD3364550@infradead.org>
References: <20210112220124.837960-1-christian.brauner@ubuntu.com>
 <20210112220124.837960-20-christian.brauner@ubuntu.com>
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On Tue, Jan 12, 2021 at 11:01:01PM +0100, Christian Brauner wrote:
> The may_follow_link(), may_linkat(), may_lookup(), may_open(),
> may_o_create(), may_create_in_sticky(), may_delete(), and may_create()
> helpers determine whether the caller is privileged enough to perform the
> associated operations. Let them handle idmapped mounts by mapping the
> inode or fsids according to the mount's user namespace. Afterwards the
> checks are identical to non-idmapped inodes. The patch takes care to
> retrieve the mount's user namespace right before performing permission
> checks and passing it down into the fileystem so the user namespace
> can't change in between by someone idmapping a mount that is currently
> not idmapped. If the initial user namespace is passed nothing changes so
> non-idmapped mounts will see identical behavior as before.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>