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Date:   Tue, 19 Jan 2021 09:22:09 +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>,
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        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v5 10/42] capability: handle idmapped mounts
Message-ID: <20210119092209.GB3361757@infradead.org>
References: <20210112220124.837960-1-christian.brauner@ubuntu.com>
 <20210112220124.837960-11-christian.brauner@ubuntu.com>
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On Tue, Jan 12, 2021 at 11:00:52PM +0100, Christian Brauner wrote:
> In order to determine whether a caller holds privilege over a given
> inode the capability framework exposes the two helpers
> privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former
> verifies that the inode has a mapping in the caller's user namespace and
> the latter additionally verifies that the caller has the requested
> capability in their current user namespace.
> If the inode is accessed through an idmapped mount we simply need to map
> it according to the mount's user namespace. Afterwards the checks are
> identical to non-idmapped inodes. If the initial user namespace is
> passed all operations are a nop so non-idmapped mounts will not see a
> change in behavior and will also not see any performance impact.

This adds a bunch of pointless > 80 char lines, that would be nice to
fix up.

Otherwise looks good:

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