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From:   Stephen Smalley <stephen.smalley.work@gmail.com>
Date:   Tue, 10 Mar 2020 11:54:48 -0400
Message-ID: <CAEjxPJ4JJDSn+BEb_BD+Lffd9MbEt9Yr6AOyTk5m7FONcZSdLg@mail.gmail.com>
Subject: Re: [PATCH] NFS: Ensure security label is set for root inode
To:     Scott Mayhew <smayhew@redhat.com>
Cc:     trond.myklebust@hammerspace.com, anna.schumaker@netapp.com,
        Richard Haines <richard_c_haines@btinternet.com>,
        bfields@fieldses.org, Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>, linux-nfs@vger.kernel.org,
        SElinux list <selinux@vger.kernel.org>
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On Tue, Mar 3, 2020 at 5:59 PM Scott Mayhew <smayhew@redhat.com> wrote:
>
> When using NFSv4.2, the security label for the root inode should be set
> via a call to nfs_setsecurity() during the mount process, otherwise the
> inode will appear as unlabeled for up to acdirmin seconds.  Currently
> the label for the root inode is allocated, retrieved, and freed entirely
> witin nfs4_proc_get_root().
>
> Add a field for the label to the nfs_fattr struct, and allocate & free
> the label in nfs_get_root(), where we also add a call to
> nfs_setsecurity().  Note that for the call to nfs_setsecurity() to
> succeed, it's necessary to also move the logic calling
> security_sb_{set,clone}_security() from nfs_get_tree_common() down into
> nfs_get_root()... otherwise the SBLABEL_MNT flag will not be set in the
> super_block's security flags and nfs_setsecurity() will silently fail.
>
> Reported-by: Richard Haines <richard_c_haines@btinternet.com>
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Tested-by: Stephen Smalley <sds@tycho.nsa.gov>