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From:   Paul Moore <paul@paul-moore.com>
Date:   Fri, 22 Jan 2021 14:23:19 -0500
Message-ID: <CAHC9VhQV6k3LhgyvGmWSn+rQpuFY1wK4K-5p=xk-mVdUK6eDnQ@mail.gmail.com>
Subject: Re: [PATCH] NFSv4.2: fix return value of _nfs4_get_security_label()
To:     Ondrej Mosnacek <omosnace@redhat.com>
Cc:     linux-nfs@vger.kernel.org,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
        David Quigley <dpquigl@davequigley.com>
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On Fri, Jan 15, 2021 at 12:47 PM Ondrej Mosnacek <omosnace@redhat.com> wrote:
>
> An xattr 'get' handler is expected to return the length of the value on
> success, yet _nfs4_get_security_label() (and consequently also
> nfs4_xattr_get_nfs4_label(), which is used as an xattr handler) returns
> just 0 on success.
>
> Fix this by returning label.len instead, which contains the length of
> the result.
>
> Fixes: aa9c2669626c ("NFS: Client implementation of Labeled-NFS")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  fs/nfs/nfs4proc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Paul Moore <paul@paul-moore.com>

> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 2f4679a62712a..28465d8aada64 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5971,7 +5971,7 @@ static int _nfs4_get_security_label(struct inode *inode, void *buf,
>                 return ret;
>         if (!(fattr.valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL))
>                 return -ENOENT;
> -       return 0;
> +       return label.len;
>  }
>
>  static int nfs4_get_security_label(struct inode *inode, void *buf,
> --
> 2.29.2

-- 
paul moore
www.paul-moore.com