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Subject: Re: [PATCH 1 2/3] NFSD: Finish converting the NFSv2 GETACL result
 encoder
From:   Jeff Layton <jlayton@kernel.org>
To:     Chuck Lever <chuck.lever@oracle.com>, linux-nfs@vger.kernel.org
Date:   Mon, 17 Oct 2022 09:02:32 -0400
In-Reply-To: <166593522241.1710.1607659813797998942.stgit@klimt.1015granger.net>
References: <166593521604.1710.10648202421284171508.stgit@klimt.1015granger.net>
         <166593522241.1710.1607659813797998942.stgit@klimt.1015granger.net>
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On Sun, 2022-10-16 at 11:47 -0400, Chuck Lever wrote:
> The xdr_stream conversion inadvertently left some code that set the
> page_len of the send buffer. The XDR stream encoders should handle
> this automatically now.
>=20
> This oversight adds garbage past the end of the Reply message.
> Clients typically ignore the garbage, but NFSD does not need to send
> it, as it leaks stale memory contents onto the wire.
>=20
> Fixes: f8cba47344f7 ("NFSD: Update the NFSv2 GETACL result encoder to use=
 struct xdr_stream")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/nfs2acl.c |   10 ----------
>  1 file changed, 10 deletions(-)
>=20
> diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
> index 9edd3c1a30fb..87f224cd30a8 100644
> --- a/fs/nfsd/nfs2acl.c
> +++ b/fs/nfsd/nfs2acl.c
> @@ -246,7 +246,6 @@ nfsaclsvc_encode_getaclres(struct svc_rqst *rqstp, st=
ruct xdr_stream *xdr)
>  	struct nfsd3_getaclres *resp =3D rqstp->rq_resp;
>  	struct dentry *dentry =3D resp->fh.fh_dentry;
>  	struct inode *inode;
> -	int w;
> =20
>  	if (!svcxdr_encode_stat(xdr, resp->status))
>  		return false;
> @@ -260,15 +259,6 @@ nfsaclsvc_encode_getaclres(struct svc_rqst *rqstp, s=
truct xdr_stream *xdr)
>  	if (xdr_stream_encode_u32(xdr, resp->mask) < 0)
>  		return false;
> =20
> -	rqstp->rq_res.page_len =3D w =3D nfsacl_size(
> -		(resp->mask & NFS_ACL)   ? resp->acl_access  : NULL,
> -		(resp->mask & NFS_DFACL) ? resp->acl_default : NULL);
> -	while (w > 0) {
> -		if (!*(rqstp->rq_next_page++))
> -			return true;
> -		w -=3D PAGE_SIZE;
> -	}
> -
>  	if (!nfs_stream_encode_acl(xdr, inode, resp->acl_access,
>  				   resp->mask & NFS_ACL, 0))
>  		return false;
>=20
>=20

That makes a lot more sense now.

Reviewed-by: Jeff Layton <jlayton@kernel.org>