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In-Reply-To: <AA691FE9-5183-4912-BB0A-32E86629D7B1@oracle.com>
From:   Anna Schumaker <schumaker.anna@gmail.com>
Date:   Tue, 19 Sep 2023 14:27:40 -0400
Message-ID: <CAFX2Jf=hVi1sGARPvfW8BLJ189obH=Ha+qovDWD6_ptWvSpUqA@mail.gmail.com>
Subject: Re: [PATCH v2] SUNRPC: Fail quickly when server does not recognize TLS
To:     Chuck Lever III <chuck.lever@oracle.com>
Cc:     Anna Schumaker <anna.schumaker@netapp.com>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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On Mon, Sep 18, 2023 at 2:37=E2=80=AFPM Chuck Lever III <chuck.lever@oracle=
.com> wrote:
>
>
>
> > On Sep 6, 2023, at 4:05 PM, Chuck Lever <cel@kernel.org> wrote:
> >
> > From: Chuck Lever <chuck.lever@oracle.com>
> >
> > rpcauth_checkverf() should return a distinct error code when a
> > server recognizes the AUTH_TLS probe but does not support TLS so
> > that the client's header decoder can respond appropriately and
> > quickly. No retries are necessary is in this case, since the server
> > has already affirmatively answered "TLS is unsupported".
> >
> > Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
> > Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> > ---
> > net/sunrpc/auth.c     |   11 ++++++++---
> > net/sunrpc/auth_tls.c |    4 ++--
> > net/sunrpc/clnt.c     |   10 +++++++++-
> > 3 files changed, 19 insertions(+), 6 deletions(-)
> >
> > This must be applied after 'Revert "SUNRPC: Fail faster on bad verifier=
"'
> >
> > Changes since RFC:
> > - Basic testing has been done
> > - Added an explicit check for a zero-length verifier string
>
> Hi Anna, was this patch rejected?

Nope! I was under the impression Trond would be taking it for 6.7, but
if you think it's needed earlier I can include it in the next bugfixes
pull request.

Thanks,
Anna

>
>
> > diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
> > index 2f16f9d17966..814b0169f972 100644
> > --- a/net/sunrpc/auth.c
> > +++ b/net/sunrpc/auth.c
> > @@ -769,9 +769,14 @@ int rpcauth_wrap_req(struct rpc_task *task, struct=
 xdr_stream *xdr)
> >  * @task: controlling RPC task
> >  * @xdr: xdr_stream containing RPC Reply header
> >  *
> > - * On success, @xdr is updated to point past the verifier and
> > - * zero is returned. Otherwise, @xdr is in an undefined state
> > - * and a negative errno is returned.
> > + * Return values:
> > + *   %0: Verifier is valid. @xdr now points past the verifier.
> > + *   %-EIO: Verifier is corrupted or message ended early.
> > + *   %-EACCES: Verifier is intact but not valid.
> > + *   %-EPROTONOSUPPORT: Server does not support the requested auth typ=
e.
> > + *
> > + * When a negative errno is returned, @xdr is left in an undefined
> > + * state.
> >  */
> > int
> > rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
> > diff --git a/net/sunrpc/auth_tls.c b/net/sunrpc/auth_tls.c
> > index de7678f8a23d..87f570fd3b00 100644
> > --- a/net/sunrpc/auth_tls.c
> > +++ b/net/sunrpc/auth_tls.c
> > @@ -129,9 +129,9 @@ static int tls_validate(struct rpc_task *task, stru=
ct xdr_stream *xdr)
> > if (*p !=3D rpc_auth_null)
> > return -EIO;
> > if (xdr_stream_decode_opaque_inline(xdr, &str, starttls_len) !=3D start=
tls_len)
> > - return -EIO;
> > + return -EPROTONOSUPPORT;
> > if (memcmp(str, starttls_token, starttls_len))
> > - return -EIO;
> > + return -EPROTONOSUPPORT;
> > return 0;
> > }
> >
> > diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> > index 315bd59dea05..80ee97fb0bf2 100644
> > --- a/net/sunrpc/clnt.c
> > +++ b/net/sunrpc/clnt.c
> > @@ -2722,7 +2722,15 @@ rpc_decode_header(struct rpc_task *task, struct =
xdr_stream *xdr)
> >
> > out_verifier:
> > trace_rpc_bad_verifier(task);
> > - goto out_garbage;
> > + switch (error) {
> > + case -EPROTONOSUPPORT:
> > + goto out_err;
> > + case -EACCES:
> > + /* Re-encode with a fresh cred */
> > + fallthrough;
> > + default:
> > + goto out_garbage;
> > + }
> >
> > out_msg_denied:
> > error =3D -EACCES;
> >
> >
>
> --
> Chuck Lever
>
>