Subject: Re: [PATCH] sunrpc: Add comment defining gssd upcall API keywords
To: Chuck Lever <chuck.lever@oracle.com>, bfields@fieldses.org
Cc: linux-nfs@vger.kernel.org, simo@redhat.com
References: <20180820143801.10060.61177.stgit@klimt.1015granger.net>
From: Steve Dickson <SteveD@RedHat.com>
Message-ID: <4c37c307-c0c9-f833-45b4-01d6c5d4d1a5@RedHat.com>
Date: Mon, 20 Aug 2018 11:55:30 -0400
MIME-Version: 1.0
In-Reply-To: <20180820143801.10060.61177.stgit@klimt.1015granger.net>
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Sender: linux-nfs-owner@vger.kernel.org

Hello,

I found your examples in the "Enable the kernel to specify the hostname..."
thread to be very useful. See below.

On 08/20/2018 10:39 AM, Chuck Lever wrote:
> During review, it was found that the target, service, and srchost
> keywords are easily conflated. Add an explainer.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  net/sunrpc/auth_gss/auth_gss.c |   17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> Hi Bruce-
> 
> I've received no objections to this patch. Can you include it in
> v4.19 with the other patches I've already submitted?
> 
> 
> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
> index 1943e11..2460759 100644
> --- a/net/sunrpc/auth_gss/auth_gss.c
> +++ b/net/sunrpc/auth_gss/auth_gss.c
> @@ -461,12 +461,28 @@ static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
>  	buflen -= len;
>  	p += len;
>  	gss_msg->msg.len = len;
> +
> +	/*
> +	 * target= is a full service principal that names the remote
> +	 * identity that we are authenticating to.
         *  In full, the target is:
         *     host/manet.example.net@EXAMPLE.NET
> +	 */
>  	if (target_name) {
>  		len = scnprintf(p, buflen, "target=%s ", target_name);
>  		buflen -= len;
>  		p += len;
>  		gss_msg->msg.len += len;
>  	}
> +
> +	/*
> +	 * gssd uses service= and srchost= to select a matching key from
> +	 * the system's keytab to use as the source principal.
> +	 *
> +	 * service= is the service name part of the source principal,
> +	 * or "*" (meaning choose any).
> +	 *
> +	 * srchost= is the hostname part of the source principal. When
> +	 * not provided, gssd uses the local hostname. 
         * Thus the full source principal has to be:
         *      nfs/klimt.ib.example.net@EXAMPLE.NET
> +	 */
Just a suggestion... 

steved.
>  	if (service_name) {
>  		char *c = strchr(service_name, '@');
>  
> @@ -482,6 +498,7 @@ static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
>  		p += len;
>  		gss_msg->msg.len += len;
>  	}
> +
>  	if (mech->gm_upcall_enctypes) {
>  		len = scnprintf(p, buflen, "enctypes=%s ",
>  				mech->gm_upcall_enctypes);
>