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Commit a1a23777 authored by Chuck Lever's avatar Chuck Lever Committed by J. Bruce Fields
Browse files

sunrpc: Enable the kernel to specify the hostname part of service principals 



A multi-homed NFS server may have more than one "nfs" key in its
keytab. Enable the kernel to pick the key it wants as a machine
credential when establishing a GSS context.

This is useful for GSS-protected NFSv4.0 callbacks, which are
required by RFC 7530 S3.3.3 to use the same principal as the service
principal the client used when establishing its lease.

A complementary modification to rpc.gssd is required to fully enable
this feature.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 44090cc8

net/sunrpc/auth_gss/auth_gss.c

+17 −3
Original line number Diff line number Diff line
@@ -284,7 +284,12 @@ gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct 
	return p;

}



#define UPCALL_BUF_LEN 128

/* XXX: Need some documentation about why UPCALL_BUF_LEN is so small.

 *	Is user space expecting no more than UPCALL_BUF_LEN bytes?

 *	Note that there are now _two_ NI_MAXHOST sized data items

 *	being passed in this string.

 */

#define UPCALL_BUF_LEN	256



struct gss_upcall_msg {

	refcount_t count;
@@ -462,8 +467,17 @@ static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg, 
		p += len;

		gss_msg->msg.len += len;

	}

	if (service_name != NULL) {

		len = scnprintf(p, buflen, "service=%s ", service_name);

	if (service_name) {

		char *c = strchr(service_name, '@');



		if (!c)

			len = scnprintf(p, buflen, "service=%s ",

					service_name);

		else

			len = scnprintf(p, buflen,

					"service=%.*s srchost=%s ",

					(int)(c - service_name),

					service_name, c + 1);

		buflen -= len;

		p += len;

		gss_msg->msg.len += len;