Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2127 insertions, 0 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
new file mode 100644
index 000000000..e61c48c1b
--- /dev/null
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -0,0 +1,2127 @@
+/*
+ * linux/net/sunrpc/auth_gss/auth_gss.c
+ *
+ * RPCSEC_GSS client authentication.
+ *
+ *  Copyright (c) 2000 The Regents of the University of Michigan.
+ *  All rights reserved.
+ *
+ *  Dug Song       <dugsong@monkey.org>
+ *  Andy Adamson   <andros@umich.edu>
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the University nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/auth.h>
+#include <linux/sunrpc/auth_gss.h>
+#include <linux/sunrpc/svcauth_gss.h>
+#include <linux/sunrpc/gss_err.h>
+#include <linux/workqueue.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+#include <linux/sunrpc/gss_api.h>
+#include <linux/uaccess.h>
+#include <linux/hashtable.h>
+
+#include "auth_gss_internal.h"
+#include "../netns.h"
+
+static const struct rpc_authops authgss_ops;
+
+static const struct rpc_credops gss_credops;
+static const struct rpc_credops gss_nullops;
+
+#define GSS_RETRY_EXPIRED 5
+static unsigned int gss_expired_cred_retry_delay = GSS_RETRY_EXPIRED;
+
+#define GSS_KEY_EXPIRE_TIMEO 240
+static unsigned int gss_key_expire_timeo = GSS_KEY_EXPIRE_TIMEO;
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+# define RPCDBG_FACILITY	RPCDBG_AUTH
+#endif
+
+#define GSS_CRED_SLACK		(RPC_MAX_AUTH_SIZE * 2)
+/* length of a krb5 verifier (48), plus data added before arguments when
+ * using integrity (two 4-byte integers): */
+#define GSS_VERF_SLACK		100
+
+static DEFINE_HASHTABLE(gss_auth_hash_table, 4);
+static DEFINE_SPINLOCK(gss_auth_hash_lock);
+
+struct gss_pipe {
+	struct rpc_pipe_dir_object pdo;
+	struct rpc_pipe *pipe;
+	struct rpc_clnt *clnt;
+	const char *name;
+	struct kref kref;
+};
+
+struct gss_auth {
+	struct kref kref;
+	struct hlist_node hash;
+	struct rpc_auth rpc_auth;
+	struct gss_api_mech *mech;
+	enum rpc_gss_svc service;
+	struct rpc_clnt *client;
+	struct net *net;
+	/*
+	 * There are two upcall pipes; dentry[1], named "gssd", is used
+	 * for the new text-based upcall; dentry[0] is named after the
+	 * mechanism (for example, "krb5") and exists for
+	 * backwards-compatibility with older gssd's.
+	 */
+	struct gss_pipe *gss_pipe[2];
+	const char *target_name;
+};
+
+/* pipe_version >= 0 if and only if someone has a pipe open. */
+static DEFINE_SPINLOCK(pipe_version_lock);
+static struct rpc_wait_queue pipe_version_rpc_waitqueue;
+static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
+static void gss_put_auth(struct gss_auth *gss_auth);
+
+static void gss_free_ctx(struct gss_cl_ctx *);
+static const struct rpc_pipe_ops gss_upcall_ops_v0;
+static const struct rpc_pipe_ops gss_upcall_ops_v1;
+
+static inline struct gss_cl_ctx *
+gss_get_ctx(struct gss_cl_ctx *ctx)
+{
+	refcount_inc(&ctx->count);
+	return ctx;
+}
+
+static inline void
+gss_put_ctx(struct gss_cl_ctx *ctx)
+{
+	if (refcount_dec_and_test(&ctx->count))
+		gss_free_ctx(ctx);
+}
+
+/* gss_cred_set_ctx:
+ * called by gss_upcall_callback and gss_create_upcall in order
+ * to set the gss context. The actual exchange of an old context
+ * and a new one is protected by the pipe->lock.
+ */
+static void
+gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
+{
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+
+	if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
+		return;
+	gss_get_ctx(ctx);
+	rcu_assign_pointer(gss_cred->gc_ctx, ctx);
+	set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	smp_mb__before_atomic();
+	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
+}
+
+static struct gss_cl_ctx *
+gss_cred_get_ctx(struct rpc_cred *cred)
+{
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+	struct gss_cl_ctx *ctx = NULL;
+
+	rcu_read_lock();
+	ctx = rcu_dereference(gss_cred->gc_ctx);
+	if (ctx)
+		gss_get_ctx(ctx);
+	rcu_read_unlock();
+	return ctx;
+}
+
+static struct gss_cl_ctx *
+gss_alloc_context(void)
+{
+	struct gss_cl_ctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
+	if (ctx != NULL) {
+		ctx->gc_proc = RPC_GSS_PROC_DATA;
+		ctx->gc_seq = 1;	/* NetApp 6.4R1 doesn't accept seq. no. 0 */
+		spin_lock_init(&ctx->gc_seq_lock);
+		refcount_set(&ctx->count,1);
+	}
+	return ctx;
+}
+
+#define GSSD_MIN_TIMEOUT (60 * 60)
+static const void *
+gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
+{
+	const void *q;
+	unsigned int seclen;
+	unsigned int timeout;
+	unsigned long now = jiffies;
+	u32 window_size;
+	int ret;
+
+	/* First unsigned int gives the remaining lifetime in seconds of the
+	 * credential - e.g. the remaining TGT lifetime for Kerberos or
+	 * the -t value passed to GSSD.
+	 */
+	p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
+	if (IS_ERR(p))
+		goto err;
+	if (timeout == 0)
+		timeout = GSSD_MIN_TIMEOUT;
+	ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
+	/* Sequence number window. Determines the maximum number of
+	 * simultaneous requests
+	 */
+	p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
+	if (IS_ERR(p))
+		goto err;
+	ctx->gc_win = window_size;
+	/* gssd signals an error by passing ctx->gc_win = 0: */
+	if (ctx->gc_win == 0) {
+		/*
+		 * in which case, p points to an error code. Anything other
+		 * than -EKEYEXPIRED gets converted to -EACCES.
+		 */
+		p = simple_get_bytes(p, end, &ret, sizeof(ret));
+		if (!IS_ERR(p))
+			p = (ret == -EKEYEXPIRED) ? ERR_PTR(-EKEYEXPIRED) :
+						    ERR_PTR(-EACCES);
+		goto err;
+	}
+	/* copy the opaque wire context */
+	p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
+	if (IS_ERR(p))
+		goto err;
+	/* import the opaque security context */
+	p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
+	if (IS_ERR(p))
+		goto err;
+	q = (const void *)((const char *)p + seclen);
+	if (unlikely(q > end || q < p)) {
+		p = ERR_PTR(-EFAULT);
+		goto err;
+	}
+	ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx, NULL, GFP_NOFS);
+	if (ret < 0) {
+		p = ERR_PTR(ret);
+		goto err;
+	}
+
+	/* is there any trailing data? */
+	if (q == end) {
+		p = q;
+		goto done;
+	}
+
+	/* pull in acceptor name (if there is one) */
+	p = simple_get_netobj(q, end, &ctx->gc_acceptor);
+	if (IS_ERR(p))
+		goto err;
+done:
+	dprintk("RPC:       %s Success. gc_expiry %lu now %lu timeout %u acceptor %.*s\n",
+		__func__, ctx->gc_expiry, now, timeout, ctx->gc_acceptor.len,
+		ctx->gc_acceptor.data);
+	return p;
+err:
+	dprintk("RPC:       %s returns error %ld\n", __func__, -PTR_ERR(p));
+	return p;
+}
+
+/* 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;
+	kuid_t	uid;
+	struct rpc_pipe_msg msg;
+	struct list_head list;
+	struct gss_auth *auth;
+	struct rpc_pipe *pipe;
+	struct rpc_wait_queue rpc_waitqueue;
+	wait_queue_head_t waitqueue;
+	struct gss_cl_ctx *ctx;
+	char databuf[UPCALL_BUF_LEN];
+};
+
+static int get_pipe_version(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	int ret;
+
+	spin_lock(&pipe_version_lock);
+	if (sn->pipe_version >= 0) {
+		atomic_inc(&sn->pipe_users);
+		ret = sn->pipe_version;
+	} else
+		ret = -EAGAIN;
+	spin_unlock(&pipe_version_lock);
+	return ret;
+}
+
+static void put_pipe_version(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+	if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
+		sn->pipe_version = -1;
+		spin_unlock(&pipe_version_lock);
+	}
+}
+
+static void
+gss_release_msg(struct gss_upcall_msg *gss_msg)
+{
+	struct net *net = gss_msg->auth->net;
+	if (!refcount_dec_and_test(&gss_msg->count))
+		return;
+	put_pipe_version(net);
+	BUG_ON(!list_empty(&gss_msg->list));
+	if (gss_msg->ctx != NULL)
+		gss_put_ctx(gss_msg->ctx);
+	rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
+	gss_put_auth(gss_msg->auth);
+	kfree(gss_msg);
+}
+
+static struct gss_upcall_msg *
+__gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth)
+{
+	struct gss_upcall_msg *pos;
+	list_for_each_entry(pos, &pipe->in_downcall, list) {
+		if (!uid_eq(pos->uid, uid))
+			continue;
+		if (auth && pos->auth->service != auth->service)
+			continue;
+		refcount_inc(&pos->count);
+		dprintk("RPC:       %s found msg %p\n", __func__, pos);
+		return pos;
+	}
+	dprintk("RPC:       %s found nothing\n", __func__);
+	return NULL;
+}
+
+/* Try to add an upcall to the pipefs queue.
+ * If an upcall owned by our uid already exists, then we return a reference
+ * to that upcall instead of adding the new upcall.
+ */
+static inline struct gss_upcall_msg *
+gss_add_msg(struct gss_upcall_msg *gss_msg)
+{
+	struct rpc_pipe *pipe = gss_msg->pipe;
+	struct gss_upcall_msg *old;
+
+	spin_lock(&pipe->lock);
+	old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth);
+	if (old == NULL) {
+		refcount_inc(&gss_msg->count);
+		list_add(&gss_msg->list, &pipe->in_downcall);
+	} else
+		gss_msg = old;
+	spin_unlock(&pipe->lock);
+	return gss_msg;
+}
+
+static void
+__gss_unhash_msg(struct gss_upcall_msg *gss_msg)
+{
+	list_del_init(&gss_msg->list);
+	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
+	wake_up_all(&gss_msg->waitqueue);
+	refcount_dec(&gss_msg->count);
+}
+
+static void
+gss_unhash_msg(struct gss_upcall_msg *gss_msg)
+{
+	struct rpc_pipe *pipe = gss_msg->pipe;
+
+	if (list_empty(&gss_msg->list))
+		return;
+	spin_lock(&pipe->lock);
+	if (!list_empty(&gss_msg->list))
+		__gss_unhash_msg(gss_msg);
+	spin_unlock(&pipe->lock);
+}
+
+static void
+gss_handle_downcall_result(struct gss_cred *gss_cred, struct gss_upcall_msg *gss_msg)
+{
+	switch (gss_msg->msg.errno) {
+	case 0:
+		if (gss_msg->ctx == NULL)
+			break;
+		clear_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
+		gss_cred_set_ctx(&gss_cred->gc_base, gss_msg->ctx);
+		break;
+	case -EKEYEXPIRED:
+		set_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
+	}
+	gss_cred->gc_upcall_timestamp = jiffies;
+	gss_cred->gc_upcall = NULL;
+	rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
+}
+
+static void
+gss_upcall_callback(struct rpc_task *task)
+{
+	struct gss_cred *gss_cred = container_of(task->tk_rqstp->rq_cred,
+			struct gss_cred, gc_base);
+	struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
+	struct rpc_pipe *pipe = gss_msg->pipe;
+
+	spin_lock(&pipe->lock);
+	gss_handle_downcall_result(gss_cred, gss_msg);
+	spin_unlock(&pipe->lock);
+	task->tk_status = gss_msg->msg.errno;
+	gss_release_msg(gss_msg);
+}
+
+static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
+{
+	uid_t uid = from_kuid(&init_user_ns, gss_msg->uid);
+	memcpy(gss_msg->databuf, &uid, sizeof(uid));
+	gss_msg->msg.data = gss_msg->databuf;
+	gss_msg->msg.len = sizeof(uid);
+
+	BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
+}
+
+static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
+				const char *service_name,
+				const char *target_name)
+{
+	struct gss_api_mech *mech = gss_msg->auth->mech;
+	char *p = gss_msg->databuf;
+	size_t buflen = sizeof(gss_msg->databuf);
+	int len;
+
+	len = scnprintf(p, buflen, "mech=%s uid=%d ", mech->gm_name,
+			from_kuid(&init_user_ns, gss_msg->uid));
+	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.
+	 */
+	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.
+	 */
+	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;
+	}
+
+	if (mech->gm_upcall_enctypes) {
+		len = scnprintf(p, buflen, "enctypes=%s ",
+				mech->gm_upcall_enctypes);
+		buflen -= len;
+		p += len;
+		gss_msg->msg.len += len;
+	}
+	len = scnprintf(p, buflen, "\n");
+	if (len == 0)
+		goto out_overflow;
+	gss_msg->msg.len += len;
+
+	gss_msg->msg.data = gss_msg->databuf;
+	return 0;
+out_overflow:
+	WARN_ON_ONCE(1);
+	return -ENOMEM;
+}
+
+static struct gss_upcall_msg *
+gss_alloc_msg(struct gss_auth *gss_auth,
+		kuid_t uid, const char *service_name)
+{
+	struct gss_upcall_msg *gss_msg;
+	int vers;
+	int err = -ENOMEM;
+
+	gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
+	if (gss_msg == NULL)
+		goto err;
+	vers = get_pipe_version(gss_auth->net);
+	err = vers;
+	if (err < 0)
+		goto err_free_msg;
+	gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
+	INIT_LIST_HEAD(&gss_msg->list);
+	rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
+	init_waitqueue_head(&gss_msg->waitqueue);
+	refcount_set(&gss_msg->count, 1);
+	gss_msg->uid = uid;
+	gss_msg->auth = gss_auth;
+	switch (vers) {
+	case 0:
+		gss_encode_v0_msg(gss_msg);
+		break;
+	default:
+		err = gss_encode_v1_msg(gss_msg, service_name, gss_auth->target_name);
+		if (err)
+			goto err_put_pipe_version;
+	}
+	kref_get(&gss_auth->kref);
+	return gss_msg;
+err_put_pipe_version:
+	put_pipe_version(gss_auth->net);
+err_free_msg:
+	kfree(gss_msg);
+err:
+	return ERR_PTR(err);
+}
+
+static struct gss_upcall_msg *
+gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred)
+{
+	struct gss_cred *gss_cred = container_of(cred,
+			struct gss_cred, gc_base);
+	struct gss_upcall_msg *gss_new, *gss_msg;
+	kuid_t uid = cred->cr_uid;
+
+	gss_new = gss_alloc_msg(gss_auth, uid, gss_cred->gc_principal);
+	if (IS_ERR(gss_new))
+		return gss_new;
+	gss_msg = gss_add_msg(gss_new);
+	if (gss_msg == gss_new) {
+		int res;
+		refcount_inc(&gss_msg->count);
+		res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg);
+		if (res) {
+			gss_unhash_msg(gss_new);
+			refcount_dec(&gss_msg->count);
+			gss_release_msg(gss_new);
+			gss_msg = ERR_PTR(res);
+		}
+	} else
+		gss_release_msg(gss_new);
+	return gss_msg;
+}
+
+static void warn_gssd(void)
+{
+	dprintk("AUTH_GSS upcall failed. Please check user daemon is running.\n");
+}
+
+static inline int
+gss_refresh_upcall(struct rpc_task *task)
+{
+	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	struct gss_auth *gss_auth = container_of(cred->cr_auth,
+			struct gss_auth, rpc_auth);
+	struct gss_cred *gss_cred = container_of(cred,
+			struct gss_cred, gc_base);
+	struct gss_upcall_msg *gss_msg;
+	struct rpc_pipe *pipe;
+	int err = 0;
+
+	dprintk("RPC: %5u %s for uid %u\n",
+		task->tk_pid, __func__, from_kuid(&init_user_ns, cred->cr_uid));
+	gss_msg = gss_setup_upcall(gss_auth, cred);
+	if (PTR_ERR(gss_msg) == -EAGAIN) {
+		/* XXX: warning on the first, under the assumption we
+		 * shouldn't normally hit this case on a refresh. */
+		warn_gssd();
+		task->tk_timeout = 15*HZ;
+		rpc_sleep_on(&pipe_version_rpc_waitqueue, task, NULL);
+		return -EAGAIN;
+	}
+	if (IS_ERR(gss_msg)) {
+		err = PTR_ERR(gss_msg);
+		goto out;
+	}
+	pipe = gss_msg->pipe;
+	spin_lock(&pipe->lock);
+	if (gss_cred->gc_upcall != NULL)
+		rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
+	else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
+		task->tk_timeout = 0;
+		gss_cred->gc_upcall = gss_msg;
+		/* gss_upcall_callback will release the reference to gss_upcall_msg */
+		refcount_inc(&gss_msg->count);
+		rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
+	} else {
+		gss_handle_downcall_result(gss_cred, gss_msg);
+		err = gss_msg->msg.errno;
+	}
+	spin_unlock(&pipe->lock);
+	gss_release_msg(gss_msg);
+out:
+	dprintk("RPC: %5u %s for uid %u result %d\n",
+		task->tk_pid, __func__,
+		from_kuid(&init_user_ns, cred->cr_uid),	err);
+	return err;
+}
+
+static inline int
+gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
+{
+	struct net *net = gss_auth->net;
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct rpc_pipe *pipe;
+	struct rpc_cred *cred = &gss_cred->gc_base;
+	struct gss_upcall_msg *gss_msg;
+	DEFINE_WAIT(wait);
+	int err;
+
+	dprintk("RPC:       %s for uid %u\n",
+		__func__, from_kuid(&init_user_ns, cred->cr_uid));
+retry:
+	err = 0;
+	/* if gssd is down, just skip upcalling altogether */
+	if (!gssd_running(net)) {
+		warn_gssd();
+		return -EACCES;
+	}
+	gss_msg = gss_setup_upcall(gss_auth, cred);
+	if (PTR_ERR(gss_msg) == -EAGAIN) {
+		err = wait_event_interruptible_timeout(pipe_version_waitqueue,
+				sn->pipe_version >= 0, 15 * HZ);
+		if (sn->pipe_version < 0) {
+			warn_gssd();
+			err = -EACCES;
+		}
+		if (err < 0)
+			goto out;
+		goto retry;
+	}
+	if (IS_ERR(gss_msg)) {
+		err = PTR_ERR(gss_msg);
+		goto out;
+	}
+	pipe = gss_msg->pipe;
+	for (;;) {
+		prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_KILLABLE);
+		spin_lock(&pipe->lock);
+		if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
+			break;
+		}
+		spin_unlock(&pipe->lock);
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto out_intr;
+		}
+		schedule();
+	}
+	if (gss_msg->ctx)
+		gss_cred_set_ctx(cred, gss_msg->ctx);
+	else
+		err = gss_msg->msg.errno;
+	spin_unlock(&pipe->lock);
+out_intr:
+	finish_wait(&gss_msg->waitqueue, &wait);
+	gss_release_msg(gss_msg);
+out:
+	dprintk("RPC:       %s for uid %u result %d\n",
+		__func__, from_kuid(&init_user_ns, cred->cr_uid), err);
+	return err;
+}
+
+#define MSG_BUF_MAXSIZE 1024
+
+static ssize_t
+gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
+{
+	const void *p, *end;
+	void *buf;
+	struct gss_upcall_msg *gss_msg;
+	struct rpc_pipe *pipe = RPC_I(file_inode(filp))->pipe;
+	struct gss_cl_ctx *ctx;
+	uid_t id;
+	kuid_t uid;
+	ssize_t err = -EFBIG;
+
+	if (mlen > MSG_BUF_MAXSIZE)
+		goto out;
+	err = -ENOMEM;
+	buf = kmalloc(mlen, GFP_NOFS);
+	if (!buf)
+		goto out;
+
+	err = -EFAULT;
+	if (copy_from_user(buf, src, mlen))
+		goto err;
+
+	end = (const void *)((char *)buf + mlen);
+	p = simple_get_bytes(buf, end, &id, sizeof(id));
+	if (IS_ERR(p)) {
+		err = PTR_ERR(p);
+		goto err;
+	}
+
+	uid = make_kuid(&init_user_ns, id);
+	if (!uid_valid(uid)) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	err = -ENOMEM;
+	ctx = gss_alloc_context();
+	if (ctx == NULL)
+		goto err;
+
+	err = -ENOENT;
+	/* Find a matching upcall */
+	spin_lock(&pipe->lock);
+	gss_msg = __gss_find_upcall(pipe, uid, NULL);
+	if (gss_msg == NULL) {
+		spin_unlock(&pipe->lock);
+		goto err_put_ctx;
+	}
+	list_del_init(&gss_msg->list);
+	spin_unlock(&pipe->lock);
+
+	p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
+	if (IS_ERR(p)) {
+		err = PTR_ERR(p);
+		switch (err) {
+		case -EACCES:
+		case -EKEYEXPIRED:
+			gss_msg->msg.errno = err;
+			err = mlen;
+			break;
+		case -EFAULT:
+		case -ENOMEM:
+		case -EINVAL:
+		case -ENOSYS:
+			gss_msg->msg.errno = -EAGAIN;
+			break;
+		default:
+			printk(KERN_CRIT "%s: bad return from "
+				"gss_fill_context: %zd\n", __func__, err);
+			gss_msg->msg.errno = -EIO;
+		}
+		goto err_release_msg;
+	}
+	gss_msg->ctx = gss_get_ctx(ctx);
+	err = mlen;
+
+err_release_msg:
+	spin_lock(&pipe->lock);
+	__gss_unhash_msg(gss_msg);
+	spin_unlock(&pipe->lock);
+	gss_release_msg(gss_msg);
+err_put_ctx:
+	gss_put_ctx(ctx);
+err:
+	kfree(buf);
+out:
+	dprintk("RPC:       %s returning %zd\n", __func__, err);
+	return err;
+}
+
+static int gss_pipe_open(struct inode *inode, int new_version)
+{
+	struct net *net = inode->i_sb->s_fs_info;
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	int ret = 0;
+
+	spin_lock(&pipe_version_lock);
+	if (sn->pipe_version < 0) {
+		/* First open of any gss pipe determines the version: */
+		sn->pipe_version = new_version;
+		rpc_wake_up(&pipe_version_rpc_waitqueue);
+		wake_up(&pipe_version_waitqueue);
+	} else if (sn->pipe_version != new_version) {
+		/* Trying to open a pipe of a different version */
+		ret = -EBUSY;
+		goto out;
+	}
+	atomic_inc(&sn->pipe_users);
+out:
+	spin_unlock(&pipe_version_lock);
+	return ret;
+
+}
+
+static int gss_pipe_open_v0(struct inode *inode)
+{
+	return gss_pipe_open(inode, 0);
+}
+
+static int gss_pipe_open_v1(struct inode *inode)
+{
+	return gss_pipe_open(inode, 1);
+}
+
+static void
+gss_pipe_release(struct inode *inode)
+{
+	struct net *net = inode->i_sb->s_fs_info;
+	struct rpc_pipe *pipe = RPC_I(inode)->pipe;
+	struct gss_upcall_msg *gss_msg;
+
+restart:
+	spin_lock(&pipe->lock);
+	list_for_each_entry(gss_msg, &pipe->in_downcall, list) {
+
+		if (!list_empty(&gss_msg->msg.list))
+			continue;
+		gss_msg->msg.errno = -EPIPE;
+		refcount_inc(&gss_msg->count);
+		__gss_unhash_msg(gss_msg);
+		spin_unlock(&pipe->lock);
+		gss_release_msg(gss_msg);
+		goto restart;
+	}
+	spin_unlock(&pipe->lock);
+
+	put_pipe_version(net);
+}
+
+static void
+gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
+{
+	struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
+
+	if (msg->errno < 0) {
+		dprintk("RPC:       %s releasing msg %p\n",
+			__func__, gss_msg);
+		refcount_inc(&gss_msg->count);
+		gss_unhash_msg(gss_msg);
+		if (msg->errno == -ETIMEDOUT)
+			warn_gssd();
+		gss_release_msg(gss_msg);
+	}
+	gss_release_msg(gss_msg);
+}
+
+static void gss_pipe_dentry_destroy(struct dentry *dir,
+		struct rpc_pipe_dir_object *pdo)
+{
+	struct gss_pipe *gss_pipe = pdo->pdo_data;
+	struct rpc_pipe *pipe = gss_pipe->pipe;
+
+	if (pipe->dentry != NULL) {
+		rpc_unlink(pipe->dentry);
+		pipe->dentry = NULL;
+	}
+}
+
+static int gss_pipe_dentry_create(struct dentry *dir,
+		struct rpc_pipe_dir_object *pdo)
+{
+	struct gss_pipe *p = pdo->pdo_data;
+	struct dentry *dentry;
+
+	dentry = rpc_mkpipe_dentry(dir, p->name, p->clnt, p->pipe);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	p->pipe->dentry = dentry;
+	return 0;
+}
+
+static const struct rpc_pipe_dir_object_ops gss_pipe_dir_object_ops = {
+	.create = gss_pipe_dentry_create,
+	.destroy = gss_pipe_dentry_destroy,
+};
+
+static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
+		const char *name,
+		const struct rpc_pipe_ops *upcall_ops)
+{
+	struct gss_pipe *p;
+	int err = -ENOMEM;
+
+	p = kmalloc(sizeof(*p), GFP_KERNEL);
+	if (p == NULL)
+		goto err;
+	p->pipe = rpc_mkpipe_data(upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
+	if (IS_ERR(p->pipe)) {
+		err = PTR_ERR(p->pipe);
+		goto err_free_gss_pipe;
+	}
+	p->name = name;
+	p->clnt = clnt;
+	kref_init(&p->kref);
+	rpc_init_pipe_dir_object(&p->pdo,
+			&gss_pipe_dir_object_ops,
+			p);
+	return p;
+err_free_gss_pipe:
+	kfree(p);
+err:
+	return ERR_PTR(err);
+}
+
+struct gss_alloc_pdo {
+	struct rpc_clnt *clnt;
+	const char *name;
+	const struct rpc_pipe_ops *upcall_ops;
+};
+
+static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
+{
+	struct gss_pipe *gss_pipe;
+	struct gss_alloc_pdo *args = data;
+
+	if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
+		return 0;
+	gss_pipe = container_of(pdo, struct gss_pipe, pdo);
+	if (strcmp(gss_pipe->name, args->name) != 0)
+		return 0;
+	if (!kref_get_unless_zero(&gss_pipe->kref))
+		return 0;
+	return 1;
+}
+
+static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
+{
+	struct gss_pipe *gss_pipe;
+	struct gss_alloc_pdo *args = data;
+
+	gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
+	if (!IS_ERR(gss_pipe))
+		return &gss_pipe->pdo;
+	return NULL;
+}
+
+static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
+		const char *name,
+		const struct rpc_pipe_ops *upcall_ops)
+{
+	struct net *net = rpc_net_ns(clnt);
+	struct rpc_pipe_dir_object *pdo;
+	struct gss_alloc_pdo args = {
+		.clnt = clnt,
+		.name = name,
+		.upcall_ops = upcall_ops,
+	};
+
+	pdo = rpc_find_or_alloc_pipe_dir_object(net,
+			&clnt->cl_pipedir_objects,
+			gss_pipe_match_pdo,
+			gss_pipe_alloc_pdo,
+			&args);
+	if (pdo != NULL)
+		return container_of(pdo, struct gss_pipe, pdo);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void __gss_pipe_free(struct gss_pipe *p)
+{
+	struct rpc_clnt *clnt = p->clnt;
+	struct net *net = rpc_net_ns(clnt);
+
+	rpc_remove_pipe_dir_object(net,
+			&clnt->cl_pipedir_objects,
+			&p->pdo);
+	rpc_destroy_pipe_data(p->pipe);
+	kfree(p);
+}
+
+static void __gss_pipe_release(struct kref *kref)
+{
+	struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
+
+	__gss_pipe_free(p);
+}
+
+static void gss_pipe_free(struct gss_pipe *p)
+{
+	if (p != NULL)
+		kref_put(&p->kref, __gss_pipe_release);
+}
+
+/*
+ * NOTE: we have the opportunity to use different
+ * parameters based on the input flavor (which must be a pseudoflavor)
+ */
+static struct gss_auth *
+gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
+{
+	rpc_authflavor_t flavor = args->pseudoflavor;
+	struct gss_auth *gss_auth;
+	struct gss_pipe *gss_pipe;
+	struct rpc_auth * auth;
+	int err = -ENOMEM; /* XXX? */
+
+	dprintk("RPC:       creating GSS authenticator for client %p\n", clnt);
+
+	if (!try_module_get(THIS_MODULE))
+		return ERR_PTR(err);
+	if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
+		goto out_dec;
+	INIT_HLIST_NODE(&gss_auth->hash);
+	gss_auth->target_name = NULL;
+	if (args->target_name) {
+		gss_auth->target_name = kstrdup(args->target_name, GFP_KERNEL);
+		if (gss_auth->target_name == NULL)
+			goto err_free;
+	}
+	gss_auth->client = clnt;
+	gss_auth->net = get_net(rpc_net_ns(clnt));
+	err = -EINVAL;
+	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
+	if (!gss_auth->mech) {
+		dprintk("RPC:       Pseudoflavor %d not found!\n", flavor);
+		goto err_put_net;
+	}
+	gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
+	if (gss_auth->service == 0)
+		goto err_put_mech;
+	if (!gssd_running(gss_auth->net))
+		goto err_put_mech;
+	auth = &gss_auth->rpc_auth;
+	auth->au_cslack = GSS_CRED_SLACK >> 2;
+	auth->au_rslack = GSS_VERF_SLACK >> 2;
+	auth->au_flags = 0;
+	auth->au_ops = &authgss_ops;
+	auth->au_flavor = flavor;
+	if (gss_pseudoflavor_to_datatouch(gss_auth->mech, flavor))
+		auth->au_flags |= RPCAUTH_AUTH_DATATOUCH;
+	atomic_set(&auth->au_count, 1);
+	kref_init(&gss_auth->kref);
+
+	err = rpcauth_init_credcache(auth);
+	if (err)
+		goto err_put_mech;
+	/*
+	 * Note: if we created the old pipe first, then someone who
+	 * examined the directory at the right moment might conclude
+	 * that we supported only the old pipe.  So we instead create
+	 * the new pipe first.
+	 */
+	gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
+	if (IS_ERR(gss_pipe)) {
+		err = PTR_ERR(gss_pipe);
+		goto err_destroy_credcache;
+	}
+	gss_auth->gss_pipe[1] = gss_pipe;
+
+	gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
+			&gss_upcall_ops_v0);
+	if (IS_ERR(gss_pipe)) {
+		err = PTR_ERR(gss_pipe);
+		goto err_destroy_pipe_1;
+	}
+	gss_auth->gss_pipe[0] = gss_pipe;
+
+	return gss_auth;
+err_destroy_pipe_1:
+	gss_pipe_free(gss_auth->gss_pipe[1]);
+err_destroy_credcache:
+	rpcauth_destroy_credcache(auth);
+err_put_mech:
+	gss_mech_put(gss_auth->mech);
+err_put_net:
+	put_net(gss_auth->net);
+err_free:
+	kfree(gss_auth->target_name);
+	kfree(gss_auth);
+out_dec:
+	module_put(THIS_MODULE);
+	return ERR_PTR(err);
+}
+
+static void
+gss_free(struct gss_auth *gss_auth)
+{
+	gss_pipe_free(gss_auth->gss_pipe[0]);
+	gss_pipe_free(gss_auth->gss_pipe[1]);
+	gss_mech_put(gss_auth->mech);
+	put_net(gss_auth->net);
+	kfree(gss_auth->target_name);
+
+	kfree(gss_auth);
+	module_put(THIS_MODULE);
+}
+
+static void
+gss_free_callback(struct kref *kref)
+{
+	struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
+
+	gss_free(gss_auth);
+}
+
+static void
+gss_put_auth(struct gss_auth *gss_auth)
+{
+	kref_put(&gss_auth->kref, gss_free_callback);
+}
+
+static void
+gss_destroy(struct rpc_auth *auth)
+{
+	struct gss_auth *gss_auth = container_of(auth,
+			struct gss_auth, rpc_auth);
+
+	dprintk("RPC:       destroying GSS authenticator %p flavor %d\n",
+			auth, auth->au_flavor);
+
+	if (hash_hashed(&gss_auth->hash)) {
+		spin_lock(&gss_auth_hash_lock);
+		hash_del(&gss_auth->hash);
+		spin_unlock(&gss_auth_hash_lock);
+	}
+
+	gss_pipe_free(gss_auth->gss_pipe[0]);
+	gss_auth->gss_pipe[0] = NULL;
+	gss_pipe_free(gss_auth->gss_pipe[1]);
+	gss_auth->gss_pipe[1] = NULL;
+	rpcauth_destroy_credcache(auth);
+
+	gss_put_auth(gss_auth);
+}
+
+/*
+ * Auths may be shared between rpc clients that were cloned from a
+ * common client with the same xprt, if they also share the flavor and
+ * target_name.
+ *
+ * The auth is looked up from the oldest parent sharing the same
+ * cl_xprt, and the auth itself references only that common parent
+ * (which is guaranteed to last as long as any of its descendants).
+ */
+static struct gss_auth *
+gss_auth_find_or_add_hashed(const struct rpc_auth_create_args *args,
+		struct rpc_clnt *clnt,
+		struct gss_auth *new)
+{
+	struct gss_auth *gss_auth;
+	unsigned long hashval = (unsigned long)clnt;
+
+	spin_lock(&gss_auth_hash_lock);
+	hash_for_each_possible(gss_auth_hash_table,
+			gss_auth,
+			hash,
+			hashval) {
+		if (gss_auth->client != clnt)
+			continue;
+		if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor)
+			continue;
+		if (gss_auth->target_name != args->target_name) {
+			if (gss_auth->target_name == NULL)
+				continue;
+			if (args->target_name == NULL)
+				continue;
+			if (strcmp(gss_auth->target_name, args->target_name))
+				continue;
+		}
+		if (!atomic_inc_not_zero(&gss_auth->rpc_auth.au_count))
+			continue;
+		goto out;
+	}
+	if (new)
+		hash_add(gss_auth_hash_table, &new->hash, hashval);
+	gss_auth = new;
+out:
+	spin_unlock(&gss_auth_hash_lock);
+	return gss_auth;
+}
+
+static struct gss_auth *
+gss_create_hashed(const struct rpc_auth_create_args *args,
+		  struct rpc_clnt *clnt)
+{
+	struct gss_auth *gss_auth;
+	struct gss_auth *new;
+
+	gss_auth = gss_auth_find_or_add_hashed(args, clnt, NULL);
+	if (gss_auth != NULL)
+		goto out;
+	new = gss_create_new(args, clnt);
+	if (IS_ERR(new))
+		return new;
+	gss_auth = gss_auth_find_or_add_hashed(args, clnt, new);
+	if (gss_auth != new)
+		gss_destroy(&new->rpc_auth);
+out:
+	return gss_auth;
+}
+
+static struct rpc_auth *
+gss_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
+{
+	struct gss_auth *gss_auth;
+	struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
+
+	while (clnt != clnt->cl_parent) {
+		struct rpc_clnt *parent = clnt->cl_parent;
+		/* Find the original parent for this transport */
+		if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
+			break;
+		clnt = parent;
+	}
+
+	gss_auth = gss_create_hashed(args, clnt);
+	if (IS_ERR(gss_auth))
+		return ERR_CAST(gss_auth);
+	return &gss_auth->rpc_auth;
+}
+
+/*
+ * gss_destroying_context will cause the RPCSEC_GSS to send a NULL RPC call
+ * to the server with the GSS control procedure field set to
+ * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
+ * all RPCSEC_GSS state associated with that context.
+ */
+static int
+gss_destroying_context(struct rpc_cred *cred)
+{
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
+	struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
+	struct rpc_task *task;
+
+	if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
+		return 0;
+
+	ctx->gc_proc = RPC_GSS_PROC_DESTROY;
+	cred->cr_ops = &gss_nullops;
+
+	/* Take a reference to ensure the cred will be destroyed either
+	 * by the RPC call or by the put_rpccred() below */
+	get_rpccred(cred);
+
+	task = rpc_call_null(gss_auth->client, cred, RPC_TASK_ASYNC|RPC_TASK_SOFT);
+	if (!IS_ERR(task))
+		rpc_put_task(task);
+
+	put_rpccred(cred);
+	return 1;
+}
+
+/* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
+ * to create a new cred or context, so they check that things have been
+ * allocated before freeing them. */
+static void
+gss_do_free_ctx(struct gss_cl_ctx *ctx)
+{
+	dprintk("RPC:       %s\n", __func__);
+
+	gss_delete_sec_context(&ctx->gc_gss_ctx);
+	kfree(ctx->gc_wire_ctx.data);
+	kfree(ctx->gc_acceptor.data);
+	kfree(ctx);
+}
+
+static void
+gss_free_ctx_callback(struct rcu_head *head)
+{
+	struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
+	gss_do_free_ctx(ctx);
+}
+
+static void
+gss_free_ctx(struct gss_cl_ctx *ctx)
+{
+	call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
+}
+
+static void
+gss_free_cred(struct gss_cred *gss_cred)
+{
+	dprintk("RPC:       %s cred=%p\n", __func__, gss_cred);
+	kfree(gss_cred);
+}
+
+static void
+gss_free_cred_callback(struct rcu_head *head)
+{
+	struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
+	gss_free_cred(gss_cred);
+}
+
+static void
+gss_destroy_nullcred(struct rpc_cred *cred)
+{
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
+	struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
+
+	RCU_INIT_POINTER(gss_cred->gc_ctx, NULL);
+	call_rcu(&cred->cr_rcu, gss_free_cred_callback);
+	if (ctx)
+		gss_put_ctx(ctx);
+	gss_put_auth(gss_auth);
+}
+
+static void
+gss_destroy_cred(struct rpc_cred *cred)
+{
+
+	if (gss_destroying_context(cred))
+		return;
+	gss_destroy_nullcred(cred);
+}
+
+static int
+gss_hash_cred(struct auth_cred *acred, unsigned int hashbits)
+{
+	return hash_64(from_kuid(&init_user_ns, acred->uid), hashbits);
+}
+
+/*
+ * Lookup RPCSEC_GSS cred for the current process
+ */
+static struct rpc_cred *
+gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
+{
+	return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
+}
+
+static struct rpc_cred *
+gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
+{
+	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
+	struct gss_cred	*cred = NULL;
+	int err = -ENOMEM;
+
+	dprintk("RPC:       %s for uid %d, flavor %d\n",
+		__func__, from_kuid(&init_user_ns, acred->uid),
+		auth->au_flavor);
+
+	if (!(cred = kzalloc(sizeof(*cred), gfp)))
+		goto out_err;
+
+	rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
+	/*
+	 * Note: in order to force a call to call_refresh(), we deliberately
+	 * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
+	 */
+	cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
+	cred->gc_service = gss_auth->service;
+	cred->gc_principal = NULL;
+	if (acred->machine_cred)
+		cred->gc_principal = acred->principal;
+	kref_get(&gss_auth->kref);
+	return &cred->gc_base;
+
+out_err:
+	dprintk("RPC:       %s failed with error %d\n", __func__, err);
+	return ERR_PTR(err);
+}
+
+static int
+gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
+{
+	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
+	struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
+	int err;
+
+	do {
+		err = gss_create_upcall(gss_auth, gss_cred);
+	} while (err == -EAGAIN);
+	return err;
+}
+
+static char *
+gss_stringify_acceptor(struct rpc_cred *cred)
+{
+	char *string = NULL;
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+	struct gss_cl_ctx *ctx;
+	unsigned int len;
+	struct xdr_netobj *acceptor;
+
+	rcu_read_lock();
+	ctx = rcu_dereference(gss_cred->gc_ctx);
+	if (!ctx)
+		goto out;
+
+	len = ctx->gc_acceptor.len;
+	rcu_read_unlock();
+
+	/* no point if there's no string */
+	if (!len)
+		return NULL;
+realloc:
+	string = kmalloc(len + 1, GFP_KERNEL);
+	if (!string)
+		return NULL;
+
+	rcu_read_lock();
+	ctx = rcu_dereference(gss_cred->gc_ctx);
+
+	/* did the ctx disappear or was it replaced by one with no acceptor? */
+	if (!ctx || !ctx->gc_acceptor.len) {
+		kfree(string);
+		string = NULL;
+		goto out;
+	}
+
+	acceptor = &ctx->gc_acceptor;
+
+	/*
+	 * Did we find a new acceptor that's longer than the original? Allocate
+	 * a longer buffer and try again.
+	 */
+	if (len < acceptor->len) {
+		len = acceptor->len;
+		rcu_read_unlock();
+		kfree(string);
+		goto realloc;
+	}
+
+	memcpy(string, acceptor->data, acceptor->len);
+	string[acceptor->len] = '\0';
+out:
+	rcu_read_unlock();
+	return string;
+}
+
+/*
+ * Returns -EACCES if GSS context is NULL or will expire within the
+ * timeout (miliseconds)
+ */
+static int
+gss_key_timeout(struct rpc_cred *rc)
+{
+	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
+	struct gss_cl_ctx *ctx;
+	unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ);
+	int ret = 0;
+
+	rcu_read_lock();
+	ctx = rcu_dereference(gss_cred->gc_ctx);
+	if (!ctx || time_after(timeout, ctx->gc_expiry))
+		ret = -EACCES;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int
+gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
+{
+	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
+	struct gss_cl_ctx *ctx;
+	int ret;
+
+	if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
+		goto out;
+	/* Don't match with creds that have expired. */
+	rcu_read_lock();
+	ctx = rcu_dereference(gss_cred->gc_ctx);
+	if (!ctx || time_after(jiffies, ctx->gc_expiry)) {
+		rcu_read_unlock();
+		return 0;
+	}
+	rcu_read_unlock();
+	if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
+		return 0;
+out:
+	if (acred->principal != NULL) {
+		if (gss_cred->gc_principal == NULL)
+			return 0;
+		ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
+		goto check_expire;
+	}
+	if (gss_cred->gc_principal != NULL)
+		return 0;
+	ret = uid_eq(rc->cr_uid, acred->uid);
+
+check_expire:
+	if (ret == 0)
+		return ret;
+
+	/* Notify acred users of GSS context expiration timeout */
+	if (test_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags) &&
+	    (gss_key_timeout(rc) != 0)) {
+		/* test will now be done from generic cred */
+		test_and_clear_bit(RPC_CRED_NOTIFY_TIMEOUT, &acred->ac_flags);
+		/* tell NFS layer that key will expire soon */
+		set_bit(RPC_CRED_KEY_EXPIRE_SOON, &acred->ac_flags);
+	}
+	return ret;
+}
+
+/*
+* Marshal credentials.
+* Maybe we should keep a cached credential for performance reasons.
+*/
+static __be32 *
+gss_marshal(struct rpc_task *task, __be32 *p)
+{
+	struct rpc_rqst *req = task->tk_rqstp;
+	struct rpc_cred *cred = req->rq_cred;
+	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
+						 gc_base);
+	struct gss_cl_ctx	*ctx = gss_cred_get_ctx(cred);
+	__be32		*cred_len;
+	u32             maj_stat = 0;
+	struct xdr_netobj mic;
+	struct kvec	iov;
+	struct xdr_buf	verf_buf;
+
+	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
+
+	*p++ = htonl(RPC_AUTH_GSS);
+	cred_len = p++;
+
+	spin_lock(&ctx->gc_seq_lock);
+	req->rq_seqno = ctx->gc_seq++;
+	spin_unlock(&ctx->gc_seq_lock);
+
+	*p++ = htonl((u32) RPC_GSS_VERSION);
+	*p++ = htonl((u32) ctx->gc_proc);
+	*p++ = htonl((u32) req->rq_seqno);
+	*p++ = htonl((u32) gss_cred->gc_service);
+	p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
+	*cred_len = htonl((p - (cred_len + 1)) << 2);
+
+	/* We compute the checksum for the verifier over the xdr-encoded bytes
+	 * starting with the xid and ending at the end of the credential: */
+	iov.iov_base = xprt_skip_transport_header(req->rq_xprt,
+					req->rq_snd_buf.head[0].iov_base);
+	iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
+	xdr_buf_from_iov(&iov, &verf_buf);
+
+	/* set verifier flavor*/
+	*p++ = htonl(RPC_AUTH_GSS);
+
+	mic.data = (u8 *)(p + 1);
+	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	} else if (maj_stat != 0) {
+		printk("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
+		goto out_put_ctx;
+	}
+	p = xdr_encode_opaque(p, NULL, mic.len);
+	gss_put_ctx(ctx);
+	return p;
+out_put_ctx:
+	gss_put_ctx(ctx);
+	return NULL;
+}
+
+static int gss_renew_cred(struct rpc_task *task)
+{
+	struct rpc_cred *oldcred = task->tk_rqstp->rq_cred;
+	struct gss_cred *gss_cred = container_of(oldcred,
+						 struct gss_cred,
+						 gc_base);
+	struct rpc_auth *auth = oldcred->cr_auth;
+	struct auth_cred acred = {
+		.uid = oldcred->cr_uid,
+		.principal = gss_cred->gc_principal,
+		.machine_cred = (gss_cred->gc_principal != NULL ? 1 : 0),
+	};
+	struct rpc_cred *new;
+
+	new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+	task->tk_rqstp->rq_cred = new;
+	put_rpccred(oldcred);
+	return 0;
+}
+
+static int gss_cred_is_negative_entry(struct rpc_cred *cred)
+{
+	if (test_bit(RPCAUTH_CRED_NEGATIVE, &cred->cr_flags)) {
+		unsigned long now = jiffies;
+		unsigned long begin, expire;
+		struct gss_cred *gss_cred;
+
+		gss_cred = container_of(cred, struct gss_cred, gc_base);
+		begin = gss_cred->gc_upcall_timestamp;
+		expire = begin + gss_expired_cred_retry_delay * HZ;
+
+		if (time_in_range_open(now, begin, expire))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+* Refresh credentials. XXX - finish
+*/
+static int
+gss_refresh(struct rpc_task *task)
+{
+	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	int ret = 0;
+
+	if (gss_cred_is_negative_entry(cred))
+		return -EKEYEXPIRED;
+
+	if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
+			!test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
+		ret = gss_renew_cred(task);
+		if (ret < 0)
+			goto out;
+		cred = task->tk_rqstp->rq_cred;
+	}
+
+	if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
+		ret = gss_refresh_upcall(task);
+out:
+	return ret;
+}
+
+/* Dummy refresh routine: used only when destroying the context */
+static int
+gss_refresh_null(struct rpc_task *task)
+{
+	return 0;
+}
+
+static __be32 *
+gss_validate(struct rpc_task *task, __be32 *p)
+{
+	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
+	__be32		*seq = NULL;
+	struct kvec	iov;
+	struct xdr_buf	verf_buf;
+	struct xdr_netobj mic;
+	u32		flav,len;
+	u32		maj_stat;
+	__be32		*ret = ERR_PTR(-EIO);
+
+	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
+
+	flav = ntohl(*p++);
+	if ((len = ntohl(*p++)) > RPC_MAX_AUTH_SIZE)
+		goto out_bad;
+	if (flav != RPC_AUTH_GSS)
+		goto out_bad;
+	seq = kmalloc(4, GFP_NOFS);
+	if (!seq)
+		goto out_bad;
+	*seq = htonl(task->tk_rqstp->rq_seqno);
+	iov.iov_base = seq;
+	iov.iov_len = 4;
+	xdr_buf_from_iov(&iov, &verf_buf);
+	mic.data = (u8 *)p;
+	mic.len = len;
+
+	ret = ERR_PTR(-EACCES);
+	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	if (maj_stat) {
+		dprintk("RPC: %5u %s: gss_verify_mic returned error 0x%08x\n",
+			task->tk_pid, __func__, maj_stat);
+		goto out_bad;
+	}
+	/* We leave it to unwrap to calculate au_rslack. For now we just
+	 * calculate the length of the verifier: */
+	cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
+	gss_put_ctx(ctx);
+	dprintk("RPC: %5u %s: gss_verify_mic succeeded.\n",
+			task->tk_pid, __func__);
+	kfree(seq);
+	return p + XDR_QUADLEN(len);
+out_bad:
+	gss_put_ctx(ctx);
+	dprintk("RPC: %5u %s failed ret %ld.\n", task->tk_pid, __func__,
+		PTR_ERR(ret));
+	kfree(seq);
+	return ret;
+}
+
+static void gss_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
+				__be32 *p, void *obj)
+{
+	struct xdr_stream xdr;
+
+	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, p);
+	encode(rqstp, &xdr, obj);
+}
+
+static inline int
+gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+		   kxdreproc_t encode, struct rpc_rqst *rqstp,
+		   __be32 *p, void *obj)
+{
+	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
+	struct xdr_buf	integ_buf;
+	__be32          *integ_len = NULL;
+	struct xdr_netobj mic;
+	u32		offset;
+	__be32		*q;
+	struct kvec	*iov;
+	u32             maj_stat = 0;
+	int		status = -EIO;
+
+	integ_len = p++;
+	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
+	*p++ = htonl(rqstp->rq_seqno);
+
+	gss_wrap_req_encode(encode, rqstp, p, obj);
+
+	if (xdr_buf_subsegment(snd_buf, &integ_buf,
+				offset, snd_buf->len - offset))
+		return status;
+	*integ_len = htonl(integ_buf.len);
+
+	/* guess whether we're in the head or the tail: */
+	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
+		iov = snd_buf->tail;
+	else
+		iov = snd_buf->head;
+	p = iov->iov_base + iov->iov_len;
+	mic.data = (u8 *)(p + 1);
+
+	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
+	status = -EIO; /* XXX? */
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	else if (maj_stat)
+		return status;
+	q = xdr_encode_opaque(p, NULL, mic.len);
+
+	offset = (u8 *)q - (u8 *)p;
+	iov->iov_len += offset;
+	snd_buf->len += offset;
+	return 0;
+}
+
+static void
+priv_release_snd_buf(struct rpc_rqst *rqstp)
+{
+	int i;
+
+	for (i=0; i < rqstp->rq_enc_pages_num; i++)
+		__free_page(rqstp->rq_enc_pages[i]);
+	kfree(rqstp->rq_enc_pages);
+	rqstp->rq_release_snd_buf = NULL;
+}
+
+static int
+alloc_enc_pages(struct rpc_rqst *rqstp)
+{
+	struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
+	int first, last, i;
+
+	if (rqstp->rq_release_snd_buf)
+		rqstp->rq_release_snd_buf(rqstp);
+
+	if (snd_buf->page_len == 0) {
+		rqstp->rq_enc_pages_num = 0;
+		return 0;
+	}
+
+	first = snd_buf->page_base >> PAGE_SHIFT;
+	last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
+	rqstp->rq_enc_pages_num = last - first + 1 + 1;
+	rqstp->rq_enc_pages
+		= kmalloc_array(rqstp->rq_enc_pages_num,
+				sizeof(struct page *),
+				GFP_NOFS);
+	if (!rqstp->rq_enc_pages)
+		goto out;
+	for (i=0; i < rqstp->rq_enc_pages_num; i++) {
+		rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
+		if (rqstp->rq_enc_pages[i] == NULL)
+			goto out_free;
+	}
+	rqstp->rq_release_snd_buf = priv_release_snd_buf;
+	return 0;
+out_free:
+	rqstp->rq_enc_pages_num = i;
+	priv_release_snd_buf(rqstp);
+out:
+	return -EAGAIN;
+}
+
+static inline int
+gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+		  kxdreproc_t encode, struct rpc_rqst *rqstp,
+		  __be32 *p, void *obj)
+{
+	struct xdr_buf	*snd_buf = &rqstp->rq_snd_buf;
+	u32		offset;
+	u32             maj_stat;
+	int		status;
+	__be32		*opaque_len;
+	struct page	**inpages;
+	int		first;
+	int		pad;
+	struct kvec	*iov;
+	char		*tmp;
+
+	opaque_len = p++;
+	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
+	*p++ = htonl(rqstp->rq_seqno);
+
+	gss_wrap_req_encode(encode, rqstp, p, obj);
+
+	status = alloc_enc_pages(rqstp);
+	if (status)
+		return status;
+	first = snd_buf->page_base >> PAGE_SHIFT;
+	inpages = snd_buf->pages + first;
+	snd_buf->pages = rqstp->rq_enc_pages;
+	snd_buf->page_base -= first << PAGE_SHIFT;
+	/*
+	 * Give the tail its own page, in case we need extra space in the
+	 * head when wrapping:
+	 *
+	 * call_allocate() allocates twice the slack space required
+	 * by the authentication flavor to rq_callsize.
+	 * For GSS, slack is GSS_CRED_SLACK.
+	 */
+	if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
+		tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
+		memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
+		snd_buf->tail[0].iov_base = tmp;
+	}
+	maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
+	/* slack space should prevent this ever happening: */
+	BUG_ON(snd_buf->len > snd_buf->buflen);
+	status = -EIO;
+	/* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
+	 * done anyway, so it's safe to put the request on the wire: */
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	else if (maj_stat)
+		return status;
+
+	*opaque_len = htonl(snd_buf->len - offset);
+	/* guess whether we're in the head or the tail: */
+	if (snd_buf->page_len || snd_buf->tail[0].iov_len)
+		iov = snd_buf->tail;
+	else
+		iov = snd_buf->head;
+	p = iov->iov_base + iov->iov_len;
+	pad = 3 - ((snd_buf->len - offset - 1) & 3);
+	memset(p, 0, pad);
+	iov->iov_len += pad;
+	snd_buf->len += pad;
+
+	return 0;
+}
+
+static int
+gss_wrap_req(struct rpc_task *task,
+	     kxdreproc_t encode, void *rqstp, __be32 *p, void *obj)
+{
+	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
+			gc_base);
+	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
+	int             status = -EIO;
+
+	dprintk("RPC: %5u %s\n", task->tk_pid, __func__);
+	if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
+		/* The spec seems a little ambiguous here, but I think that not
+		 * wrapping context destruction requests makes the most sense.
+		 */
+		gss_wrap_req_encode(encode, rqstp, p, obj);
+		status = 0;
+		goto out;
+	}
+	switch (gss_cred->gc_service) {
+	case RPC_GSS_SVC_NONE:
+		gss_wrap_req_encode(encode, rqstp, p, obj);
+		status = 0;
+		break;
+	case RPC_GSS_SVC_INTEGRITY:
+		status = gss_wrap_req_integ(cred, ctx, encode, rqstp, p, obj);
+		break;
+	case RPC_GSS_SVC_PRIVACY:
+		status = gss_wrap_req_priv(cred, ctx, encode, rqstp, p, obj);
+		break;
+	}
+out:
+	gss_put_ctx(ctx);
+	dprintk("RPC: %5u %s returning %d\n", task->tk_pid, __func__, status);
+	return status;
+}
+
+static inline int
+gss_unwrap_resp_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+		struct rpc_rqst *rqstp, __be32 **p)
+{
+	struct xdr_buf	*rcv_buf = &rqstp->rq_rcv_buf;
+	struct xdr_buf integ_buf;
+	struct xdr_netobj mic;
+	u32 data_offset, mic_offset;
+	u32 integ_len;
+	u32 maj_stat;
+	int status = -EIO;
+
+	integ_len = ntohl(*(*p)++);
+	if (integ_len & 3)
+		return status;
+	data_offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
+	mic_offset = integ_len + data_offset;
+	if (mic_offset > rcv_buf->len)
+		return status;
+	if (ntohl(*(*p)++) != rqstp->rq_seqno)
+		return status;
+
+	if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset,
+				mic_offset - data_offset))
+		return status;
+
+	if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
+		return status;
+
+	maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	if (maj_stat != GSS_S_COMPLETE)
+		return status;
+	return 0;
+}
+
+static inline int
+gss_unwrap_resp_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+		struct rpc_rqst *rqstp, __be32 **p)
+{
+	struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
+	u32 offset;
+	u32 opaque_len;
+	u32 maj_stat;
+	int status = -EIO;
+
+	opaque_len = ntohl(*(*p)++);
+	offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
+	if (offset + opaque_len > rcv_buf->len)
+		return status;
+	/* remove padding: */
+	rcv_buf->len = offset + opaque_len;
+
+	maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
+	if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+	if (maj_stat != GSS_S_COMPLETE)
+		return status;
+	if (ntohl(*(*p)++) != rqstp->rq_seqno)
+		return status;
+
+	return 0;
+}
+
+static int
+gss_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
+		      __be32 *p, void *obj)
+{
+	struct xdr_stream xdr;
+
+	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
+	return decode(rqstp, &xdr, obj);
+}
+
+static int
+gss_unwrap_resp(struct rpc_task *task,
+		kxdrdproc_t decode, void *rqstp, __be32 *p, void *obj)
+{
+	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
+			gc_base);
+	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
+	__be32		*savedp = p;
+	struct kvec	*head = ((struct rpc_rqst *)rqstp)->rq_rcv_buf.head;
+	int		savedlen = head->iov_len;
+	int             status = -EIO;
+
+	if (ctx->gc_proc != RPC_GSS_PROC_DATA)
+		goto out_decode;
+	switch (gss_cred->gc_service) {
+	case RPC_GSS_SVC_NONE:
+		break;
+	case RPC_GSS_SVC_INTEGRITY:
+		status = gss_unwrap_resp_integ(cred, ctx, rqstp, &p);
+		if (status)
+			goto out;
+		break;
+	case RPC_GSS_SVC_PRIVACY:
+		status = gss_unwrap_resp_priv(cred, ctx, rqstp, &p);
+		if (status)
+			goto out;
+		break;
+	}
+	/* take into account extra slack for integrity and privacy cases: */
+	cred->cr_auth->au_rslack = cred->cr_auth->au_verfsize + (p - savedp)
+						+ (savedlen - head->iov_len);
+out_decode:
+	status = gss_unwrap_req_decode(decode, rqstp, p, obj);
+out:
+	gss_put_ctx(ctx);
+	dprintk("RPC: %5u %s returning %d\n",
+		task->tk_pid, __func__, status);
+	return status;
+}
+
+static const struct rpc_authops authgss_ops = {
+	.owner		= THIS_MODULE,
+	.au_flavor	= RPC_AUTH_GSS,
+	.au_name	= "RPCSEC_GSS",
+	.create		= gss_create,
+	.destroy	= gss_destroy,
+	.hash_cred	= gss_hash_cred,
+	.lookup_cred	= gss_lookup_cred,
+	.crcreate	= gss_create_cred,
+	.list_pseudoflavors = gss_mech_list_pseudoflavors,
+	.info2flavor	= gss_mech_info2flavor,
+	.flavor2info	= gss_mech_flavor2info,
+};
+
+static const struct rpc_credops gss_credops = {
+	.cr_name		= "AUTH_GSS",
+	.crdestroy		= gss_destroy_cred,
+	.cr_init		= gss_cred_init,
+	.crbind			= rpcauth_generic_bind_cred,
+	.crmatch		= gss_match,
+	.crmarshal		= gss_marshal,
+	.crrefresh		= gss_refresh,
+	.crvalidate		= gss_validate,
+	.crwrap_req		= gss_wrap_req,
+	.crunwrap_resp		= gss_unwrap_resp,
+	.crkey_timeout		= gss_key_timeout,
+	.crstringify_acceptor	= gss_stringify_acceptor,
+};
+
+static const struct rpc_credops gss_nullops = {
+	.cr_name		= "AUTH_GSS",
+	.crdestroy		= gss_destroy_nullcred,
+	.crbind			= rpcauth_generic_bind_cred,
+	.crmatch		= gss_match,
+	.crmarshal		= gss_marshal,
+	.crrefresh		= gss_refresh_null,
+	.crvalidate		= gss_validate,
+	.crwrap_req		= gss_wrap_req,
+	.crunwrap_resp		= gss_unwrap_resp,
+	.crstringify_acceptor	= gss_stringify_acceptor,
+};
+
+static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
+	.upcall		= rpc_pipe_generic_upcall,
+	.downcall	= gss_pipe_downcall,
+	.destroy_msg	= gss_pipe_destroy_msg,
+	.open_pipe	= gss_pipe_open_v0,
+	.release_pipe	= gss_pipe_release,
+};
+
+static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
+	.upcall		= rpc_pipe_generic_upcall,
+	.downcall	= gss_pipe_downcall,
+	.destroy_msg	= gss_pipe_destroy_msg,
+	.open_pipe	= gss_pipe_open_v1,
+	.release_pipe	= gss_pipe_release,
+};
+
+static __net_init int rpcsec_gss_init_net(struct net *net)
+{
+	return gss_svc_init_net(net);
+}
+
+static __net_exit void rpcsec_gss_exit_net(struct net *net)
+{
+	gss_svc_shutdown_net(net);
+}
+
+static struct pernet_operations rpcsec_gss_net_ops = {
+	.init = rpcsec_gss_init_net,
+	.exit = rpcsec_gss_exit_net,
+};
+
+/*
+ * Initialize RPCSEC_GSS module
+ */
+static int __init init_rpcsec_gss(void)
+{
+	int err = 0;
+
+	err = rpcauth_register(&authgss_ops);
+	if (err)
+		goto out;
+	err = gss_svc_init();
+	if (err)
+		goto out_unregister;
+	err = register_pernet_subsys(&rpcsec_gss_net_ops);
+	if (err)
+		goto out_svc_exit;
+	rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
+	return 0;
+out_svc_exit:
+	gss_svc_shutdown();
+out_unregister:
+	rpcauth_unregister(&authgss_ops);
+out:
+	return err;
+}
+
+static void __exit exit_rpcsec_gss(void)
+{
+	unregister_pernet_subsys(&rpcsec_gss_net_ops);
+	gss_svc_shutdown();
+	rpcauth_unregister(&authgss_ops);
+	rcu_barrier(); /* Wait for completion of call_rcu()'s */
+}
+
+MODULE_ALIAS("rpc-auth-6");
+MODULE_LICENSE("GPL");
+module_param_named(expired_cred_retry_delay,
+		   gss_expired_cred_retry_delay,
+		   uint, 0644);
+MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
+		"the RPC engine retries an expired credential");
+
+module_param_named(key_expire_timeo,
+		   gss_key_expire_timeo,
+		   uint, 0644);
+MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
+		"credential keys lifetime where the NFS layer cleans up "
+		"prior to key expiration");
+
+module_init(init_rpcsec_gss)
+module_exit(exit_rpcsec_gss)