/*

   * 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 "../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 const void *
  simple_get_bytes(const void *p, const void *end, void *res, size_t len)
  {
  	const void *q = (const void *)((const char *)p + len);
  	if (unlikely(q > end || q < p))
  		return ERR_PTR(-EFAULT);
  	memcpy(res, p, len);
  	return q;
  }
  
  static inline const void *
  simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
  {
  	const void *q;
  	unsigned int len;
  
  	p = simple_get_bytes(p, end, &len, sizeof(len));
  	if (IS_ERR(p))
  		return p;
  	q = (const void *)((const char *)p + len);
  	if (unlikely(q > end || q < p))
  		return ERR_PTR(-EFAULT);

  	dest->data = kmemdup(p, len, GFP_NOFS);

  	if (unlikely(dest->data == NULL))
  		return ERR_PTR(-ENOMEM);
  	dest->len = len;

  	return q;
  }
  
  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
  ",
  		__func__, ctx->gc_expiry, now, timeout, ctx->gc_acceptor.len,
  		ctx->gc_acceptor.data);
  	return p;

  err:

  	dprintk("RPC:       %s returns error %ld
  ", __func__, -PTR_ERR(p));

  	return p;
  }

  #define UPCALL_BUF_LEN 128

  
  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
  ", __func__, pos);

  		return pos;
  	}

  	dprintk("RPC:       %s found nothing
  ", __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;

  	if (target_name) {

  		len = scnprintf(p, buflen, "target=%s ", target_name);
  		buflen -= len;

  		p += len;
  		gss_msg->msg.len += len;
  	}

  	if (service_name != NULL) {

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

  }

  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
  ",

  		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
  ",

  		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
  ",
  		__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
  ",

  		__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
  ", __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
  ", __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
  ",
  			__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(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
  ", 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!
  ", 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
  ",
  			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(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(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(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
  ", __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
  ", __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
  ",

  		__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
  ", __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
  ", 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)
  ", 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
  ", task->tk_pid, __func__);

  
  	flav = ntohl(*p++);
  	if ((len = ntohl(*p++)) > RPC_MAX_AUTH_SIZE)

  		goto out_bad;