Adding upstream version 5.10.209.upstream/5.10.209

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

1 files changed, 2012 insertions, 0 deletions

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
new file mode 100644
index 000000000..406ff7f8b
--- /dev/null
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -0,0 +1,2012 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Neil Brown <neilb@cse.unsw.edu.au>
+ * J. Bruce Fields <bfields@umich.edu>
+ * Andy Adamson <andros@umich.edu>
+ * Dug Song <dugsong@monkey.org>
+ *
+ * RPCSEC_GSS server authentication.
+ * This implements RPCSEC_GSS as defined in rfc2203 (rpcsec_gss) and rfc2078
+ * (gssapi)
+ *
+ * The RPCSEC_GSS involves three stages:
+ *  1/ context creation
+ *  2/ data exchange
+ *  3/ context destruction
+ *
+ * Context creation is handled largely by upcalls to user-space.
+ *  In particular, GSS_Accept_sec_context is handled by an upcall
+ * Data exchange is handled entirely within the kernel
+ *  In particular, GSS_GetMIC, GSS_VerifyMIC, GSS_Seal, GSS_Unseal are in-kernel.
+ * Context destruction is handled in-kernel
+ *  GSS_Delete_sec_context is in-kernel
+ *
+ * Context creation is initiated by a RPCSEC_GSS_INIT request arriving.
+ * The context handle and gss_token are used as a key into the rpcsec_init cache.
+ * The content of this cache includes some of the outputs of GSS_Accept_sec_context,
+ * being major_status, minor_status, context_handle, reply_token.
+ * These are sent back to the client.
+ * Sequence window management is handled by the kernel.  The window size if currently
+ * a compile time constant.
+ *
+ * When user-space is happy that a context is established, it places an entry
+ * in the rpcsec_context cache. The key for this cache is the context_handle.
+ * The content includes:
+ *   uid/gidlist - for determining access rights
+ *   mechanism type
+ *   mechanism specific information, such as a key
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/user_namespace.h>
+
+#include <linux/sunrpc/auth_gss.h>
+#include <linux/sunrpc/gss_err.h>
+#include <linux/sunrpc/svcauth.h>
+#include <linux/sunrpc/svcauth_gss.h>
+#include <linux/sunrpc/cache.h>
+
+#include <trace/events/rpcgss.h>
+
+#include "gss_rpc_upcall.h"
+
+
+/* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests
+ * into replies.
+ *
+ * Key is context handle (\x if empty) and gss_token.
+ * Content is major_status minor_status (integers) context_handle, reply_token.
+ *
+ */
+
+static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
+{
+	return a->len == b->len && 0 == memcmp(a->data, b->data, a->len);
+}
+
+#define	RSI_HASHBITS	6
+#define	RSI_HASHMAX	(1<<RSI_HASHBITS)
+
+struct rsi {
+	struct cache_head	h;
+	struct xdr_netobj	in_handle, in_token;
+	struct xdr_netobj	out_handle, out_token;
+	int			major_status, minor_status;
+	struct rcu_head		rcu_head;
+};
+
+static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old);
+static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item);
+
+static void rsi_free(struct rsi *rsii)
+{
+	kfree(rsii->in_handle.data);
+	kfree(rsii->in_token.data);
+	kfree(rsii->out_handle.data);
+	kfree(rsii->out_token.data);
+}
+
+static void rsi_free_rcu(struct rcu_head *head)
+{
+	struct rsi *rsii = container_of(head, struct rsi, rcu_head);
+
+	rsi_free(rsii);
+	kfree(rsii);
+}
+
+static void rsi_put(struct kref *ref)
+{
+	struct rsi *rsii = container_of(ref, struct rsi, h.ref);
+
+	call_rcu(&rsii->rcu_head, rsi_free_rcu);
+}
+
+static inline int rsi_hash(struct rsi *item)
+{
+	return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS)
+	     ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS);
+}
+
+static int rsi_match(struct cache_head *a, struct cache_head *b)
+{
+	struct rsi *item = container_of(a, struct rsi, h);
+	struct rsi *tmp = container_of(b, struct rsi, h);
+	return netobj_equal(&item->in_handle, &tmp->in_handle) &&
+	       netobj_equal(&item->in_token, &tmp->in_token);
+}
+
+static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len)
+{
+	dst->len = len;
+	dst->data = (len ? kmemdup(src, len, GFP_KERNEL) : NULL);
+	if (len && !dst->data)
+		return -ENOMEM;
+	return 0;
+}
+
+static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src)
+{
+	return dup_to_netobj(dst, src->data, src->len);
+}
+
+static void rsi_init(struct cache_head *cnew, struct cache_head *citem)
+{
+	struct rsi *new = container_of(cnew, struct rsi, h);
+	struct rsi *item = container_of(citem, struct rsi, h);
+
+	new->out_handle.data = NULL;
+	new->out_handle.len = 0;
+	new->out_token.data = NULL;
+	new->out_token.len = 0;
+	new->in_handle.len = item->in_handle.len;
+	item->in_handle.len = 0;
+	new->in_token.len = item->in_token.len;
+	item->in_token.len = 0;
+	new->in_handle.data = item->in_handle.data;
+	item->in_handle.data = NULL;
+	new->in_token.data = item->in_token.data;
+	item->in_token.data = NULL;
+}
+
+static void update_rsi(struct cache_head *cnew, struct cache_head *citem)
+{
+	struct rsi *new = container_of(cnew, struct rsi, h);
+	struct rsi *item = container_of(citem, struct rsi, h);
+
+	BUG_ON(new->out_handle.data || new->out_token.data);
+	new->out_handle.len = item->out_handle.len;
+	item->out_handle.len = 0;
+	new->out_token.len = item->out_token.len;
+	item->out_token.len = 0;
+	new->out_handle.data = item->out_handle.data;
+	item->out_handle.data = NULL;
+	new->out_token.data = item->out_token.data;
+	item->out_token.data = NULL;
+
+	new->major_status = item->major_status;
+	new->minor_status = item->minor_status;
+}
+
+static struct cache_head *rsi_alloc(void)
+{
+	struct rsi *rsii = kmalloc(sizeof(*rsii), GFP_KERNEL);
+	if (rsii)
+		return &rsii->h;
+	else
+		return NULL;
+}
+
+static int rsi_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return sunrpc_cache_pipe_upcall_timeout(cd, h);
+}
+
+static void rsi_request(struct cache_detail *cd,
+		       struct cache_head *h,
+		       char **bpp, int *blen)
+{
+	struct rsi *rsii = container_of(h, struct rsi, h);
+
+	qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
+	qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
+	(*bpp)[-1] = '\n';
+}
+
+static int rsi_parse(struct cache_detail *cd,
+		    char *mesg, int mlen)
+{
+	/* context token expiry major minor context token */
+	char *buf = mesg;
+	char *ep;
+	int len;
+	struct rsi rsii, *rsip = NULL;
+	time64_t expiry;
+	int status = -EINVAL;
+
+	memset(&rsii, 0, sizeof(rsii));
+	/* handle */
+	len = qword_get(&mesg, buf, mlen);
+	if (len < 0)
+		goto out;
+	status = -ENOMEM;
+	if (dup_to_netobj(&rsii.in_handle, buf, len))
+		goto out;
+
+	/* token */
+	len = qword_get(&mesg, buf, mlen);
+	status = -EINVAL;
+	if (len < 0)
+		goto out;
+	status = -ENOMEM;
+	if (dup_to_netobj(&rsii.in_token, buf, len))
+		goto out;
+
+	rsip = rsi_lookup(cd, &rsii);
+	if (!rsip)
+		goto out;
+
+	rsii.h.flags = 0;
+	/* expiry */
+	expiry = get_expiry(&mesg);
+	status = -EINVAL;
+	if (expiry == 0)
+		goto out;
+
+	/* major/minor */
+	len = qword_get(&mesg, buf, mlen);
+	if (len <= 0)
+		goto out;
+	rsii.major_status = simple_strtoul(buf, &ep, 10);
+	if (*ep)
+		goto out;
+	len = qword_get(&mesg, buf, mlen);
+	if (len <= 0)
+		goto out;
+	rsii.minor_status = simple_strtoul(buf, &ep, 10);
+	if (*ep)
+		goto out;
+
+	/* out_handle */
+	len = qword_get(&mesg, buf, mlen);
+	if (len < 0)
+		goto out;
+	status = -ENOMEM;
+	if (dup_to_netobj(&rsii.out_handle, buf, len))
+		goto out;
+
+	/* out_token */
+	len = qword_get(&mesg, buf, mlen);
+	status = -EINVAL;
+	if (len < 0)
+		goto out;
+	status = -ENOMEM;
+	if (dup_to_netobj(&rsii.out_token, buf, len))
+		goto out;
+	rsii.h.expiry_time = expiry;
+	rsip = rsi_update(cd, &rsii, rsip);
+	status = 0;
+out:
+	rsi_free(&rsii);
+	if (rsip)
+		cache_put(&rsip->h, cd);
+	else
+		status = -ENOMEM;
+	return status;
+}
+
+static const struct cache_detail rsi_cache_template = {
+	.owner		= THIS_MODULE,
+	.hash_size	= RSI_HASHMAX,
+	.name           = "auth.rpcsec.init",
+	.cache_put      = rsi_put,
+	.cache_upcall	= rsi_upcall,
+	.cache_request  = rsi_request,
+	.cache_parse    = rsi_parse,
+	.match		= rsi_match,
+	.init		= rsi_init,
+	.update		= update_rsi,
+	.alloc		= rsi_alloc,
+};
+
+static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item)
+{
+	struct cache_head *ch;
+	int hash = rsi_hash(item);
+
+	ch = sunrpc_cache_lookup_rcu(cd, &item->h, hash);
+	if (ch)
+		return container_of(ch, struct rsi, h);
+	else
+		return NULL;
+}
+
+static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old)
+{
+	struct cache_head *ch;
+	int hash = rsi_hash(new);
+
+	ch = sunrpc_cache_update(cd, &new->h,
+				 &old->h, hash);
+	if (ch)
+		return container_of(ch, struct rsi, h);
+	else
+		return NULL;
+}
+
+
+/*
+ * The rpcsec_context cache is used to store a context that is
+ * used in data exchange.
+ * The key is a context handle. The content is:
+ *  uid, gidlist, mechanism, service-set, mech-specific-data
+ */
+
+#define	RSC_HASHBITS	10
+#define	RSC_HASHMAX	(1<<RSC_HASHBITS)
+
+#define GSS_SEQ_WIN	128
+
+struct gss_svc_seq_data {
+	/* highest seq number seen so far: */
+	u32			sd_max;
+	/* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of
+	 * sd_win is nonzero iff sequence number i has been seen already: */
+	unsigned long		sd_win[GSS_SEQ_WIN/BITS_PER_LONG];
+	spinlock_t		sd_lock;
+};
+
+struct rsc {
+	struct cache_head	h;
+	struct xdr_netobj	handle;
+	struct svc_cred		cred;
+	struct gss_svc_seq_data	seqdata;
+	struct gss_ctx		*mechctx;
+	struct rcu_head		rcu_head;
+};
+
+static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old);
+static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item);
+
+static void rsc_free(struct rsc *rsci)
+{
+	kfree(rsci->handle.data);
+	if (rsci->mechctx)
+		gss_delete_sec_context(&rsci->mechctx);
+	free_svc_cred(&rsci->cred);
+}
+
+static void rsc_free_rcu(struct rcu_head *head)
+{
+	struct rsc *rsci = container_of(head, struct rsc, rcu_head);
+
+	kfree(rsci->handle.data);
+	kfree(rsci);
+}
+
+static void rsc_put(struct kref *ref)
+{
+	struct rsc *rsci = container_of(ref, struct rsc, h.ref);
+
+	if (rsci->mechctx)
+		gss_delete_sec_context(&rsci->mechctx);
+	free_svc_cred(&rsci->cred);
+	call_rcu(&rsci->rcu_head, rsc_free_rcu);
+}
+
+static inline int
+rsc_hash(struct rsc *rsci)
+{
+	return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS);
+}
+
+static int
+rsc_match(struct cache_head *a, struct cache_head *b)
+{
+	struct rsc *new = container_of(a, struct rsc, h);
+	struct rsc *tmp = container_of(b, struct rsc, h);
+
+	return netobj_equal(&new->handle, &tmp->handle);
+}
+
+static void
+rsc_init(struct cache_head *cnew, struct cache_head *ctmp)
+{
+	struct rsc *new = container_of(cnew, struct rsc, h);
+	struct rsc *tmp = container_of(ctmp, struct rsc, h);
+
+	new->handle.len = tmp->handle.len;
+	tmp->handle.len = 0;
+	new->handle.data = tmp->handle.data;
+	tmp->handle.data = NULL;
+	new->mechctx = NULL;
+	init_svc_cred(&new->cred);
+}
+
+static void
+update_rsc(struct cache_head *cnew, struct cache_head *ctmp)
+{
+	struct rsc *new = container_of(cnew, struct rsc, h);
+	struct rsc *tmp = container_of(ctmp, struct rsc, h);
+
+	new->mechctx = tmp->mechctx;
+	tmp->mechctx = NULL;
+	memset(&new->seqdata, 0, sizeof(new->seqdata));
+	spin_lock_init(&new->seqdata.sd_lock);
+	new->cred = tmp->cred;
+	init_svc_cred(&tmp->cred);
+}
+
+static struct cache_head *
+rsc_alloc(void)
+{
+	struct rsc *rsci = kmalloc(sizeof(*rsci), GFP_KERNEL);
+	if (rsci)
+		return &rsci->h;
+	else
+		return NULL;
+}
+
+static int rsc_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return -EINVAL;
+}
+
+static int rsc_parse(struct cache_detail *cd,
+		     char *mesg, int mlen)
+{
+	/* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
+	char *buf = mesg;
+	int id;
+	int len, rv;
+	struct rsc rsci, *rscp = NULL;
+	time64_t expiry;
+	int status = -EINVAL;
+	struct gss_api_mech *gm = NULL;
+
+	memset(&rsci, 0, sizeof(rsci));
+	/* context handle */
+	len = qword_get(&mesg, buf, mlen);
+	if (len < 0) goto out;
+	status = -ENOMEM;
+	if (dup_to_netobj(&rsci.handle, buf, len))
+		goto out;
+
+	rsci.h.flags = 0;
+	/* expiry */
+	expiry = get_expiry(&mesg);
+	status = -EINVAL;
+	if (expiry == 0)
+		goto out;
+
+	rscp = rsc_lookup(cd, &rsci);
+	if (!rscp)
+		goto out;
+
+	/* uid, or NEGATIVE */
+	rv = get_int(&mesg, &id);
+	if (rv == -EINVAL)
+		goto out;
+	if (rv == -ENOENT)
+		set_bit(CACHE_NEGATIVE, &rsci.h.flags);
+	else {
+		int N, i;
+
+		/*
+		 * NOTE: we skip uid_valid()/gid_valid() checks here:
+		 * instead, * -1 id's are later mapped to the
+		 * (export-specific) anonymous id by nfsd_setuser.
+		 *
+		 * (But supplementary gid's get no such special
+		 * treatment so are checked for validity here.)
+		 */
+		/* uid */
+		rsci.cred.cr_uid = make_kuid(current_user_ns(), id);
+
+		/* gid */
+		if (get_int(&mesg, &id))
+			goto out;
+		rsci.cred.cr_gid = make_kgid(current_user_ns(), id);
+
+		/* number of additional gid's */
+		if (get_int(&mesg, &N))
+			goto out;
+		if (N < 0 || N > NGROUPS_MAX)
+			goto out;
+		status = -ENOMEM;
+		rsci.cred.cr_group_info = groups_alloc(N);
+		if (rsci.cred.cr_group_info == NULL)
+			goto out;
+
+		/* gid's */
+		status = -EINVAL;
+		for (i=0; i<N; i++) {
+			kgid_t kgid;
+			if (get_int(&mesg, &id))
+				goto out;
+			kgid = make_kgid(current_user_ns(), id);
+			if (!gid_valid(kgid))
+				goto out;
+			rsci.cred.cr_group_info->gid[i] = kgid;
+		}
+		groups_sort(rsci.cred.cr_group_info);
+
+		/* mech name */
+		len = qword_get(&mesg, buf, mlen);
+		if (len < 0)
+			goto out;
+		gm = rsci.cred.cr_gss_mech = gss_mech_get_by_name(buf);
+		status = -EOPNOTSUPP;
+		if (!gm)
+			goto out;
+
+		status = -EINVAL;
+		/* mech-specific data: */
+		len = qword_get(&mesg, buf, mlen);
+		if (len < 0)
+			goto out;
+		status = gss_import_sec_context(buf, len, gm, &rsci.mechctx,
+						NULL, GFP_KERNEL);
+		if (status)
+			goto out;
+
+		/* get client name */
+		len = qword_get(&mesg, buf, mlen);
+		if (len > 0) {
+			rsci.cred.cr_principal = kstrdup(buf, GFP_KERNEL);
+			if (!rsci.cred.cr_principal) {
+				status = -ENOMEM;
+				goto out;
+			}
+		}
+
+	}
+	rsci.h.expiry_time = expiry;
+	rscp = rsc_update(cd, &rsci, rscp);
+	status = 0;
+out:
+	rsc_free(&rsci);
+	if (rscp)
+		cache_put(&rscp->h, cd);
+	else
+		status = -ENOMEM;
+	return status;
+}
+
+static const struct cache_detail rsc_cache_template = {
+	.owner		= THIS_MODULE,
+	.hash_size	= RSC_HASHMAX,
+	.name		= "auth.rpcsec.context",
+	.cache_put	= rsc_put,
+	.cache_upcall	= rsc_upcall,
+	.cache_parse	= rsc_parse,
+	.match		= rsc_match,
+	.init		= rsc_init,
+	.update		= update_rsc,
+	.alloc		= rsc_alloc,
+};
+
+static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item)
+{
+	struct cache_head *ch;
+	int hash = rsc_hash(item);
+
+	ch = sunrpc_cache_lookup_rcu(cd, &item->h, hash);
+	if (ch)
+		return container_of(ch, struct rsc, h);
+	else
+		return NULL;
+}
+
+static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old)
+{
+	struct cache_head *ch;
+	int hash = rsc_hash(new);
+
+	ch = sunrpc_cache_update(cd, &new->h,
+				 &old->h, hash);
+	if (ch)
+		return container_of(ch, struct rsc, h);
+	else
+		return NULL;
+}
+
+
+static struct rsc *
+gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle)
+{
+	struct rsc rsci;
+	struct rsc *found;
+
+	memset(&rsci, 0, sizeof(rsci));
+	if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
+		return NULL;
+	found = rsc_lookup(cd, &rsci);
+	rsc_free(&rsci);
+	if (!found)
+		return NULL;
+	if (cache_check(cd, &found->h, NULL))
+		return NULL;
+	return found;
+}
+
+/**
+ * gss_check_seq_num - GSS sequence number window check
+ * @rqstp: RPC Call to use when reporting errors
+ * @rsci: cached GSS context state (updated on return)
+ * @seq_num: sequence number to check
+ *
+ * Implements sequence number algorithm as specified in
+ * RFC 2203, Section 5.3.3.1. "Context Management".
+ *
+ * Return values:
+ *   %true: @rqstp's GSS sequence number is inside the window
+ *   %false: @rqstp's GSS sequence number is outside the window
+ */
+static bool gss_check_seq_num(const struct svc_rqst *rqstp, struct rsc *rsci,
+			      u32 seq_num)
+{
+	struct gss_svc_seq_data *sd = &rsci->seqdata;
+	bool result = false;
+
+	spin_lock(&sd->sd_lock);
+	if (seq_num > sd->sd_max) {
+		if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
+			memset(sd->sd_win, 0, sizeof(sd->sd_win));
+			sd->sd_max = seq_num;
+		} else while (sd->sd_max < seq_num) {
+			sd->sd_max++;
+			__clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
+		}
+		__set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
+		goto ok;
+	} else if (seq_num + GSS_SEQ_WIN <= sd->sd_max) {
+		goto toolow;
+	}
+	if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
+		goto alreadyseen;
+
+ok:
+	result = true;
+out:
+	spin_unlock(&sd->sd_lock);
+	return result;
+
+toolow:
+	trace_rpcgss_svc_seqno_low(rqstp, seq_num,
+				   sd->sd_max - GSS_SEQ_WIN,
+				   sd->sd_max);
+	goto out;
+alreadyseen:
+	trace_rpcgss_svc_seqno_seen(rqstp, seq_num);
+	goto out;
+}
+
+static inline u32 round_up_to_quad(u32 i)
+{
+	return (i + 3 ) & ~3;
+}
+
+static inline int
+svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
+{
+	int l;
+
+	if (argv->iov_len < 4)
+		return -1;
+	o->len = svc_getnl(argv);
+	l = round_up_to_quad(o->len);
+	if (argv->iov_len < l)
+		return -1;
+	o->data = argv->iov_base;
+	argv->iov_base += l;
+	argv->iov_len -= l;
+	return 0;
+}
+
+static inline int
+svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
+{
+	u8 *p;
+
+	if (resv->iov_len + 4 > PAGE_SIZE)
+		return -1;
+	svc_putnl(resv, o->len);
+	p = resv->iov_base + resv->iov_len;
+	resv->iov_len += round_up_to_quad(o->len);
+	if (resv->iov_len > PAGE_SIZE)
+		return -1;
+	memcpy(p, o->data, o->len);
+	memset(p + o->len, 0, round_up_to_quad(o->len) - o->len);
+	return 0;
+}
+
+/*
+ * Verify the checksum on the header and return SVC_OK on success.
+ * Otherwise, return SVC_DROP (in the case of a bad sequence number)
+ * or return SVC_DENIED and indicate error in authp.
+ */
+static int
+gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
+		  __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp)
+{
+	struct gss_ctx		*ctx_id = rsci->mechctx;
+	struct xdr_buf		rpchdr;
+	struct xdr_netobj	checksum;
+	u32			flavor = 0;
+	struct kvec		*argv = &rqstp->rq_arg.head[0];
+	struct kvec		iov;
+
+	/* data to compute the checksum over: */
+	iov.iov_base = rpcstart;
+	iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
+	xdr_buf_from_iov(&iov, &rpchdr);
+
+	*authp = rpc_autherr_badverf;
+	if (argv->iov_len < 4)
+		return SVC_DENIED;
+	flavor = svc_getnl(argv);
+	if (flavor != RPC_AUTH_GSS)
+		return SVC_DENIED;
+	if (svc_safe_getnetobj(argv, &checksum))
+		return SVC_DENIED;
+
+	if (rqstp->rq_deferred) /* skip verification of revisited request */
+		return SVC_OK;
+	if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) {
+		*authp = rpcsec_gsserr_credproblem;
+		return SVC_DENIED;
+	}
+
+	if (gc->gc_seq > MAXSEQ) {
+		trace_rpcgss_svc_seqno_large(rqstp, gc->gc_seq);
+		*authp = rpcsec_gsserr_ctxproblem;
+		return SVC_DENIED;
+	}
+	if (!gss_check_seq_num(rqstp, rsci, gc->gc_seq))
+		return SVC_DROP;
+	return SVC_OK;
+}
+
+static int
+gss_write_null_verf(struct svc_rqst *rqstp)
+{
+	__be32     *p;
+
+	svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL);
+	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
+	/* don't really need to check if head->iov_len > PAGE_SIZE ... */
+	*p++ = 0;
+	if (!xdr_ressize_check(rqstp, p))
+		return -1;
+	return 0;
+}
+
+static int
+gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
+{
+	__be32			*xdr_seq;
+	u32			maj_stat;
+	struct xdr_buf		verf_data;
+	struct xdr_netobj	mic;
+	__be32			*p;
+	struct kvec		iov;
+	int err = -1;
+
+	svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
+	xdr_seq = kmalloc(4, GFP_KERNEL);
+	if (!xdr_seq)
+		return -1;
+	*xdr_seq = htonl(seq);
+
+	iov.iov_base = xdr_seq;
+	iov.iov_len = 4;
+	xdr_buf_from_iov(&iov, &verf_data);
+	p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
+	mic.data = (u8 *)(p + 1);
+	maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
+	if (maj_stat != GSS_S_COMPLETE)
+		goto out;
+	*p++ = htonl(mic.len);
+	memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
+	p += XDR_QUADLEN(mic.len);
+	if (!xdr_ressize_check(rqstp, p))
+		goto out;
+	err = 0;
+out:
+	kfree(xdr_seq);
+	return err;
+}
+
+struct gss_domain {
+	struct auth_domain	h;
+	u32			pseudoflavor;
+};
+
+static struct auth_domain *
+find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
+{
+	char *name;
+
+	name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
+	if (!name)
+		return NULL;
+	return auth_domain_find(name);
+}
+
+static struct auth_ops svcauthops_gss;
+
+u32 svcauth_gss_flavor(struct auth_domain *dom)
+{
+	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
+
+	return gd->pseudoflavor;
+}
+
+EXPORT_SYMBOL_GPL(svcauth_gss_flavor);
+
+struct auth_domain *
+svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
+{
+	struct gss_domain	*new;
+	struct auth_domain	*test;
+	int			stat = -ENOMEM;
+
+	new = kmalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		goto out;
+	kref_init(&new->h.ref);
+	new->h.name = kstrdup(name, GFP_KERNEL);
+	if (!new->h.name)
+		goto out_free_dom;
+	new->h.flavour = &svcauthops_gss;
+	new->pseudoflavor = pseudoflavor;
+
+	test = auth_domain_lookup(name, &new->h);
+	if (test != &new->h) {
+		pr_warn("svc: duplicate registration of gss pseudo flavour %s.\n",
+			name);
+		stat = -EADDRINUSE;
+		auth_domain_put(test);
+		goto out_free_name;
+	}
+	return test;
+
+out_free_name:
+	kfree(new->h.name);
+out_free_dom:
+	kfree(new);
+out:
+	return ERR_PTR(stat);
+}
+EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor);
+
+static inline int
+read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
+{
+	__be32  raw;
+	int     status;
+
+	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
+	if (status)
+		return status;
+	*obj = ntohl(raw);
+	return 0;
+}
+
+/* It would be nice if this bit of code could be shared with the client.
+ * Obstacles:
+ *	The client shouldn't malloc(), would have to pass in own memory.
+ *	The server uses base of head iovec as read pointer, while the
+ *	client uses separate pointer. */
+static int
+unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
+{
+	u32 integ_len, rseqno, maj_stat;
+	int stat = -EINVAL;
+	struct xdr_netobj mic;
+	struct xdr_buf integ_buf;
+
+	mic.data = NULL;
+
+	/* NFS READ normally uses splice to send data in-place. However
+	 * the data in cache can change after the reply's MIC is computed
+	 * but before the RPC reply is sent. To prevent the client from
+	 * rejecting the server-computed MIC in this somewhat rare case,
+	 * do not use splice with the GSS integrity service.
+	 */
+	clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
+
+	/* Did we already verify the signature on the original pass through? */
+	if (rqstp->rq_deferred)
+		return 0;
+
+	integ_len = svc_getnl(&buf->head[0]);
+	if (integ_len & 3)
+		goto unwrap_failed;
+	if (integ_len > buf->len)
+		goto unwrap_failed;
+	if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len))
+		goto unwrap_failed;
+
+	/* copy out mic... */
+	if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
+		goto unwrap_failed;
+	if (mic.len > RPC_MAX_AUTH_SIZE)
+		goto unwrap_failed;
+	mic.data = kmalloc(mic.len, GFP_KERNEL);
+	if (!mic.data)
+		goto unwrap_failed;
+	if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
+		goto unwrap_failed;
+	maj_stat = gss_verify_mic(ctx, &integ_buf, &mic);
+	if (maj_stat != GSS_S_COMPLETE)
+		goto bad_mic;
+	rseqno = svc_getnl(&buf->head[0]);
+	if (rseqno != seq)
+		goto bad_seqno;
+	/* trim off the mic and padding at the end before returning */
+	xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
+	stat = 0;
+out:
+	kfree(mic.data);
+	return stat;
+
+unwrap_failed:
+	trace_rpcgss_svc_unwrap_failed(rqstp);
+	goto out;
+bad_seqno:
+	trace_rpcgss_svc_seqno_bad(rqstp, seq, rseqno);
+	goto out;
+bad_mic:
+	trace_rpcgss_svc_mic(rqstp, maj_stat);
+	goto out;
+}
+
+static inline int
+total_buf_len(struct xdr_buf *buf)
+{
+	return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len;
+}
+
+static void
+fix_priv_head(struct xdr_buf *buf, int pad)
+{
+	if (buf->page_len == 0) {
+		/* We need to adjust head and buf->len in tandem in this
+		 * case to make svc_defer() work--it finds the original
+		 * buffer start using buf->len - buf->head[0].iov_len. */
+		buf->head[0].iov_len -= pad;
+	}
+}
+
+static int
+unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
+{
+	u32 priv_len, maj_stat;
+	int pad, remaining_len, offset;
+	u32 rseqno;
+
+	clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
+
+	priv_len = svc_getnl(&buf->head[0]);
+	if (rqstp->rq_deferred) {
+		/* Already decrypted last time through! The sequence number
+		 * check at out_seq is unnecessary but harmless: */
+		goto out_seq;
+	}
+	/* buf->len is the number of bytes from the original start of the
+	 * request to the end, where head[0].iov_len is just the bytes
+	 * not yet read from the head, so these two values are different: */
+	remaining_len = total_buf_len(buf);
+	if (priv_len > remaining_len)
+		goto unwrap_failed;
+	pad = remaining_len - priv_len;
+	buf->len -= pad;
+	fix_priv_head(buf, pad);
+
+	maj_stat = gss_unwrap(ctx, 0, priv_len, buf);
+	pad = priv_len - buf->len;
+	/* The upper layers assume the buffer is aligned on 4-byte boundaries.
+	 * In the krb5p case, at least, the data ends up offset, so we need to
+	 * move it around. */
+	/* XXX: This is very inefficient.  It would be better to either do
+	 * this while we encrypt, or maybe in the receive code, if we can peak
+	 * ahead and work out the service and mechanism there. */
+	offset = xdr_pad_size(buf->head[0].iov_len);
+	if (offset) {
+		buf->buflen = RPCSVC_MAXPAYLOAD;
+		xdr_shift_buf(buf, offset);
+		fix_priv_head(buf, pad);
+	}
+	if (maj_stat != GSS_S_COMPLETE)
+		goto bad_unwrap;
+out_seq:
+	rseqno = svc_getnl(&buf->head[0]);
+	if (rseqno != seq)
+		goto bad_seqno;
+	return 0;
+
+unwrap_failed:
+	trace_rpcgss_svc_unwrap_failed(rqstp);
+	return -EINVAL;
+bad_seqno:
+	trace_rpcgss_svc_seqno_bad(rqstp, seq, rseqno);
+	return -EINVAL;
+bad_unwrap:
+	trace_rpcgss_svc_unwrap(rqstp, maj_stat);
+	return -EINVAL;
+}
+
+struct gss_svc_data {
+	/* decoded gss client cred: */
+	struct rpc_gss_wire_cred	clcred;
+	/* save a pointer to the beginning of the encoded verifier,
+	 * for use in encryption/checksumming in svcauth_gss_release: */
+	__be32				*verf_start;
+	struct rsc			*rsci;
+};
+
+static int
+svcauth_gss_set_client(struct svc_rqst *rqstp)
+{
+	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
+	struct rsc *rsci = svcdata->rsci;
+	struct rpc_gss_wire_cred *gc = &svcdata->clcred;
+	int stat;
+
+	/*
+	 * A gss export can be specified either by:
+	 * 	export	*(sec=krb5,rw)
+	 * or by
+	 * 	export gss/krb5(rw)
+	 * The latter is deprecated; but for backwards compatibility reasons
+	 * the nfsd code will still fall back on trying it if the former
+	 * doesn't work; so we try to make both available to nfsd, below.
+	 */
+	rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
+	if (rqstp->rq_gssclient == NULL)
+		return SVC_DENIED;
+	stat = svcauth_unix_set_client(rqstp);
+	if (stat == SVC_DROP || stat == SVC_CLOSE)
+		return stat;
+	return SVC_OK;
+}
+
+static inline int
+gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
+		struct xdr_netobj *out_handle, int *major_status)
+{
+	struct rsc *rsci;
+	int        rc;
+
+	if (*major_status != GSS_S_COMPLETE)
+		return gss_write_null_verf(rqstp);
+	rsci = gss_svc_searchbyctx(cd, out_handle);
+	if (rsci == NULL) {
+		*major_status = GSS_S_NO_CONTEXT;
+		return gss_write_null_verf(rqstp);
+	}
+	rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN);
+	cache_put(&rsci->h, cd);
+	return rc;
+}
+
+static inline int
+gss_read_common_verf(struct rpc_gss_wire_cred *gc,
+		     struct kvec *argv, __be32 *authp,
+		     struct xdr_netobj *in_handle)
+{
+	/* Read the verifier; should be NULL: */
+	*authp = rpc_autherr_badverf;
+	if (argv->iov_len < 2 * 4)
+		return SVC_DENIED;
+	if (svc_getnl(argv) != RPC_AUTH_NULL)
+		return SVC_DENIED;
+	if (svc_getnl(argv) != 0)
+		return SVC_DENIED;
+	/* Martial context handle and token for upcall: */
+	*authp = rpc_autherr_badcred;
+	if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
+		return SVC_DENIED;
+	if (dup_netobj(in_handle, &gc->gc_ctx))
+		return SVC_CLOSE;
+	*authp = rpc_autherr_badverf;
+
+	return 0;
+}
+
+static inline int
+gss_read_verf(struct rpc_gss_wire_cred *gc,
+	      struct kvec *argv, __be32 *authp,
+	      struct xdr_netobj *in_handle,
+	      struct xdr_netobj *in_token)
+{
+	struct xdr_netobj tmpobj;
+	int res;
+
+	res = gss_read_common_verf(gc, argv, authp, in_handle);
+	if (res)
+		return res;
+
+	if (svc_safe_getnetobj(argv, &tmpobj)) {
+		kfree(in_handle->data);
+		return SVC_DENIED;
+	}
+	if (dup_netobj(in_token, &tmpobj)) {
+		kfree(in_handle->data);
+		return SVC_CLOSE;
+	}
+
+	return 0;
+}
+
+static void gss_free_in_token_pages(struct gssp_in_token *in_token)
+{
+	u32 inlen;
+	int i;
+
+	i = 0;
+	inlen = in_token->page_len;
+	while (inlen) {
+		if (in_token->pages[i])
+			put_page(in_token->pages[i]);
+		inlen -= inlen > PAGE_SIZE ? PAGE_SIZE : inlen;
+	}
+
+	kfree(in_token->pages);
+	in_token->pages = NULL;
+}
+
+static int gss_read_proxy_verf(struct svc_rqst *rqstp,
+			       struct rpc_gss_wire_cred *gc, __be32 *authp,
+			       struct xdr_netobj *in_handle,
+			       struct gssp_in_token *in_token)
+{
+	struct kvec *argv = &rqstp->rq_arg.head[0];
+	unsigned int length, pgto_offs, pgfrom_offs;
+	int pages, i, res, pgto, pgfrom;
+	size_t inlen, to_offs, from_offs;
+
+	res = gss_read_common_verf(gc, argv, authp, in_handle);
+	if (res)
+		return res;
+
+	inlen = svc_getnl(argv);
+	if (inlen > (argv->iov_len + rqstp->rq_arg.page_len)) {
+		kfree(in_handle->data);
+		return SVC_DENIED;
+	}
+
+	pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
+	in_token->pages = kcalloc(pages, sizeof(struct page *), GFP_KERNEL);
+	if (!in_token->pages) {
+		kfree(in_handle->data);
+		return SVC_DENIED;
+	}
+	in_token->page_base = 0;
+	in_token->page_len = inlen;
+	for (i = 0; i < pages; i++) {
+		in_token->pages[i] = alloc_page(GFP_KERNEL);
+		if (!in_token->pages[i]) {
+			kfree(in_handle->data);
+			gss_free_in_token_pages(in_token);
+			return SVC_DENIED;
+		}
+	}
+
+	length = min_t(unsigned int, inlen, argv->iov_len);
+	memcpy(page_address(in_token->pages[0]), argv->iov_base, length);
+	inlen -= length;
+
+	to_offs = length;
+	from_offs = rqstp->rq_arg.page_base;
+	while (inlen) {
+		pgto = to_offs >> PAGE_SHIFT;
+		pgfrom = from_offs >> PAGE_SHIFT;
+		pgto_offs = to_offs & ~PAGE_MASK;
+		pgfrom_offs = from_offs & ~PAGE_MASK;
+
+		length = min_t(unsigned int, inlen,
+			 min_t(unsigned int, PAGE_SIZE - pgto_offs,
+			       PAGE_SIZE - pgfrom_offs));
+		memcpy(page_address(in_token->pages[pgto]) + pgto_offs,
+		       page_address(rqstp->rq_arg.pages[pgfrom]) + pgfrom_offs,
+		       length);
+
+		to_offs += length;
+		from_offs += length;
+		inlen -= length;
+	}
+	return 0;
+}
+
+static inline int
+gss_write_resv(struct kvec *resv, size_t size_limit,
+	       struct xdr_netobj *out_handle, struct xdr_netobj *out_token,
+	       int major_status, int minor_status)
+{
+	if (resv->iov_len + 4 > size_limit)
+		return -1;
+	svc_putnl(resv, RPC_SUCCESS);
+	if (svc_safe_putnetobj(resv, out_handle))
+		return -1;
+	if (resv->iov_len + 3 * 4 > size_limit)
+		return -1;
+	svc_putnl(resv, major_status);
+	svc_putnl(resv, minor_status);
+	svc_putnl(resv, GSS_SEQ_WIN);
+	if (svc_safe_putnetobj(resv, out_token))
+		return -1;
+	return 0;
+}
+
+/*
+ * Having read the cred already and found we're in the context
+ * initiation case, read the verifier and initiate (or check the results
+ * of) upcalls to userspace for help with context initiation.  If
+ * the upcall results are available, write the verifier and result.
+ * Otherwise, drop the request pending an answer to the upcall.
+ */
+static int svcauth_gss_legacy_init(struct svc_rqst *rqstp,
+			struct rpc_gss_wire_cred *gc, __be32 *authp)
+{
+	struct kvec *argv = &rqstp->rq_arg.head[0];
+	struct kvec *resv = &rqstp->rq_res.head[0];
+	struct rsi *rsip, rsikey;
+	int ret;
+	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);
+
+	memset(&rsikey, 0, sizeof(rsikey));
+	ret = gss_read_verf(gc, argv, authp,
+			    &rsikey.in_handle, &rsikey.in_token);
+	if (ret)
+		return ret;
+
+	/* Perform upcall, or find upcall result: */
+	rsip = rsi_lookup(sn->rsi_cache, &rsikey);
+	rsi_free(&rsikey);
+	if (!rsip)
+		return SVC_CLOSE;
+	if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0)
+		/* No upcall result: */
+		return SVC_CLOSE;
+
+	ret = SVC_CLOSE;
+	/* Got an answer to the upcall; use it: */
+	if (gss_write_init_verf(sn->rsc_cache, rqstp,
+				&rsip->out_handle, &rsip->major_status))
+		goto out;
+	if (gss_write_resv(resv, PAGE_SIZE,
+			   &rsip->out_handle, &rsip->out_token,
+			   rsip->major_status, rsip->minor_status))
+		goto out;
+
+	ret = SVC_COMPLETE;
+out:
+	cache_put(&rsip->h, sn->rsi_cache);
+	return ret;
+}
+
+static int gss_proxy_save_rsc(struct cache_detail *cd,
+				struct gssp_upcall_data *ud,
+				uint64_t *handle)
+{
+	struct rsc rsci, *rscp = NULL;
+	static atomic64_t ctxhctr;
+	long long ctxh;
+	struct gss_api_mech *gm = NULL;
+	time64_t expiry;
+	int status = -EINVAL;
+
+	memset(&rsci, 0, sizeof(rsci));
+	/* context handle */
+	status = -ENOMEM;
+	/* the handle needs to be just a unique id,
+	 * use a static counter */
+	ctxh = atomic64_inc_return(&ctxhctr);
+
+	/* make a copy for the caller */
+	*handle = ctxh;
+
+	/* make a copy for the rsc cache */
+	if (dup_to_netobj(&rsci.handle, (char *)handle, sizeof(uint64_t)))
+		goto out;
+	rscp = rsc_lookup(cd, &rsci);
+	if (!rscp)
+		goto out;
+
+	/* creds */
+	if (!ud->found_creds) {
+		/* userspace seem buggy, we should always get at least a
+		 * mapping to nobody */
+		goto out;
+	} else {
+		struct timespec64 boot;
+
+		/* steal creds */
+		rsci.cred = ud->creds;
+		memset(&ud->creds, 0, sizeof(struct svc_cred));
+
+		status = -EOPNOTSUPP;
+		/* get mech handle from OID */
+		gm = gss_mech_get_by_OID(&ud->mech_oid);
+		if (!gm)
+			goto out;
+		rsci.cred.cr_gss_mech = gm;
+
+		status = -EINVAL;
+		/* mech-specific data: */
+		status = gss_import_sec_context(ud->out_handle.data,
+						ud->out_handle.len,
+						gm, &rsci.mechctx,
+						&expiry, GFP_KERNEL);
+		if (status)
+			goto out;
+
+		getboottime64(&boot);
+		expiry -= boot.tv_sec;
+	}
+
+	rsci.h.expiry_time = expiry;
+	rscp = rsc_update(cd, &rsci, rscp);
+	status = 0;
+out:
+	rsc_free(&rsci);
+	if (rscp)
+		cache_put(&rscp->h, cd);
+	else
+		status = -ENOMEM;
+	return status;
+}
+
+static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
+			struct rpc_gss_wire_cred *gc, __be32 *authp)
+{
+	struct kvec *resv = &rqstp->rq_res.head[0];
+	struct xdr_netobj cli_handle;
+	struct gssp_upcall_data ud;
+	uint64_t handle;
+	int status;
+	int ret;
+	struct net *net = SVC_NET(rqstp);
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+	memset(&ud, 0, sizeof(ud));
+	ret = gss_read_proxy_verf(rqstp, gc, authp,
+				  &ud.in_handle, &ud.in_token);
+	if (ret)
+		return ret;
+
+	ret = SVC_CLOSE;
+
+	/* Perform synchronous upcall to gss-proxy */
+	status = gssp_accept_sec_context_upcall(net, &ud);
+	if (status)
+		goto out;
+
+	trace_rpcgss_svc_accept_upcall(rqstp, ud.major_status, ud.minor_status);
+
+	switch (ud.major_status) {
+	case GSS_S_CONTINUE_NEEDED:
+		cli_handle = ud.out_handle;
+		break;
+	case GSS_S_COMPLETE:
+		status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
+		if (status)
+			goto out;
+		cli_handle.data = (u8 *)&handle;
+		cli_handle.len = sizeof(handle);
+		break;
+	default:
+		goto out;
+	}
+
+	/* Got an answer to the upcall; use it: */
+	if (gss_write_init_verf(sn->rsc_cache, rqstp,
+				&cli_handle, &ud.major_status))
+		goto out;
+	if (gss_write_resv(resv, PAGE_SIZE,
+			   &cli_handle, &ud.out_token,
+			   ud.major_status, ud.minor_status))
+		goto out;
+
+	ret = SVC_COMPLETE;
+out:
+	gss_free_in_token_pages(&ud.in_token);
+	gssp_free_upcall_data(&ud);
+	return ret;
+}
+
+/*
+ * Try to set the sn->use_gss_proxy variable to a new value. We only allow
+ * it to be changed if it's currently undefined (-1). If it's any other value
+ * then return -EBUSY unless the type wouldn't have changed anyway.
+ */
+static int set_gss_proxy(struct net *net, int type)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	int ret;
+
+	WARN_ON_ONCE(type != 0 && type != 1);
+	ret = cmpxchg(&sn->use_gss_proxy, -1, type);
+	if (ret != -1 && ret != type)
+		return -EBUSY;
+	return 0;
+}
+
+static bool use_gss_proxy(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+	/* If use_gss_proxy is still undefined, then try to disable it */
+	if (sn->use_gss_proxy == -1)
+		set_gss_proxy(net, 0);
+	return sn->use_gss_proxy;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static ssize_t write_gssp(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	struct net *net = PDE_DATA(file_inode(file));
+	char tbuf[20];
+	unsigned long i;
+	int res;
+
+	if (*ppos || count > sizeof(tbuf)-1)
+		return -EINVAL;
+	if (copy_from_user(tbuf, buf, count))
+		return -EFAULT;
+
+	tbuf[count] = 0;
+	res = kstrtoul(tbuf, 0, &i);
+	if (res)
+		return res;
+	if (i != 1)
+		return -EINVAL;
+	res = set_gssp_clnt(net);
+	if (res)
+		return res;
+	res = set_gss_proxy(net, 1);
+	if (res)
+		return res;
+	return count;
+}
+
+static ssize_t read_gssp(struct file *file, char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	struct net *net = PDE_DATA(file_inode(file));
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	unsigned long p = *ppos;
+	char tbuf[10];
+	size_t len;
+
+	snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
+	len = strlen(tbuf);
+	if (p >= len)
+		return 0;
+	len -= p;
+	if (len > count)
+		len = count;
+	if (copy_to_user(buf, (void *)(tbuf+p), len))
+		return -EFAULT;
+	*ppos += len;
+	return len;
+}
+
+static const struct proc_ops use_gss_proxy_proc_ops = {
+	.proc_open	= nonseekable_open,
+	.proc_write	= write_gssp,
+	.proc_read	= read_gssp,
+};
+
+static int create_use_gss_proxy_proc_entry(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct proc_dir_entry **p = &sn->use_gssp_proc;
+
+	sn->use_gss_proxy = -1;
+	*p = proc_create_data("use-gss-proxy", S_IFREG | 0600,
+			      sn->proc_net_rpc,
+			      &use_gss_proxy_proc_ops, net);
+	if (!*p)
+		return -ENOMEM;
+	init_gssp_clnt(sn);
+	return 0;
+}
+
+static void destroy_use_gss_proxy_proc_entry(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+	if (sn->use_gssp_proc) {
+		remove_proc_entry("use-gss-proxy", sn->proc_net_rpc);
+		clear_gssp_clnt(sn);
+	}
+}
+#else /* CONFIG_PROC_FS */
+
+static int create_use_gss_proxy_proc_entry(struct net *net)
+{
+	return 0;
+}
+
+static void destroy_use_gss_proxy_proc_entry(struct net *net) {}
+
+#endif /* CONFIG_PROC_FS */
+
+/*
+ * Accept an rpcsec packet.
+ * If context establishment, punt to user space
+ * If data exchange, verify/decrypt
+ * If context destruction, handle here
+ * In the context establishment and destruction case we encode
+ * response here and return SVC_COMPLETE.
+ */
+static int
+svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
+{
+	struct kvec	*argv = &rqstp->rq_arg.head[0];
+	struct kvec	*resv = &rqstp->rq_res.head[0];
+	u32		crlen;
+	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
+	struct rpc_gss_wire_cred *gc;
+	struct rsc	*rsci = NULL;
+	__be32		*rpcstart;
+	__be32		*reject_stat = resv->iov_base + resv->iov_len;
+	int		ret;
+	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);
+
+	*authp = rpc_autherr_badcred;
+	if (!svcdata)
+		svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
+	if (!svcdata)
+		goto auth_err;
+	rqstp->rq_auth_data = svcdata;
+	svcdata->verf_start = NULL;
+	svcdata->rsci = NULL;
+	gc = &svcdata->clcred;
+
+	/* start of rpc packet is 7 u32's back from here:
+	 * xid direction rpcversion prog vers proc flavour
+	 */
+	rpcstart = argv->iov_base;
+	rpcstart -= 7;
+
+	/* credential is:
+	 *   version(==1), proc(0,1,2,3), seq, service (1,2,3), handle
+	 * at least 5 u32s, and is preceded by length, so that makes 6.
+	 */
+
+	if (argv->iov_len < 5 * 4)
+		goto auth_err;
+	crlen = svc_getnl(argv);
+	if (svc_getnl(argv) != RPC_GSS_VERSION)
+		goto auth_err;
+	gc->gc_proc = svc_getnl(argv);
+	gc->gc_seq = svc_getnl(argv);
+	gc->gc_svc = svc_getnl(argv);
+	if (svc_safe_getnetobj(argv, &gc->gc_ctx))
+		goto auth_err;
+	if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4)
+		goto auth_err;
+
+	if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
+		goto auth_err;
+
+	*authp = rpc_autherr_badverf;
+	switch (gc->gc_proc) {
+	case RPC_GSS_PROC_INIT:
+	case RPC_GSS_PROC_CONTINUE_INIT:
+		if (use_gss_proxy(SVC_NET(rqstp)))
+			return svcauth_gss_proxy_init(rqstp, gc, authp);
+		else
+			return svcauth_gss_legacy_init(rqstp, gc, authp);
+	case RPC_GSS_PROC_DATA:
+	case RPC_GSS_PROC_DESTROY:
+		/* Look up the context, and check the verifier: */
+		*authp = rpcsec_gsserr_credproblem;
+		rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx);
+		if (!rsci)
+			goto auth_err;
+		switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) {
+		case SVC_OK:
+			break;
+		case SVC_DENIED:
+			goto auth_err;
+		case SVC_DROP:
+			goto drop;
+		}
+		break;
+	default:
+		*authp = rpc_autherr_rejectedcred;
+		goto auth_err;
+	}
+
+	/* now act upon the command: */
+	switch (gc->gc_proc) {
+	case RPC_GSS_PROC_DESTROY:
+		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
+			goto auth_err;
+		/* Delete the entry from the cache_list and call cache_put */
+		sunrpc_cache_unhash(sn->rsc_cache, &rsci->h);
+		if (resv->iov_len + 4 > PAGE_SIZE)
+			goto drop;
+		svc_putnl(resv, RPC_SUCCESS);
+		goto complete;
+	case RPC_GSS_PROC_DATA:
+		*authp = rpcsec_gsserr_ctxproblem;
+		svcdata->verf_start = resv->iov_base + resv->iov_len;
+		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
+			goto auth_err;
+		rqstp->rq_cred = rsci->cred;
+		get_group_info(rsci->cred.cr_group_info);
+		*authp = rpc_autherr_badcred;
+		switch (gc->gc_svc) {
+		case RPC_GSS_SVC_NONE:
+			break;
+		case RPC_GSS_SVC_INTEGRITY:
+			/* placeholders for length and seq. number: */
+			svc_putnl(resv, 0);
+			svc_putnl(resv, 0);
+			if (unwrap_integ_data(rqstp, &rqstp->rq_arg,
+					gc->gc_seq, rsci->mechctx))
+				goto garbage_args;
+			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE;
+			break;
+		case RPC_GSS_SVC_PRIVACY:
+			/* placeholders for length and seq. number: */
+			svc_putnl(resv, 0);
+			svc_putnl(resv, 0);
+			if (unwrap_priv_data(rqstp, &rqstp->rq_arg,
+					gc->gc_seq, rsci->mechctx))
+				goto garbage_args;
+			rqstp->rq_auth_slack = RPC_MAX_AUTH_SIZE * 2;
+			break;
+		default:
+			goto auth_err;
+		}
+		svcdata->rsci = rsci;
+		cache_get(&rsci->h);
+		rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
+					rsci->mechctx->mech_type,
+					GSS_C_QOP_DEFAULT,
+					gc->gc_svc);
+		ret = SVC_OK;
+		trace_rpcgss_svc_authenticate(rqstp, gc);
+		goto out;
+	}
+garbage_args:
+	ret = SVC_GARBAGE;
+	goto out;
+auth_err:
+	/* Restore write pointer to its original value: */
+	xdr_ressize_check(rqstp, reject_stat);
+	ret = SVC_DENIED;
+	goto out;
+complete:
+	ret = SVC_COMPLETE;
+	goto out;
+drop:
+	ret = SVC_CLOSE;
+out:
+	if (rsci)
+		cache_put(&rsci->h, sn->rsc_cache);
+	return ret;
+}
+
+static __be32 *
+svcauth_gss_prepare_to_wrap(struct xdr_buf *resbuf, struct gss_svc_data *gsd)
+{
+	__be32 *p;
+	u32 verf_len;
+
+	p = gsd->verf_start;
+	gsd->verf_start = NULL;
+
+	/* If the reply stat is nonzero, don't wrap: */
+	if (*(p-1) != rpc_success)
+		return NULL;
+	/* Skip the verifier: */
+	p += 1;
+	verf_len = ntohl(*p++);
+	p += XDR_QUADLEN(verf_len);
+	/* move accept_stat to right place: */
+	memcpy(p, p + 2, 4);
+	/* Also don't wrap if the accept stat is nonzero: */
+	if (*p != rpc_success) {
+		resbuf->head[0].iov_len -= 2 * 4;
+		return NULL;
+	}
+	p++;
+	return p;
+}
+
+static inline int
+svcauth_gss_wrap_resp_integ(struct svc_rqst *rqstp)
+{
+	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
+	struct rpc_gss_wire_cred *gc = &gsd->clcred;
+	struct xdr_buf *resbuf = &rqstp->rq_res;
+	struct xdr_buf integ_buf;
+	struct xdr_netobj mic;
+	struct kvec *resv;
+	__be32 *p;
+	int integ_offset, integ_len;
+	int stat = -EINVAL;
+
+	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
+	if (p == NULL)
+		goto out;
+	integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base;
+	integ_len = resbuf->len - integ_offset;
+	if (integ_len & 3)
+		goto out;
+	*p++ = htonl(integ_len);
+	*p++ = htonl(gc->gc_seq);
+	if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset, integ_len)) {
+		WARN_ON_ONCE(1);
+		goto out_err;
+	}
+	if (resbuf->tail[0].iov_base == NULL) {
+		if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE > PAGE_SIZE)
+			goto out_err;
+		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
+						+ resbuf->head[0].iov_len;
+		resbuf->tail[0].iov_len = 0;
+	}
+	resv = &resbuf->tail[0];
+	mic.data = (u8 *)resv->iov_base + resv->iov_len + 4;
+	if (gss_get_mic(gsd->rsci->mechctx, &integ_buf, &mic))
+		goto out_err;
+	svc_putnl(resv, mic.len);
+	memset(mic.data + mic.len, 0,
+			round_up_to_quad(mic.len) - mic.len);
+	resv->iov_len += XDR_QUADLEN(mic.len) << 2;
+	/* not strictly required: */
+	resbuf->len += XDR_QUADLEN(mic.len) << 2;
+	if (resv->iov_len > PAGE_SIZE)
+		goto out_err;
+out:
+	stat = 0;
+out_err:
+	return stat;
+}
+
+static inline int
+svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
+{
+	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
+	struct rpc_gss_wire_cred *gc = &gsd->clcred;
+	struct xdr_buf *resbuf = &rqstp->rq_res;
+	struct page **inpages = NULL;
+	__be32 *p, *len;
+	int offset;
+	int pad;
+
+	p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
+	if (p == NULL)
+		return 0;
+	len = p++;
+	offset = (u8 *)p - (u8 *)resbuf->head[0].iov_base;
+	*p++ = htonl(gc->gc_seq);
+	inpages = resbuf->pages;
+	/* XXX: Would be better to write some xdr helper functions for
+	 * nfs{2,3,4}xdr.c that place the data right, instead of copying: */
+
+	/*
+	 * If there is currently tail data, make sure there is
+	 * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in
+	 * the page, and move the current tail data such that
+	 * there is RPC_MAX_AUTH_SIZE slack space available in
+	 * both the head and tail.
+	 */
+	if (resbuf->tail[0].iov_base) {
+		if (resbuf->tail[0].iov_base >=
+			resbuf->head[0].iov_base + PAGE_SIZE)
+			return -EINVAL;
+		if (resbuf->tail[0].iov_base < resbuf->head[0].iov_base)
+			return -EINVAL;
+		if (resbuf->tail[0].iov_len + resbuf->head[0].iov_len
+				+ 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
+			return -ENOMEM;
+		memmove(resbuf->tail[0].iov_base + RPC_MAX_AUTH_SIZE,
+			resbuf->tail[0].iov_base,
+			resbuf->tail[0].iov_len);
+		resbuf->tail[0].iov_base += RPC_MAX_AUTH_SIZE;
+	}
+	/*
+	 * If there is no current tail data, make sure there is
+	 * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the
+	 * allotted page, and set up tail information such that there
+	 * is RPC_MAX_AUTH_SIZE slack space available in both the
+	 * head and tail.
+	 */
+	if (resbuf->tail[0].iov_base == NULL) {
+		if (resbuf->head[0].iov_len + 2*RPC_MAX_AUTH_SIZE > PAGE_SIZE)
+			return -ENOMEM;
+		resbuf->tail[0].iov_base = resbuf->head[0].iov_base
+			+ resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE;
+		resbuf->tail[0].iov_len = 0;
+	}
+	if (gss_wrap(gsd->rsci->mechctx, offset, resbuf, inpages))
+		return -ENOMEM;
+	*len = htonl(resbuf->len - offset);
+	pad = 3 - ((resbuf->len - offset - 1)&3);
+	p = (__be32 *)(resbuf->tail[0].iov_base + resbuf->tail[0].iov_len);
+	memset(p, 0, pad);
+	resbuf->tail[0].iov_len += pad;
+	resbuf->len += pad;
+	return 0;
+}
+
+static int
+svcauth_gss_release(struct svc_rqst *rqstp)
+{
+	struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
+	struct rpc_gss_wire_cred *gc;
+	struct xdr_buf *resbuf = &rqstp->rq_res;
+	int stat = -EINVAL;
+	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);
+
+	if (!gsd)
+		goto out;
+	gc = &gsd->clcred;
+	if (gc->gc_proc != RPC_GSS_PROC_DATA)
+		goto out;
+	/* Release can be called twice, but we only wrap once. */
+	if (gsd->verf_start == NULL)
+		goto out;
+	/* normally not set till svc_send, but we need it here: */
+	/* XXX: what for?  Do we mess it up the moment we call svc_putu32
+	 * or whatever? */
+	resbuf->len = total_buf_len(resbuf);
+	switch (gc->gc_svc) {
+	case RPC_GSS_SVC_NONE:
+		break;
+	case RPC_GSS_SVC_INTEGRITY:
+		stat = svcauth_gss_wrap_resp_integ(rqstp);
+		if (stat)
+			goto out_err;
+		break;
+	case RPC_GSS_SVC_PRIVACY:
+		stat = svcauth_gss_wrap_resp_priv(rqstp);
+		if (stat)
+			goto out_err;
+		break;
+	/*
+	 * For any other gc_svc value, svcauth_gss_accept() already set
+	 * the auth_error appropriately; just fall through:
+	 */
+	}
+
+out:
+	stat = 0;
+out_err:
+	if (rqstp->rq_client)
+		auth_domain_put(rqstp->rq_client);
+	rqstp->rq_client = NULL;
+	if (rqstp->rq_gssclient)
+		auth_domain_put(rqstp->rq_gssclient);
+	rqstp->rq_gssclient = NULL;
+	if (rqstp->rq_cred.cr_group_info)
+		put_group_info(rqstp->rq_cred.cr_group_info);
+	rqstp->rq_cred.cr_group_info = NULL;
+	if (gsd && gsd->rsci) {
+		cache_put(&gsd->rsci->h, sn->rsc_cache);
+		gsd->rsci = NULL;
+	}
+	return stat;
+}
+
+static void
+svcauth_gss_domain_release_rcu(struct rcu_head *head)
+{
+	struct auth_domain *dom = container_of(head, struct auth_domain, rcu_head);
+	struct gss_domain *gd = container_of(dom, struct gss_domain, h);
+
+	kfree(dom->name);
+	kfree(gd);
+}
+
+static void
+svcauth_gss_domain_release(struct auth_domain *dom)
+{
+	call_rcu(&dom->rcu_head, svcauth_gss_domain_release_rcu);
+}
+
+static struct auth_ops svcauthops_gss = {
+	.name		= "rpcsec_gss",
+	.owner		= THIS_MODULE,
+	.flavour	= RPC_AUTH_GSS,
+	.accept		= svcauth_gss_accept,
+	.release	= svcauth_gss_release,
+	.domain_release = svcauth_gss_domain_release,
+	.set_client	= svcauth_gss_set_client,
+};
+
+static int rsi_cache_create_net(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct cache_detail *cd;
+	int err;
+
+	cd = cache_create_net(&rsi_cache_template, net);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+	err = cache_register_net(cd, net);
+	if (err) {
+		cache_destroy_net(cd, net);
+		return err;
+	}
+	sn->rsi_cache = cd;
+	return 0;
+}
+
+static void rsi_cache_destroy_net(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct cache_detail *cd = sn->rsi_cache;
+
+	sn->rsi_cache = NULL;
+	cache_purge(cd);
+	cache_unregister_net(cd, net);
+	cache_destroy_net(cd, net);
+}
+
+static int rsc_cache_create_net(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct cache_detail *cd;
+	int err;
+
+	cd = cache_create_net(&rsc_cache_template, net);
+	if (IS_ERR(cd))
+		return PTR_ERR(cd);
+	err = cache_register_net(cd, net);
+	if (err) {
+		cache_destroy_net(cd, net);
+		return err;
+	}
+	sn->rsc_cache = cd;
+	return 0;
+}
+
+static void rsc_cache_destroy_net(struct net *net)
+{
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+	struct cache_detail *cd = sn->rsc_cache;
+
+	sn->rsc_cache = NULL;
+	cache_purge(cd);
+	cache_unregister_net(cd, net);
+	cache_destroy_net(cd, net);
+}
+
+int
+gss_svc_init_net(struct net *net)
+{
+	int rv;
+
+	rv = rsc_cache_create_net(net);
+	if (rv)
+		return rv;
+	rv = rsi_cache_create_net(net);
+	if (rv)
+		goto out1;
+	rv = create_use_gss_proxy_proc_entry(net);
+	if (rv)
+		goto out2;
+	return 0;
+out2:
+	rsi_cache_destroy_net(net);
+out1:
+	rsc_cache_destroy_net(net);
+	return rv;
+}
+
+void
+gss_svc_shutdown_net(struct net *net)
+{
+	destroy_use_gss_proxy_proc_entry(net);
+	rsi_cache_destroy_net(net);
+	rsc_cache_destroy_net(net);
+}
+
+int
+gss_svc_init(void)
+{
+	return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
+}
+
+void
+gss_svc_shutdown(void)
+{
+	svc_auth_unregister(RPC_AUTH_GSS);
+}