Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull user namespace and namespace infrastructure changes from Eric W Biederman:
 "This set of changes starts with a few small enhnacements to the user
  namespace.  reboot support, allowing more arbitrary mappings, and
  support for mounting devpts, ramfs, tmpfs, and mqueuefs as just the
  user namespace root.

  I do my best to document that if you care about limiting your
  unprivileged users that when you have the user namespace support
  enabled you will need to enable memory control groups.

  There is a minor bug fix to prevent overflowing the stack if someone
  creates way too many user namespaces.

  The bulk of the changes are a continuation of the kuid/kgid push down
  work through the filesystems.  These changes make using uids and gids
  typesafe which ensures that these filesystems are safe to use when
  multiple user namespaces are in use.  The filesystems converted for
  3.9 are ceph, 9p, afs, ocfs2, gfs2, ncpfs, nfs, nfsd, and cifs.  The
  changes for these filesystems were a little more involved so I split
  the changes into smaller hopefully obviously correct changes.

  XFS is the only filesystem that remains.  I was hoping I could get
  that in this release so that user namespace support would be enabled
  with an allyesconfig or an allmodconfig but it looks like the xfs
  changes need another couple of days before it they are ready."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (93 commits)
  cifs: Enable building with user namespaces enabled.
  cifs: Convert struct cifs_ses to use a kuid_t and a kgid_t
  cifs: Convert struct cifs_sb_info to use kuids and kgids
  cifs: Modify struct smb_vol to use kuids and kgids
  cifs: Convert struct cifsFileInfo to use a kuid
  cifs: Convert struct cifs_fattr to use kuid and kgids
  cifs: Convert struct tcon_link to use a kuid.
  cifs: Modify struct cifs_unix_set_info_args to hold a kuid_t and a kgid_t
  cifs: Convert from a kuid before printing current_fsuid
  cifs: Use kuids and kgids SID to uid/gid mapping
  cifs: Pass GLOBAL_ROOT_UID and GLOBAL_ROOT_GID to keyring_alloc
  cifs: Use BUILD_BUG_ON to validate uids and gids are the same size
  cifs: Override unmappable incoming uids and gids
  nfsd: Enable building with user namespaces enabled.
  nfsd: Properly compare and initialize kuids and kgids
  nfsd: Store ex_anon_uid and ex_anon_gid as kuids and kgids
  nfsd: Modify nfsd4_cb_sec to use kuids and kgids
  nfsd: Handle kuids and kgids in the nfs4acl to posix_acl conversion
  nfsd: Convert nfsxdr to use kuids and kgids
  nfsd: Convert nfs3xdr to use kuids and kgids
  ...

6 files changed, 96 insertions, 68 deletions

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index b5c067bccc4..392adc41e2e 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -412,7 +412,7 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 			*entry, *new;
 	unsigned int nr;
 
-	nr = hash_long(acred->uid, cache->hashbits);
+	nr = hash_long(from_kuid(&init_user_ns, acred->uid), cache->hashbits);
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
@@ -519,8 +519,8 @@ rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 {
 	struct rpc_auth *auth = task->tk_client->cl_auth;
 	struct auth_cred acred = {
-		.uid = 0,
-		.gid = 0,
+		.uid = GLOBAL_ROOT_UID,
+		.gid = GLOBAL_ROOT_GID,
 	};
 
 	dprintk("RPC: %5u looking up %s cred\n",
diff --git a/net/sunrpc/auth_generic.c b/net/sunrpc/auth_generic.c
index 6ed6f201b02..b6badafc649 100644
--- a/net/sunrpc/auth_generic.c
+++ b/net/sunrpc/auth_generic.c
@@ -18,8 +18,8 @@
 # define RPCDBG_FACILITY	RPCDBG_AUTH
 #endif
 
-#define RPC_MACHINE_CRED_USERID		((uid_t)0)
-#define RPC_MACHINE_CRED_GROUPID	((gid_t)0)
+#define RPC_MACHINE_CRED_USERID		GLOBAL_ROOT_UID
+#define RPC_MACHINE_CRED_GROUPID	GLOBAL_ROOT_GID
 
 struct generic_cred {
 	struct rpc_cred gc_base;
@@ -96,7 +96,9 @@ generic_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 
 	dprintk("RPC:       allocated %s cred %p for uid %d gid %d\n",
 			gcred->acred.machine_cred ? "machine" : "generic",
-			gcred, acred->uid, acred->gid);
+			gcred,
+			from_kuid(&init_user_ns, acred->uid),
+			from_kgid(&init_user_ns, acred->gid));
 	return &gcred->gc_base;
 }
 
@@ -129,8 +131,8 @@ machine_cred_match(struct auth_cred *acred, struct generic_cred *gcred, int flag
 {
 	if (!gcred->acred.machine_cred ||
 	    gcred->acred.principal != acred->principal ||
-	    gcred->acred.uid != acred->uid ||
-	    gcred->acred.gid != acred->gid)
+	    !uid_eq(gcred->acred.uid, acred->uid) ||
+	    !gid_eq(gcred->acred.gid, acred->gid))
 		return 0;
 	return 1;
 }
@@ -147,8 +149,8 @@ generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 	if (acred->machine_cred)
 		return machine_cred_match(acred, gcred, flags);
 
-	if (gcred->acred.uid != acred->uid ||
-	    gcred->acred.gid != acred->gid ||
+	if (!uid_eq(gcred->acred.uid, acred->uid) ||
+	    !gid_eq(gcred->acred.gid, acred->gid) ||
 	    gcred->acred.machine_cred != 0)
 		goto out_nomatch;
 
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 911ef008b70..6ea29f4ed6c 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -255,7 +255,7 @@ err:
 
 struct gss_upcall_msg {
 	atomic_t count;
-	uid_t	uid;
+	kuid_t	uid;
 	struct rpc_pipe_msg msg;
 	struct list_head list;
 	struct gss_auth *auth;
@@ -302,11 +302,11 @@ gss_release_msg(struct gss_upcall_msg *gss_msg)
 }
 
 static struct gss_upcall_msg *
-__gss_find_upcall(struct rpc_pipe *pipe, uid_t uid)
+__gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid)
 {
 	struct gss_upcall_msg *pos;
 	list_for_each_entry(pos, &pipe->in_downcall, list) {
-		if (pos->uid != uid)
+		if (!uid_eq(pos->uid, uid))
 			continue;
 		atomic_inc(&pos->count);
 		dprintk("RPC:       %s found msg %p\n", __func__, pos);
@@ -394,8 +394,11 @@ gss_upcall_callback(struct rpc_task *task)
 
 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
 {
-	gss_msg->msg.data = &gss_msg->uid;
-	gss_msg->msg.len = sizeof(gss_msg->uid);
+	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);
+	BUG_ON(sizeof(uid) > UPCALL_BUF_LEN);
 }
 
 static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
@@ -408,7 +411,7 @@ static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 
 	gss_msg->msg.len = sprintf(gss_msg->databuf, "mech=%s uid=%d ",
 				   mech->gm_name,
-				   gss_msg->uid);
+				   from_kuid(&init_user_ns, gss_msg->uid));
 	p += gss_msg->msg.len;
 	if (clnt->cl_principal) {
 		len = sprintf(p, "target=%s ", clnt->cl_principal);
@@ -444,7 +447,7 @@ static void gss_encode_msg(struct gss_upcall_msg *gss_msg,
 
 static struct gss_upcall_msg *
 gss_alloc_msg(struct gss_auth *gss_auth, struct rpc_clnt *clnt,
-		uid_t uid, const char *service_name)
+		kuid_t uid, const char *service_name)
 {
 	struct gss_upcall_msg *gss_msg;
 	int vers;
@@ -474,7 +477,7 @@ gss_setup_upcall(struct rpc_clnt *clnt, struct gss_auth *gss_auth, struct rpc_cr
 	struct gss_cred *gss_cred = container_of(cred,
 			struct gss_cred, gc_base);
 	struct gss_upcall_msg *gss_new, *gss_msg;
-	uid_t uid = cred->cr_uid;
+	kuid_t uid = cred->cr_uid;
 
 	gss_new = gss_alloc_msg(gss_auth, clnt, uid, gss_cred->gc_principal);
 	if (IS_ERR(gss_new))
@@ -516,7 +519,7 @@ gss_refresh_upcall(struct rpc_task *task)
 	int err = 0;
 
 	dprintk("RPC: %5u %s for uid %u\n",
-		task->tk_pid, __func__, cred->cr_uid);
+		task->tk_pid, __func__, from_kuid(&init_user_ns, cred->cr_uid));
 	gss_msg = gss_setup_upcall(task->tk_client, gss_auth, cred);
 	if (PTR_ERR(gss_msg) == -EAGAIN) {
 		/* XXX: warning on the first, under the assumption we
@@ -548,7 +551,8 @@ gss_refresh_upcall(struct rpc_task *task)
 	gss_release_msg(gss_msg);
 out:
 	dprintk("RPC: %5u %s for uid %u result %d\n",
-		task->tk_pid, __func__, cred->cr_uid, err);
+		task->tk_pid, __func__,
+		from_kuid(&init_user_ns, cred->cr_uid),	err);
 	return err;
 }
 
@@ -561,7 +565,8 @@ gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
 	DEFINE_WAIT(wait);
 	int err = 0;
 
-	dprintk("RPC:       %s for uid %u\n", __func__, cred->cr_uid);
+	dprintk("RPC:       %s for uid %u\n",
+		__func__, from_kuid(&init_user_ns, cred->cr_uid));
 retry:
 	gss_msg = gss_setup_upcall(gss_auth->client, gss_auth, cred);
 	if (PTR_ERR(gss_msg) == -EAGAIN) {
@@ -603,7 +608,7 @@ out_intr:
 	gss_release_msg(gss_msg);
 out:
 	dprintk("RPC:       %s for uid %u result %d\n",
-		__func__, cred->cr_uid, err);
+		__func__, from_kuid(&init_user_ns, cred->cr_uid), err);
 	return err;
 }
 
@@ -617,7 +622,8 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 	struct gss_upcall_msg *gss_msg;
 	struct rpc_pipe *pipe = RPC_I(filp->f_dentry->d_inode)->pipe;
 	struct gss_cl_ctx *ctx;
-	uid_t uid;
+	uid_t id;
+	kuid_t uid;
 	ssize_t err = -EFBIG;
 
 	if (mlen > MSG_BUF_MAXSIZE)
@@ -632,12 +638,18 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 		goto err;
 
 	end = (const void *)((char *)buf + mlen);
-	p = simple_get_bytes(buf, end, &uid, sizeof(uid));
+	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)
@@ -1058,7 +1070,8 @@ gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 	int err = -ENOMEM;
 
 	dprintk("RPC:       %s for uid %d, flavor %d\n",
-		__func__, acred->uid, auth->au_flavor);
+		__func__, from_kuid(&init_user_ns, acred->uid),
+		auth->au_flavor);
 
 	if (!(cred = kzalloc(sizeof(*cred), GFP_NOFS)))
 		goto out_err;
@@ -1114,7 +1127,7 @@ out:
 	}
 	if (gss_cred->gc_principal != NULL)
 		return 0;
-	return rc->cr_uid == acred->uid;
+	return uid_eq(rc->cr_uid, acred->uid);
 }
 
 /*
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 73e95738660..ecd1d58bf61 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -418,6 +418,7 @@ static int rsc_parse(struct cache_detail *cd,
 {
 	/* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
 	char *buf = mesg;
+	int id;
 	int len, rv;
 	struct rsc rsci, *rscp = NULL;
 	time_t expiry;
@@ -444,7 +445,7 @@ static int rsc_parse(struct cache_detail *cd,
 		goto out;
 
 	/* uid, or NEGATIVE */
-	rv = get_int(&mesg, &rsci.cred.cr_uid);
+	rv = get_int(&mesg, &id);
 	if (rv == -EINVAL)
 		goto out;
 	if (rv == -ENOENT)
@@ -452,8 +453,16 @@ static int rsc_parse(struct cache_detail *cd,
 	else {
 		int N, i;
 
+		/* uid */
+		rsci.cred.cr_uid = make_kuid(&init_user_ns, id);
+		if (!uid_valid(rsci.cred.cr_uid))
+			goto out;
+
 		/* gid */
-		if (get_int(&mesg, &rsci.cred.cr_gid))
+		if (get_int(&mesg, &id))
+			goto out;
+		rsci.cred.cr_gid = make_kgid(&init_user_ns, id);
+		if (!gid_valid(rsci.cred.cr_gid))
 			goto out;
 
 		/* number of additional gid's */
@@ -467,11 +476,10 @@ static int rsc_parse(struct cache_detail *cd,
 		/* gid's */
 		status = -EINVAL;
 		for (i=0; i<N; i++) {
-			gid_t gid;
 			kgid_t kgid;
-			if (get_int(&mesg, &gid))
+			if (get_int(&mesg, &id))
 				goto out;
-			kgid = make_kgid(&init_user_ns, gid);
+			kgid = make_kgid(&init_user_ns, id);
 			if (!gid_valid(kgid))
 				goto out;
 			GROUP_AT(rsci.cred.cr_group_info, i) = kgid;
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 52c5abdee21..dc37021fc3e 100644
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -18,8 +18,8 @@
 
 struct unx_cred {
 	struct rpc_cred		uc_base;
-	gid_t			uc_gid;
-	gid_t			uc_gids[NFS_NGROUPS];
+	kgid_t			uc_gid;
+	kgid_t			uc_gids[NFS_NGROUPS];
 };
 #define uc_uid			uc_base.cr_uid
 
@@ -65,7 +65,8 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 	unsigned int i;
 
 	dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
-			acred->uid, acred->gid);
+			from_kuid(&init_user_ns, acred->uid),
+			from_kgid(&init_user_ns, acred->gid));
 
 	if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
 		return ERR_PTR(-ENOMEM);
@@ -79,13 +80,10 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 		groups = NFS_NGROUPS;
 
 	cred->uc_gid = acred->gid;
-	for (i = 0; i < groups; i++) {
-		gid_t gid;
-		gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
-		cred->uc_gids[i] = gid;
-	}
+	for (i = 0; i < groups; i++)
+		cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
 	if (i < NFS_NGROUPS)
-		cred->uc_gids[i] = NOGROUP;
+		cred->uc_gids[i] = INVALID_GID;
 
 	return &cred->uc_base;
 }
@@ -123,21 +121,17 @@ unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 	unsigned int i;
 
 
-	if (cred->uc_uid != acred->uid || cred->uc_gid != acred->gid)
+	if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid))
 		return 0;
 
 	if (acred->group_info != NULL)
 		groups = acred->group_info->ngroups;
 	if (groups > NFS_NGROUPS)
 		groups = NFS_NGROUPS;
-	for (i = 0; i < groups ; i++) {
-		gid_t gid;
-		gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
-		if (cred->uc_gids[i] != gid)
+	for (i = 0; i < groups ; i++)
+		if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i)))
 			return 0;
-	}
-	if (groups < NFS_NGROUPS &&
-	    cred->uc_gids[groups] != NOGROUP)
+	if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups]))
 		return 0;
 	return 1;
 }
@@ -163,11 +157,11 @@ unx_marshal(struct rpc_task *task, __be32 *p)
 	 */
 	p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 
-	*p++ = htonl((u32) cred->uc_uid);
-	*p++ = htonl((u32) cred->uc_gid);
+	*p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
+	*p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
 	hold = p++;
-	for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)
-		*p++ = htonl((u32) cred->uc_gids[i]);
+	for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++)
+		*p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
 	*hold = htonl(p - hold - 1);		/* gid array length */
 	*base = htonl((p - base - 1) << 2);	/* cred length */
 
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 4d012920373..a1852e19ed0 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -415,10 +415,15 @@ svcauth_unix_info_release(struct svc_xprt *xpt)
 
 struct unix_gid {
 	struct cache_head	h;
-	uid_t			uid;
+	kuid_t			uid;
 	struct group_info	*gi;
 };
 
+static int unix_gid_hash(kuid_t uid)
+{
+	return hash_long(from_kuid(&init_user_ns, uid), GID_HASHBITS);
+}
+
 static void unix_gid_put(struct kref *kref)
 {
 	struct cache_head *item = container_of(kref, struct cache_head, ref);
@@ -433,7 +438,7 @@ static int unix_gid_match(struct cache_head *corig, struct cache_head *cnew)
 {
 	struct unix_gid *orig = container_of(corig, struct unix_gid, h);
 	struct unix_gid *new = container_of(cnew, struct unix_gid, h);
-	return orig->uid == new->uid;
+	return uid_eq(orig->uid, new->uid);
 }
 static void unix_gid_init(struct cache_head *cnew, struct cache_head *citem)
 {
@@ -465,7 +470,7 @@ static void unix_gid_request(struct cache_detail *cd,
 	char tuid[20];
 	struct unix_gid *ug = container_of(h, struct unix_gid, h);
 
-	snprintf(tuid, 20, "%u", ug->uid);
+	snprintf(tuid, 20, "%u", from_kuid(&init_user_ns, ug->uid));
 	qword_add(bpp, blen, tuid);
 	(*bpp)[-1] = '\n';
 }
@@ -475,13 +480,14 @@ static int unix_gid_upcall(struct cache_detail *cd, struct cache_head *h)
 	return sunrpc_cache_pipe_upcall(cd, h, unix_gid_request);
 }
 
-static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, uid_t uid);
+static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, kuid_t uid);
 
 static int unix_gid_parse(struct cache_detail *cd,
 			char *mesg, int mlen)
 {
 	/* uid expiry Ngid gid0 gid1 ... gidN-1 */
-	int uid;
+	int id;
+	kuid_t uid;
 	int gids;
 	int rv;
 	int i;
@@ -493,9 +499,12 @@ static int unix_gid_parse(struct cache_detail *cd,
 		return -EINVAL;
 	mesg[mlen-1] = 0;
 
-	rv = get_int(&mesg, &uid);
+	rv = get_int(&mesg, &id);
 	if (rv)
 		return -EINVAL;
+	uid = make_kuid(&init_user_ns, id);
+	if (!uid_valid(uid))
+		return -EINVAL;
 	ug.uid = uid;
 
 	expiry = get_expiry(&mesg);
@@ -530,7 +539,7 @@ static int unix_gid_parse(struct cache_detail *cd,
 		ug.h.expiry_time = expiry;
 		ch = sunrpc_cache_update(cd,
 					 &ug.h, &ugp->h,
-					 hash_long(uid, GID_HASHBITS));
+					 unix_gid_hash(uid));
 		if (!ch)
 			err = -ENOMEM;
 		else {
@@ -549,7 +558,7 @@ static int unix_gid_show(struct seq_file *m,
 			 struct cache_detail *cd,
 			 struct cache_head *h)
 {
-	struct user_namespace *user_ns = current_user_ns();
+	struct user_namespace *user_ns = &init_user_ns;
 	struct unix_gid *ug;
 	int i;
 	int glen;
@@ -565,7 +574,7 @@ static int unix_gid_show(struct seq_file *m,
 	else
 		glen = 0;
 
-	seq_printf(m, "%u %d:", ug->uid, glen);
+	seq_printf(m, "%u %d:", from_kuid_munged(user_ns, ug->uid), glen);
 	for (i = 0; i < glen; i++)
 		seq_printf(m, " %d", from_kgid_munged(user_ns, GROUP_AT(ug->gi, i)));
 	seq_printf(m, "\n");
@@ -615,20 +624,20 @@ void unix_gid_cache_destroy(struct net *net)
 	cache_destroy_net(cd, net);
 }
 
-static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, uid_t uid)
+static struct unix_gid *unix_gid_lookup(struct cache_detail *cd, kuid_t uid)
 {
 	struct unix_gid ug;
 	struct cache_head *ch;
 
 	ug.uid = uid;
-	ch = sunrpc_cache_lookup(cd, &ug.h, hash_long(uid, GID_HASHBITS));
+	ch = sunrpc_cache_lookup(cd, &ug.h, unix_gid_hash(uid));
 	if (ch)
 		return container_of(ch, struct unix_gid, h);
 	else
 		return NULL;
 }
 
-static struct group_info *unix_gid_find(uid_t uid, struct svc_rqst *rqstp)
+static struct group_info *unix_gid_find(kuid_t uid, struct svc_rqst *rqstp)
 {
 	struct unix_gid *ug;
 	struct group_info *gi;
@@ -750,8 +759,8 @@ svcauth_null_accept(struct svc_rqst *rqstp, __be32 *authp)
 	}
 
 	/* Signal that mapping to nobody uid/gid is required */
-	cred->cr_uid = (uid_t) -1;
-	cred->cr_gid = (gid_t) -1;
+	cred->cr_uid = INVALID_UID;
+	cred->cr_gid = INVALID_GID;
 	cred->cr_group_info = groups_alloc(0);
 	if (cred->cr_group_info == NULL)
 		return SVC_CLOSE; /* kmalloc failure - client must retry */
@@ -812,8 +821,10 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp)
 	argv->iov_base = (void*)((__be32*)argv->iov_base + slen);	/* skip machname */
 	argv->iov_len -= slen*4;
 
-	cred->cr_uid = svc_getnl(argv);		/* uid */
-	cred->cr_gid = svc_getnl(argv);		/* gid */
+	cred->cr_uid = make_kuid(&init_user_ns, svc_getnl(argv)); /* uid */
+	cred->cr_gid = make_kgid(&init_user_ns, svc_getnl(argv)); /* gid */
+	if (!uid_valid(cred->cr_uid) || !gid_valid(cred->cr_gid))
+		goto badcred;
 	slen = svc_getnl(argv);			/* gids length */
 	if (slen > 16 || (len -= (slen + 2)*4) < 0)
 		goto badcred;