v4.19.13 snapshot.
diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
new file mode 100644
index 0000000..185e56d
--- /dev/null
+++ b/net/sunrpc/auth_unix.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/net/sunrpc/auth_unix.c
+ *
+ * UNIX-style authentication; no AUTH_SHORT support
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/auth.h>
+#include <linux/user_namespace.h>
+
+struct unx_cred {
+ struct rpc_cred uc_base;
+ kgid_t uc_gid;
+ kgid_t uc_gids[UNX_NGROUPS];
+};
+#define uc_uid uc_base.cr_uid
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+# define RPCDBG_FACILITY RPCDBG_AUTH
+#endif
+
+static struct rpc_auth unix_auth;
+static const struct rpc_credops unix_credops;
+
+static struct rpc_auth *
+unx_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
+{
+ dprintk("RPC: creating UNIX authenticator for client %p\n",
+ clnt);
+ atomic_inc(&unix_auth.au_count);
+ return &unix_auth;
+}
+
+static void
+unx_destroy(struct rpc_auth *auth)
+{
+ dprintk("RPC: destroying UNIX authenticator %p\n", auth);
+ rpcauth_clear_credcache(auth->au_credcache);
+}
+
+static int
+unx_hash_cred(struct auth_cred *acred, unsigned int hashbits)
+{
+ return hash_64(from_kgid(&init_user_ns, acred->gid) |
+ ((u64)from_kuid(&init_user_ns, acred->uid) <<
+ (sizeof(gid_t) * 8)), hashbits);
+}
+
+/*
+ * Lookup AUTH_UNIX creds for current process
+ */
+static struct rpc_cred *
+unx_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 *
+unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
+{
+ struct unx_cred *cred;
+ unsigned int groups = 0;
+ unsigned int i;
+
+ dprintk("RPC: allocating UNIX cred for uid %d gid %d\n",
+ from_kuid(&init_user_ns, acred->uid),
+ from_kgid(&init_user_ns, acred->gid));
+
+ if (!(cred = kmalloc(sizeof(*cred), gfp)))
+ return ERR_PTR(-ENOMEM);
+
+ rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
+ cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
+
+ if (acred->group_info != NULL)
+ groups = acred->group_info->ngroups;
+ if (groups > UNX_NGROUPS)
+ groups = UNX_NGROUPS;
+
+ cred->uc_gid = acred->gid;
+ for (i = 0; i < groups; i++)
+ cred->uc_gids[i] = acred->group_info->gid[i];
+ if (i < UNX_NGROUPS)
+ cred->uc_gids[i] = INVALID_GID;
+
+ return &cred->uc_base;
+}
+
+static void
+unx_free_cred(struct unx_cred *unx_cred)
+{
+ dprintk("RPC: unx_free_cred %p\n", unx_cred);
+ kfree(unx_cred);
+}
+
+static void
+unx_free_cred_callback(struct rcu_head *head)
+{
+ struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
+ unx_free_cred(unx_cred);
+}
+
+static void
+unx_destroy_cred(struct rpc_cred *cred)
+{
+ call_rcu(&cred->cr_rcu, unx_free_cred_callback);
+}
+
+/*
+ * Match credentials against current process creds.
+ * The root_override argument takes care of cases where the caller may
+ * request root creds (e.g. for NFS swapping).
+ */
+static int
+unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
+{
+ struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
+ unsigned int groups = 0;
+ unsigned int i;
+
+
+ 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 > UNX_NGROUPS)
+ groups = UNX_NGROUPS;
+ for (i = 0; i < groups ; i++)
+ if (!gid_eq(cred->uc_gids[i], acred->group_info->gid[i]))
+ return 0;
+ if (groups < UNX_NGROUPS && gid_valid(cred->uc_gids[groups]))
+ return 0;
+ return 1;
+}
+
+/*
+ * Marshal credentials.
+ * Maybe we should keep a cached credential for performance reasons.
+ */
+static __be32 *
+unx_marshal(struct rpc_task *task, __be32 *p)
+{
+ struct rpc_clnt *clnt = task->tk_client;
+ struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
+ __be32 *base, *hold;
+ int i;
+
+ *p++ = htonl(RPC_AUTH_UNIX);
+ base = p++;
+ *p++ = htonl(jiffies/HZ);
+
+ /*
+ * Copy the UTS nodename captured when the client was created.
+ */
+ p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
+
+ *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 < UNX_NGROUPS && 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 */
+
+ *p++ = htonl(RPC_AUTH_NULL);
+ *p++ = htonl(0);
+
+ return p;
+}
+
+/*
+ * Refresh credentials. This is a no-op for AUTH_UNIX
+ */
+static int
+unx_refresh(struct rpc_task *task)
+{
+ set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
+ return 0;
+}
+
+static __be32 *
+unx_validate(struct rpc_task *task, __be32 *p)
+{
+ rpc_authflavor_t flavor;
+ u32 size;
+
+ flavor = ntohl(*p++);
+ if (flavor != RPC_AUTH_NULL &&
+ flavor != RPC_AUTH_UNIX &&
+ flavor != RPC_AUTH_SHORT) {
+ printk("RPC: bad verf flavor: %u\n", flavor);
+ return ERR_PTR(-EIO);
+ }
+
+ size = ntohl(*p++);
+ if (size > RPC_MAX_AUTH_SIZE) {
+ printk("RPC: giant verf size: %u\n", size);
+ return ERR_PTR(-EIO);
+ }
+ task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
+ p += (size >> 2);
+
+ return p;
+}
+
+int __init rpc_init_authunix(void)
+{
+ return rpcauth_init_credcache(&unix_auth);
+}
+
+void rpc_destroy_authunix(void)
+{
+ rpcauth_destroy_credcache(&unix_auth);
+}
+
+const struct rpc_authops authunix_ops = {
+ .owner = THIS_MODULE,
+ .au_flavor = RPC_AUTH_UNIX,
+ .au_name = "UNIX",
+ .create = unx_create,
+ .destroy = unx_destroy,
+ .hash_cred = unx_hash_cred,
+ .lookup_cred = unx_lookup_cred,
+ .crcreate = unx_create_cred,
+};
+
+static
+struct rpc_auth unix_auth = {
+ .au_cslack = UNX_CALLSLACK,
+ .au_rslack = NUL_REPLYSLACK,
+ .au_flags = RPCAUTH_AUTH_NO_CRKEY_TIMEOUT,
+ .au_ops = &authunix_ops,
+ .au_flavor = RPC_AUTH_UNIX,
+ .au_count = ATOMIC_INIT(0),
+};
+
+static
+const struct rpc_credops unix_credops = {
+ .cr_name = "AUTH_UNIX",
+ .crdestroy = unx_destroy_cred,
+ .crbind = rpcauth_generic_bind_cred,
+ .crmatch = unx_match,
+ .crmarshal = unx_marshal,
+ .crrefresh = unx_refresh,
+ .crvalidate = unx_validate,
+};