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