linux/include/linux/sunrpc/auth.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * linux/include/linux/sunrpc/auth.h
   4 *
   5 * Declarations for the RPC client authentication machinery.
   6 *
   7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   8 */
   9
  10#ifndef _LINUX_SUNRPC_AUTH_H
  11#define _LINUX_SUNRPC_AUTH_H
  12
  13#ifdef __KERNEL__
  14
  15#include <linux/sunrpc/sched.h>
  16#include <linux/sunrpc/msg_prot.h>
  17#include <linux/sunrpc/xdr.h>
  18
  19#include <linux/atomic.h>
  20#include <linux/rcupdate.h>
  21#include <linux/uidgid.h>
  22#include <linux/utsname.h>
  23
  24/*
  25 * Maximum size of AUTH_NONE authentication information, in XDR words.
  26 */
  27#define NUL_CALLSLACK   (4)
  28#define NUL_REPLYSLACK  (2)
  29
  30/*
  31 * Size of the nodename buffer. RFC1831 specifies a hard limit of 255 bytes,
  32 * but Linux hostnames are actually limited to __NEW_UTS_LEN bytes.
  33 */
  34#define UNX_MAXNODENAME __NEW_UTS_LEN
  35#define UNX_CALLSLACK   (21 + XDR_QUADLEN(UNX_MAXNODENAME))
  36#define UNX_NGROUPS     16
  37
  38struct rpcsec_gss_info;
  39
  40/* auth_cred ac_flags bits */
  41enum {
  42        RPC_CRED_KEY_EXPIRE_SOON = 1, /* underlying cred key will expire soon */
  43        RPC_CRED_NOTIFY_TIMEOUT = 2,   /* nofity generic cred when underlying
  44                                        key will expire soon */
  45};
  46
  47/* Work around the lack of a VFS credential */
  48struct auth_cred {
  49        kuid_t  uid;
  50        kgid_t  gid;
  51        struct group_info *group_info;
  52        const char *principal;
  53        unsigned long ac_flags;
  54        unsigned char machine_cred : 1;
  55};
  56
  57/*
  58 * Client user credentials
  59 */
  60struct rpc_auth;
  61struct rpc_credops;
  62struct rpc_cred {
  63        struct hlist_node       cr_hash;        /* hash chain */
  64        struct list_head        cr_lru;         /* lru garbage collection */
  65        struct rcu_head         cr_rcu;
  66        struct rpc_auth *       cr_auth;
  67        const struct rpc_credops *cr_ops;
  68        unsigned long           cr_expire;      /* when to gc */
  69        unsigned long           cr_flags;       /* various flags */
  70        atomic_t                cr_count;       /* ref count */
  71
  72        kuid_t                  cr_uid;
  73
  74        /* per-flavor data */
  75};
  76#define RPCAUTH_CRED_NEW        0
  77#define RPCAUTH_CRED_UPTODATE   1
  78#define RPCAUTH_CRED_HASHED     2
  79#define RPCAUTH_CRED_NEGATIVE   3
  80
  81/* rpc_auth au_flags */
  82#define RPCAUTH_AUTH_NO_CRKEY_TIMEOUT   0x0001 /* underlying cred has no key timeout */
  83
  84/*
  85 * Client authentication handle
  86 */
  87struct rpc_cred_cache;
  88struct rpc_authops;
  89struct rpc_auth {
  90        unsigned int            au_cslack;      /* call cred size estimate */
  91                                /* guess at number of u32's auth adds before
  92                                 * reply data; normally the verifier size: */
  93        unsigned int            au_rslack;
  94                                /* for gss, used to calculate au_rslack: */
  95        unsigned int            au_verfsize;
  96
  97        unsigned int            au_flags;       /* various flags */
  98        const struct rpc_authops *au_ops;               /* operations */
  99        rpc_authflavor_t        au_flavor;      /* pseudoflavor (note may
 100                                                 * differ from the flavor in
 101                                                 * au_ops->au_flavor in gss
 102                                                 * case) */
 103        atomic_t                au_count;       /* Reference counter */
 104
 105        struct rpc_cred_cache * au_credcache;
 106        /* per-flavor data */
 107};
 108
 109/* rpc_auth au_flags */
 110#define RPCAUTH_AUTH_DATATOUCH  0x00000002
 111
 112struct rpc_auth_create_args {
 113        rpc_authflavor_t pseudoflavor;
 114        const char *target_name;
 115};
 116
 117/* Flags for rpcauth_lookupcred() */
 118#define RPCAUTH_LOOKUP_NEW              0x01    /* Accept an uninitialised cred */
 119#define RPCAUTH_LOOKUP_RCU              0x02    /* lock-less lookup */
 120
 121/*
 122 * Client authentication ops
 123 */
 124struct rpc_authops {
 125        struct module           *owner;
 126        rpc_authflavor_t        au_flavor;      /* flavor (RPC_AUTH_*) */
 127        char *                  au_name;
 128        struct rpc_auth *       (*create)(struct rpc_auth_create_args *, struct rpc_clnt *);
 129        void                    (*destroy)(struct rpc_auth *);
 130
 131        int                     (*hash_cred)(struct auth_cred *, unsigned int);
 132        struct rpc_cred *       (*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
 133        struct rpc_cred *       (*crcreate)(struct rpc_auth*, struct auth_cred *, int, gfp_t);
 134        int                     (*list_pseudoflavors)(rpc_authflavor_t *, int);
 135        rpc_authflavor_t        (*info2flavor)(struct rpcsec_gss_info *);
 136        int                     (*flavor2info)(rpc_authflavor_t,
 137                                                struct rpcsec_gss_info *);
 138        int                     (*key_timeout)(struct rpc_auth *,
 139                                                struct rpc_cred *);
 140};
 141
 142struct rpc_credops {
 143        const char *            cr_name;        /* Name of the auth flavour */
 144        int                     (*cr_init)(struct rpc_auth *, struct rpc_cred *);
 145        void                    (*crdestroy)(struct rpc_cred *);
 146
 147        int                     (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
 148        struct rpc_cred *       (*crbind)(struct rpc_task *, struct rpc_cred *, int);
 149        __be32 *                (*crmarshal)(struct rpc_task *, __be32 *);
 150        int                     (*crrefresh)(struct rpc_task *);
 151        __be32 *                (*crvalidate)(struct rpc_task *, __be32 *);
 152        int                     (*crwrap_req)(struct rpc_task *, kxdreproc_t,
 153                                                void *, __be32 *, void *);
 154        int                     (*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
 155                                                void *, __be32 *, void *);
 156        int                     (*crkey_timeout)(struct rpc_cred *);
 157        bool                    (*crkey_to_expire)(struct rpc_cred *);
 158        char *                  (*crstringify_acceptor)(struct rpc_cred *);
 159};
 160
 161extern const struct rpc_authops authunix_ops;
 162extern const struct rpc_authops authnull_ops;
 163
 164int __init              rpc_init_authunix(void);
 165int __init              rpc_init_generic_auth(void);
 166int __init              rpcauth_init_module(void);
 167void                    rpcauth_remove_module(void);
 168void                    rpc_destroy_generic_auth(void);
 169void                    rpc_destroy_authunix(void);
 170
 171struct rpc_cred *       rpc_lookup_cred(void);
 172struct rpc_cred *       rpc_lookup_cred_nonblock(void);
 173struct rpc_cred *       rpc_lookup_generic_cred(struct auth_cred *, int, gfp_t);
 174struct rpc_cred *       rpc_lookup_machine_cred(const char *service_name);
 175int                     rpcauth_register(const struct rpc_authops *);
 176int                     rpcauth_unregister(const struct rpc_authops *);
 177struct rpc_auth *       rpcauth_create(struct rpc_auth_create_args *,
 178                                struct rpc_clnt *);
 179void                    rpcauth_release(struct rpc_auth *);
 180rpc_authflavor_t        rpcauth_get_pseudoflavor(rpc_authflavor_t,
 181                                struct rpcsec_gss_info *);
 182int                     rpcauth_get_gssinfo(rpc_authflavor_t,
 183                                struct rpcsec_gss_info *);
 184int                     rpcauth_list_flavors(rpc_authflavor_t *, int);
 185struct rpc_cred *       rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int, gfp_t);
 186void                    rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 187struct rpc_cred *       rpcauth_lookupcred(struct rpc_auth *, int);
 188struct rpc_cred *       rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
 189void                    put_rpccred(struct rpc_cred *);
 190__be32 *                rpcauth_marshcred(struct rpc_task *, __be32 *);
 191__be32 *                rpcauth_checkverf(struct rpc_task *, __be32 *);
 192int                     rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
 193int                     rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
 194int                     rpcauth_refreshcred(struct rpc_task *);
 195void                    rpcauth_invalcred(struct rpc_task *);
 196int                     rpcauth_uptodatecred(struct rpc_task *);
 197int                     rpcauth_init_credcache(struct rpc_auth *);
 198void                    rpcauth_destroy_credcache(struct rpc_auth *);
 199void                    rpcauth_clear_credcache(struct rpc_cred_cache *);
 200int                     rpcauth_key_timeout_notify(struct rpc_auth *,
 201                                                struct rpc_cred *);
 202bool                    rpcauth_cred_key_to_expire(struct rpc_auth *, struct rpc_cred *);
 203char *                  rpcauth_stringify_acceptor(struct rpc_cred *);
 204
 205static inline
 206struct rpc_cred *       get_rpccred(struct rpc_cred *cred)
 207{
 208        if (cred != NULL)
 209                atomic_inc(&cred->cr_count);
 210        return cred;
 211}
 212
 213/**
 214 * get_rpccred_rcu - get a reference to a cred using rcu-protected pointer
 215 * @cred: cred of which to take a reference
 216 *
 217 * In some cases, we may have a pointer to a credential to which we
 218 * want to take a reference, but don't already have one. Because these
 219 * objects are freed using RCU, we can access the cr_count while its
 220 * on its way to destruction and only take a reference if it's not already
 221 * zero.
 222 */
 223static inline struct rpc_cred *
 224get_rpccred_rcu(struct rpc_cred *cred)
 225{
 226        if (atomic_inc_not_zero(&cred->cr_count))
 227                return cred;
 228        return NULL;
 229}
 230
 231#endif /* __KERNEL__ */
 232#endif /* _LINUX_SUNRPC_AUTH_H */
 233
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