LXR linux/include/linux/sunrpc/auth.h

   1/*
   2 * linux/include/linux/sunrpc/auth.h
   3 *
   4 * Declarations for the RPC client authentication machinery.
   5 *
   6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7 */
   8
   9#ifndef _LINUX_SUNRPC_AUTH_H
  10#define _LINUX_SUNRPC_AUTH_H
  11
  12#ifdef __KERNEL__
  13
  14#include <linux/sunrpc/sched.h>
  15#include <linux/sunrpc/msg_prot.h>
  16#include <linux/sunrpc/xdr.h>
  17
  18#include <linux/atomic.h>
  19#include <linux/rcupdate.h>
  20#include <linux/uidgid.h>
  21#include <linux/utsname.h>
  22
  23/*
  24 * Maximum size of AUTH_NONE authentication information, in XDR words.
  25 */
  26#define NUL_CALLSLACK   (4)
  27#define NUL_REPLYSLACK  (2)
  28
  29/*
  30 * Size of the nodename buffer. RFC1831 specifies a hard limit of 255 bytes,
  31 * but Linux hostnames are actually limited to __NEW_UTS_LEN bytes.
  32 */
  33#define UNX_MAXNODENAME __NEW_UTS_LEN
  34#define UNX_CALLSLACK   (21 + XDR_QUADLEN(UNX_MAXNODENAME))
  35
  36struct rpcsec_gss_info;
  37
  38/* auth_cred ac_flags bits */
  39enum {
  40        RPC_CRED_KEY_EXPIRE_SOON = 1, /* underlying cred key will expire soon */
  41        RPC_CRED_NOTIFY_TIMEOUT = 2,   /* nofity generic cred when underlying
  42                                        key will expire soon */
  43};
  44
  45/* Work around the lack of a VFS credential */
  46struct auth_cred {
  47        kuid_t  uid;
  48        kgid_t  gid;
  49        struct group_info *group_info;
  50        const char *principal;
  51        unsigned long ac_flags;
  52        unsigned char machine_cred : 1;
  53};
  54
  55/*
  56 * Client user credentials
  57 */
  58struct rpc_auth;
  59struct rpc_credops;
  60struct rpc_cred {
  61        struct hlist_node       cr_hash;        /* hash chain */
  62        struct list_head        cr_lru;         /* lru garbage collection */
  63        struct rcu_head         cr_rcu;
  64        struct rpc_auth *       cr_auth;
  65        const struct rpc_credops *cr_ops;
  66#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  67        unsigned long           cr_magic;       /* 0x0f4aa4f0 */
  68#endif
  69        unsigned long           cr_expire;      /* when to gc */
  70        unsigned long           cr_flags;       /* various flags */
  71        atomic_t                cr_count;       /* ref count */
  72
  73        kuid_t                  cr_uid;
  74
  75        /* per-flavor data */
  76};
  77#define RPCAUTH_CRED_NEW        0
  78#define RPCAUTH_CRED_UPTODATE   1
  79#define RPCAUTH_CRED_HASHED     2
  80#define RPCAUTH_CRED_NEGATIVE   3
  81
  82#define RPCAUTH_CRED_MAGIC      0x0f4aa4f0
  83
  84/* rpc_auth au_flags */
  85#define RPCAUTH_AUTH_NO_CRKEY_TIMEOUT   0x0001 /* underlying cred has no key timeout */
  86
  87/*
  88 * Client authentication handle
  89 */
  90struct rpc_cred_cache;
  91struct rpc_authops;
  92struct rpc_auth {
  93        unsigned int            au_cslack;      /* call cred size estimate */
  94                                /* guess at number of u32's auth adds before
  95                                 * reply data; normally the verifier size: */
  96        unsigned int            au_rslack;
  97                                /* for gss, used to calculate au_rslack: */
  98        unsigned int            au_verfsize;
  99
 100        unsigned int            au_flags;       /* various flags */
 101        const struct rpc_authops *au_ops;               /* operations */
 102        rpc_authflavor_t        au_flavor;      /* pseudoflavor (note may
 103                                                 * differ from the flavor in
 104                                                 * au_ops->au_flavor in gss
 105                                                 * case) */
 106        atomic_t                au_count;       /* Reference counter */
 107
 108        struct rpc_cred_cache * au_credcache;
 109        /* per-flavor data */
 110};
 111
 112/* rpc_auth au_flags */
 113#define RPCAUTH_AUTH_DATATOUCH  0x00000002
 114
 115struct rpc_auth_create_args {
 116        rpc_authflavor_t pseudoflavor;
 117        const char *target_name;
 118};
 119
 120/* Flags for rpcauth_lookupcred() */
 121#define RPCAUTH_LOOKUP_NEW              0x01    /* Accept an uninitialised cred */
 122#define RPCAUTH_LOOKUP_RCU              0x02    /* lock-less lookup */
 123
 124/*
 125 * Client authentication ops
 126 */
 127struct rpc_authops {
 128        struct module           *owner;
 129        rpc_authflavor_t        au_flavor;      /* flavor (RPC_AUTH_*) */
 130        char *                  au_name;
 131        struct rpc_auth *       (*create)(struct rpc_auth_create_args *, struct rpc_clnt *);
 132        void                    (*destroy)(struct rpc_auth *);
 133
 134        int                     (*hash_cred)(struct auth_cred *, unsigned int);
 135        struct rpc_cred *       (*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
 136        struct rpc_cred *       (*crcreate)(struct rpc_auth*, struct auth_cred *, int, gfp_t);
 137        int                     (*list_pseudoflavors)(rpc_authflavor_t *, int);
 138        rpc_authflavor_t        (*info2flavor)(struct rpcsec_gss_info *);
 139        int                     (*flavor2info)(rpc_authflavor_t,
 140                                                struct rpcsec_gss_info *);
 141        int                     (*key_timeout)(struct rpc_auth *,
 142                                                struct rpc_cred *);
 143};
 144
 145struct rpc_credops {
 146        const char *            cr_name;        /* Name of the auth flavour */
 147        int                     (*cr_init)(struct rpc_auth *, struct rpc_cred *);
 148        void                    (*crdestroy)(struct rpc_cred *);
 149
 150        int                     (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
 151        struct rpc_cred *       (*crbind)(struct rpc_task *, struct rpc_cred *, int);
 152        __be32 *                (*crmarshal)(struct rpc_task *, __be32 *);
 153        int                     (*crrefresh)(struct rpc_task *);
 154        __be32 *                (*crvalidate)(struct rpc_task *, __be32 *);
 155        int                     (*crwrap_req)(struct rpc_task *, kxdreproc_t,
 156                                                void *, __be32 *, void *);
 157        int                     (*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
 158                                                void *, __be32 *, void *);
 159        int                     (*crkey_timeout)(struct rpc_cred *);
 160        bool                    (*crkey_to_expire)(struct rpc_cred *);
 161        char *                  (*crstringify_acceptor)(struct rpc_cred *);
 162};
 163
 164extern const struct rpc_authops authunix_ops;
 165extern const struct rpc_authops authnull_ops;
 166
 167int __init              rpc_init_authunix(void);
 168int __init              rpc_init_generic_auth(void);
 169int __init              rpcauth_init_module(void);
 170void                    rpcauth_remove_module(void);
 171void                    rpc_destroy_generic_auth(void);
 172void                    rpc_destroy_authunix(void);
 173
 174struct rpc_cred *       rpc_lookup_cred(void);
 175struct rpc_cred *       rpc_lookup_cred_nonblock(void);
 176struct rpc_cred *       rpc_lookup_generic_cred(struct auth_cred *, int, gfp_t);
 177struct rpc_cred *       rpc_lookup_machine_cred(const char *service_name);
 178int                     rpcauth_register(const struct rpc_authops *);
 179int                     rpcauth_unregister(const struct rpc_authops *);
 180struct rpc_auth *       rpcauth_create(struct rpc_auth_create_args *,
 181                                struct rpc_clnt *);
 182void                    rpcauth_release(struct rpc_auth *);
 183rpc_authflavor_t        rpcauth_get_pseudoflavor(rpc_authflavor_t,
 184                                struct rpcsec_gss_info *);
 185int                     rpcauth_get_gssinfo(rpc_authflavor_t,
 186                                struct rpcsec_gss_info *);
 187int                     rpcauth_list_flavors(rpc_authflavor_t *, int);
 188struct rpc_cred *       rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int, gfp_t);
 189void                    rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 190struct rpc_cred *       rpcauth_lookupcred(struct rpc_auth *, int);
 191struct rpc_cred *       rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
 192void                    put_rpccred(struct rpc_cred *);
 193__be32 *                rpcauth_marshcred(struct rpc_task *, __be32 *);
 194__be32 *                rpcauth_checkverf(struct rpc_task *, __be32 *);
 195int                     rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
 196int                     rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
 197int                     rpcauth_refreshcred(struct rpc_task *);
 198void                    rpcauth_invalcred(struct rpc_task *);
 199int                     rpcauth_uptodatecred(struct rpc_task *);
 200int                     rpcauth_init_credcache(struct rpc_auth *);
 201void                    rpcauth_destroy_credcache(struct rpc_auth *);
 202void                    rpcauth_clear_credcache(struct rpc_cred_cache *);
 203int                     rpcauth_key_timeout_notify(struct rpc_auth *,
 204                                                struct rpc_cred *);
 205bool                    rpcauth_cred_key_to_expire(struct rpc_auth *, struct rpc_cred *);
 206char *                  rpcauth_stringify_acceptor(struct rpc_cred *);
 207
 208static inline
 209struct rpc_cred *       get_rpccred(struct rpc_cred *cred)
 210{
 211        if (cred != NULL)
 212                atomic_inc(&cred->cr_count);
 213        return cred;
 214}
 215
 216/**
 217 * get_rpccred_rcu - get a reference to a cred using rcu-protected pointer
 218 * @cred: cred of which to take a reference
 219 *
 220 * In some cases, we may have a pointer to a credential to which we
 221 * want to take a reference, but don't already have one. Because these
 222 * objects are freed using RCU, we can access the cr_count while its
 223 * on its way to destruction and only take a reference if it's not already
 224 * zero.
 225 */
 226static inline struct rpc_cred *
 227get_rpccred_rcu(struct rpc_cred *cred)
 228{
 229        if (atomic_inc_not_zero(&cred->cr_count))
 230                return cred;
 231        return NULL;
 232}
 233
 234#endif /* __KERNEL__ */
 235#endif /* _LINUX_SUNRPC_AUTH_H */
 236