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