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
  36 struct rpcsec_gss_info;
  37
  38 /* auth_cred ac_flags bits */
  39 enum {
  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 */
  46 struct 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  */
  58 struct rpc_auth;
  59 struct rpc_credops;
  60 struct 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  */
  90 struct rpc_cred_cache;
  91 struct rpc_authops;
  92 struct 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
 115 struct 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  */
 127 struct 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         struct rpc_cred *       (*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
 135         struct rpc_cred *       (*crcreate)(struct rpc_auth*, struct auth_cred *, int, gfp_t);
 136         int                     (*list_pseudoflavors)(rpc_authflavor_t *, int);
 137         rpc_authflavor_t        (*info2flavor)(struct rpcsec_gss_info *);
 138         int                     (*flavor2info)(rpc_authflavor_t,
 139                                                 struct rpcsec_gss_info *);
 140         int                     (*key_timeout)(struct rpc_auth *,
 141                                                 struct rpc_cred *);
 142 };
 143
 144 struct rpc_credops {
 145         const char *            cr_name;        /* Name of the auth flavour */
 146         int                     (*cr_init)(struct rpc_auth *, struct rpc_cred *);
 147         void                    (*crdestroy)(struct rpc_cred *);
 148
 149         int                     (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
 150         struct rpc_cred *       (*crbind)(struct rpc_task *, struct rpc_cred *, int);
 151         __be32 *                (*crmarshal)(struct rpc_task *, __be32 *);
 152         int                     (*crrefresh)(struct rpc_task *);
 153         __be32 *                (*crvalidate)(struct rpc_task *, __be32 *);
 154         int                     (*crwrap_req)(struct rpc_task *, kxdreproc_t,
 155                                                 void *, __be32 *, void *);
 156         int                     (*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
 157                                                 void *, __be32 *, void *);
 158         int                     (*crkey_timeout)(struct rpc_cred *);
 159         bool                    (*crkey_to_expire)(struct rpc_cred *);
 160         char *                  (*crstringify_acceptor)(struct rpc_cred *);
 161 };
 162
 163 extern const struct rpc_authops authunix_ops;
 164 extern const struct rpc_authops authnull_ops;
 165
 166 int __init              rpc_init_authunix(void);
 167 int __init              rpc_init_generic_auth(void);
 168 int __init              rpcauth_init_module(void);
 169 void                    rpcauth_remove_module(void);
 170 void                    rpc_destroy_generic_auth(void);
 171 void                    rpc_destroy_authunix(void);
 172
 173 struct rpc_cred *       rpc_lookup_cred(void);
 174 struct rpc_cred *       rpc_lookup_cred_nonblock(void);
 175 struct rpc_cred *       rpc_lookup_generic_cred(struct auth_cred *, int, gfp_t);
 176 struct rpc_cred *       rpc_lookup_machine_cred(const char *service_name);
 177 int                     rpcauth_register(const struct rpc_authops *);
 178 int                     rpcauth_unregister(const struct rpc_authops *);
 179 struct rpc_auth *       rpcauth_create(struct rpc_auth_create_args *,
 180                                 struct rpc_clnt *);
 181 void                    rpcauth_release(struct rpc_auth *);
 182 rpc_authflavor_t        rpcauth_get_pseudoflavor(rpc_authflavor_t,
 183                                 struct rpcsec_gss_info *);
 184 int                     rpcauth_get_gssinfo(rpc_authflavor_t,
 185                                 struct rpcsec_gss_info *);
 186 int                     rpcauth_list_flavors(rpc_authflavor_t *, int);
 187 struct rpc_cred *       rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int, gfp_t);
 188 void                    rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 189 struct rpc_cred *       rpcauth_lookupcred(struct rpc_auth *, int);
 190 struct rpc_cred *       rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
 191 void                    put_rpccred(struct rpc_cred *);
 192 __be32 *                rpcauth_marshcred(struct rpc_task *, __be32 *);
 193 __be32 *                rpcauth_checkverf(struct rpc_task *, __be32 *);
 194 int                     rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
 195 int                     rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
 196 int                     rpcauth_refreshcred(struct rpc_task *);
 197 void                    rpcauth_invalcred(struct rpc_task *);
 198 int                     rpcauth_uptodatecred(struct rpc_task *);
 199 int                     rpcauth_init_credcache(struct rpc_auth *);
 200 void                    rpcauth_destroy_credcache(struct rpc_auth *);
 201 void                    rpcauth_clear_credcache(struct rpc_cred_cache *);
 202 int                     rpcauth_key_timeout_notify(struct rpc_auth *,
 203                                                 struct rpc_cred *);
 204 bool                    rpcauth_cred_key_to_expire(struct rpc_auth *, struct rpc_cred *);
 205 char *                  rpcauth_stringify_acceptor(struct rpc_cred *);
 206
 207 static inline
 208 struct rpc_cred *       get_rpccred(struct rpc_cred *cred)
 209 {
 210         if (cred != NULL)
 211                 atomic_inc(&cred->cr_count);
 212         return cred;
 213 }
 214
 215 /**
 216  * get_rpccred_rcu - get a reference to a cred using rcu-protected pointer
 217  * @cred: cred of which to take a reference
 218  *
 219  * In some cases, we may have a pointer to a credential to which we
 220  * want to take a reference, but don't already have one. Because these
 221  * objects are freed using RCU, we can access the cr_count while its
 222  * on its way to destruction and only take a reference if it's not already
 223  * zero.
 224  */
 225 static inline struct rpc_cred *
 226 get_rpccred_rcu(struct rpc_cred *cred)
 227 {
 228         if (atomic_inc_not_zero(&cred->cr_count))
 229                 return cred;
 230         return NULL;
 231 }
 232
 233 #endif /* __KERNEL__ */
 234 #endif /* _LINUX_SUNRPC_AUTH_H */