include/linux/sunrpc/auth.h

   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
  38 struct rpcsec_gss_info;
  39
  40 /* auth_cred ac_flags bits */
  41 enum {
  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 */
  48 struct 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  */
  60 struct rpc_auth;
  61 struct rpc_credops;
  62 struct 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  */
  87 struct rpc_cred_cache;
  88 struct rpc_authops;
  89 struct 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
 112 struct 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  */
 124 struct rpc_authops {
 125         struct module           *owner;
 126         rpc_authflavor_t        au_flavor;      /* flavor (RPC_AUTH_*) */
 127         char *                  au_name;
 128         struct rpc_auth *       (*create)(const struct rpc_auth_create_args *,
 129                                           struct rpc_clnt *);
 130         void                    (*destroy)(struct rpc_auth *);
 131
 132         int                     (*hash_cred)(struct auth_cred *, unsigned int);
 133         struct rpc_cred *       (*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
 134         struct rpc_cred *       (*crcreate)(struct rpc_auth*, struct auth_cred *, int, gfp_t);
 135         int                     (*list_pseudoflavors)(rpc_authflavor_t *, int);
 136         rpc_authflavor_t        (*info2flavor)(struct rpcsec_gss_info *);
 137         int                     (*flavor2info)(rpc_authflavor_t,
 138                                                 struct rpcsec_gss_info *);
 139         int                     (*key_timeout)(struct rpc_auth *,
 140                                                 struct rpc_cred *);
 141 };
 142
 143 struct rpc_credops {
 144         const char *            cr_name;        /* Name of the auth flavour */
 145         int                     (*cr_init)(struct rpc_auth *, struct rpc_cred *);
 146         void                    (*crdestroy)(struct rpc_cred *);
 147
 148         int                     (*crmatch)(struct auth_cred *, struct rpc_cred *, int);
 149         struct rpc_cred *       (*crbind)(struct rpc_task *, struct rpc_cred *, int);
 150         __be32 *                (*crmarshal)(struct rpc_task *, __be32 *);
 151         int                     (*crrefresh)(struct rpc_task *);
 152         __be32 *                (*crvalidate)(struct rpc_task *, __be32 *);
 153         int                     (*crwrap_req)(struct rpc_task *, kxdreproc_t,
 154                                                 void *, __be32 *, void *);
 155         int                     (*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
 156                                                 void *, __be32 *, void *);
 157         int                     (*crkey_timeout)(struct rpc_cred *);
 158         bool                    (*crkey_to_expire)(struct rpc_cred *);
 159         char *                  (*crstringify_acceptor)(struct rpc_cred *);
 160 };
 161
 162 extern const struct rpc_authops authunix_ops;
 163 extern const struct rpc_authops authnull_ops;
 164
 165 int __init              rpc_init_authunix(void);
 166 int __init              rpc_init_generic_auth(void);
 167 int __init              rpcauth_init_module(void);
 168 void                    rpcauth_remove_module(void);
 169 void                    rpc_destroy_generic_auth(void);
 170 void                    rpc_destroy_authunix(void);
 171
 172 struct rpc_cred *       rpc_lookup_cred(void);
 173 struct rpc_cred *       rpc_lookup_cred_nonblock(void);
 174 struct rpc_cred *       rpc_lookup_generic_cred(struct auth_cred *, int, gfp_t);
 175 struct rpc_cred *       rpc_lookup_machine_cred(const char *service_name);
 176 int                     rpcauth_register(const struct rpc_authops *);
 177 int                     rpcauth_unregister(const struct rpc_authops *);
 178 struct rpc_auth *       rpcauth_create(const struct rpc_auth_create_args *,
 179                                 struct rpc_clnt *);
 180 void                    rpcauth_release(struct rpc_auth *);
 181 rpc_authflavor_t        rpcauth_get_pseudoflavor(rpc_authflavor_t,
 182                                 struct rpcsec_gss_info *);
 183 int                     rpcauth_get_gssinfo(rpc_authflavor_t,
 184                                 struct rpcsec_gss_info *);
 185 int                     rpcauth_list_flavors(rpc_authflavor_t *, int);
 186 struct rpc_cred *       rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int, gfp_t);
 187 void                    rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 188 struct rpc_cred *       rpcauth_lookupcred(struct rpc_auth *, int);
 189 struct rpc_cred *       rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
 190 void                    put_rpccred(struct rpc_cred *);
 191 __be32 *                rpcauth_marshcred(struct rpc_task *, __be32 *);
 192 __be32 *                rpcauth_checkverf(struct rpc_task *, __be32 *);
 193 int                     rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
 194 int                     rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
 195 int                     rpcauth_refreshcred(struct rpc_task *);
 196 void                    rpcauth_invalcred(struct rpc_task *);
 197 int                     rpcauth_uptodatecred(struct rpc_task *);
 198 int                     rpcauth_init_credcache(struct rpc_auth *);
 199 void                    rpcauth_destroy_credcache(struct rpc_auth *);
 200 void                    rpcauth_clear_credcache(struct rpc_cred_cache *);
 201 int                     rpcauth_key_timeout_notify(struct rpc_auth *,
 202                                                 struct rpc_cred *);
 203 bool                    rpcauth_cred_key_to_expire(struct rpc_auth *, struct rpc_cred *);
 204 char *                  rpcauth_stringify_acceptor(struct rpc_cred *);
 205
 206 static inline
 207 struct rpc_cred *       get_rpccred(struct rpc_cred *cred)
 208 {
 209         if (cred != NULL)
 210                 atomic_inc(&cred->cr_count);
 211         return cred;
 212 }
 213
 214 /**
 215  * get_rpccred_rcu - get a reference to a cred using rcu-protected pointer
 216  * @cred: cred of which to take a reference
 217  *
 218  * In some cases, we may have a pointer to a credential to which we
 219  * want to take a reference, but don't already have one. Because these
 220  * objects are freed using RCU, we can access the cr_count while its
 221  * on its way to destruction and only take a reference if it's not already
 222  * zero.
 223  */
 224 static inline struct rpc_cred *
 225 get_rpccred_rcu(struct rpc_cred *cred)
 226 {
 227         if (atomic_inc_not_zero(&cred->cr_count))
 228                 return cred;
 229         return NULL;
 230 }
 231
 232 #endif /* __KERNEL__ */
 233 #endif /* _LINUX_SUNRPC_AUTH_H */