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)(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
142 struct 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
161 extern const struct rpc_authops authunix_ops;
162 extern const struct rpc_authops authnull_ops;
163
164 int __init rpc_init_authunix(void);
165 int __init rpc_init_generic_auth(void);
166 int __init rpcauth_init_module(void);
167 void rpcauth_remove_module(void);
168 void rpc_destroy_generic_auth(void);
169 void rpc_destroy_authunix(void);
170
171 struct rpc_cred * rpc_lookup_cred(void);
172 struct rpc_cred * rpc_lookup_cred_nonblock(void);
173 struct rpc_cred * rpc_lookup_generic_cred(struct auth_cred *, int, gfp_t);
174 struct rpc_cred * rpc_lookup_machine_cred(const char *service_name);
175 int rpcauth_register(const struct rpc_authops *);
176 int rpcauth_unregister(const struct rpc_authops *);
177 struct rpc_auth * rpcauth_create(struct rpc_auth_create_args *,
178 struct rpc_clnt *);
179 void rpcauth_release(struct rpc_auth *);
180 rpc_authflavor_t rpcauth_get_pseudoflavor(rpc_authflavor_t,
181 struct rpcsec_gss_info *);
182 int rpcauth_get_gssinfo(rpc_authflavor_t,
183 struct rpcsec_gss_info *);
184 int rpcauth_list_flavors(rpc_authflavor_t *, int);
185 struct rpc_cred * rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int, gfp_t);
186 void rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
187 struct rpc_cred * rpcauth_lookupcred(struct rpc_auth *, int);
188 struct rpc_cred * rpcauth_generic_bind_cred(struct rpc_task *, struct rpc_cred *, int);
189 void put_rpccred(struct rpc_cred *);
190 __be32 * rpcauth_marshcred(struct rpc_task *, __be32 *);
191 __be32 * rpcauth_checkverf(struct rpc_task *, __be32 *);
192 int rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
193 int rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
194 int rpcauth_refreshcred(struct rpc_task *);
195 void rpcauth_invalcred(struct rpc_task *);
196 int rpcauth_uptodatecred(struct rpc_task *);
197 int rpcauth_init_credcache(struct rpc_auth *);
198 void rpcauth_destroy_credcache(struct rpc_auth *);
199 void rpcauth_clear_credcache(struct rpc_cred_cache *);
200 int rpcauth_key_timeout_notify(struct rpc_auth *,
201 struct rpc_cred *);
202 bool rpcauth_cred_key_to_expire(struct rpc_auth *, struct rpc_cred *);
203 char * rpcauth_stringify_acceptor(struct rpc_cred *);
204
205 static inline
get_rpccred(struct rpc_cred * cred)206 struct 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 */
223 static inline struct rpc_cred *
get_rpccred_rcu(struct rpc_cred * cred)224 get_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