1 /*
2 * linux/net/sunrpc/auth_unix.c
3 *
4 * UNIX-style authentication; no AUTH_SHORT support
5 *
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
8
9 #include <linux/slab.h>
10 #include <linux/types.h>
11 #include <linux/sched.h>
12 #include <linux/module.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/sunrpc/auth.h>
15 #include <linux/user_namespace.h>
16
17 #define NFS_NGROUPS 16
18
19 struct unx_cred {
20 struct rpc_cred uc_base;
21 kgid_t uc_gid;
22 kgid_t uc_gids[NFS_NGROUPS];
23 };
24 #define uc_uid uc_base.cr_uid
25
26 #define UNX_WRITESLACK (21 + (UNX_MAXNODENAME >> 2))
27
28 #ifdef RPC_DEBUG
29 # define RPCDBG_FACILITY RPCDBG_AUTH
30 #endif
31
32 static struct rpc_auth unix_auth;
33 static const struct rpc_credops unix_credops;
34
35 static struct rpc_auth *
unx_create(struct rpc_auth_create_args * args,struct rpc_clnt * clnt)36 unx_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
37 {
38 dprintk("RPC: creating UNIX authenticator for client %p\n",
39 clnt);
40 atomic_inc(&unix_auth.au_count);
41 return &unix_auth;
42 }
43
44 static void
unx_destroy(struct rpc_auth * auth)45 unx_destroy(struct rpc_auth *auth)
46 {
47 dprintk("RPC: destroying UNIX authenticator %p\n", auth);
48 rpcauth_clear_credcache(auth->au_credcache);
49 }
50
51 /*
52 * Lookup AUTH_UNIX creds for current process
53 */
54 static struct rpc_cred *
unx_lookup_cred(struct rpc_auth * auth,struct auth_cred * acred,int flags)55 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
56 {
57 return rpcauth_lookup_credcache(auth, acred, flags);
58 }
59
60 static struct rpc_cred *
unx_create_cred(struct rpc_auth * auth,struct auth_cred * acred,int flags)61 unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
62 {
63 struct unx_cred *cred;
64 unsigned int groups = 0;
65 unsigned int i;
66
67 dprintk("RPC: allocating UNIX cred for uid %d gid %d\n",
68 from_kuid(&init_user_ns, acred->uid),
69 from_kgid(&init_user_ns, acred->gid));
70
71 if (!(cred = kmalloc(sizeof(*cred), GFP_NOFS)))
72 return ERR_PTR(-ENOMEM);
73
74 rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
75 cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
76
77 if (acred->group_info != NULL)
78 groups = acred->group_info->ngroups;
79 if (groups > NFS_NGROUPS)
80 groups = NFS_NGROUPS;
81
82 cred->uc_gid = acred->gid;
83 for (i = 0; i < groups; i++)
84 cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
85 if (i < NFS_NGROUPS)
86 cred->uc_gids[i] = INVALID_GID;
87
88 return &cred->uc_base;
89 }
90
91 static void
unx_free_cred(struct unx_cred * unx_cred)92 unx_free_cred(struct unx_cred *unx_cred)
93 {
94 dprintk("RPC: unx_free_cred %p\n", unx_cred);
95 kfree(unx_cred);
96 }
97
98 static void
unx_free_cred_callback(struct rcu_head * head)99 unx_free_cred_callback(struct rcu_head *head)
100 {
101 struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
102 unx_free_cred(unx_cred);
103 }
104
105 static void
unx_destroy_cred(struct rpc_cred * cred)106 unx_destroy_cred(struct rpc_cred *cred)
107 {
108 call_rcu(&cred->cr_rcu, unx_free_cred_callback);
109 }
110
111 /*
112 * Match credentials against current process creds.
113 * The root_override argument takes care of cases where the caller may
114 * request root creds (e.g. for NFS swapping).
115 */
116 static int
unx_match(struct auth_cred * acred,struct rpc_cred * rcred,int flags)117 unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
118 {
119 struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
120 unsigned int groups = 0;
121 unsigned int i;
122
123
124 if (!uid_eq(cred->uc_uid, acred->uid) || !gid_eq(cred->uc_gid, acred->gid))
125 return 0;
126
127 if (acred->group_info != NULL)
128 groups = acred->group_info->ngroups;
129 if (groups > NFS_NGROUPS)
130 groups = NFS_NGROUPS;
131 for (i = 0; i < groups ; i++)
132 if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i)))
133 return 0;
134 if (groups < NFS_NGROUPS && gid_valid(cred->uc_gids[groups]))
135 return 0;
136 return 1;
137 }
138
139 /*
140 * Marshal credentials.
141 * Maybe we should keep a cached credential for performance reasons.
142 */
143 static __be32 *
unx_marshal(struct rpc_task * task,__be32 * p)144 unx_marshal(struct rpc_task *task, __be32 *p)
145 {
146 struct rpc_clnt *clnt = task->tk_client;
147 struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
148 __be32 *base, *hold;
149 int i;
150
151 *p++ = htonl(RPC_AUTH_UNIX);
152 base = p++;
153 *p++ = htonl(jiffies/HZ);
154
155 /*
156 * Copy the UTS nodename captured when the client was created.
157 */
158 p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
159
160 *p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
161 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
162 hold = p++;
163 for (i = 0; i < 16 && gid_valid(cred->uc_gids[i]); i++)
164 *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
165 *hold = htonl(p - hold - 1); /* gid array length */
166 *base = htonl((p - base - 1) << 2); /* cred length */
167
168 *p++ = htonl(RPC_AUTH_NULL);
169 *p++ = htonl(0);
170
171 return p;
172 }
173
174 /*
175 * Refresh credentials. This is a no-op for AUTH_UNIX
176 */
177 static int
unx_refresh(struct rpc_task * task)178 unx_refresh(struct rpc_task *task)
179 {
180 set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
181 return 0;
182 }
183
184 static __be32 *
unx_validate(struct rpc_task * task,__be32 * p)185 unx_validate(struct rpc_task *task, __be32 *p)
186 {
187 rpc_authflavor_t flavor;
188 u32 size;
189
190 flavor = ntohl(*p++);
191 if (flavor != RPC_AUTH_NULL &&
192 flavor != RPC_AUTH_UNIX &&
193 flavor != RPC_AUTH_SHORT) {
194 printk("RPC: bad verf flavor: %u\n", flavor);
195 return ERR_PTR(-EIO);
196 }
197
198 size = ntohl(*p++);
199 if (size > RPC_MAX_AUTH_SIZE) {
200 printk("RPC: giant verf size: %u\n", size);
201 return ERR_PTR(-EIO);
202 }
203 task->tk_rqstp->rq_cred->cr_auth->au_rslack = (size >> 2) + 2;
204 p += (size >> 2);
205
206 return p;
207 }
208
rpc_init_authunix(void)209 int __init rpc_init_authunix(void)
210 {
211 return rpcauth_init_credcache(&unix_auth);
212 }
213
rpc_destroy_authunix(void)214 void rpc_destroy_authunix(void)
215 {
216 rpcauth_destroy_credcache(&unix_auth);
217 }
218
219 const struct rpc_authops authunix_ops = {
220 .owner = THIS_MODULE,
221 .au_flavor = RPC_AUTH_UNIX,
222 .au_name = "UNIX",
223 .create = unx_create,
224 .destroy = unx_destroy,
225 .lookup_cred = unx_lookup_cred,
226 .crcreate = unx_create_cred,
227 };
228
229 static
230 struct rpc_auth unix_auth = {
231 .au_cslack = UNX_WRITESLACK,
232 .au_rslack = 2, /* assume AUTH_NULL verf */
233 .au_ops = &authunix_ops,
234 .au_flavor = RPC_AUTH_UNIX,
235 .au_count = ATOMIC_INIT(0),
236 };
237
238 static
239 const struct rpc_credops unix_credops = {
240 .cr_name = "AUTH_UNIX",
241 .crdestroy = unx_destroy_cred,
242 .crbind = rpcauth_generic_bind_cred,
243 .crmatch = unx_match,
244 .crmarshal = unx_marshal,
245 .crrefresh = unx_refresh,
246 .crvalidate = unx_validate,
247 };
248