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