Merge tag 'acpi-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[sfrench/cifs-2.6.git] / net / sunrpc / auth_unix.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/net/sunrpc/auth_unix.c
4  *
5  * UNIX-style authentication; no AUTH_SHORT support
6  *
7  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
8  */
9
10 #include <linux/slab.h>
11 #include <linux/types.h>
12 #include <linux/sched.h>
13 #include <linux/module.h>
14 #include <linux/mempool.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/auth.h>
17 #include <linux/user_namespace.h>
18
19
20 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
21 # define RPCDBG_FACILITY        RPCDBG_AUTH
22 #endif
23
24 static struct rpc_auth          unix_auth;
25 static const struct rpc_credops unix_credops;
26 static mempool_t                *unix_pool;
27
28 static struct rpc_auth *
29 unx_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
30 {
31         refcount_inc(&unix_auth.au_count);
32         return &unix_auth;
33 }
34
35 static void
36 unx_destroy(struct rpc_auth *auth)
37 {
38 }
39
40 /*
41  * Lookup AUTH_UNIX creds for current process
42  */
43 static struct rpc_cred *
44 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
45 {
46         struct rpc_cred *ret = mempool_alloc(unix_pool, GFP_NOFS);
47
48         rpcauth_init_cred(ret, acred, auth, &unix_credops);
49         ret->cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
50         return ret;
51 }
52
53 static void
54 unx_free_cred_callback(struct rcu_head *head)
55 {
56         struct rpc_cred *rpc_cred = container_of(head, struct rpc_cred, cr_rcu);
57
58         put_cred(rpc_cred->cr_cred);
59         mempool_free(rpc_cred, unix_pool);
60 }
61
62 static void
63 unx_destroy_cred(struct rpc_cred *cred)
64 {
65         call_rcu(&cred->cr_rcu, unx_free_cred_callback);
66 }
67
68 /*
69  * Match credentials against current the auth_cred.
70  */
71 static int
72 unx_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
73 {
74         unsigned int groups = 0;
75         unsigned int i;
76
77         if (cred->cr_cred == acred->cred)
78                 return 1;
79
80         if (!uid_eq(cred->cr_cred->fsuid, acred->cred->fsuid) || !gid_eq(cred->cr_cred->fsgid, acred->cred->fsgid))
81                 return 0;
82
83         if (acred->cred->group_info != NULL)
84                 groups = acred->cred->group_info->ngroups;
85         if (groups > UNX_NGROUPS)
86                 groups = UNX_NGROUPS;
87         if (cred->cr_cred->group_info == NULL)
88                 return groups == 0;
89         if (groups != cred->cr_cred->group_info->ngroups)
90                 return 0;
91
92         for (i = 0; i < groups ; i++)
93                 if (!gid_eq(cred->cr_cred->group_info->gid[i], acred->cred->group_info->gid[i]))
94                         return 0;
95         return 1;
96 }
97
98 /*
99  * Marshal credentials.
100  * Maybe we should keep a cached credential for performance reasons.
101  */
102 static int
103 unx_marshal(struct rpc_task *task, struct xdr_stream *xdr)
104 {
105         struct rpc_clnt *clnt = task->tk_client;
106         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
107         __be32          *p, *cred_len, *gidarr_len;
108         int             i;
109         struct group_info *gi = cred->cr_cred->group_info;
110
111         /* Credential */
112
113         p = xdr_reserve_space(xdr, 3 * sizeof(*p));
114         if (!p)
115                 goto marshal_failed;
116         *p++ = rpc_auth_unix;
117         cred_len = p++;
118         *p++ = xdr_zero;        /* stamp */
119         if (xdr_stream_encode_opaque(xdr, clnt->cl_nodename,
120                                      clnt->cl_nodelen) < 0)
121                 goto marshal_failed;
122         p = xdr_reserve_space(xdr, 3 * sizeof(*p));
123         if (!p)
124                 goto marshal_failed;
125         *p++ = cpu_to_be32(from_kuid(&init_user_ns, cred->cr_cred->fsuid));
126         *p++ = cpu_to_be32(from_kgid(&init_user_ns, cred->cr_cred->fsgid));
127
128         gidarr_len = p++;
129         if (gi)
130                 for (i = 0; i < UNX_NGROUPS && i < gi->ngroups; i++)
131                         *p++ = cpu_to_be32(from_kgid(&init_user_ns,
132                                                      gi->gid[i]));
133         *gidarr_len = cpu_to_be32(p - gidarr_len - 1);
134         *cred_len = cpu_to_be32((p - cred_len - 1) << 2);
135         p = xdr_reserve_space(xdr, (p - gidarr_len - 1) << 2);
136         if (!p)
137                 goto marshal_failed;
138
139         /* Verifier */
140
141         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
142         if (!p)
143                 goto marshal_failed;
144         *p++ = rpc_auth_null;
145         *p   = xdr_zero;
146
147         return 0;
148
149 marshal_failed:
150         return -EMSGSIZE;
151 }
152
153 /*
154  * Refresh credentials. This is a no-op for AUTH_UNIX
155  */
156 static int
157 unx_refresh(struct rpc_task *task)
158 {
159         set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
160         return 0;
161 }
162
163 static int
164 unx_validate(struct rpc_task *task, struct xdr_stream *xdr)
165 {
166         struct rpc_auth *auth = task->tk_rqstp->rq_cred->cr_auth;
167         __be32 *p;
168         u32 size;
169
170         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
171         if (!p)
172                 return -EIO;
173         switch (*p++) {
174         case rpc_auth_null:
175         case rpc_auth_unix:
176         case rpc_auth_short:
177                 break;
178         default:
179                 return -EIO;
180         }
181         size = be32_to_cpup(p);
182         if (size > RPC_MAX_AUTH_SIZE)
183                 return -EIO;
184         p = xdr_inline_decode(xdr, size);
185         if (!p)
186                 return -EIO;
187
188         auth->au_verfsize = XDR_QUADLEN(size) + 2;
189         auth->au_rslack = XDR_QUADLEN(size) + 2;
190         auth->au_ralign = XDR_QUADLEN(size) + 2;
191         return 0;
192 }
193
194 int __init rpc_init_authunix(void)
195 {
196         unix_pool = mempool_create_kmalloc_pool(16, sizeof(struct rpc_cred));
197         return unix_pool ? 0 : -ENOMEM;
198 }
199
200 void rpc_destroy_authunix(void)
201 {
202         mempool_destroy(unix_pool);
203 }
204
205 const struct rpc_authops authunix_ops = {
206         .owner          = THIS_MODULE,
207         .au_flavor      = RPC_AUTH_UNIX,
208         .au_name        = "UNIX",
209         .create         = unx_create,
210         .destroy        = unx_destroy,
211         .lookup_cred    = unx_lookup_cred,
212 };
213
214 static
215 struct rpc_auth         unix_auth = {
216         .au_cslack      = UNX_CALLSLACK,
217         .au_rslack      = NUL_REPLYSLACK,
218         .au_verfsize    = NUL_REPLYSLACK,
219         .au_ops         = &authunix_ops,
220         .au_flavor      = RPC_AUTH_UNIX,
221         .au_count       = REFCOUNT_INIT(1),
222 };
223
224 static
225 const struct rpc_credops unix_credops = {
226         .cr_name        = "AUTH_UNIX",
227         .crdestroy      = unx_destroy_cred,
228         .crmatch        = unx_match,
229         .crmarshal      = unx_marshal,
230         .crwrap_req     = rpcauth_wrap_req_encode,
231         .crrefresh      = unx_refresh,
232         .crvalidate     = unx_validate,
233         .crunwrap_resp  = rpcauth_unwrap_resp_decode,
234 };