Commit | Line | Data |
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973c9f4f | 1 | /* Request key authorisation token key definition. |
3e30148c DH |
2 | * |
3 | * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
f1a9badc | 10 | * |
3db38ed7 | 11 | * See Documentation/security/keys/request-key.rst |
3e30148c DH |
12 | */ |
13 | ||
3e30148c DH |
14 | #include <linux/sched.h> |
15 | #include <linux/err.h> | |
16 | #include <linux/seq_file.h> | |
fdb89bce | 17 | #include <linux/slab.h> |
7c0f6ba6 | 18 | #include <linux/uaccess.h> |
3e30148c | 19 | #include "internal.h" |
822ad64d | 20 | #include <keys/request_key_auth-type.h> |
3e30148c | 21 | |
f1dcde91 DH |
22 | static int request_key_auth_preparse(struct key_preparsed_payload *); |
23 | static void request_key_auth_free_preparse(struct key_preparsed_payload *); | |
cf7f601c DH |
24 | static int request_key_auth_instantiate(struct key *, |
25 | struct key_preparsed_payload *); | |
3e30148c | 26 | static void request_key_auth_describe(const struct key *, struct seq_file *); |
04c567d9 | 27 | static void request_key_auth_revoke(struct key *); |
3e30148c | 28 | static void request_key_auth_destroy(struct key *); |
b5f545c8 | 29 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
3e30148c DH |
30 | |
31 | /* | |
973c9f4f | 32 | * The request-key authorisation key type definition. |
3e30148c DH |
33 | */ |
34 | struct key_type key_type_request_key_auth = { | |
35 | .name = ".request_key_auth", | |
36 | .def_datalen = sizeof(struct request_key_auth), | |
f1dcde91 DH |
37 | .preparse = request_key_auth_preparse, |
38 | .free_preparse = request_key_auth_free_preparse, | |
3e30148c DH |
39 | .instantiate = request_key_auth_instantiate, |
40 | .describe = request_key_auth_describe, | |
04c567d9 | 41 | .revoke = request_key_auth_revoke, |
3e30148c | 42 | .destroy = request_key_auth_destroy, |
b5f545c8 | 43 | .read = request_key_auth_read, |
3e30148c DH |
44 | }; |
45 | ||
8da79b64 | 46 | static int request_key_auth_preparse(struct key_preparsed_payload *prep) |
f1dcde91 DH |
47 | { |
48 | return 0; | |
49 | } | |
50 | ||
8da79b64 | 51 | static void request_key_auth_free_preparse(struct key_preparsed_payload *prep) |
f1dcde91 DH |
52 | { |
53 | } | |
54 | ||
3e30148c | 55 | /* |
973c9f4f | 56 | * Instantiate a request-key authorisation key. |
3e30148c DH |
57 | */ |
58 | static int request_key_auth_instantiate(struct key *key, | |
cf7f601c | 59 | struct key_preparsed_payload *prep) |
3e30148c | 60 | { |
e59428f7 | 61 | rcu_assign_keypointer(key, (struct request_key_auth *)prep->data); |
b5f545c8 | 62 | return 0; |
a8b17ed0 | 63 | } |
3e30148c | 64 | |
3e30148c | 65 | /* |
973c9f4f | 66 | * Describe an authorisation token. |
3e30148c DH |
67 | */ |
68 | static void request_key_auth_describe(const struct key *key, | |
69 | struct seq_file *m) | |
70 | { | |
e59428f7 | 71 | struct request_key_auth *rka = dereference_key_rcu(key); |
3e30148c DH |
72 | |
73 | seq_puts(m, "key:"); | |
74 | seq_puts(m, key->description); | |
363b02da | 75 | if (key_is_positive(key)) |
78b7280c | 76 | seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); |
a8b17ed0 | 77 | } |
3e30148c | 78 | |
b5f545c8 | 79 | /* |
973c9f4f | 80 | * Read the callout_info data (retrieves the callout information). |
b5f545c8 DH |
81 | * - the key's semaphore is read-locked |
82 | */ | |
83 | static long request_key_auth_read(const struct key *key, | |
84 | char __user *buffer, size_t buflen) | |
85 | { | |
e59428f7 | 86 | struct request_key_auth *rka = dereference_key_locked(key); |
b5f545c8 DH |
87 | size_t datalen; |
88 | long ret; | |
89 | ||
4a38e122 | 90 | datalen = rka->callout_len; |
b5f545c8 DH |
91 | ret = datalen; |
92 | ||
93 | /* we can return the data as is */ | |
94 | if (buffer && buflen > 0) { | |
95 | if (buflen > datalen) | |
96 | buflen = datalen; | |
97 | ||
98 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) | |
99 | ret = -EFAULT; | |
100 | } | |
101 | ||
102 | return ret; | |
a8b17ed0 | 103 | } |
b5f545c8 | 104 | |
44d81433 EB |
105 | static void free_request_key_auth(struct request_key_auth *rka) |
106 | { | |
107 | if (!rka) | |
108 | return; | |
109 | key_put(rka->target_key); | |
110 | key_put(rka->dest_keyring); | |
111 | if (rka->cred) | |
112 | put_cred(rka->cred); | |
113 | kfree(rka->callout_info); | |
114 | kfree(rka); | |
115 | } | |
116 | ||
e59428f7 DH |
117 | /* |
118 | * Dispose of the request_key_auth record under RCU conditions | |
119 | */ | |
120 | static void request_key_auth_rcu_disposal(struct rcu_head *rcu) | |
121 | { | |
122 | struct request_key_auth *rka = | |
123 | container_of(rcu, struct request_key_auth, rcu); | |
124 | ||
125 | free_request_key_auth(rka); | |
126 | } | |
127 | ||
128 | /* | |
129 | * Handle revocation of an authorisation token key. | |
130 | * | |
131 | * Called with the key sem write-locked. | |
132 | */ | |
133 | static void request_key_auth_revoke(struct key *key) | |
134 | { | |
135 | struct request_key_auth *rka = dereference_key_locked(key); | |
136 | ||
137 | kenter("{%d}", key->serial); | |
138 | rcu_assign_keypointer(key, NULL); | |
139 | call_rcu(&rka->rcu, request_key_auth_rcu_disposal); | |
140 | } | |
141 | ||
3e30148c | 142 | /* |
973c9f4f | 143 | * Destroy an instantiation authorisation token key. |
3e30148c DH |
144 | */ |
145 | static void request_key_auth_destroy(struct key *key) | |
146 | { | |
e59428f7 | 147 | struct request_key_auth *rka = rcu_access_pointer(key->payload.rcu_data0); |
3e30148c DH |
148 | |
149 | kenter("{%d}", key->serial); | |
e59428f7 DH |
150 | if (rka) { |
151 | rcu_assign_keypointer(key, NULL); | |
152 | call_rcu(&rka->rcu, request_key_auth_rcu_disposal); | |
153 | } | |
a8b17ed0 | 154 | } |
3e30148c | 155 | |
3e30148c | 156 | /* |
973c9f4f DH |
157 | * Create an authorisation token for /sbin/request-key or whoever to gain |
158 | * access to the caller's security data. | |
3e30148c | 159 | */ |
822ad64d DH |
160 | struct key *request_key_auth_new(struct key *target, const char *op, |
161 | const void *callout_info, size_t callout_len, | |
162 | struct key *dest_keyring) | |
3e30148c | 163 | { |
b5f545c8 | 164 | struct request_key_auth *rka, *irka; |
7936d16d | 165 | const struct cred *cred = current_cred(); |
b5f545c8 | 166 | struct key *authkey = NULL; |
3e30148c | 167 | char desc[20]; |
44d81433 | 168 | int ret = -ENOMEM; |
3e30148c DH |
169 | |
170 | kenter("%d,", target->serial); | |
171 | ||
b5f545c8 | 172 | /* allocate a auth record */ |
44d81433 EB |
173 | rka = kzalloc(sizeof(*rka), GFP_KERNEL); |
174 | if (!rka) | |
175 | goto error; | |
e007ce9c | 176 | rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL); |
44d81433 EB |
177 | if (!rka->callout_info) |
178 | goto error_free_rka; | |
e007ce9c | 179 | rka->callout_len = callout_len; |
822ad64d | 180 | strlcpy(rka->op, op, sizeof(rka->op)); |
3e30148c | 181 | |
b5f545c8 DH |
182 | /* see if the calling process is already servicing the key request of |
183 | * another process */ | |
d84f4f99 | 184 | if (cred->request_key_auth) { |
b5f545c8 | 185 | /* it is - use that instantiation context here too */ |
d84f4f99 | 186 | down_read(&cred->request_key_auth->sem); |
04c567d9 DH |
187 | |
188 | /* if the auth key has been revoked, then the key we're | |
189 | * servicing is already instantiated */ | |
44d81433 EB |
190 | if (test_bit(KEY_FLAG_REVOKED, |
191 | &cred->request_key_auth->flags)) { | |
192 | up_read(&cred->request_key_auth->sem); | |
193 | ret = -EKEYREVOKED; | |
194 | goto error_free_rka; | |
195 | } | |
04c567d9 | 196 | |
146aa8b1 | 197 | irka = cred->request_key_auth->payload.data[0]; |
d84f4f99 | 198 | rka->cred = get_cred(irka->cred); |
b5f545c8 | 199 | rka->pid = irka->pid; |
04c567d9 | 200 | |
d84f4f99 | 201 | up_read(&cred->request_key_auth->sem); |
3e30148c | 202 | } |
b5f545c8 DH |
203 | else { |
204 | /* it isn't - use this process as the context */ | |
d84f4f99 | 205 | rka->cred = get_cred(cred); |
b5f545c8 DH |
206 | rka->pid = current->pid; |
207 | } | |
208 | ||
209 | rka->target_key = key_get(target); | |
8bbf4976 | 210 | rka->dest_keyring = key_get(dest_keyring); |
3e30148c DH |
211 | |
212 | /* allocate the auth key */ | |
213 | sprintf(desc, "%x", target->serial); | |
214 | ||
b5f545c8 | 215 | authkey = key_alloc(&key_type_request_key_auth, desc, |
d84f4f99 | 216 | cred->fsuid, cred->fsgid, cred, |
f7f13945 | 217 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | KEY_POS_LINK | |
5ac7eace | 218 | KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL); |
b5f545c8 DH |
219 | if (IS_ERR(authkey)) { |
220 | ret = PTR_ERR(authkey); | |
44d81433 | 221 | goto error_free_rka; |
3e30148c DH |
222 | } |
223 | ||
d84f4f99 | 224 | /* construct the auth key */ |
b5f545c8 DH |
225 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
226 | if (ret < 0) | |
44d81433 | 227 | goto error_put_authkey; |
3e30148c | 228 | |
fff29291 | 229 | kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage)); |
b5f545c8 DH |
230 | return authkey; |
231 | ||
44d81433 | 232 | error_put_authkey: |
b5f545c8 | 233 | key_put(authkey); |
44d81433 EB |
234 | error_free_rka: |
235 | free_request_key_auth(rka); | |
236 | error: | |
b5f545c8 DH |
237 | kleave("= %d", ret); |
238 | return ERR_PTR(ret); | |
a8b17ed0 | 239 | } |
3e30148c | 240 | |
3e30148c | 241 | /* |
973c9f4f DH |
242 | * Search the current process's keyrings for the authorisation key for |
243 | * instantiation of a key. | |
3e30148c DH |
244 | */ |
245 | struct key *key_get_instantiation_authkey(key_serial_t target_id) | |
246 | { | |
d0a059ca | 247 | char description[16]; |
4bdf0bc3 DH |
248 | struct keyring_search_context ctx = { |
249 | .index_key.type = &key_type_request_key_auth, | |
d0a059ca | 250 | .index_key.description = description, |
4bdf0bc3 | 251 | .cred = current_cred(), |
c06cfb08 | 252 | .match_data.cmp = key_default_cmp, |
46291959 DH |
253 | .match_data.raw_data = description, |
254 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
054f6180 | 255 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, |
4bdf0bc3 | 256 | }; |
b5f545c8 DH |
257 | struct key *authkey; |
258 | key_ref_t authkey_ref; | |
259 | ||
ede0fa98 | 260 | ctx.index_key.desc_len = sprintf(description, "%x", target_id); |
d0a059ca | 261 | |
e59428f7 DH |
262 | rcu_read_lock(); |
263 | authkey_ref = search_process_keyrings_rcu(&ctx); | |
264 | rcu_read_unlock(); | |
b5f545c8 DH |
265 | |
266 | if (IS_ERR(authkey_ref)) { | |
e231c2ee | 267 | authkey = ERR_CAST(authkey_ref); |
4d67431f DH |
268 | if (authkey == ERR_PTR(-EAGAIN)) |
269 | authkey = ERR_PTR(-ENOKEY); | |
b5f545c8 DH |
270 | goto error; |
271 | } | |
3e30148c | 272 | |
b5f545c8 DH |
273 | authkey = key_ref_to_ptr(authkey_ref); |
274 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { | |
275 | key_put(authkey); | |
276 | authkey = ERR_PTR(-EKEYREVOKED); | |
277 | } | |
3e30148c | 278 | |
b5f545c8 DH |
279 | error: |
280 | return authkey; | |
a8b17ed0 | 281 | } |