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 DH |
10 | * |
11 | * See Documentation/keys-request-key.txt | |
3e30148c DH |
12 | */ |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/sched.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/seq_file.h> | |
fdb89bce | 18 | #include <linux/slab.h> |
b5f545c8 | 19 | #include <asm/uaccess.h> |
3e30148c DH |
20 | #include "internal.h" |
21 | ||
22 | static int request_key_auth_instantiate(struct key *, const void *, size_t); | |
23 | static void request_key_auth_describe(const struct key *, struct seq_file *); | |
04c567d9 | 24 | static void request_key_auth_revoke(struct key *); |
3e30148c | 25 | static void request_key_auth_destroy(struct key *); |
b5f545c8 | 26 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
3e30148c DH |
27 | |
28 | /* | |
973c9f4f | 29 | * The request-key authorisation key type definition. |
3e30148c DH |
30 | */ |
31 | struct key_type key_type_request_key_auth = { | |
32 | .name = ".request_key_auth", | |
33 | .def_datalen = sizeof(struct request_key_auth), | |
34 | .instantiate = request_key_auth_instantiate, | |
35 | .describe = request_key_auth_describe, | |
04c567d9 | 36 | .revoke = request_key_auth_revoke, |
3e30148c | 37 | .destroy = request_key_auth_destroy, |
b5f545c8 | 38 | .read = request_key_auth_read, |
3e30148c DH |
39 | }; |
40 | ||
3e30148c | 41 | /* |
973c9f4f | 42 | * Instantiate a request-key authorisation key. |
3e30148c DH |
43 | */ |
44 | static int request_key_auth_instantiate(struct key *key, | |
45 | const void *data, | |
46 | size_t datalen) | |
47 | { | |
b5f545c8 DH |
48 | key->payload.data = (struct request_key_auth *) data; |
49 | return 0; | |
a8b17ed0 | 50 | } |
3e30148c | 51 | |
3e30148c | 52 | /* |
973c9f4f | 53 | * Describe an authorisation token. |
3e30148c DH |
54 | */ |
55 | static void request_key_auth_describe(const struct key *key, | |
56 | struct seq_file *m) | |
57 | { | |
58 | struct request_key_auth *rka = key->payload.data; | |
59 | ||
60 | seq_puts(m, "key:"); | |
61 | seq_puts(m, key->description); | |
4a38e122 | 62 | seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); |
a8b17ed0 | 63 | } |
3e30148c | 64 | |
b5f545c8 | 65 | /* |
973c9f4f | 66 | * Read the callout_info data (retrieves the callout information). |
b5f545c8 DH |
67 | * - the key's semaphore is read-locked |
68 | */ | |
69 | static long request_key_auth_read(const struct key *key, | |
70 | char __user *buffer, size_t buflen) | |
71 | { | |
72 | struct request_key_auth *rka = key->payload.data; | |
73 | size_t datalen; | |
74 | long ret; | |
75 | ||
4a38e122 | 76 | datalen = rka->callout_len; |
b5f545c8 DH |
77 | ret = datalen; |
78 | ||
79 | /* we can return the data as is */ | |
80 | if (buffer && buflen > 0) { | |
81 | if (buflen > datalen) | |
82 | buflen = datalen; | |
83 | ||
84 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) | |
85 | ret = -EFAULT; | |
86 | } | |
87 | ||
88 | return ret; | |
a8b17ed0 | 89 | } |
b5f545c8 | 90 | |
04c567d9 | 91 | /* |
973c9f4f DH |
92 | * Handle revocation of an authorisation token key. |
93 | * | |
94 | * Called with the key sem write-locked. | |
04c567d9 DH |
95 | */ |
96 | static void request_key_auth_revoke(struct key *key) | |
97 | { | |
98 | struct request_key_auth *rka = key->payload.data; | |
99 | ||
100 | kenter("{%d}", key->serial); | |
101 | ||
d84f4f99 DH |
102 | if (rka->cred) { |
103 | put_cred(rka->cred); | |
104 | rka->cred = NULL; | |
04c567d9 | 105 | } |
a8b17ed0 | 106 | } |
04c567d9 | 107 | |
3e30148c | 108 | /* |
973c9f4f | 109 | * Destroy an instantiation authorisation token key. |
3e30148c DH |
110 | */ |
111 | static void request_key_auth_destroy(struct key *key) | |
112 | { | |
113 | struct request_key_auth *rka = key->payload.data; | |
114 | ||
115 | kenter("{%d}", key->serial); | |
116 | ||
d84f4f99 DH |
117 | if (rka->cred) { |
118 | put_cred(rka->cred); | |
119 | rka->cred = NULL; | |
04c567d9 DH |
120 | } |
121 | ||
3e30148c | 122 | key_put(rka->target_key); |
8bbf4976 | 123 | key_put(rka->dest_keyring); |
76181c13 | 124 | kfree(rka->callout_info); |
74fd92c5 | 125 | kfree(rka); |
a8b17ed0 | 126 | } |
3e30148c | 127 | |
3e30148c | 128 | /* |
973c9f4f DH |
129 | * Create an authorisation token for /sbin/request-key or whoever to gain |
130 | * access to the caller's security data. | |
3e30148c | 131 | */ |
4a38e122 | 132 | struct key *request_key_auth_new(struct key *target, const void *callout_info, |
8bbf4976 | 133 | size_t callout_len, struct key *dest_keyring) |
3e30148c | 134 | { |
b5f545c8 | 135 | struct request_key_auth *rka, *irka; |
d84f4f99 | 136 | const struct cred *cred = current->cred; |
b5f545c8 | 137 | struct key *authkey = NULL; |
3e30148c DH |
138 | char desc[20]; |
139 | int ret; | |
140 | ||
141 | kenter("%d,", target->serial); | |
142 | ||
b5f545c8 DH |
143 | /* allocate a auth record */ |
144 | rka = kmalloc(sizeof(*rka), GFP_KERNEL); | |
145 | if (!rka) { | |
146 | kleave(" = -ENOMEM"); | |
147 | return ERR_PTR(-ENOMEM); | |
148 | } | |
4a38e122 | 149 | rka->callout_info = kmalloc(callout_len, GFP_KERNEL); |
76181c13 DH |
150 | if (!rka->callout_info) { |
151 | kleave(" = -ENOMEM"); | |
152 | kfree(rka); | |
153 | return ERR_PTR(-ENOMEM); | |
154 | } | |
3e30148c | 155 | |
b5f545c8 DH |
156 | /* see if the calling process is already servicing the key request of |
157 | * another process */ | |
d84f4f99 | 158 | if (cred->request_key_auth) { |
b5f545c8 | 159 | /* it is - use that instantiation context here too */ |
d84f4f99 | 160 | down_read(&cred->request_key_auth->sem); |
04c567d9 DH |
161 | |
162 | /* if the auth key has been revoked, then the key we're | |
163 | * servicing is already instantiated */ | |
d84f4f99 | 164 | if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags)) |
04c567d9 DH |
165 | goto auth_key_revoked; |
166 | ||
d84f4f99 DH |
167 | irka = cred->request_key_auth->payload.data; |
168 | rka->cred = get_cred(irka->cred); | |
b5f545c8 | 169 | rka->pid = irka->pid; |
04c567d9 | 170 | |
d84f4f99 | 171 | up_read(&cred->request_key_auth->sem); |
3e30148c | 172 | } |
b5f545c8 DH |
173 | else { |
174 | /* it isn't - use this process as the context */ | |
d84f4f99 | 175 | rka->cred = get_cred(cred); |
b5f545c8 DH |
176 | rka->pid = current->pid; |
177 | } | |
178 | ||
179 | rka->target_key = key_get(target); | |
8bbf4976 | 180 | rka->dest_keyring = key_get(dest_keyring); |
4a38e122 DH |
181 | memcpy(rka->callout_info, callout_info, callout_len); |
182 | rka->callout_len = callout_len; | |
3e30148c DH |
183 | |
184 | /* allocate the auth key */ | |
185 | sprintf(desc, "%x", target->serial); | |
186 | ||
b5f545c8 | 187 | authkey = key_alloc(&key_type_request_key_auth, desc, |
d84f4f99 | 188 | cred->fsuid, cred->fsgid, cred, |
b5f545c8 | 189 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
7e047ef5 | 190 | KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA); |
b5f545c8 DH |
191 | if (IS_ERR(authkey)) { |
192 | ret = PTR_ERR(authkey); | |
193 | goto error_alloc; | |
3e30148c DH |
194 | } |
195 | ||
d84f4f99 | 196 | /* construct the auth key */ |
b5f545c8 DH |
197 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
198 | if (ret < 0) | |
199 | goto error_inst; | |
3e30148c | 200 | |
d84f4f99 | 201 | kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage)); |
b5f545c8 DH |
202 | return authkey; |
203 | ||
04c567d9 | 204 | auth_key_revoked: |
d84f4f99 | 205 | up_read(&cred->request_key_auth->sem); |
76181c13 | 206 | kfree(rka->callout_info); |
04c567d9 DH |
207 | kfree(rka); |
208 | kleave("= -EKEYREVOKED"); | |
209 | return ERR_PTR(-EKEYREVOKED); | |
210 | ||
b5f545c8 DH |
211 | error_inst: |
212 | key_revoke(authkey); | |
213 | key_put(authkey); | |
214 | error_alloc: | |
215 | key_put(rka->target_key); | |
8bbf4976 | 216 | key_put(rka->dest_keyring); |
76181c13 | 217 | kfree(rka->callout_info); |
b5f545c8 DH |
218 | kfree(rka); |
219 | kleave("= %d", ret); | |
220 | return ERR_PTR(ret); | |
a8b17ed0 | 221 | } |
3e30148c | 222 | |
b5f545c8 | 223 | /* |
973c9f4f | 224 | * See if an authorisation key is associated with a particular key. |
b5f545c8 DH |
225 | */ |
226 | static int key_get_instantiation_authkey_match(const struct key *key, | |
227 | const void *_id) | |
228 | { | |
229 | struct request_key_auth *rka = key->payload.data; | |
230 | key_serial_t id = (key_serial_t)(unsigned long) _id; | |
231 | ||
232 | return rka->target_key->serial == id; | |
a8b17ed0 | 233 | } |
b5f545c8 | 234 | |
3e30148c | 235 | /* |
973c9f4f DH |
236 | * Search the current process's keyrings for the authorisation key for |
237 | * instantiation of a key. | |
3e30148c DH |
238 | */ |
239 | struct key *key_get_instantiation_authkey(key_serial_t target_id) | |
240 | { | |
d84f4f99 | 241 | const struct cred *cred = current_cred(); |
b5f545c8 DH |
242 | struct key *authkey; |
243 | key_ref_t authkey_ref; | |
244 | ||
245 | authkey_ref = search_process_keyrings( | |
246 | &key_type_request_key_auth, | |
247 | (void *) (unsigned long) target_id, | |
248 | key_get_instantiation_authkey_match, | |
d84f4f99 | 249 | cred); |
b5f545c8 DH |
250 | |
251 | if (IS_ERR(authkey_ref)) { | |
e231c2ee | 252 | authkey = ERR_CAST(authkey_ref); |
b5f545c8 DH |
253 | goto error; |
254 | } | |
3e30148c | 255 | |
b5f545c8 DH |
256 | authkey = key_ref_to_ptr(authkey_ref); |
257 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { | |
258 | key_put(authkey); | |
259 | authkey = ERR_PTR(-EKEYREVOKED); | |
260 | } | |
3e30148c | 261 | |
b5f545c8 DH |
262 | error: |
263 | return authkey; | |
a8b17ed0 | 264 | } |