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 | * |
d410fa4e | 11 | * See Documentation/security/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 | ||
cf7f601c DH |
22 | static int request_key_auth_instantiate(struct key *, |
23 | struct key_preparsed_payload *); | |
3e30148c | 24 | static void request_key_auth_describe(const struct key *, struct seq_file *); |
04c567d9 | 25 | static void request_key_auth_revoke(struct key *); |
3e30148c | 26 | static void request_key_auth_destroy(struct key *); |
b5f545c8 | 27 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
3e30148c DH |
28 | |
29 | /* | |
973c9f4f | 30 | * The request-key authorisation key type definition. |
3e30148c DH |
31 | */ |
32 | struct key_type key_type_request_key_auth = { | |
33 | .name = ".request_key_auth", | |
34 | .def_datalen = sizeof(struct request_key_auth), | |
35 | .instantiate = request_key_auth_instantiate, | |
36 | .describe = request_key_auth_describe, | |
04c567d9 | 37 | .revoke = request_key_auth_revoke, |
3e30148c | 38 | .destroy = request_key_auth_destroy, |
b5f545c8 | 39 | .read = request_key_auth_read, |
3e30148c DH |
40 | }; |
41 | ||
3e30148c | 42 | /* |
973c9f4f | 43 | * Instantiate a request-key authorisation key. |
3e30148c DH |
44 | */ |
45 | static int request_key_auth_instantiate(struct key *key, | |
cf7f601c | 46 | struct key_preparsed_payload *prep) |
3e30148c | 47 | { |
cf7f601c | 48 | key->payload.data = (struct request_key_auth *)prep->data; |
b5f545c8 | 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); | |
78b7280c DH |
62 | if (key_is_instantiated(key)) |
63 | seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); | |
a8b17ed0 | 64 | } |
3e30148c | 65 | |
b5f545c8 | 66 | /* |
973c9f4f | 67 | * Read the callout_info data (retrieves the callout information). |
b5f545c8 DH |
68 | * - the key's semaphore is read-locked |
69 | */ | |
70 | static long request_key_auth_read(const struct key *key, | |
71 | char __user *buffer, size_t buflen) | |
72 | { | |
73 | struct request_key_auth *rka = key->payload.data; | |
74 | size_t datalen; | |
75 | long ret; | |
76 | ||
4a38e122 | 77 | datalen = rka->callout_len; |
b5f545c8 DH |
78 | ret = datalen; |
79 | ||
80 | /* we can return the data as is */ | |
81 | if (buffer && buflen > 0) { | |
82 | if (buflen > datalen) | |
83 | buflen = datalen; | |
84 | ||
85 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) | |
86 | ret = -EFAULT; | |
87 | } | |
88 | ||
89 | return ret; | |
a8b17ed0 | 90 | } |
b5f545c8 | 91 | |
04c567d9 | 92 | /* |
973c9f4f DH |
93 | * Handle revocation of an authorisation token key. |
94 | * | |
95 | * Called with the key sem write-locked. | |
04c567d9 DH |
96 | */ |
97 | static void request_key_auth_revoke(struct key *key) | |
98 | { | |
99 | struct request_key_auth *rka = key->payload.data; | |
100 | ||
101 | kenter("{%d}", key->serial); | |
102 | ||
d84f4f99 DH |
103 | if (rka->cred) { |
104 | put_cred(rka->cred); | |
105 | rka->cred = NULL; | |
04c567d9 | 106 | } |
a8b17ed0 | 107 | } |
04c567d9 | 108 | |
3e30148c | 109 | /* |
973c9f4f | 110 | * Destroy an instantiation authorisation token key. |
3e30148c DH |
111 | */ |
112 | static void request_key_auth_destroy(struct key *key) | |
113 | { | |
114 | struct request_key_auth *rka = key->payload.data; | |
115 | ||
116 | kenter("{%d}", key->serial); | |
117 | ||
d84f4f99 DH |
118 | if (rka->cred) { |
119 | put_cred(rka->cred); | |
120 | rka->cred = NULL; | |
04c567d9 DH |
121 | } |
122 | ||
3e30148c | 123 | key_put(rka->target_key); |
8bbf4976 | 124 | key_put(rka->dest_keyring); |
76181c13 | 125 | kfree(rka->callout_info); |
74fd92c5 | 126 | kfree(rka); |
a8b17ed0 | 127 | } |
3e30148c | 128 | |
3e30148c | 129 | /* |
973c9f4f DH |
130 | * Create an authorisation token for /sbin/request-key or whoever to gain |
131 | * access to the caller's security data. | |
3e30148c | 132 | */ |
4a38e122 | 133 | struct key *request_key_auth_new(struct key *target, const void *callout_info, |
8bbf4976 | 134 | size_t callout_len, struct key *dest_keyring) |
3e30148c | 135 | { |
b5f545c8 | 136 | struct request_key_auth *rka, *irka; |
d84f4f99 | 137 | const struct cred *cred = current->cred; |
b5f545c8 | 138 | struct key *authkey = NULL; |
3e30148c DH |
139 | char desc[20]; |
140 | int ret; | |
141 | ||
142 | kenter("%d,", target->serial); | |
143 | ||
b5f545c8 DH |
144 | /* allocate a auth record */ |
145 | rka = kmalloc(sizeof(*rka), GFP_KERNEL); | |
146 | if (!rka) { | |
147 | kleave(" = -ENOMEM"); | |
148 | return ERR_PTR(-ENOMEM); | |
149 | } | |
4a38e122 | 150 | rka->callout_info = kmalloc(callout_len, GFP_KERNEL); |
76181c13 DH |
151 | if (!rka->callout_info) { |
152 | kleave(" = -ENOMEM"); | |
153 | kfree(rka); | |
154 | return ERR_PTR(-ENOMEM); | |
155 | } | |
3e30148c | 156 | |
b5f545c8 DH |
157 | /* see if the calling process is already servicing the key request of |
158 | * another process */ | |
d84f4f99 | 159 | if (cred->request_key_auth) { |
b5f545c8 | 160 | /* it is - use that instantiation context here too */ |
d84f4f99 | 161 | down_read(&cred->request_key_auth->sem); |
04c567d9 DH |
162 | |
163 | /* if the auth key has been revoked, then the key we're | |
164 | * servicing is already instantiated */ | |
d84f4f99 | 165 | if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags)) |
04c567d9 DH |
166 | goto auth_key_revoked; |
167 | ||
d84f4f99 DH |
168 | irka = cred->request_key_auth->payload.data; |
169 | rka->cred = get_cred(irka->cred); | |
b5f545c8 | 170 | rka->pid = irka->pid; |
04c567d9 | 171 | |
d84f4f99 | 172 | up_read(&cred->request_key_auth->sem); |
3e30148c | 173 | } |
b5f545c8 DH |
174 | else { |
175 | /* it isn't - use this process as the context */ | |
d84f4f99 | 176 | rka->cred = get_cred(cred); |
b5f545c8 DH |
177 | rka->pid = current->pid; |
178 | } | |
179 | ||
180 | rka->target_key = key_get(target); | |
8bbf4976 | 181 | rka->dest_keyring = key_get(dest_keyring); |
4a38e122 DH |
182 | memcpy(rka->callout_info, callout_info, callout_len); |
183 | rka->callout_len = callout_len; | |
3e30148c DH |
184 | |
185 | /* allocate the auth key */ | |
186 | sprintf(desc, "%x", target->serial); | |
187 | ||
b5f545c8 | 188 | authkey = key_alloc(&key_type_request_key_auth, desc, |
d84f4f99 | 189 | cred->fsuid, cred->fsgid, cred, |
b5f545c8 | 190 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
7e047ef5 | 191 | KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA); |
b5f545c8 DH |
192 | if (IS_ERR(authkey)) { |
193 | ret = PTR_ERR(authkey); | |
194 | goto error_alloc; | |
3e30148c DH |
195 | } |
196 | ||
d84f4f99 | 197 | /* construct the auth key */ |
b5f545c8 DH |
198 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
199 | if (ret < 0) | |
200 | goto error_inst; | |
3e30148c | 201 | |
d84f4f99 | 202 | kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage)); |
b5f545c8 DH |
203 | return authkey; |
204 | ||
04c567d9 | 205 | auth_key_revoked: |
d84f4f99 | 206 | up_read(&cred->request_key_auth->sem); |
76181c13 | 207 | kfree(rka->callout_info); |
04c567d9 DH |
208 | kfree(rka); |
209 | kleave("= -EKEYREVOKED"); | |
210 | return ERR_PTR(-EKEYREVOKED); | |
211 | ||
b5f545c8 DH |
212 | error_inst: |
213 | key_revoke(authkey); | |
214 | key_put(authkey); | |
215 | error_alloc: | |
216 | key_put(rka->target_key); | |
8bbf4976 | 217 | key_put(rka->dest_keyring); |
76181c13 | 218 | kfree(rka->callout_info); |
b5f545c8 DH |
219 | kfree(rka); |
220 | kleave("= %d", ret); | |
221 | return ERR_PTR(ret); | |
a8b17ed0 | 222 | } |
3e30148c | 223 | |
b5f545c8 | 224 | /* |
973c9f4f | 225 | * See if an authorisation key is associated with a particular key. |
b5f545c8 DH |
226 | */ |
227 | static int key_get_instantiation_authkey_match(const struct key *key, | |
228 | const void *_id) | |
229 | { | |
230 | struct request_key_auth *rka = key->payload.data; | |
231 | key_serial_t id = (key_serial_t)(unsigned long) _id; | |
232 | ||
233 | return rka->target_key->serial == id; | |
a8b17ed0 | 234 | } |
b5f545c8 | 235 | |
3e30148c | 236 | /* |
973c9f4f DH |
237 | * Search the current process's keyrings for the authorisation key for |
238 | * instantiation of a key. | |
3e30148c DH |
239 | */ |
240 | struct key *key_get_instantiation_authkey(key_serial_t target_id) | |
241 | { | |
d84f4f99 | 242 | const struct cred *cred = current_cred(); |
b5f545c8 DH |
243 | struct key *authkey; |
244 | key_ref_t authkey_ref; | |
245 | ||
246 | authkey_ref = search_process_keyrings( | |
247 | &key_type_request_key_auth, | |
248 | (void *) (unsigned long) target_id, | |
249 | key_get_instantiation_authkey_match, | |
61ea0c0b | 250 | false, cred); |
b5f545c8 DH |
251 | |
252 | if (IS_ERR(authkey_ref)) { | |
e231c2ee | 253 | authkey = ERR_CAST(authkey_ref); |
4d67431f DH |
254 | if (authkey == ERR_PTR(-EAGAIN)) |
255 | authkey = ERR_PTR(-ENOKEY); | |
b5f545c8 DH |
256 | goto error; |
257 | } | |
3e30148c | 258 | |
b5f545c8 DH |
259 | authkey = key_ref_to_ptr(authkey_ref); |
260 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { | |
261 | key_put(authkey); | |
262 | authkey = ERR_PTR(-EKEYREVOKED); | |
263 | } | |
3e30148c | 264 | |
b5f545c8 DH |
265 | error: |
266 | return authkey; | |
a8b17ed0 | 267 | } |