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 | 20 | #include "internal.h" |
d0a059ca | 21 | #include <keys/user-type.h> |
3e30148c | 22 | |
cf7f601c DH |
23 | static int request_key_auth_instantiate(struct key *, |
24 | struct key_preparsed_payload *); | |
3e30148c | 25 | static void request_key_auth_describe(const struct key *, struct seq_file *); |
04c567d9 | 26 | static void request_key_auth_revoke(struct key *); |
3e30148c | 27 | static void request_key_auth_destroy(struct key *); |
b5f545c8 | 28 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
3e30148c DH |
29 | |
30 | /* | |
973c9f4f | 31 | * The request-key authorisation key type definition. |
3e30148c DH |
32 | */ |
33 | struct key_type key_type_request_key_auth = { | |
34 | .name = ".request_key_auth", | |
35 | .def_datalen = sizeof(struct request_key_auth), | |
36 | .instantiate = request_key_auth_instantiate, | |
37 | .describe = request_key_auth_describe, | |
04c567d9 | 38 | .revoke = request_key_auth_revoke, |
3e30148c | 39 | .destroy = request_key_auth_destroy, |
b5f545c8 | 40 | .read = request_key_auth_read, |
3e30148c DH |
41 | }; |
42 | ||
3e30148c | 43 | /* |
973c9f4f | 44 | * Instantiate a request-key authorisation key. |
3e30148c DH |
45 | */ |
46 | static int request_key_auth_instantiate(struct key *key, | |
cf7f601c | 47 | struct key_preparsed_payload *prep) |
3e30148c | 48 | { |
cf7f601c | 49 | key->payload.data = (struct request_key_auth *)prep->data; |
b5f545c8 | 50 | return 0; |
a8b17ed0 | 51 | } |
3e30148c | 52 | |
3e30148c | 53 | /* |
973c9f4f | 54 | * Describe an authorisation token. |
3e30148c DH |
55 | */ |
56 | static void request_key_auth_describe(const struct key *key, | |
57 | struct seq_file *m) | |
58 | { | |
59 | struct request_key_auth *rka = key->payload.data; | |
60 | ||
61 | seq_puts(m, "key:"); | |
62 | seq_puts(m, key->description); | |
78b7280c DH |
63 | if (key_is_instantiated(key)) |
64 | seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); | |
a8b17ed0 | 65 | } |
3e30148c | 66 | |
b5f545c8 | 67 | /* |
973c9f4f | 68 | * Read the callout_info data (retrieves the callout information). |
b5f545c8 DH |
69 | * - the key's semaphore is read-locked |
70 | */ | |
71 | static long request_key_auth_read(const struct key *key, | |
72 | char __user *buffer, size_t buflen) | |
73 | { | |
74 | struct request_key_auth *rka = key->payload.data; | |
75 | size_t datalen; | |
76 | long ret; | |
77 | ||
4a38e122 | 78 | datalen = rka->callout_len; |
b5f545c8 DH |
79 | ret = datalen; |
80 | ||
81 | /* we can return the data as is */ | |
82 | if (buffer && buflen > 0) { | |
83 | if (buflen > datalen) | |
84 | buflen = datalen; | |
85 | ||
86 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) | |
87 | ret = -EFAULT; | |
88 | } | |
89 | ||
90 | return ret; | |
a8b17ed0 | 91 | } |
b5f545c8 | 92 | |
04c567d9 | 93 | /* |
973c9f4f DH |
94 | * Handle revocation of an authorisation token key. |
95 | * | |
96 | * Called with the key sem write-locked. | |
04c567d9 DH |
97 | */ |
98 | static void request_key_auth_revoke(struct key *key) | |
99 | { | |
100 | struct request_key_auth *rka = key->payload.data; | |
101 | ||
102 | kenter("{%d}", key->serial); | |
103 | ||
d84f4f99 DH |
104 | if (rka->cred) { |
105 | put_cred(rka->cred); | |
106 | rka->cred = NULL; | |
04c567d9 | 107 | } |
a8b17ed0 | 108 | } |
04c567d9 | 109 | |
3e30148c | 110 | /* |
973c9f4f | 111 | * Destroy an instantiation authorisation token key. |
3e30148c DH |
112 | */ |
113 | static void request_key_auth_destroy(struct key *key) | |
114 | { | |
115 | struct request_key_auth *rka = key->payload.data; | |
116 | ||
117 | kenter("{%d}", key->serial); | |
118 | ||
d84f4f99 DH |
119 | if (rka->cred) { |
120 | put_cred(rka->cred); | |
121 | rka->cred = NULL; | |
04c567d9 DH |
122 | } |
123 | ||
3e30148c | 124 | key_put(rka->target_key); |
8bbf4976 | 125 | key_put(rka->dest_keyring); |
76181c13 | 126 | kfree(rka->callout_info); |
74fd92c5 | 127 | kfree(rka); |
a8b17ed0 | 128 | } |
3e30148c | 129 | |
3e30148c | 130 | /* |
973c9f4f DH |
131 | * Create an authorisation token for /sbin/request-key or whoever to gain |
132 | * access to the caller's security data. | |
3e30148c | 133 | */ |
4a38e122 | 134 | struct key *request_key_auth_new(struct key *target, const void *callout_info, |
8bbf4976 | 135 | size_t callout_len, struct key *dest_keyring) |
3e30148c | 136 | { |
b5f545c8 | 137 | struct request_key_auth *rka, *irka; |
d84f4f99 | 138 | const struct cred *cred = current->cred; |
b5f545c8 | 139 | struct key *authkey = NULL; |
3e30148c DH |
140 | char desc[20]; |
141 | int ret; | |
142 | ||
143 | kenter("%d,", target->serial); | |
144 | ||
b5f545c8 DH |
145 | /* allocate a auth record */ |
146 | rka = kmalloc(sizeof(*rka), GFP_KERNEL); | |
147 | if (!rka) { | |
148 | kleave(" = -ENOMEM"); | |
149 | return ERR_PTR(-ENOMEM); | |
150 | } | |
4a38e122 | 151 | rka->callout_info = kmalloc(callout_len, GFP_KERNEL); |
76181c13 DH |
152 | if (!rka->callout_info) { |
153 | kleave(" = -ENOMEM"); | |
154 | kfree(rka); | |
155 | return ERR_PTR(-ENOMEM); | |
156 | } | |
3e30148c | 157 | |
b5f545c8 DH |
158 | /* see if the calling process is already servicing the key request of |
159 | * another process */ | |
d84f4f99 | 160 | if (cred->request_key_auth) { |
b5f545c8 | 161 | /* it is - use that instantiation context here too */ |
d84f4f99 | 162 | down_read(&cred->request_key_auth->sem); |
04c567d9 DH |
163 | |
164 | /* if the auth key has been revoked, then the key we're | |
165 | * servicing is already instantiated */ | |
d84f4f99 | 166 | if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags)) |
04c567d9 DH |
167 | goto auth_key_revoked; |
168 | ||
d84f4f99 DH |
169 | irka = cred->request_key_auth->payload.data; |
170 | rka->cred = get_cred(irka->cred); | |
b5f545c8 | 171 | rka->pid = irka->pid; |
04c567d9 | 172 | |
d84f4f99 | 173 | up_read(&cred->request_key_auth->sem); |
3e30148c | 174 | } |
b5f545c8 DH |
175 | else { |
176 | /* it isn't - use this process as the context */ | |
d84f4f99 | 177 | rka->cred = get_cred(cred); |
b5f545c8 DH |
178 | rka->pid = current->pid; |
179 | } | |
180 | ||
181 | rka->target_key = key_get(target); | |
8bbf4976 | 182 | rka->dest_keyring = key_get(dest_keyring); |
4a38e122 DH |
183 | memcpy(rka->callout_info, callout_info, callout_len); |
184 | rka->callout_len = callout_len; | |
3e30148c DH |
185 | |
186 | /* allocate the auth key */ | |
187 | sprintf(desc, "%x", target->serial); | |
188 | ||
b5f545c8 | 189 | authkey = key_alloc(&key_type_request_key_auth, desc, |
d84f4f99 | 190 | cred->fsuid, cred->fsgid, cred, |
b5f545c8 | 191 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
7e047ef5 | 192 | KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA); |
b5f545c8 DH |
193 | if (IS_ERR(authkey)) { |
194 | ret = PTR_ERR(authkey); | |
195 | goto error_alloc; | |
3e30148c DH |
196 | } |
197 | ||
d84f4f99 | 198 | /* construct the auth key */ |
b5f545c8 DH |
199 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
200 | if (ret < 0) | |
201 | goto error_inst; | |
3e30148c | 202 | |
d84f4f99 | 203 | kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage)); |
b5f545c8 DH |
204 | return authkey; |
205 | ||
04c567d9 | 206 | auth_key_revoked: |
d84f4f99 | 207 | up_read(&cred->request_key_auth->sem); |
76181c13 | 208 | kfree(rka->callout_info); |
04c567d9 DH |
209 | kfree(rka); |
210 | kleave("= -EKEYREVOKED"); | |
211 | return ERR_PTR(-EKEYREVOKED); | |
212 | ||
b5f545c8 DH |
213 | error_inst: |
214 | key_revoke(authkey); | |
215 | key_put(authkey); | |
216 | error_alloc: | |
217 | key_put(rka->target_key); | |
8bbf4976 | 218 | key_put(rka->dest_keyring); |
76181c13 | 219 | kfree(rka->callout_info); |
b5f545c8 DH |
220 | kfree(rka); |
221 | kleave("= %d", ret); | |
222 | return ERR_PTR(ret); | |
a8b17ed0 | 223 | } |
3e30148c | 224 | |
3e30148c | 225 | /* |
973c9f4f DH |
226 | * Search the current process's keyrings for the authorisation key for |
227 | * instantiation of a key. | |
3e30148c DH |
228 | */ |
229 | struct key *key_get_instantiation_authkey(key_serial_t target_id) | |
230 | { | |
d0a059ca | 231 | char description[16]; |
4bdf0bc3 DH |
232 | struct keyring_search_context ctx = { |
233 | .index_key.type = &key_type_request_key_auth, | |
d0a059ca | 234 | .index_key.description = description, |
4bdf0bc3 | 235 | .cred = current_cred(), |
d0a059ca DH |
236 | .match = user_match, |
237 | .match_data = description, | |
4bdf0bc3 DH |
238 | .flags = KEYRING_SEARCH_LOOKUP_DIRECT, |
239 | }; | |
b5f545c8 DH |
240 | struct key *authkey; |
241 | key_ref_t authkey_ref; | |
242 | ||
d0a059ca DH |
243 | sprintf(description, "%x", target_id); |
244 | ||
4bdf0bc3 | 245 | authkey_ref = search_process_keyrings(&ctx); |
b5f545c8 DH |
246 | |
247 | if (IS_ERR(authkey_ref)) { | |
e231c2ee | 248 | authkey = ERR_CAST(authkey_ref); |
4d67431f DH |
249 | if (authkey == ERR_PTR(-EAGAIN)) |
250 | authkey = ERR_PTR(-ENOKEY); | |
b5f545c8 DH |
251 | goto error; |
252 | } | |
3e30148c | 253 | |
b5f545c8 DH |
254 | authkey = key_ref_to_ptr(authkey_ref); |
255 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { | |
256 | key_put(authkey); | |
257 | authkey = ERR_PTR(-EKEYREVOKED); | |
258 | } | |
3e30148c | 259 | |
b5f545c8 DH |
260 | error: |
261 | return authkey; | |
a8b17ed0 | 262 | } |