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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 | ||
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> |
7c0f6ba6 | 19 | #include <linux/uaccess.h> |
3e30148c | 20 | #include "internal.h" |
f6052007 | 21 | #include <keys/request_key_auth-type.h> |
3e30148c | 22 | |
f1dcde91 DH |
23 | static int request_key_auth_preparse(struct key_preparsed_payload *); |
24 | static void request_key_auth_free_preparse(struct key_preparsed_payload *); | |
cf7f601c DH |
25 | static int request_key_auth_instantiate(struct key *, |
26 | struct key_preparsed_payload *); | |
3e30148c | 27 | static void request_key_auth_describe(const struct key *, struct seq_file *); |
04c567d9 | 28 | static void request_key_auth_revoke(struct key *); |
3e30148c | 29 | static void request_key_auth_destroy(struct key *); |
b5f545c8 | 30 | static long request_key_auth_read(const struct key *, char __user *, size_t); |
3e30148c DH |
31 | |
32 | /* | |
973c9f4f | 33 | * The request-key authorisation key type definition. |
3e30148c DH |
34 | */ |
35 | struct key_type key_type_request_key_auth = { | |
36 | .name = ".request_key_auth", | |
37 | .def_datalen = sizeof(struct request_key_auth), | |
f1dcde91 DH |
38 | .preparse = request_key_auth_preparse, |
39 | .free_preparse = request_key_auth_free_preparse, | |
3e30148c DH |
40 | .instantiate = request_key_auth_instantiate, |
41 | .describe = request_key_auth_describe, | |
04c567d9 | 42 | .revoke = request_key_auth_revoke, |
3e30148c | 43 | .destroy = request_key_auth_destroy, |
b5f545c8 | 44 | .read = request_key_auth_read, |
3e30148c DH |
45 | }; |
46 | ||
8da79b64 | 47 | static int request_key_auth_preparse(struct key_preparsed_payload *prep) |
f1dcde91 DH |
48 | { |
49 | return 0; | |
50 | } | |
51 | ||
8da79b64 | 52 | static void request_key_auth_free_preparse(struct key_preparsed_payload *prep) |
f1dcde91 DH |
53 | { |
54 | } | |
55 | ||
3e30148c | 56 | /* |
973c9f4f | 57 | * Instantiate a request-key authorisation key. |
3e30148c DH |
58 | */ |
59 | static int request_key_auth_instantiate(struct key *key, | |
cf7f601c | 60 | struct key_preparsed_payload *prep) |
3e30148c | 61 | { |
146aa8b1 | 62 | key->payload.data[0] = (struct request_key_auth *)prep->data; |
b5f545c8 | 63 | return 0; |
a8b17ed0 | 64 | } |
3e30148c | 65 | |
3e30148c | 66 | /* |
973c9f4f | 67 | * Describe an authorisation token. |
3e30148c DH |
68 | */ |
69 | static void request_key_auth_describe(const struct key *key, | |
70 | struct seq_file *m) | |
71 | { | |
f6052007 | 72 | struct request_key_auth *rka = get_request_key_auth(key); |
3e30148c | 73 | |
7a92b3ed HD |
74 | if (!rka) |
75 | return; | |
76 | ||
3e30148c DH |
77 | seq_puts(m, "key:"); |
78 | seq_puts(m, key->description); | |
363b02da | 79 | if (key_is_positive(key)) |
78b7280c | 80 | seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); |
a8b17ed0 | 81 | } |
3e30148c | 82 | |
b5f545c8 | 83 | /* |
973c9f4f | 84 | * Read the callout_info data (retrieves the callout information). |
b5f545c8 DH |
85 | * - the key's semaphore is read-locked |
86 | */ | |
87 | static long request_key_auth_read(const struct key *key, | |
88 | char __user *buffer, size_t buflen) | |
89 | { | |
f6052007 | 90 | struct request_key_auth *rka = get_request_key_auth(key); |
b5f545c8 DH |
91 | size_t datalen; |
92 | long ret; | |
93 | ||
7a92b3ed HD |
94 | if (!rka) |
95 | return -EKEYREVOKED; | |
96 | ||
4a38e122 | 97 | datalen = rka->callout_len; |
b5f545c8 DH |
98 | ret = datalen; |
99 | ||
100 | /* we can return the data as is */ | |
101 | if (buffer && buflen > 0) { | |
102 | if (buflen > datalen) | |
103 | buflen = datalen; | |
104 | ||
105 | if (copy_to_user(buffer, rka->callout_info, buflen) != 0) | |
106 | ret = -EFAULT; | |
107 | } | |
108 | ||
109 | return ret; | |
a8b17ed0 | 110 | } |
b5f545c8 | 111 | |
04c567d9 | 112 | /* |
973c9f4f DH |
113 | * Handle revocation of an authorisation token key. |
114 | * | |
115 | * Called with the key sem write-locked. | |
04c567d9 DH |
116 | */ |
117 | static void request_key_auth_revoke(struct key *key) | |
118 | { | |
f6052007 | 119 | struct request_key_auth *rka = get_request_key_auth(key); |
04c567d9 DH |
120 | |
121 | kenter("{%d}", key->serial); | |
122 | ||
d84f4f99 DH |
123 | if (rka->cred) { |
124 | put_cred(rka->cred); | |
125 | rka->cred = NULL; | |
04c567d9 | 126 | } |
a8b17ed0 | 127 | } |
04c567d9 | 128 | |
44d81433 EB |
129 | static void free_request_key_auth(struct request_key_auth *rka) |
130 | { | |
131 | if (!rka) | |
132 | return; | |
133 | key_put(rka->target_key); | |
134 | key_put(rka->dest_keyring); | |
135 | if (rka->cred) | |
136 | put_cred(rka->cred); | |
137 | kfree(rka->callout_info); | |
138 | kfree(rka); | |
139 | } | |
140 | ||
3e30148c | 141 | /* |
973c9f4f | 142 | * Destroy an instantiation authorisation token key. |
3e30148c DH |
143 | */ |
144 | static void request_key_auth_destroy(struct key *key) | |
145 | { | |
f6052007 | 146 | struct request_key_auth *rka = get_request_key_auth(key); |
3e30148c DH |
147 | |
148 | kenter("{%d}", key->serial); | |
149 | ||
44d81433 | 150 | free_request_key_auth(rka); |
a8b17ed0 | 151 | } |
3e30148c | 152 | |
3e30148c | 153 | /* |
973c9f4f DH |
154 | * Create an authorisation token for /sbin/request-key or whoever to gain |
155 | * access to the caller's security data. | |
3e30148c | 156 | */ |
f6052007 DH |
157 | struct key *request_key_auth_new(struct key *target, const char *op, |
158 | const void *callout_info, size_t callout_len, | |
159 | struct key *dest_keyring) | |
3e30148c | 160 | { |
b5f545c8 | 161 | struct request_key_auth *rka, *irka; |
d84f4f99 | 162 | const struct cred *cred = current->cred; |
b5f545c8 | 163 | struct key *authkey = NULL; |
3e30148c | 164 | char desc[20]; |
44d81433 | 165 | int ret = -ENOMEM; |
3e30148c DH |
166 | |
167 | kenter("%d,", target->serial); | |
168 | ||
b5f545c8 | 169 | /* allocate a auth record */ |
44d81433 EB |
170 | rka = kzalloc(sizeof(*rka), GFP_KERNEL); |
171 | if (!rka) | |
172 | goto error; | |
e007ce9c | 173 | rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL); |
44d81433 EB |
174 | if (!rka->callout_info) |
175 | goto error_free_rka; | |
e007ce9c | 176 | rka->callout_len = callout_len; |
f6052007 | 177 | strlcpy(rka->op, op, sizeof(rka->op)); |
3e30148c | 178 | |
b5f545c8 DH |
179 | /* see if the calling process is already servicing the key request of |
180 | * another process */ | |
d84f4f99 | 181 | if (cred->request_key_auth) { |
b5f545c8 | 182 | /* it is - use that instantiation context here too */ |
d84f4f99 | 183 | down_read(&cred->request_key_auth->sem); |
04c567d9 DH |
184 | |
185 | /* if the auth key has been revoked, then the key we're | |
186 | * servicing is already instantiated */ | |
44d81433 EB |
187 | if (test_bit(KEY_FLAG_REVOKED, |
188 | &cred->request_key_auth->flags)) { | |
189 | up_read(&cred->request_key_auth->sem); | |
190 | ret = -EKEYREVOKED; | |
191 | goto error_free_rka; | |
192 | } | |
04c567d9 | 193 | |
146aa8b1 | 194 | irka = cred->request_key_auth->payload.data[0]; |
d84f4f99 | 195 | rka->cred = get_cred(irka->cred); |
b5f545c8 | 196 | rka->pid = irka->pid; |
04c567d9 | 197 | |
d84f4f99 | 198 | up_read(&cred->request_key_auth->sem); |
3e30148c | 199 | } |
b5f545c8 DH |
200 | else { |
201 | /* it isn't - use this process as the context */ | |
d84f4f99 | 202 | rka->cred = get_cred(cred); |
b5f545c8 DH |
203 | rka->pid = current->pid; |
204 | } | |
205 | ||
206 | rka->target_key = key_get(target); | |
8bbf4976 | 207 | rka->dest_keyring = key_get(dest_keyring); |
3e30148c DH |
208 | |
209 | /* allocate the auth key */ | |
210 | sprintf(desc, "%x", target->serial); | |
211 | ||
b5f545c8 | 212 | authkey = key_alloc(&key_type_request_key_auth, desc, |
d84f4f99 | 213 | cred->fsuid, cred->fsgid, cred, |
b5f545c8 | 214 | KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
5ac7eace | 215 | KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL); |
b5f545c8 DH |
216 | if (IS_ERR(authkey)) { |
217 | ret = PTR_ERR(authkey); | |
44d81433 | 218 | goto error_free_rka; |
3e30148c DH |
219 | } |
220 | ||
d84f4f99 | 221 | /* construct the auth key */ |
b5f545c8 DH |
222 | ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
223 | if (ret < 0) | |
44d81433 | 224 | goto error_put_authkey; |
3e30148c | 225 | |
fff29291 | 226 | kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage)); |
b5f545c8 DH |
227 | return authkey; |
228 | ||
44d81433 | 229 | error_put_authkey: |
b5f545c8 | 230 | key_put(authkey); |
44d81433 EB |
231 | error_free_rka: |
232 | free_request_key_auth(rka); | |
233 | error: | |
b5f545c8 DH |
234 | kleave("= %d", ret); |
235 | return ERR_PTR(ret); | |
a8b17ed0 | 236 | } |
3e30148c | 237 | |
3e30148c | 238 | /* |
973c9f4f DH |
239 | * Search the current process's keyrings for the authorisation key for |
240 | * instantiation of a key. | |
3e30148c DH |
241 | */ |
242 | struct key *key_get_instantiation_authkey(key_serial_t target_id) | |
243 | { | |
d0a059ca | 244 | char description[16]; |
4bdf0bc3 DH |
245 | struct keyring_search_context ctx = { |
246 | .index_key.type = &key_type_request_key_auth, | |
d0a059ca | 247 | .index_key.description = description, |
4bdf0bc3 | 248 | .cred = current_cred(), |
c06cfb08 | 249 | .match_data.cmp = key_default_cmp, |
46291959 DH |
250 | .match_data.raw_data = description, |
251 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
054f6180 | 252 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, |
4bdf0bc3 | 253 | }; |
b5f545c8 DH |
254 | struct key *authkey; |
255 | key_ref_t authkey_ref; | |
256 | ||
58c7f008 | 257 | ctx.index_key.desc_len = sprintf(description, "%x", target_id); |
d0a059ca | 258 | |
4bdf0bc3 | 259 | authkey_ref = search_process_keyrings(&ctx); |
b5f545c8 DH |
260 | |
261 | if (IS_ERR(authkey_ref)) { | |
e231c2ee | 262 | authkey = ERR_CAST(authkey_ref); |
4d67431f DH |
263 | if (authkey == ERR_PTR(-EAGAIN)) |
264 | authkey = ERR_PTR(-ENOKEY); | |
b5f545c8 DH |
265 | goto error; |
266 | } | |
3e30148c | 267 | |
b5f545c8 DH |
268 | authkey = key_ref_to_ptr(authkey_ref); |
269 | if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { | |
270 | key_put(authkey); | |
271 | authkey = ERR_PTR(-EKEYREVOKED); | |
272 | } | |
3e30148c | 273 | |
b5f545c8 DH |
274 | error: |
275 | return authkey; | |
a8b17ed0 | 276 | } |