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