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a38f7907 SK |
1 | /* |
2 | * Crypto user configuration API. | |
3 | * | |
4 | * Copyright (C) 2011 secunet Security Networks AG | |
5 | * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms and conditions of the GNU General Public License, | |
9 | * version 2, as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along with | |
17 | * this program; if not, write to the Free Software Foundation, Inc., | |
18 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/crypto.h> | |
23 | #include <linux/cryptouser.h> | |
24 | #include <net/netlink.h> | |
25 | #include <linux/security.h> | |
26 | #include <net/net_namespace.h> | |
27 | #include "internal.h" | |
28 | ||
29 | DEFINE_MUTEX(crypto_cfg_mutex); | |
30 | ||
31 | /* The crypto netlink socket */ | |
32 | static struct sock *crypto_nlsk; | |
33 | ||
34 | struct crypto_dump_info { | |
35 | struct sk_buff *in_skb; | |
36 | struct sk_buff *out_skb; | |
37 | u32 nlmsg_seq; | |
38 | u16 nlmsg_flags; | |
39 | }; | |
40 | ||
41 | static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact) | |
42 | { | |
43 | int match; | |
44 | struct crypto_alg *q, *alg = NULL; | |
45 | ||
46 | down_read(&crypto_alg_sem); | |
47 | ||
48 | if (list_empty(&crypto_alg_list)) | |
49 | return NULL; | |
50 | ||
51 | list_for_each_entry(q, &crypto_alg_list, cra_list) { | |
52 | ||
53 | if ((q->cra_flags ^ p->cru_type) & p->cru_mask) | |
54 | continue; | |
55 | ||
56 | if (strlen(p->cru_driver_name)) | |
57 | match = !strcmp(q->cra_driver_name, | |
58 | p->cru_driver_name); | |
59 | else if (!exact) | |
60 | match = !strcmp(q->cra_name, p->cru_name); | |
61 | ||
62 | if (match) { | |
63 | alg = q; | |
64 | break; | |
65 | } | |
66 | } | |
67 | ||
68 | up_read(&crypto_alg_sem); | |
69 | ||
70 | return alg; | |
71 | } | |
72 | ||
73 | static int crypto_report_one(struct crypto_alg *alg, | |
74 | struct crypto_user_alg *ualg, struct sk_buff *skb) | |
75 | { | |
76 | memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name)); | |
77 | memcpy(&ualg->cru_driver_name, &alg->cra_driver_name, | |
78 | sizeof(ualg->cru_driver_name)); | |
79 | memcpy(&ualg->cru_module_name, module_name(alg->cra_module), | |
80 | CRYPTO_MAX_ALG_NAME); | |
81 | ||
82 | ualg->cru_flags = alg->cra_flags; | |
83 | ualg->cru_refcnt = atomic_read(&alg->cra_refcnt); | |
84 | ||
85 | NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority); | |
86 | ||
87 | return 0; | |
88 | ||
89 | nla_put_failure: | |
90 | return -EMSGSIZE; | |
91 | } | |
92 | ||
93 | static int crypto_report_alg(struct crypto_alg *alg, | |
94 | struct crypto_dump_info *info) | |
95 | { | |
96 | struct sk_buff *in_skb = info->in_skb; | |
97 | struct sk_buff *skb = info->out_skb; | |
98 | struct nlmsghdr *nlh; | |
99 | struct crypto_user_alg *ualg; | |
100 | int err = 0; | |
101 | ||
102 | nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq, | |
103 | CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags); | |
104 | if (!nlh) { | |
105 | err = -EMSGSIZE; | |
106 | goto out; | |
107 | } | |
108 | ||
109 | ualg = nlmsg_data(nlh); | |
110 | ||
111 | err = crypto_report_one(alg, ualg, skb); | |
112 | if (err) { | |
113 | nlmsg_cancel(skb, nlh); | |
114 | goto out; | |
115 | } | |
116 | ||
117 | nlmsg_end(skb, nlh); | |
118 | ||
119 | out: | |
120 | return err; | |
121 | } | |
122 | ||
123 | static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh, | |
124 | struct nlattr **attrs) | |
125 | { | |
126 | struct crypto_user_alg *p = nlmsg_data(in_nlh); | |
127 | struct crypto_alg *alg; | |
128 | struct sk_buff *skb; | |
129 | struct crypto_dump_info info; | |
130 | int err; | |
131 | ||
132 | if (!p->cru_driver_name) | |
133 | return -EINVAL; | |
134 | ||
135 | alg = crypto_alg_match(p, 1); | |
136 | if (!alg) | |
137 | return -ENOENT; | |
138 | ||
139 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); | |
140 | if (!skb) | |
141 | return -ENOMEM; | |
142 | ||
143 | info.in_skb = in_skb; | |
144 | info.out_skb = skb; | |
145 | info.nlmsg_seq = in_nlh->nlmsg_seq; | |
146 | info.nlmsg_flags = 0; | |
147 | ||
148 | err = crypto_report_alg(alg, &info); | |
149 | if (err) | |
150 | return err; | |
151 | ||
152 | return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid); | |
153 | } | |
154 | ||
155 | static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb) | |
156 | { | |
157 | struct crypto_alg *alg; | |
158 | struct crypto_dump_info info; | |
159 | int err; | |
160 | ||
161 | if (cb->args[0]) | |
162 | goto out; | |
163 | ||
164 | cb->args[0] = 1; | |
165 | ||
166 | info.in_skb = cb->skb; | |
167 | info.out_skb = skb; | |
168 | info.nlmsg_seq = cb->nlh->nlmsg_seq; | |
169 | info.nlmsg_flags = NLM_F_MULTI; | |
170 | ||
171 | list_for_each_entry(alg, &crypto_alg_list, cra_list) { | |
172 | err = crypto_report_alg(alg, &info); | |
173 | if (err) | |
174 | goto out_err; | |
175 | } | |
176 | ||
177 | out: | |
178 | return skb->len; | |
179 | out_err: | |
180 | return err; | |
181 | } | |
182 | ||
183 | static int crypto_dump_report_done(struct netlink_callback *cb) | |
184 | { | |
185 | return 0; | |
186 | } | |
187 | ||
188 | static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh, | |
189 | struct nlattr **attrs) | |
190 | { | |
191 | struct crypto_alg *alg; | |
192 | struct crypto_user_alg *p = nlmsg_data(nlh); | |
193 | struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL]; | |
194 | LIST_HEAD(list); | |
195 | ||
196 | if (priority && !strlen(p->cru_driver_name)) | |
197 | return -EINVAL; | |
198 | ||
199 | alg = crypto_alg_match(p, 1); | |
200 | if (!alg) | |
201 | return -ENOENT; | |
202 | ||
203 | down_write(&crypto_alg_sem); | |
204 | ||
205 | crypto_remove_spawns(alg, &list, NULL); | |
206 | ||
207 | if (priority) | |
208 | alg->cra_priority = nla_get_u32(priority); | |
209 | ||
210 | up_write(&crypto_alg_sem); | |
211 | ||
212 | crypto_remove_final(&list); | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
217 | static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh, | |
218 | struct nlattr **attrs) | |
219 | { | |
220 | struct crypto_alg *alg; | |
221 | struct crypto_user_alg *p = nlmsg_data(nlh); | |
222 | ||
223 | alg = crypto_alg_match(p, 1); | |
224 | if (!alg) | |
225 | return -ENOENT; | |
226 | ||
227 | /* We can not unregister core algorithms such as aes-generic. | |
228 | * We would loose the reference in the crypto_alg_list to this algorithm | |
229 | * if we try to unregister. Unregistering such an algorithm without | |
230 | * removing the module is not possible, so we restrict to crypto | |
231 | * instances that are build from templates. */ | |
232 | if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE)) | |
233 | return -EINVAL; | |
234 | ||
235 | if (atomic_read(&alg->cra_refcnt) != 1) | |
236 | return -EBUSY; | |
237 | ||
238 | return crypto_unregister_alg(alg); | |
239 | } | |
240 | ||
241 | static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh, | |
242 | struct nlattr **attrs) | |
243 | { | |
244 | int exact; | |
245 | const char *name; | |
246 | struct crypto_alg *alg; | |
247 | struct crypto_user_alg *p = nlmsg_data(nlh); | |
248 | struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL]; | |
249 | ||
250 | if (strlen(p->cru_driver_name)) | |
251 | exact = 1; | |
252 | ||
253 | if (priority && !exact) | |
254 | return -EINVAL; | |
255 | ||
256 | alg = crypto_alg_match(p, exact); | |
257 | if (alg) | |
258 | return -EEXIST; | |
259 | ||
260 | if (strlen(p->cru_driver_name)) | |
261 | name = p->cru_driver_name; | |
262 | else | |
263 | name = p->cru_name; | |
264 | ||
265 | alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask); | |
266 | if (IS_ERR(alg)) | |
267 | return PTR_ERR(alg); | |
268 | ||
269 | down_write(&crypto_alg_sem); | |
270 | ||
271 | if (priority) | |
272 | alg->cra_priority = nla_get_u32(priority); | |
273 | ||
274 | up_write(&crypto_alg_sem); | |
275 | ||
276 | crypto_mod_put(alg); | |
277 | ||
278 | return 0; | |
279 | } | |
280 | ||
281 | #define MSGSIZE(type) sizeof(struct type) | |
282 | ||
283 | static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = { | |
284 | [CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg), | |
285 | [CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg), | |
286 | [CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg), | |
287 | [CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg), | |
288 | }; | |
289 | ||
290 | static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = { | |
291 | [CRYPTOCFGA_PRIORITY_VAL] = { .type = NLA_U32}, | |
292 | }; | |
293 | ||
294 | #undef MSGSIZE | |
295 | ||
296 | static struct crypto_link { | |
297 | int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **); | |
298 | int (*dump)(struct sk_buff *, struct netlink_callback *); | |
299 | int (*done)(struct netlink_callback *); | |
300 | } crypto_dispatch[CRYPTO_NR_MSGTYPES] = { | |
301 | [CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg}, | |
302 | [CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg}, | |
303 | [CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg}, | |
304 | [CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = { .doit = crypto_report, | |
305 | .dump = crypto_dump_report, | |
306 | .done = crypto_dump_report_done}, | |
307 | }; | |
308 | ||
309 | static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
310 | { | |
311 | struct nlattr *attrs[CRYPTOCFGA_MAX+1]; | |
312 | struct crypto_link *link; | |
313 | int type, err; | |
314 | ||
315 | type = nlh->nlmsg_type; | |
316 | if (type > CRYPTO_MSG_MAX) | |
317 | return -EINVAL; | |
318 | ||
319 | type -= CRYPTO_MSG_BASE; | |
320 | link = &crypto_dispatch[type]; | |
321 | ||
322 | if (security_netlink_recv(skb, CAP_NET_ADMIN)) | |
323 | return -EPERM; | |
324 | ||
325 | if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) && | |
326 | (nlh->nlmsg_flags & NLM_F_DUMP))) { | |
327 | if (link->dump == NULL) | |
328 | return -EINVAL; | |
329 | ||
330 | return netlink_dump_start(crypto_nlsk, skb, nlh, | |
331 | link->dump, link->done, 0); | |
332 | } | |
333 | ||
334 | err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX, | |
335 | crypto_policy); | |
336 | if (err < 0) | |
337 | return err; | |
338 | ||
339 | if (link->doit == NULL) | |
340 | return -EINVAL; | |
341 | ||
342 | return link->doit(skb, nlh, attrs); | |
343 | } | |
344 | ||
345 | static void crypto_netlink_rcv(struct sk_buff *skb) | |
346 | { | |
347 | mutex_lock(&crypto_cfg_mutex); | |
348 | netlink_rcv_skb(skb, &crypto_user_rcv_msg); | |
349 | mutex_unlock(&crypto_cfg_mutex); | |
350 | } | |
351 | ||
352 | static int __init crypto_user_init(void) | |
353 | { | |
354 | crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, | |
355 | 0, crypto_netlink_rcv, | |
356 | NULL, THIS_MODULE); | |
357 | if (!crypto_nlsk) | |
358 | return -ENOMEM; | |
359 | ||
360 | return 0; | |
361 | } | |
362 | ||
363 | static void __exit crypto_user_exit(void) | |
364 | { | |
365 | netlink_kernel_release(crypto_nlsk); | |
366 | } | |
367 | ||
368 | module_init(crypto_user_init); | |
369 | module_exit(crypto_user_exit); | |
370 | MODULE_LICENSE("GPL"); | |
371 | MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); | |
372 | MODULE_DESCRIPTION("Crypto userspace configuration API"); |