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Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[karo-tx-linux.git] / crypto / crypto_user.c
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 <linux/sched.h>
25 #include <net/netlink.h>
26 #include <linux/security.h>
27 #include <net/net_namespace.h>
28 #include <crypto/internal/skcipher.h>
29 #include <crypto/internal/rng.h>
30 #include <crypto/akcipher.h>
31
32 #include "internal.h"
33
34 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
35
36 static DEFINE_MUTEX(crypto_cfg_mutex);
37
38 /* The crypto netlink socket */
39 static struct sock *crypto_nlsk;
40
41 struct crypto_dump_info {
42         struct sk_buff *in_skb;
43         struct sk_buff *out_skb;
44         u32 nlmsg_seq;
45         u16 nlmsg_flags;
46 };
47
48 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
49 {
50         struct crypto_alg *q, *alg = NULL;
51
52         down_read(&crypto_alg_sem);
53
54         list_for_each_entry(q, &crypto_alg_list, cra_list) {
55                 int match = 0;
56
57                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
58                         continue;
59
60                 if (strlen(p->cru_driver_name))
61                         match = !strcmp(q->cra_driver_name,
62                                         p->cru_driver_name);
63                 else if (!exact)
64                         match = !strcmp(q->cra_name, p->cru_name);
65
66                 if (!match)
67                         continue;
68
69                 if (unlikely(!crypto_mod_get(q)))
70                         continue;
71
72                 alg = q;
73                 break;
74         }
75
76         up_read(&crypto_alg_sem);
77
78         return alg;
79 }
80
81 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
82 {
83         struct crypto_report_cipher rcipher;
84
85         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
86
87         rcipher.blocksize = alg->cra_blocksize;
88         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
89         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
90
91         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
92                     sizeof(struct crypto_report_cipher), &rcipher))
93                 goto nla_put_failure;
94         return 0;
95
96 nla_put_failure:
97         return -EMSGSIZE;
98 }
99
100 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
101 {
102         struct crypto_report_comp rcomp;
103
104         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
105         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
106                     sizeof(struct crypto_report_comp), &rcomp))
107                 goto nla_put_failure;
108         return 0;
109
110 nla_put_failure:
111         return -EMSGSIZE;
112 }
113
114 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
115 {
116         struct crypto_report_akcipher rakcipher;
117
118         strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
119
120         if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
121                     sizeof(struct crypto_report_akcipher), &rakcipher))
122                 goto nla_put_failure;
123         return 0;
124
125 nla_put_failure:
126         return -EMSGSIZE;
127 }
128
129 static int crypto_report_one(struct crypto_alg *alg,
130                              struct crypto_user_alg *ualg, struct sk_buff *skb)
131 {
132         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
133         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
134                 sizeof(ualg->cru_driver_name));
135         strncpy(ualg->cru_module_name, module_name(alg->cra_module),
136                 sizeof(ualg->cru_module_name));
137
138         ualg->cru_type = 0;
139         ualg->cru_mask = 0;
140         ualg->cru_flags = alg->cra_flags;
141         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
142
143         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
144                 goto nla_put_failure;
145         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
146                 struct crypto_report_larval rl;
147
148                 strncpy(rl.type, "larval", sizeof(rl.type));
149                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
150                             sizeof(struct crypto_report_larval), &rl))
151                         goto nla_put_failure;
152                 goto out;
153         }
154
155         if (alg->cra_type && alg->cra_type->report) {
156                 if (alg->cra_type->report(skb, alg))
157                         goto nla_put_failure;
158
159                 goto out;
160         }
161
162         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
163         case CRYPTO_ALG_TYPE_CIPHER:
164                 if (crypto_report_cipher(skb, alg))
165                         goto nla_put_failure;
166
167                 break;
168         case CRYPTO_ALG_TYPE_COMPRESS:
169                 if (crypto_report_comp(skb, alg))
170                         goto nla_put_failure;
171
172                 break;
173
174         case CRYPTO_ALG_TYPE_AKCIPHER:
175                 if (crypto_report_akcipher(skb, alg))
176                         goto nla_put_failure;
177
178                 break;
179         }
180
181 out:
182         return 0;
183
184 nla_put_failure:
185         return -EMSGSIZE;
186 }
187
188 static int crypto_report_alg(struct crypto_alg *alg,
189                              struct crypto_dump_info *info)
190 {
191         struct sk_buff *in_skb = info->in_skb;
192         struct sk_buff *skb = info->out_skb;
193         struct nlmsghdr *nlh;
194         struct crypto_user_alg *ualg;
195         int err = 0;
196
197         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
198                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
199         if (!nlh) {
200                 err = -EMSGSIZE;
201                 goto out;
202         }
203
204         ualg = nlmsg_data(nlh);
205
206         err = crypto_report_one(alg, ualg, skb);
207         if (err) {
208                 nlmsg_cancel(skb, nlh);
209                 goto out;
210         }
211
212         nlmsg_end(skb, nlh);
213
214 out:
215         return err;
216 }
217
218 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
219                          struct nlattr **attrs)
220 {
221         struct crypto_user_alg *p = nlmsg_data(in_nlh);
222         struct crypto_alg *alg;
223         struct sk_buff *skb;
224         struct crypto_dump_info info;
225         int err;
226
227         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
228                 return -EINVAL;
229
230         alg = crypto_alg_match(p, 0);
231         if (!alg)
232                 return -ENOENT;
233
234         err = -ENOMEM;
235         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
236         if (!skb)
237                 goto drop_alg;
238
239         info.in_skb = in_skb;
240         info.out_skb = skb;
241         info.nlmsg_seq = in_nlh->nlmsg_seq;
242         info.nlmsg_flags = 0;
243
244         err = crypto_report_alg(alg, &info);
245
246 drop_alg:
247         crypto_mod_put(alg);
248
249         if (err)
250                 return err;
251
252         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
253 }
254
255 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
256 {
257         struct crypto_alg *alg;
258         struct crypto_dump_info info;
259         int err;
260
261         if (cb->args[0])
262                 goto out;
263
264         cb->args[0] = 1;
265
266         info.in_skb = cb->skb;
267         info.out_skb = skb;
268         info.nlmsg_seq = cb->nlh->nlmsg_seq;
269         info.nlmsg_flags = NLM_F_MULTI;
270
271         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
272                 err = crypto_report_alg(alg, &info);
273                 if (err)
274                         goto out_err;
275         }
276
277 out:
278         return skb->len;
279 out_err:
280         return err;
281 }
282
283 static int crypto_dump_report_done(struct netlink_callback *cb)
284 {
285         return 0;
286 }
287
288 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
289                              struct nlattr **attrs)
290 {
291         struct crypto_alg *alg;
292         struct crypto_user_alg *p = nlmsg_data(nlh);
293         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
294         LIST_HEAD(list);
295
296         if (!netlink_capable(skb, CAP_NET_ADMIN))
297                 return -EPERM;
298
299         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
300                 return -EINVAL;
301
302         if (priority && !strlen(p->cru_driver_name))
303                 return -EINVAL;
304
305         alg = crypto_alg_match(p, 1);
306         if (!alg)
307                 return -ENOENT;
308
309         down_write(&crypto_alg_sem);
310
311         crypto_remove_spawns(alg, &list, NULL);
312
313         if (priority)
314                 alg->cra_priority = nla_get_u32(priority);
315
316         up_write(&crypto_alg_sem);
317
318         crypto_mod_put(alg);
319         crypto_remove_final(&list);
320
321         return 0;
322 }
323
324 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
325                           struct nlattr **attrs)
326 {
327         struct crypto_alg *alg;
328         struct crypto_user_alg *p = nlmsg_data(nlh);
329         int err;
330
331         if (!netlink_capable(skb, CAP_NET_ADMIN))
332                 return -EPERM;
333
334         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
335                 return -EINVAL;
336
337         alg = crypto_alg_match(p, 1);
338         if (!alg)
339                 return -ENOENT;
340
341         /* We can not unregister core algorithms such as aes-generic.
342          * We would loose the reference in the crypto_alg_list to this algorithm
343          * if we try to unregister. Unregistering such an algorithm without
344          * removing the module is not possible, so we restrict to crypto
345          * instances that are build from templates. */
346         err = -EINVAL;
347         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
348                 goto drop_alg;
349
350         err = -EBUSY;
351         if (atomic_read(&alg->cra_refcnt) > 2)
352                 goto drop_alg;
353
354         err = crypto_unregister_instance((struct crypto_instance *)alg);
355
356 drop_alg:
357         crypto_mod_put(alg);
358         return err;
359 }
360
361 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
362                                                    u32 mask)
363 {
364         int err;
365         struct crypto_alg *alg;
366
367         type = crypto_skcipher_type(type);
368         mask = crypto_skcipher_mask(mask);
369
370         for (;;) {
371                 alg = crypto_lookup_skcipher(name,  type, mask);
372                 if (!IS_ERR(alg))
373                         return alg;
374
375                 err = PTR_ERR(alg);
376                 if (err != -EAGAIN)
377                         break;
378                 if (signal_pending(current)) {
379                         err = -EINTR;
380                         break;
381                 }
382         }
383
384         return ERR_PTR(err);
385 }
386
387 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
388                           struct nlattr **attrs)
389 {
390         int exact = 0;
391         const char *name;
392         struct crypto_alg *alg;
393         struct crypto_user_alg *p = nlmsg_data(nlh);
394         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
395
396         if (!netlink_capable(skb, CAP_NET_ADMIN))
397                 return -EPERM;
398
399         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
400                 return -EINVAL;
401
402         if (strlen(p->cru_driver_name))
403                 exact = 1;
404
405         if (priority && !exact)
406                 return -EINVAL;
407
408         alg = crypto_alg_match(p, exact);
409         if (alg) {
410                 crypto_mod_put(alg);
411                 return -EEXIST;
412         }
413
414         if (strlen(p->cru_driver_name))
415                 name = p->cru_driver_name;
416         else
417                 name = p->cru_name;
418
419         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
420         case CRYPTO_ALG_TYPE_GIVCIPHER:
421         case CRYPTO_ALG_TYPE_BLKCIPHER:
422         case CRYPTO_ALG_TYPE_ABLKCIPHER:
423                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
424                 break;
425         default:
426                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
427         }
428
429         if (IS_ERR(alg))
430                 return PTR_ERR(alg);
431
432         down_write(&crypto_alg_sem);
433
434         if (priority)
435                 alg->cra_priority = nla_get_u32(priority);
436
437         up_write(&crypto_alg_sem);
438
439         crypto_mod_put(alg);
440
441         return 0;
442 }
443
444 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
445                           struct nlattr **attrs)
446 {
447         if (!netlink_capable(skb, CAP_NET_ADMIN))
448                 return -EPERM;
449         return crypto_del_default_rng();
450 }
451
452 #define MSGSIZE(type) sizeof(struct type)
453
454 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
455         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
456         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
457         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
458         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
459 };
460
461 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
462         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
463 };
464
465 #undef MSGSIZE
466
467 static const struct crypto_link {
468         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
469         int (*dump)(struct sk_buff *, struct netlink_callback *);
470         int (*done)(struct netlink_callback *);
471 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
472         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
473         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
474         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
475         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
476                                                        .dump = crypto_dump_report,
477                                                        .done = crypto_dump_report_done},
478         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
479 };
480
481 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
482 {
483         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
484         const struct crypto_link *link;
485         int type, err;
486
487         type = nlh->nlmsg_type;
488         if (type > CRYPTO_MSG_MAX)
489                 return -EINVAL;
490
491         type -= CRYPTO_MSG_BASE;
492         link = &crypto_dispatch[type];
493
494         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
495             (nlh->nlmsg_flags & NLM_F_DUMP))) {
496                 struct crypto_alg *alg;
497                 u16 dump_alloc = 0;
498
499                 if (link->dump == NULL)
500                         return -EINVAL;
501
502                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
503                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
504
505                 {
506                         struct netlink_dump_control c = {
507                                 .dump = link->dump,
508                                 .done = link->done,
509                                 .min_dump_alloc = dump_alloc,
510                         };
511                         return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
512                 }
513         }
514
515         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
516                           crypto_policy);
517         if (err < 0)
518                 return err;
519
520         if (link->doit == NULL)
521                 return -EINVAL;
522
523         return link->doit(skb, nlh, attrs);
524 }
525
526 static void crypto_netlink_rcv(struct sk_buff *skb)
527 {
528         mutex_lock(&crypto_cfg_mutex);
529         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
530         mutex_unlock(&crypto_cfg_mutex);
531 }
532
533 static int __init crypto_user_init(void)
534 {
535         struct netlink_kernel_cfg cfg = {
536                 .input  = crypto_netlink_rcv,
537         };
538
539         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
540         if (!crypto_nlsk)
541                 return -ENOMEM;
542
543         return 0;
544 }
545
546 static void __exit crypto_user_exit(void)
547 {
548         netlink_kernel_release(crypto_nlsk);
549 }
550
551 module_init(crypto_user_init);
552 module_exit(crypto_user_exit);
553 MODULE_LICENSE("GPL");
554 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
555 MODULE_DESCRIPTION("Crypto userspace configuration API");
556 MODULE_ALIAS("net-pf-16-proto-21");