um: several x86 hw-dependent crypto modules won't build on uml
[linux-2.6.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/aead.h>
29 #include <crypto/internal/skcipher.h>
30
31 #include "internal.h"
32
33 DEFINE_MUTEX(crypto_cfg_mutex);
34
35 /* The crypto netlink socket */
36 static struct sock *crypto_nlsk;
37
38 struct crypto_dump_info {
39         struct sk_buff *in_skb;
40         struct sk_buff *out_skb;
41         u32 nlmsg_seq;
42         u16 nlmsg_flags;
43 };
44
45 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
46 {
47         struct crypto_alg *q, *alg = NULL;
48
49         down_read(&crypto_alg_sem);
50
51         list_for_each_entry(q, &crypto_alg_list, cra_list) {
52                 int match = 0;
53
54                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
55                         continue;
56
57                 if (strlen(p->cru_driver_name))
58                         match = !strcmp(q->cra_driver_name,
59                                         p->cru_driver_name);
60                 else if (!exact)
61                         match = !strcmp(q->cra_name, p->cru_name);
62
63                 if (match) {
64                         alg = q;
65                         break;
66                 }
67         }
68
69         up_read(&crypto_alg_sem);
70
71         return alg;
72 }
73
74 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
75 {
76         struct crypto_report_cipher rcipher;
77
78         snprintf(rcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "cipher");
79
80         rcipher.blocksize = alg->cra_blocksize;
81         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
82         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
83
84         NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
85                 sizeof(struct crypto_report_cipher), &rcipher);
86
87         return 0;
88
89 nla_put_failure:
90         return -EMSGSIZE;
91 }
92
93 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
94 {
95         struct crypto_report_comp rcomp;
96
97         snprintf(rcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "compression");
98
99         NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
100                 sizeof(struct crypto_report_comp), &rcomp);
101
102         return 0;
103
104 nla_put_failure:
105         return -EMSGSIZE;
106 }
107
108 static int crypto_report_one(struct crypto_alg *alg,
109                              struct crypto_user_alg *ualg, struct sk_buff *skb)
110 {
111         memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name));
112         memcpy(&ualg->cru_driver_name, &alg->cra_driver_name,
113                sizeof(ualg->cru_driver_name));
114         memcpy(&ualg->cru_module_name, module_name(alg->cra_module),
115                CRYPTO_MAX_ALG_NAME);
116
117         ualg->cru_flags = alg->cra_flags;
118         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
119
120         NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);
121
122         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
123                 struct crypto_report_larval rl;
124
125                 snprintf(rl.type, CRYPTO_MAX_ALG_NAME, "%s", "larval");
126
127                 NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
128                         sizeof(struct crypto_report_larval), &rl);
129
130                 goto out;
131         }
132
133         if (alg->cra_type && alg->cra_type->report) {
134                 if (alg->cra_type->report(skb, alg))
135                         goto nla_put_failure;
136
137                 goto out;
138         }
139
140         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
141         case CRYPTO_ALG_TYPE_CIPHER:
142                 if (crypto_report_cipher(skb, alg))
143                         goto nla_put_failure;
144
145                 break;
146         case CRYPTO_ALG_TYPE_COMPRESS:
147                 if (crypto_report_comp(skb, alg))
148                         goto nla_put_failure;
149
150                 break;
151         }
152
153 out:
154         return 0;
155
156 nla_put_failure:
157         return -EMSGSIZE;
158 }
159
160 static int crypto_report_alg(struct crypto_alg *alg,
161                              struct crypto_dump_info *info)
162 {
163         struct sk_buff *in_skb = info->in_skb;
164         struct sk_buff *skb = info->out_skb;
165         struct nlmsghdr *nlh;
166         struct crypto_user_alg *ualg;
167         int err = 0;
168
169         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
170                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
171         if (!nlh) {
172                 err = -EMSGSIZE;
173                 goto out;
174         }
175
176         ualg = nlmsg_data(nlh);
177
178         err = crypto_report_one(alg, ualg, skb);
179         if (err) {
180                 nlmsg_cancel(skb, nlh);
181                 goto out;
182         }
183
184         nlmsg_end(skb, nlh);
185
186 out:
187         return err;
188 }
189
190 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
191                          struct nlattr **attrs)
192 {
193         struct crypto_user_alg *p = nlmsg_data(in_nlh);
194         struct crypto_alg *alg;
195         struct sk_buff *skb;
196         struct crypto_dump_info info;
197         int err;
198
199         if (!p->cru_driver_name)
200                 return -EINVAL;
201
202         alg = crypto_alg_match(p, 1);
203         if (!alg)
204                 return -ENOENT;
205
206         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
207         if (!skb)
208                 return -ENOMEM;
209
210         info.in_skb = in_skb;
211         info.out_skb = skb;
212         info.nlmsg_seq = in_nlh->nlmsg_seq;
213         info.nlmsg_flags = 0;
214
215         err = crypto_report_alg(alg, &info);
216         if (err)
217                 return err;
218
219         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
220 }
221
222 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
223 {
224         struct crypto_alg *alg;
225         struct crypto_dump_info info;
226         int err;
227
228         if (cb->args[0])
229                 goto out;
230
231         cb->args[0] = 1;
232
233         info.in_skb = cb->skb;
234         info.out_skb = skb;
235         info.nlmsg_seq = cb->nlh->nlmsg_seq;
236         info.nlmsg_flags = NLM_F_MULTI;
237
238         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
239                 err = crypto_report_alg(alg, &info);
240                 if (err)
241                         goto out_err;
242         }
243
244 out:
245         return skb->len;
246 out_err:
247         return err;
248 }
249
250 static int crypto_dump_report_done(struct netlink_callback *cb)
251 {
252         return 0;
253 }
254
255 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
256                              struct nlattr **attrs)
257 {
258         struct crypto_alg *alg;
259         struct crypto_user_alg *p = nlmsg_data(nlh);
260         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
261         LIST_HEAD(list);
262
263         if (priority && !strlen(p->cru_driver_name))
264                 return -EINVAL;
265
266         alg = crypto_alg_match(p, 1);
267         if (!alg)
268                 return -ENOENT;
269
270         down_write(&crypto_alg_sem);
271
272         crypto_remove_spawns(alg, &list, NULL);
273
274         if (priority)
275                 alg->cra_priority = nla_get_u32(priority);
276
277         up_write(&crypto_alg_sem);
278
279         crypto_remove_final(&list);
280
281         return 0;
282 }
283
284 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
285                           struct nlattr **attrs)
286 {
287         struct crypto_alg *alg;
288         struct crypto_user_alg *p = nlmsg_data(nlh);
289
290         alg = crypto_alg_match(p, 1);
291         if (!alg)
292                 return -ENOENT;
293
294         /* We can not unregister core algorithms such as aes-generic.
295          * We would loose the reference in the crypto_alg_list to this algorithm
296          * if we try to unregister. Unregistering such an algorithm without
297          * removing the module is not possible, so we restrict to crypto
298          * instances that are build from templates. */
299         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
300                 return -EINVAL;
301
302         if (atomic_read(&alg->cra_refcnt) != 1)
303                 return -EBUSY;
304
305         return crypto_unregister_instance(alg);
306 }
307
308 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
309                                                    u32 mask)
310 {
311         int err;
312         struct crypto_alg *alg;
313
314         type = crypto_skcipher_type(type);
315         mask = crypto_skcipher_mask(mask);
316
317         for (;;) {
318                 alg = crypto_lookup_skcipher(name,  type, mask);
319                 if (!IS_ERR(alg))
320                         return alg;
321
322                 err = PTR_ERR(alg);
323                 if (err != -EAGAIN)
324                         break;
325                 if (signal_pending(current)) {
326                         err = -EINTR;
327                         break;
328                 }
329         }
330
331         return ERR_PTR(err);
332 }
333
334 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
335                                                u32 mask)
336 {
337         int err;
338         struct crypto_alg *alg;
339
340         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
341         type |= CRYPTO_ALG_TYPE_AEAD;
342         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
343         mask |= CRYPTO_ALG_TYPE_MASK;
344
345         for (;;) {
346                 alg = crypto_lookup_aead(name,  type, mask);
347                 if (!IS_ERR(alg))
348                         return alg;
349
350                 err = PTR_ERR(alg);
351                 if (err != -EAGAIN)
352                         break;
353                 if (signal_pending(current)) {
354                         err = -EINTR;
355                         break;
356                 }
357         }
358
359         return ERR_PTR(err);
360 }
361
362 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
363                           struct nlattr **attrs)
364 {
365         int exact = 0;
366         const char *name;
367         struct crypto_alg *alg;
368         struct crypto_user_alg *p = nlmsg_data(nlh);
369         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
370
371         if (strlen(p->cru_driver_name))
372                 exact = 1;
373
374         if (priority && !exact)
375                 return -EINVAL;
376
377         alg = crypto_alg_match(p, exact);
378         if (alg)
379                 return -EEXIST;
380
381         if (strlen(p->cru_driver_name))
382                 name = p->cru_driver_name;
383         else
384                 name = p->cru_name;
385
386         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
387         case CRYPTO_ALG_TYPE_AEAD:
388                 alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
389                 break;
390         case CRYPTO_ALG_TYPE_GIVCIPHER:
391         case CRYPTO_ALG_TYPE_BLKCIPHER:
392         case CRYPTO_ALG_TYPE_ABLKCIPHER:
393                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
394                 break;
395         default:
396                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
397         }
398
399         if (IS_ERR(alg))
400                 return PTR_ERR(alg);
401
402         down_write(&crypto_alg_sem);
403
404         if (priority)
405                 alg->cra_priority = nla_get_u32(priority);
406
407         up_write(&crypto_alg_sem);
408
409         crypto_mod_put(alg);
410
411         return 0;
412 }
413
414 #define MSGSIZE(type) sizeof(struct type)
415
416 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
417         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
418         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
419         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
420         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
421 };
422
423 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
424         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
425 };
426
427 #undef MSGSIZE
428
429 static struct crypto_link {
430         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
431         int (*dump)(struct sk_buff *, struct netlink_callback *);
432         int (*done)(struct netlink_callback *);
433 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
434         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
435         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
436         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
437         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
438                                                        .dump = crypto_dump_report,
439                                                        .done = crypto_dump_report_done},
440 };
441
442 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
443 {
444         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
445         struct crypto_link *link;
446         int type, err;
447
448         type = nlh->nlmsg_type;
449         if (type > CRYPTO_MSG_MAX)
450                 return -EINVAL;
451
452         type -= CRYPTO_MSG_BASE;
453         link = &crypto_dispatch[type];
454
455         if (!capable(CAP_NET_ADMIN))
456                 return -EPERM;
457
458         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
459             (nlh->nlmsg_flags & NLM_F_DUMP))) {
460                 struct crypto_alg *alg;
461                 u16 dump_alloc = 0;
462
463                 if (link->dump == NULL)
464                         return -EINVAL;
465
466                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
467                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
468
469                 {
470                         struct netlink_dump_control c = {
471                                 .dump = link->dump,
472                                 .done = link->done,
473                                 .min_dump_alloc = dump_alloc,
474                         };
475                         return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
476                 }
477         }
478
479         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
480                           crypto_policy);
481         if (err < 0)
482                 return err;
483
484         if (link->doit == NULL)
485                 return -EINVAL;
486
487         return link->doit(skb, nlh, attrs);
488 }
489
490 static void crypto_netlink_rcv(struct sk_buff *skb)
491 {
492         mutex_lock(&crypto_cfg_mutex);
493         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
494         mutex_unlock(&crypto_cfg_mutex);
495 }
496
497 static int __init crypto_user_init(void)
498 {
499         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
500                                             0, crypto_netlink_rcv,
501                                             NULL, THIS_MODULE);
502         if (!crypto_nlsk)
503                 return -ENOMEM;
504
505         return 0;
506 }
507
508 static void __exit crypto_user_exit(void)
509 {
510         netlink_kernel_release(crypto_nlsk);
511 }
512
513 module_init(crypto_user_init);
514 module_exit(crypto_user_exit);
515 MODULE_LICENSE("GPL");
516 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
517 MODULE_DESCRIPTION("Crypto userspace configuration API");