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[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 #include <crypto/kpp.h>
32
33 #include "internal.h"
34
35 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
36
37 static DEFINE_MUTEX(crypto_cfg_mutex);
38
39 /* The crypto netlink socket */
40 static struct sock *crypto_nlsk;
41
42 struct crypto_dump_info {
43         struct sk_buff *in_skb;
44         struct sk_buff *out_skb;
45         u32 nlmsg_seq;
46         u16 nlmsg_flags;
47 };
48
49 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
50 {
51         struct crypto_alg *q, *alg = NULL;
52
53         down_read(&crypto_alg_sem);
54
55         list_for_each_entry(q, &crypto_alg_list, cra_list) {
56                 int match = 0;
57
58                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
59                         continue;
60
61                 if (strlen(p->cru_driver_name))
62                         match = !strcmp(q->cra_driver_name,
63                                         p->cru_driver_name);
64                 else if (!exact)
65                         match = !strcmp(q->cra_name, p->cru_name);
66
67                 if (!match)
68                         continue;
69
70                 if (unlikely(!crypto_mod_get(q)))
71                         continue;
72
73                 alg = q;
74                 break;
75         }
76
77         up_read(&crypto_alg_sem);
78
79         return alg;
80 }
81
82 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
83 {
84         struct crypto_report_cipher rcipher;
85
86         strlcpy(rcipher.type, "cipher", sizeof(rcipher.type));
87
88         rcipher.blocksize = alg->cra_blocksize;
89         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
90         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
91
92         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
93                     sizeof(struct crypto_report_cipher), &rcipher))
94                 goto nla_put_failure;
95         return 0;
96
97 nla_put_failure:
98         return -EMSGSIZE;
99 }
100
101 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
102 {
103         struct crypto_report_comp rcomp;
104
105         strlcpy(rcomp.type, "compression", sizeof(rcomp.type));
106         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
107                     sizeof(struct crypto_report_comp), &rcomp))
108                 goto nla_put_failure;
109         return 0;
110
111 nla_put_failure:
112         return -EMSGSIZE;
113 }
114
115 static int crypto_report_acomp(struct sk_buff *skb, struct crypto_alg *alg)
116 {
117         struct crypto_report_acomp racomp;
118
119         strlcpy(racomp.type, "acomp", sizeof(racomp.type));
120
121         if (nla_put(skb, CRYPTOCFGA_REPORT_ACOMP,
122                     sizeof(struct crypto_report_acomp), &racomp))
123                 goto nla_put_failure;
124         return 0;
125
126 nla_put_failure:
127         return -EMSGSIZE;
128 }
129
130 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
131 {
132         struct crypto_report_akcipher rakcipher;
133
134         strlcpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
135
136         if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
137                     sizeof(struct crypto_report_akcipher), &rakcipher))
138                 goto nla_put_failure;
139         return 0;
140
141 nla_put_failure:
142         return -EMSGSIZE;
143 }
144
145 static int crypto_report_kpp(struct sk_buff *skb, struct crypto_alg *alg)
146 {
147         struct crypto_report_kpp rkpp;
148
149         strlcpy(rkpp.type, "kpp", sizeof(rkpp.type));
150
151         if (nla_put(skb, CRYPTOCFGA_REPORT_KPP,
152                     sizeof(struct crypto_report_kpp), &rkpp))
153                 goto nla_put_failure;
154         return 0;
155
156 nla_put_failure:
157         return -EMSGSIZE;
158 }
159
160 static int crypto_report_one(struct crypto_alg *alg,
161                              struct crypto_user_alg *ualg, struct sk_buff *skb)
162 {
163         strlcpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
164         strlcpy(ualg->cru_driver_name, alg->cra_driver_name,
165                 sizeof(ualg->cru_driver_name));
166         strlcpy(ualg->cru_module_name, module_name(alg->cra_module),
167                 sizeof(ualg->cru_module_name));
168
169         ualg->cru_type = 0;
170         ualg->cru_mask = 0;
171         ualg->cru_flags = alg->cra_flags;
172         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
173
174         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
175                 goto nla_put_failure;
176         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
177                 struct crypto_report_larval rl;
178
179                 strlcpy(rl.type, "larval", sizeof(rl.type));
180                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
181                             sizeof(struct crypto_report_larval), &rl))
182                         goto nla_put_failure;
183                 goto out;
184         }
185
186         if (alg->cra_type && alg->cra_type->report) {
187                 if (alg->cra_type->report(skb, alg))
188                         goto nla_put_failure;
189
190                 goto out;
191         }
192
193         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
194         case CRYPTO_ALG_TYPE_CIPHER:
195                 if (crypto_report_cipher(skb, alg))
196                         goto nla_put_failure;
197
198                 break;
199         case CRYPTO_ALG_TYPE_COMPRESS:
200                 if (crypto_report_comp(skb, alg))
201                         goto nla_put_failure;
202
203                 break;
204         case CRYPTO_ALG_TYPE_ACOMPRESS:
205                 if (crypto_report_acomp(skb, alg))
206                         goto nla_put_failure;
207
208                 break;
209         case CRYPTO_ALG_TYPE_AKCIPHER:
210                 if (crypto_report_akcipher(skb, alg))
211                         goto nla_put_failure;
212
213                 break;
214         case CRYPTO_ALG_TYPE_KPP:
215                 if (crypto_report_kpp(skb, alg))
216                         goto nla_put_failure;
217                 break;
218         }
219
220 out:
221         return 0;
222
223 nla_put_failure:
224         return -EMSGSIZE;
225 }
226
227 static int crypto_report_alg(struct crypto_alg *alg,
228                              struct crypto_dump_info *info)
229 {
230         struct sk_buff *in_skb = info->in_skb;
231         struct sk_buff *skb = info->out_skb;
232         struct nlmsghdr *nlh;
233         struct crypto_user_alg *ualg;
234         int err = 0;
235
236         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
237                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
238         if (!nlh) {
239                 err = -EMSGSIZE;
240                 goto out;
241         }
242
243         ualg = nlmsg_data(nlh);
244
245         err = crypto_report_one(alg, ualg, skb);
246         if (err) {
247                 nlmsg_cancel(skb, nlh);
248                 goto out;
249         }
250
251         nlmsg_end(skb, nlh);
252
253 out:
254         return err;
255 }
256
257 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
258                          struct nlattr **attrs)
259 {
260         struct crypto_user_alg *p = nlmsg_data(in_nlh);
261         struct crypto_alg *alg;
262         struct sk_buff *skb;
263         struct crypto_dump_info info;
264         int err;
265
266         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
267                 return -EINVAL;
268
269         alg = crypto_alg_match(p, 0);
270         if (!alg)
271                 return -ENOENT;
272
273         err = -ENOMEM;
274         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
275         if (!skb)
276                 goto drop_alg;
277
278         info.in_skb = in_skb;
279         info.out_skb = skb;
280         info.nlmsg_seq = in_nlh->nlmsg_seq;
281         info.nlmsg_flags = 0;
282
283         err = crypto_report_alg(alg, &info);
284
285 drop_alg:
286         crypto_mod_put(alg);
287
288         if (err)
289                 return err;
290
291         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
292 }
293
294 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
295 {
296         struct crypto_alg *alg;
297         struct crypto_dump_info info;
298         int err;
299
300         if (cb->args[0])
301                 goto out;
302
303         cb->args[0] = 1;
304
305         info.in_skb = cb->skb;
306         info.out_skb = skb;
307         info.nlmsg_seq = cb->nlh->nlmsg_seq;
308         info.nlmsg_flags = NLM_F_MULTI;
309
310         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
311                 err = crypto_report_alg(alg, &info);
312                 if (err)
313                         goto out_err;
314         }
315
316 out:
317         return skb->len;
318 out_err:
319         return err;
320 }
321
322 static int crypto_dump_report_done(struct netlink_callback *cb)
323 {
324         return 0;
325 }
326
327 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
328                              struct nlattr **attrs)
329 {
330         struct crypto_alg *alg;
331         struct crypto_user_alg *p = nlmsg_data(nlh);
332         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
333         LIST_HEAD(list);
334
335         if (!netlink_capable(skb, CAP_NET_ADMIN))
336                 return -EPERM;
337
338         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
339                 return -EINVAL;
340
341         if (priority && !strlen(p->cru_driver_name))
342                 return -EINVAL;
343
344         alg = crypto_alg_match(p, 1);
345         if (!alg)
346                 return -ENOENT;
347
348         down_write(&crypto_alg_sem);
349
350         crypto_remove_spawns(alg, &list, NULL);
351
352         if (priority)
353                 alg->cra_priority = nla_get_u32(priority);
354
355         up_write(&crypto_alg_sem);
356
357         crypto_mod_put(alg);
358         crypto_remove_final(&list);
359
360         return 0;
361 }
362
363 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
364                           struct nlattr **attrs)
365 {
366         struct crypto_alg *alg;
367         struct crypto_user_alg *p = nlmsg_data(nlh);
368         int err;
369
370         if (!netlink_capable(skb, CAP_NET_ADMIN))
371                 return -EPERM;
372
373         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
374                 return -EINVAL;
375
376         alg = crypto_alg_match(p, 1);
377         if (!alg)
378                 return -ENOENT;
379
380         /* We can not unregister core algorithms such as aes-generic.
381          * We would loose the reference in the crypto_alg_list to this algorithm
382          * if we try to unregister. Unregistering such an algorithm without
383          * removing the module is not possible, so we restrict to crypto
384          * instances that are build from templates. */
385         err = -EINVAL;
386         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
387                 goto drop_alg;
388
389         err = -EBUSY;
390         if (atomic_read(&alg->cra_refcnt) > 2)
391                 goto drop_alg;
392
393         err = crypto_unregister_instance((struct crypto_instance *)alg);
394
395 drop_alg:
396         crypto_mod_put(alg);
397         return err;
398 }
399
400 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
401                           struct nlattr **attrs)
402 {
403         int exact = 0;
404         const char *name;
405         struct crypto_alg *alg;
406         struct crypto_user_alg *p = nlmsg_data(nlh);
407         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
408
409         if (!netlink_capable(skb, CAP_NET_ADMIN))
410                 return -EPERM;
411
412         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
413                 return -EINVAL;
414
415         if (strlen(p->cru_driver_name))
416                 exact = 1;
417
418         if (priority && !exact)
419                 return -EINVAL;
420
421         alg = crypto_alg_match(p, exact);
422         if (alg) {
423                 crypto_mod_put(alg);
424                 return -EEXIST;
425         }
426
427         if (strlen(p->cru_driver_name))
428                 name = p->cru_driver_name;
429         else
430                 name = p->cru_name;
431
432         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
433         if (IS_ERR(alg))
434                 return PTR_ERR(alg);
435
436         down_write(&crypto_alg_sem);
437
438         if (priority)
439                 alg->cra_priority = nla_get_u32(priority);
440
441         up_write(&crypto_alg_sem);
442
443         crypto_mod_put(alg);
444
445         return 0;
446 }
447
448 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
449                           struct nlattr **attrs)
450 {
451         if (!netlink_capable(skb, CAP_NET_ADMIN))
452                 return -EPERM;
453         return crypto_del_default_rng();
454 }
455
456 #define MSGSIZE(type) sizeof(struct type)
457
458 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
459         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
460         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
461         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
462         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
463         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
464 };
465
466 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
467         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
468 };
469
470 #undef MSGSIZE
471
472 static const struct crypto_link {
473         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
474         int (*dump)(struct sk_buff *, struct netlink_callback *);
475         int (*done)(struct netlink_callback *);
476 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
477         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
478         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
479         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
480         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
481                                                        .dump = crypto_dump_report,
482                                                        .done = crypto_dump_report_done},
483         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
484 };
485
486 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
487                                struct netlink_ext_ack *extack)
488 {
489         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
490         const struct crypto_link *link;
491         int type, err;
492
493         type = nlh->nlmsg_type;
494         if (type > CRYPTO_MSG_MAX)
495                 return -EINVAL;
496
497         type -= CRYPTO_MSG_BASE;
498         link = &crypto_dispatch[type];
499
500         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
501             (nlh->nlmsg_flags & NLM_F_DUMP))) {
502                 struct crypto_alg *alg;
503                 u16 dump_alloc = 0;
504
505                 if (link->dump == NULL)
506                         return -EINVAL;
507
508                 down_read(&crypto_alg_sem);
509                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
510                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
511
512                 {
513                         struct netlink_dump_control c = {
514                                 .dump = link->dump,
515                                 .done = link->done,
516                                 .min_dump_alloc = dump_alloc,
517                         };
518                         err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
519                 }
520                 up_read(&crypto_alg_sem);
521
522                 return err;
523         }
524
525         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
526                           crypto_policy, extack);
527         if (err < 0)
528                 return err;
529
530         if (link->doit == NULL)
531                 return -EINVAL;
532
533         return link->doit(skb, nlh, attrs);
534 }
535
536 static void crypto_netlink_rcv(struct sk_buff *skb)
537 {
538         mutex_lock(&crypto_cfg_mutex);
539         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
540         mutex_unlock(&crypto_cfg_mutex);
541 }
542
543 static int __init crypto_user_init(void)
544 {
545         struct netlink_kernel_cfg cfg = {
546                 .input  = crypto_netlink_rcv,
547         };
548
549         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
550         if (!crypto_nlsk)
551                 return -ENOMEM;
552
553         return 0;
554 }
555
556 static void __exit crypto_user_exit(void)
557 {
558         netlink_kernel_release(crypto_nlsk);
559 }
560
561 module_init(crypto_user_init);
562 module_exit(crypto_user_exit);
563 MODULE_LICENSE("GPL");
564 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
565 MODULE_DESCRIPTION("Crypto userspace configuration API");
566 MODULE_ALIAS("net-pf-16-proto-21");