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

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