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 (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
269        return -EINVAL;
270
271    if (priority && !strlen(p->cru_driver_name))
272        return -EINVAL;
273
274    alg = crypto_alg_match(p, 1);
275    if (!alg)
276        return -ENOENT;
277
278    down_write(&crypto_alg_sem);
279
280    crypto_remove_spawns(alg, &list, NULL);
281
282    if (priority)
283        alg->cra_priority = nla_get_u32(priority);
284
285    up_write(&crypto_alg_sem);
286
287    crypto_remove_final(&list);
288
289    return 0;
290}
291
292static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
293              struct nlattr **attrs)
294{
295    struct crypto_alg *alg;
296    struct crypto_user_alg *p = nlmsg_data(nlh);
297
298    if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
299        return -EINVAL;
300
301    alg = crypto_alg_match(p, 1);
302    if (!alg)
303        return -ENOENT;
304
305    /* We can not unregister core algorithms such as aes-generic.
306     * We would loose the reference in the crypto_alg_list to this algorithm
307     * if we try to unregister. Unregistering such an algorithm without
308     * removing the module is not possible, so we restrict to crypto
309     * instances that are build from templates. */
310    if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
311        return -EINVAL;
312
313    if (atomic_read(&alg->cra_refcnt) != 1)
314        return -EBUSY;
315
316    return crypto_unregister_instance(alg);
317}
318
319static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
320                           u32 mask)
321{
322    int err;
323    struct crypto_alg *alg;
324
325    type = crypto_skcipher_type(type);
326    mask = crypto_skcipher_mask(mask);
327
328    for (;;) {
329        alg = crypto_lookup_skcipher(name, type, mask);
330        if (!IS_ERR(alg))
331            return alg;
332
333        err = PTR_ERR(alg);
334        if (err != -EAGAIN)
335            break;
336        if (signal_pending(current)) {
337            err = -EINTR;
338            break;
339        }
340    }
341
342    return ERR_PTR(err);
343}
344
345static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
346                           u32 mask)
347{
348    int err;
349    struct crypto_alg *alg;
350
351    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
352    type |= CRYPTO_ALG_TYPE_AEAD;
353    mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
354    mask |= CRYPTO_ALG_TYPE_MASK;
355
356    for (;;) {
357        alg = crypto_lookup_aead(name, type, mask);
358        if (!IS_ERR(alg))
359            return alg;
360
361        err = PTR_ERR(alg);
362        if (err != -EAGAIN)
363            break;
364        if (signal_pending(current)) {
365            err = -EINTR;
366            break;
367        }
368    }
369
370    return ERR_PTR(err);
371}
372
373static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
374              struct nlattr **attrs)
375{
376    int exact = 0;
377    const char *name;
378    struct crypto_alg *alg;
379    struct crypto_user_alg *p = nlmsg_data(nlh);
380    struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
381
382    if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
383        return -EINVAL;
384
385    if (strlen(p->cru_driver_name))
386        exact = 1;
387
388    if (priority && !exact)
389        return -EINVAL;
390
391    alg = crypto_alg_match(p, exact);
392    if (alg)
393        return -EEXIST;
394
395    if (strlen(p->cru_driver_name))
396        name = p->cru_driver_name;
397    else
398        name = p->cru_name;
399
400    switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
401    case CRYPTO_ALG_TYPE_AEAD:
402        alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
403        break;
404    case CRYPTO_ALG_TYPE_GIVCIPHER:
405    case CRYPTO_ALG_TYPE_BLKCIPHER:
406    case CRYPTO_ALG_TYPE_ABLKCIPHER:
407        alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
408        break;
409    default:
410        alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
411    }
412
413    if (IS_ERR(alg))
414        return PTR_ERR(alg);
415
416    down_write(&crypto_alg_sem);
417
418    if (priority)
419        alg->cra_priority = nla_get_u32(priority);
420
421    up_write(&crypto_alg_sem);
422
423    crypto_mod_put(alg);
424
425    return 0;
426}
427
428#define MSGSIZE(type) sizeof(struct type)
429
430static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
431    [CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
432    [CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
433    [CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
434    [CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
435};
436
437static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
438    [CRYPTOCFGA_PRIORITY_VAL] = { .type = NLA_U32},
439};
440
441#undef MSGSIZE
442
443static const struct crypto_link {
444    int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
445    int (*dump)(struct sk_buff *, struct netlink_callback *);
446    int (*done)(struct netlink_callback *);
447} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
448    [CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
449    [CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
450    [CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
451    [CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = { .doit = crypto_report,
452                               .dump = crypto_dump_report,
453                               .done = crypto_dump_report_done},
454};
455
456static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
457{
458    struct nlattr *attrs[CRYPTOCFGA_MAX+1];
459    const struct crypto_link *link;
460    int type, err;
461
462    type = nlh->nlmsg_type;
463    if (type > CRYPTO_MSG_MAX)
464        return -EINVAL;
465
466    type -= CRYPTO_MSG_BASE;
467    link = &crypto_dispatch[type];
468
469    if (!netlink_capable(skb, CAP_NET_ADMIN))
470        return -EPERM;
471
472    if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
473        (nlh->nlmsg_flags & NLM_F_DUMP))) {
474        struct crypto_alg *alg;
475        u16 dump_alloc = 0;
476
477        if (link->dump == NULL)
478            return -EINVAL;
479
480        list_for_each_entry(alg, &crypto_alg_list, cra_list)
481            dump_alloc += CRYPTO_REPORT_MAXSIZE;
482
483        {
484            struct netlink_dump_control c = {
485                .dump = link->dump,
486                .done = link->done,
487                .min_dump_alloc = dump_alloc,
488            };
489            return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
490        }
491    }
492
493    err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
494              crypto_policy);
495    if (err < 0)
496        return err;
497
498    if (link->doit == NULL)
499        return -EINVAL;
500
501    return link->doit(skb, nlh, attrs);
502}
503
504static void crypto_netlink_rcv(struct sk_buff *skb)
505{
506    mutex_lock(&crypto_cfg_mutex);
507    netlink_rcv_skb(skb, &crypto_user_rcv_msg);
508    mutex_unlock(&crypto_cfg_mutex);
509}
510
511static int __init crypto_user_init(void)
512{
513    struct netlink_kernel_cfg cfg = {
514        .input = crypto_netlink_rcv,
515    };
516
517    crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
518    if (!crypto_nlsk)
519        return -ENOMEM;
520
521    return 0;
522}
523
524static void __exit crypto_user_exit(void)
525{
526    netlink_kernel_release(crypto_nlsk);
527}
528
529module_init(crypto_user_init);
530module_exit(crypto_user_exit);
531MODULE_LICENSE("GPL");
532MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
533MODULE_DESCRIPTION("Crypto userspace configuration API");
534

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