Root/crypto/af_alg.c

1/*
2 * af_alg: User-space algorithm interface
3 *
4 * This file provides the user-space API for algorithms.
5 *
6 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14
15#include <asm/atomic.h>
16#include <crypto/if_alg.h>
17#include <linux/crypto.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/list.h>
21#include <linux/module.h>
22#include <linux/net.h>
23#include <linux/rwsem.h>
24
25struct alg_type_list {
26    const struct af_alg_type *type;
27    struct list_head list;
28};
29
30static atomic_long_t alg_memory_allocated;
31
32static struct proto alg_proto = {
33    .name = "ALG",
34    .owner = THIS_MODULE,
35    .memory_allocated = &alg_memory_allocated,
36    .obj_size = sizeof(struct alg_sock),
37};
38
39static LIST_HEAD(alg_types);
40static DECLARE_RWSEM(alg_types_sem);
41
42static const struct af_alg_type *alg_get_type(const char *name)
43{
44    const struct af_alg_type *type = ERR_PTR(-ENOENT);
45    struct alg_type_list *node;
46
47    down_read(&alg_types_sem);
48    list_for_each_entry(node, &alg_types, list) {
49        if (strcmp(node->type->name, name))
50            continue;
51
52        if (try_module_get(node->type->owner))
53            type = node->type;
54        break;
55    }
56    up_read(&alg_types_sem);
57
58    return type;
59}
60
61int af_alg_register_type(const struct af_alg_type *type)
62{
63    struct alg_type_list *node;
64    int err = -EEXIST;
65
66    down_write(&alg_types_sem);
67    list_for_each_entry(node, &alg_types, list) {
68        if (!strcmp(node->type->name, type->name))
69            goto unlock;
70    }
71
72    node = kmalloc(sizeof(*node), GFP_KERNEL);
73    err = -ENOMEM;
74    if (!node)
75        goto unlock;
76
77    type->ops->owner = THIS_MODULE;
78    node->type = type;
79    list_add(&node->list, &alg_types);
80    err = 0;
81
82unlock:
83    up_write(&alg_types_sem);
84
85    return err;
86}
87EXPORT_SYMBOL_GPL(af_alg_register_type);
88
89int af_alg_unregister_type(const struct af_alg_type *type)
90{
91    struct alg_type_list *node;
92    int err = -ENOENT;
93
94    down_write(&alg_types_sem);
95    list_for_each_entry(node, &alg_types, list) {
96        if (strcmp(node->type->name, type->name))
97            continue;
98
99        list_del(&node->list);
100        kfree(node);
101        err = 0;
102        break;
103    }
104    up_write(&alg_types_sem);
105
106    return err;
107}
108EXPORT_SYMBOL_GPL(af_alg_unregister_type);
109
110static void alg_do_release(const struct af_alg_type *type, void *private)
111{
112    if (!type)
113        return;
114
115    type->release(private);
116    module_put(type->owner);
117}
118
119int af_alg_release(struct socket *sock)
120{
121    if (sock->sk)
122        sock_put(sock->sk);
123    return 0;
124}
125EXPORT_SYMBOL_GPL(af_alg_release);
126
127static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
128{
129    struct sock *sk = sock->sk;
130    struct alg_sock *ask = alg_sk(sk);
131    struct sockaddr_alg *sa = (void *)uaddr;
132    const struct af_alg_type *type;
133    void *private;
134
135    if (sock->state == SS_CONNECTED)
136        return -EINVAL;
137
138    if (addr_len != sizeof(*sa))
139        return -EINVAL;
140
141    sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
142    sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
143
144    type = alg_get_type(sa->salg_type);
145    if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
146        request_module("algif-%s", sa->salg_type);
147        type = alg_get_type(sa->salg_type);
148    }
149
150    if (IS_ERR(type))
151        return PTR_ERR(type);
152
153    private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
154    if (IS_ERR(private)) {
155        module_put(type->owner);
156        return PTR_ERR(private);
157    }
158
159    lock_sock(sk);
160
161    swap(ask->type, type);
162    swap(ask->private, private);
163
164    release_sock(sk);
165
166    alg_do_release(type, private);
167
168    return 0;
169}
170
171static int alg_setkey(struct sock *sk, char __user *ukey,
172              unsigned int keylen)
173{
174    struct alg_sock *ask = alg_sk(sk);
175    const struct af_alg_type *type = ask->type;
176    u8 *key;
177    int err;
178
179    key = sock_kmalloc(sk, keylen, GFP_KERNEL);
180    if (!key)
181        return -ENOMEM;
182
183    err = -EFAULT;
184    if (copy_from_user(key, ukey, keylen))
185        goto out;
186
187    err = type->setkey(ask->private, key, keylen);
188
189out:
190    sock_kfree_s(sk, key, keylen);
191
192    return err;
193}
194
195static int alg_setsockopt(struct socket *sock, int level, int optname,
196              char __user *optval, unsigned int optlen)
197{
198    struct sock *sk = sock->sk;
199    struct alg_sock *ask = alg_sk(sk);
200    const struct af_alg_type *type;
201    int err = -ENOPROTOOPT;
202
203    lock_sock(sk);
204    type = ask->type;
205
206    if (level != SOL_ALG || !type)
207        goto unlock;
208
209    switch (optname) {
210    case ALG_SET_KEY:
211        if (sock->state == SS_CONNECTED)
212            goto unlock;
213        if (!type->setkey)
214            goto unlock;
215
216        err = alg_setkey(sk, optval, optlen);
217    }
218
219unlock:
220    release_sock(sk);
221
222    return err;
223}
224
225int af_alg_accept(struct sock *sk, struct socket *newsock)
226{
227    struct alg_sock *ask = alg_sk(sk);
228    const struct af_alg_type *type;
229    struct sock *sk2;
230    int err;
231
232    lock_sock(sk);
233    type = ask->type;
234
235    err = -EINVAL;
236    if (!type)
237        goto unlock;
238
239    sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
240    err = -ENOMEM;
241    if (!sk2)
242        goto unlock;
243
244    sock_init_data(newsock, sk2);
245    sock_graft(sk2, newsock);
246
247    err = type->accept(ask->private, sk2);
248    if (err) {
249        sk_free(sk2);
250        goto unlock;
251    }
252
253    sk2->sk_family = PF_ALG;
254
255    sock_hold(sk);
256    alg_sk(sk2)->parent = sk;
257    alg_sk(sk2)->type = type;
258
259    newsock->ops = type->ops;
260    newsock->state = SS_CONNECTED;
261
262    err = 0;
263
264unlock:
265    release_sock(sk);
266
267    return err;
268}
269EXPORT_SYMBOL_GPL(af_alg_accept);
270
271static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
272{
273    return af_alg_accept(sock->sk, newsock);
274}
275
276static const struct proto_ops alg_proto_ops = {
277    .family = PF_ALG,
278    .owner = THIS_MODULE,
279
280    .connect = sock_no_connect,
281    .socketpair = sock_no_socketpair,
282    .getname = sock_no_getname,
283    .ioctl = sock_no_ioctl,
284    .listen = sock_no_listen,
285    .shutdown = sock_no_shutdown,
286    .getsockopt = sock_no_getsockopt,
287    .mmap = sock_no_mmap,
288    .sendpage = sock_no_sendpage,
289    .sendmsg = sock_no_sendmsg,
290    .recvmsg = sock_no_recvmsg,
291    .poll = sock_no_poll,
292
293    .bind = alg_bind,
294    .release = af_alg_release,
295    .setsockopt = alg_setsockopt,
296    .accept = alg_accept,
297};
298
299static void alg_sock_destruct(struct sock *sk)
300{
301    struct alg_sock *ask = alg_sk(sk);
302
303    alg_do_release(ask->type, ask->private);
304}
305
306static int alg_create(struct net *net, struct socket *sock, int protocol,
307              int kern)
308{
309    struct sock *sk;
310    int err;
311
312    if (sock->type != SOCK_SEQPACKET)
313        return -ESOCKTNOSUPPORT;
314    if (protocol != 0)
315        return -EPROTONOSUPPORT;
316
317    err = -ENOMEM;
318    sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
319    if (!sk)
320        goto out;
321
322    sock->ops = &alg_proto_ops;
323    sock_init_data(sock, sk);
324
325    sk->sk_family = PF_ALG;
326    sk->sk_destruct = alg_sock_destruct;
327
328    return 0;
329out:
330    return err;
331}
332
333static const struct net_proto_family alg_family = {
334    .family = PF_ALG,
335    .create = alg_create,
336    .owner = THIS_MODULE,
337};
338
339int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
340           int write)
341{
342    unsigned long from = (unsigned long)addr;
343    unsigned long npages;
344    unsigned off;
345    int err;
346    int i;
347
348    err = -EFAULT;
349    if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
350        goto out;
351
352    off = from & ~PAGE_MASK;
353    npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
354    if (npages > ALG_MAX_PAGES)
355        npages = ALG_MAX_PAGES;
356
357    err = get_user_pages_fast(from, npages, write, sgl->pages);
358    if (err < 0)
359        goto out;
360
361    npages = err;
362    err = -EINVAL;
363    if (WARN_ON(npages == 0))
364        goto out;
365
366    err = 0;
367
368    sg_init_table(sgl->sg, npages);
369
370    for (i = 0; i < npages; i++) {
371        int plen = min_t(int, len, PAGE_SIZE - off);
372
373        sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
374
375        off = 0;
376        len -= plen;
377        err += plen;
378    }
379
380out:
381    return err;
382}
383EXPORT_SYMBOL_GPL(af_alg_make_sg);
384
385void af_alg_free_sg(struct af_alg_sgl *sgl)
386{
387    int i;
388
389    i = 0;
390    do {
391        put_page(sgl->pages[i]);
392    } while (!sg_is_last(sgl->sg + (i++)));
393}
394EXPORT_SYMBOL_GPL(af_alg_free_sg);
395
396int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
397{
398    struct cmsghdr *cmsg;
399
400    for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
401        if (!CMSG_OK(msg, cmsg))
402            return -EINVAL;
403        if (cmsg->cmsg_level != SOL_ALG)
404            continue;
405
406        switch(cmsg->cmsg_type) {
407        case ALG_SET_IV:
408            if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
409                return -EINVAL;
410            con->iv = (void *)CMSG_DATA(cmsg);
411            if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
412                              sizeof(*con->iv)))
413                return -EINVAL;
414            break;
415
416        case ALG_SET_OP:
417            if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
418                return -EINVAL;
419            con->op = *(u32 *)CMSG_DATA(cmsg);
420            break;
421
422        default:
423            return -EINVAL;
424        }
425    }
426
427    return 0;
428}
429EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
430
431int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
432{
433    switch (err) {
434    case -EINPROGRESS:
435    case -EBUSY:
436        wait_for_completion(&completion->completion);
437        INIT_COMPLETION(completion->completion);
438        err = completion->err;
439        break;
440    };
441
442    return err;
443}
444EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
445
446void af_alg_complete(struct crypto_async_request *req, int err)
447{
448    struct af_alg_completion *completion = req->data;
449
450    completion->err = err;
451    complete(&completion->completion);
452}
453EXPORT_SYMBOL_GPL(af_alg_complete);
454
455static int __init af_alg_init(void)
456{
457    int err = proto_register(&alg_proto, 0);
458
459    if (err)
460        goto out;
461
462    err = sock_register(&alg_family);
463    if (err != 0)
464        goto out_unregister_proto;
465
466out:
467    return err;
468
469out_unregister_proto:
470    proto_unregister(&alg_proto);
471    goto out;
472}
473
474static void __exit af_alg_exit(void)
475{
476    sock_unregister(PF_ALG);
477    proto_unregister(&alg_proto);
478}
479
480module_init(af_alg_init);
481module_exit(af_alg_exit);
482MODULE_LICENSE("GPL");
483MODULE_ALIAS_NETPROTO(AF_ALG);
484

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