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 <linux/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#include <linux/security.h>
25
26struct alg_type_list {
27    const struct af_alg_type *type;
28    struct list_head list;
29};
30
31static atomic_long_t alg_memory_allocated;
32
33static struct proto alg_proto = {
34    .name = "ALG",
35    .owner = THIS_MODULE,
36    .memory_allocated = &alg_memory_allocated,
37    .obj_size = sizeof(struct alg_sock),
38};
39
40static LIST_HEAD(alg_types);
41static DECLARE_RWSEM(alg_types_sem);
42
43static const struct af_alg_type *alg_get_type(const char *name)
44{
45    const struct af_alg_type *type = ERR_PTR(-ENOENT);
46    struct alg_type_list *node;
47
48    down_read(&alg_types_sem);
49    list_for_each_entry(node, &alg_types, list) {
50        if (strcmp(node->type->name, name))
51            continue;
52
53        if (try_module_get(node->type->owner))
54            type = node->type;
55        break;
56    }
57    up_read(&alg_types_sem);
58
59    return type;
60}
61
62int af_alg_register_type(const struct af_alg_type *type)
63{
64    struct alg_type_list *node;
65    int err = -EEXIST;
66
67    down_write(&alg_types_sem);
68    list_for_each_entry(node, &alg_types, list) {
69        if (!strcmp(node->type->name, type->name))
70            goto unlock;
71    }
72
73    node = kmalloc(sizeof(*node), GFP_KERNEL);
74    err = -ENOMEM;
75    if (!node)
76        goto unlock;
77
78    type->ops->owner = THIS_MODULE;
79    node->type = type;
80    list_add(&node->list, &alg_types);
81    err = 0;
82
83unlock:
84    up_write(&alg_types_sem);
85
86    return err;
87}
88EXPORT_SYMBOL_GPL(af_alg_register_type);
89
90int af_alg_unregister_type(const struct af_alg_type *type)
91{
92    struct alg_type_list *node;
93    int err = -ENOENT;
94
95    down_write(&alg_types_sem);
96    list_for_each_entry(node, &alg_types, list) {
97        if (strcmp(node->type->name, type->name))
98            continue;
99
100        list_del(&node->list);
101        kfree(node);
102        err = 0;
103        break;
104    }
105    up_write(&alg_types_sem);
106
107    return err;
108}
109EXPORT_SYMBOL_GPL(af_alg_unregister_type);
110
111static void alg_do_release(const struct af_alg_type *type, void *private)
112{
113    if (!type)
114        return;
115
116    type->release(private);
117    module_put(type->owner);
118}
119
120int af_alg_release(struct socket *sock)
121{
122    if (sock->sk)
123        sock_put(sock->sk);
124    return 0;
125}
126EXPORT_SYMBOL_GPL(af_alg_release);
127
128static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
129{
130    struct sock *sk = sock->sk;
131    struct alg_sock *ask = alg_sk(sk);
132    struct sockaddr_alg *sa = (void *)uaddr;
133    const struct af_alg_type *type;
134    void *private;
135
136    if (sock->state == SS_CONNECTED)
137        return -EINVAL;
138
139    if (addr_len != sizeof(*sa))
140        return -EINVAL;
141
142    sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
143    sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
144
145    type = alg_get_type(sa->salg_type);
146    if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
147        request_module("algif-%s", sa->salg_type);
148        type = alg_get_type(sa->salg_type);
149    }
150
151    if (IS_ERR(type))
152        return PTR_ERR(type);
153
154    private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
155    if (IS_ERR(private)) {
156        module_put(type->owner);
157        return PTR_ERR(private);
158    }
159
160    lock_sock(sk);
161
162    swap(ask->type, type);
163    swap(ask->private, private);
164
165    release_sock(sk);
166
167    alg_do_release(type, private);
168
169    return 0;
170}
171
172static int alg_setkey(struct sock *sk, char __user *ukey,
173              unsigned int keylen)
174{
175    struct alg_sock *ask = alg_sk(sk);
176    const struct af_alg_type *type = ask->type;
177    u8 *key;
178    int err;
179
180    key = sock_kmalloc(sk, keylen, GFP_KERNEL);
181    if (!key)
182        return -ENOMEM;
183
184    err = -EFAULT;
185    if (copy_from_user(key, ukey, keylen))
186        goto out;
187
188    err = type->setkey(ask->private, key, keylen);
189
190out:
191    sock_kfree_s(sk, key, keylen);
192
193    return err;
194}
195
196static int alg_setsockopt(struct socket *sock, int level, int optname,
197              char __user *optval, unsigned int optlen)
198{
199    struct sock *sk = sock->sk;
200    struct alg_sock *ask = alg_sk(sk);
201    const struct af_alg_type *type;
202    int err = -ENOPROTOOPT;
203
204    lock_sock(sk);
205    type = ask->type;
206
207    if (level != SOL_ALG || !type)
208        goto unlock;
209
210    switch (optname) {
211    case ALG_SET_KEY:
212        if (sock->state == SS_CONNECTED)
213            goto unlock;
214        if (!type->setkey)
215            goto unlock;
216
217        err = alg_setkey(sk, optval, optlen);
218    }
219
220unlock:
221    release_sock(sk);
222
223    return err;
224}
225
226int af_alg_accept(struct sock *sk, struct socket *newsock)
227{
228    struct alg_sock *ask = alg_sk(sk);
229    const struct af_alg_type *type;
230    struct sock *sk2;
231    int err;
232
233    lock_sock(sk);
234    type = ask->type;
235
236    err = -EINVAL;
237    if (!type)
238        goto unlock;
239
240    sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
241    err = -ENOMEM;
242    if (!sk2)
243        goto unlock;
244
245    sock_init_data(newsock, sk2);
246    sock_graft(sk2, newsock);
247    security_sk_clone(sk, sk2);
248
249    err = type->accept(ask->private, sk2);
250    if (err) {
251        sk_free(sk2);
252        goto unlock;
253    }
254
255    sk2->sk_family = PF_ALG;
256
257    sock_hold(sk);
258    alg_sk(sk2)->parent = sk;
259    alg_sk(sk2)->type = type;
260
261    newsock->ops = type->ops;
262    newsock->state = SS_CONNECTED;
263
264    err = 0;
265
266unlock:
267    release_sock(sk);
268
269    return err;
270}
271EXPORT_SYMBOL_GPL(af_alg_accept);
272
273static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
274{
275    return af_alg_accept(sock->sk, newsock);
276}
277
278static const struct proto_ops alg_proto_ops = {
279    .family = PF_ALG,
280    .owner = THIS_MODULE,
281
282    .connect = sock_no_connect,
283    .socketpair = sock_no_socketpair,
284    .getname = sock_no_getname,
285    .ioctl = sock_no_ioctl,
286    .listen = sock_no_listen,
287    .shutdown = sock_no_shutdown,
288    .getsockopt = sock_no_getsockopt,
289    .mmap = sock_no_mmap,
290    .sendpage = sock_no_sendpage,
291    .sendmsg = sock_no_sendmsg,
292    .recvmsg = sock_no_recvmsg,
293    .poll = sock_no_poll,
294
295    .bind = alg_bind,
296    .release = af_alg_release,
297    .setsockopt = alg_setsockopt,
298    .accept = alg_accept,
299};
300
301static void alg_sock_destruct(struct sock *sk)
302{
303    struct alg_sock *ask = alg_sk(sk);
304
305    alg_do_release(ask->type, ask->private);
306}
307
308static int alg_create(struct net *net, struct socket *sock, int protocol,
309              int kern)
310{
311    struct sock *sk;
312    int err;
313
314    if (sock->type != SOCK_SEQPACKET)
315        return -ESOCKTNOSUPPORT;
316    if (protocol != 0)
317        return -EPROTONOSUPPORT;
318
319    err = -ENOMEM;
320    sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
321    if (!sk)
322        goto out;
323
324    sock->ops = &alg_proto_ops;
325    sock_init_data(sock, sk);
326
327    sk->sk_family = PF_ALG;
328    sk->sk_destruct = alg_sock_destruct;
329
330    return 0;
331out:
332    return err;
333}
334
335static const struct net_proto_family alg_family = {
336    .family = PF_ALG,
337    .create = alg_create,
338    .owner = THIS_MODULE,
339};
340
341int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
342           int write)
343{
344    unsigned long from = (unsigned long)addr;
345    unsigned long npages;
346    unsigned off;
347    int err;
348    int i;
349
350    err = -EFAULT;
351    if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
352        goto out;
353
354    off = from & ~PAGE_MASK;
355    npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
356    if (npages > ALG_MAX_PAGES)
357        npages = ALG_MAX_PAGES;
358
359    err = get_user_pages_fast(from, npages, write, sgl->pages);
360    if (err < 0)
361        goto out;
362
363    npages = err;
364    err = -EINVAL;
365    if (WARN_ON(npages == 0))
366        goto out;
367
368    err = 0;
369
370    sg_init_table(sgl->sg, npages);
371
372    for (i = 0; i < npages; i++) {
373        int plen = min_t(int, len, PAGE_SIZE - off);
374
375        sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
376
377        off = 0;
378        len -= plen;
379        err += plen;
380    }
381
382out:
383    return err;
384}
385EXPORT_SYMBOL_GPL(af_alg_make_sg);
386
387void af_alg_free_sg(struct af_alg_sgl *sgl)
388{
389    int i;
390
391    i = 0;
392    do {
393        put_page(sgl->pages[i]);
394    } while (!sg_is_last(sgl->sg + (i++)));
395}
396EXPORT_SYMBOL_GPL(af_alg_free_sg);
397
398int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
399{
400    struct cmsghdr *cmsg;
401
402    for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
403        if (!CMSG_OK(msg, cmsg))
404            return -EINVAL;
405        if (cmsg->cmsg_level != SOL_ALG)
406            continue;
407
408        switch(cmsg->cmsg_type) {
409        case ALG_SET_IV:
410            if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
411                return -EINVAL;
412            con->iv = (void *)CMSG_DATA(cmsg);
413            if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
414                              sizeof(*con->iv)))
415                return -EINVAL;
416            break;
417
418        case ALG_SET_OP:
419            if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
420                return -EINVAL;
421            con->op = *(u32 *)CMSG_DATA(cmsg);
422            break;
423
424        default:
425            return -EINVAL;
426        }
427    }
428
429    return 0;
430}
431EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
432
433int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
434{
435    switch (err) {
436    case -EINPROGRESS:
437    case -EBUSY:
438        wait_for_completion(&completion->completion);
439        reinit_completion(&completion->completion);
440        err = completion->err;
441        break;
442    };
443
444    return err;
445}
446EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
447
448void af_alg_complete(struct crypto_async_request *req, int err)
449{
450    struct af_alg_completion *completion = req->data;
451
452    completion->err = err;
453    complete(&completion->completion);
454}
455EXPORT_SYMBOL_GPL(af_alg_complete);
456
457static int __init af_alg_init(void)
458{
459    int err = proto_register(&alg_proto, 0);
460
461    if (err)
462        goto out;
463
464    err = sock_register(&alg_family);
465    if (err != 0)
466        goto out_unregister_proto;
467
468out:
469    return err;
470
471out_unregister_proto:
472    proto_unregister(&alg_proto);
473    goto out;
474}
475
476static void __exit af_alg_exit(void)
477{
478    sock_unregister(PF_ALG);
479    proto_unregister(&alg_proto);
480}
481
482module_init(af_alg_init);
483module_exit(af_alg_exit);
484MODULE_LICENSE("GPL");
485MODULE_ALIAS_NETPROTO(AF_ALG);
486

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