1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * af_alg: User-space algorithm interface
4 *
5 * This file provides the user-space API for algorithms.
6 *
7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
8 */
9
10 #include <linux/atomic.h>
11 #include <crypto/if_alg.h>
12 #include <linux/crypto.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/key.h>
16 #include <linux/key-type.h>
17 #include <linux/list.h>
18 #include <linux/module.h>
19 #include <linux/net.h>
20 #include <linux/rwsem.h>
21 #include <linux/sched.h>
22 #include <linux/sched/signal.h>
23 #include <linux/security.h>
24 #include <linux/string.h>
25 #include <keys/user-type.h>
26 #include <keys/trusted-type.h>
27 #include <keys/encrypted-type.h>
28
29 struct alg_type_list {
30 const struct af_alg_type *type;
31 struct list_head list;
32 };
33
34 static struct proto alg_proto = {
35 .name = "ALG",
36 .owner = THIS_MODULE,
37 .obj_size = sizeof(struct alg_sock),
38 };
39
40 static LIST_HEAD(alg_types);
41 static DECLARE_RWSEM(alg_types_sem);
42
alg_get_type(const char * name)43 static 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
af_alg_register_type(const struct af_alg_type * type)62 int 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_obj(*node);
74 err = -ENOMEM;
75 if (!node)
76 goto unlock;
77
78 type->ops->owner = THIS_MODULE;
79 if (type->ops_nokey)
80 type->ops_nokey->owner = THIS_MODULE;
81 node->type = type;
82 list_add(&node->list, &alg_types);
83 err = 0;
84
85 unlock:
86 up_write(&alg_types_sem);
87
88 return err;
89 }
90 EXPORT_SYMBOL_GPL(af_alg_register_type);
91
af_alg_unregister_type(const struct af_alg_type * type)92 int af_alg_unregister_type(const struct af_alg_type *type)
93 {
94 struct alg_type_list *node;
95 int err = -ENOENT;
96
97 down_write(&alg_types_sem);
98 list_for_each_entry(node, &alg_types, list) {
99 if (strcmp(node->type->name, type->name))
100 continue;
101
102 list_del(&node->list);
103 kfree(node);
104 err = 0;
105 break;
106 }
107 up_write(&alg_types_sem);
108
109 return err;
110 }
111 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
112
alg_do_release(const struct af_alg_type * type,void * private)113 static void alg_do_release(const struct af_alg_type *type, void *private)
114 {
115 if (!type)
116 return;
117
118 type->release(private);
119 module_put(type->owner);
120 }
121
af_alg_release(struct socket * sock)122 int af_alg_release(struct socket *sock)
123 {
124 if (sock->sk) {
125 sock_put(sock->sk);
126 sock->sk = NULL;
127 }
128 return 0;
129 }
130 EXPORT_SYMBOL_GPL(af_alg_release);
131
af_alg_release_parent(struct sock * sk)132 void af_alg_release_parent(struct sock *sk)
133 {
134 struct alg_sock *ask = alg_sk(sk);
135 unsigned int nokey = atomic_read(&ask->nokey_refcnt);
136
137 sk = ask->parent;
138 ask = alg_sk(sk);
139
140 if (nokey)
141 atomic_dec(&ask->nokey_refcnt);
142
143 if (atomic_dec_and_test(&ask->refcnt))
144 sock_put(sk);
145 }
146 EXPORT_SYMBOL_GPL(af_alg_release_parent);
147
alg_bind(struct socket * sock,struct sockaddr_unsized * uaddr,int addr_len)148 static int alg_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len)
149 {
150 const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
151 struct sock *sk = sock->sk;
152 struct alg_sock *ask = alg_sk(sk);
153 struct sockaddr_alg_new *sa = (void *)uaddr;
154 const struct af_alg_type *type;
155 void *private;
156 int err;
157
158 if (sock->state == SS_CONNECTED)
159 return -EINVAL;
160
161 BUILD_BUG_ON(offsetof(struct sockaddr_alg_new, salg_name) !=
162 offsetof(struct sockaddr_alg, salg_name));
163 BUILD_BUG_ON(offsetof(struct sockaddr_alg, salg_name) != sizeof(*sa));
164
165 if (addr_len < sizeof(*sa) + 1)
166 return -EINVAL;
167
168 /* If caller uses non-allowed flag, return error. */
169 if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
170 return -EINVAL;
171
172 sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
173 sa->salg_name[addr_len - sizeof(*sa) - 1] = 0;
174
175 type = alg_get_type(sa->salg_type);
176 if (PTR_ERR(type) == -ENOENT) {
177 request_module("algif-%s", sa->salg_type);
178 type = alg_get_type(sa->salg_type);
179 }
180
181 if (IS_ERR(type))
182 return PTR_ERR(type);
183
184 private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
185 if (IS_ERR(private)) {
186 module_put(type->owner);
187 return PTR_ERR(private);
188 }
189
190 err = -EBUSY;
191 lock_sock(sk);
192 if (atomic_read(&ask->refcnt))
193 goto unlock;
194
195 swap(ask->type, type);
196 swap(ask->private, private);
197
198 err = 0;
199
200 unlock:
201 release_sock(sk);
202
203 alg_do_release(type, private);
204
205 return err;
206 }
207
alg_setkey(struct sock * sk,sockptr_t ukey,unsigned int keylen)208 static int alg_setkey(struct sock *sk, sockptr_t ukey, unsigned int keylen)
209 {
210 struct alg_sock *ask = alg_sk(sk);
211 const struct af_alg_type *type = ask->type;
212 u8 *key;
213 int err;
214
215 key = sock_kmalloc(sk, keylen, GFP_KERNEL);
216 if (!key)
217 return -ENOMEM;
218
219 err = -EFAULT;
220 if (copy_from_sockptr(key, ukey, keylen))
221 goto out;
222
223 err = type->setkey(ask->private, key, keylen);
224
225 out:
226 sock_kzfree_s(sk, key, keylen);
227
228 return err;
229 }
230
231 #ifdef CONFIG_KEYS
232
key_data_ptr_user(const struct key * key,unsigned int * datalen)233 static const u8 *key_data_ptr_user(const struct key *key,
234 unsigned int *datalen)
235 {
236 const struct user_key_payload *ukp;
237
238 ukp = user_key_payload_locked(key);
239 if (IS_ERR_OR_NULL(ukp))
240 return ERR_PTR(-EKEYREVOKED);
241
242 *datalen = key->datalen;
243
244 return ukp->data;
245 }
246
key_data_ptr_encrypted(const struct key * key,unsigned int * datalen)247 static const u8 *key_data_ptr_encrypted(const struct key *key,
248 unsigned int *datalen)
249 {
250 const struct encrypted_key_payload *ekp;
251
252 ekp = dereference_key_locked(key);
253 if (IS_ERR_OR_NULL(ekp))
254 return ERR_PTR(-EKEYREVOKED);
255
256 *datalen = ekp->decrypted_datalen;
257
258 return ekp->decrypted_data;
259 }
260
key_data_ptr_trusted(const struct key * key,unsigned int * datalen)261 static const u8 *key_data_ptr_trusted(const struct key *key,
262 unsigned int *datalen)
263 {
264 const struct trusted_key_payload *tkp;
265
266 tkp = dereference_key_locked(key);
267 if (IS_ERR_OR_NULL(tkp))
268 return ERR_PTR(-EKEYREVOKED);
269
270 *datalen = tkp->key_len;
271
272 return tkp->key;
273 }
274
lookup_key(key_serial_t serial)275 static struct key *lookup_key(key_serial_t serial)
276 {
277 key_ref_t key_ref;
278
279 key_ref = lookup_user_key(serial, 0, KEY_NEED_SEARCH);
280 if (IS_ERR(key_ref))
281 return ERR_CAST(key_ref);
282
283 return key_ref_to_ptr(key_ref);
284 }
285
alg_setkey_by_key_serial(struct alg_sock * ask,sockptr_t optval,unsigned int optlen)286 static int alg_setkey_by_key_serial(struct alg_sock *ask, sockptr_t optval,
287 unsigned int optlen)
288 {
289 const struct af_alg_type *type = ask->type;
290 u8 *key_data = NULL;
291 unsigned int key_datalen;
292 key_serial_t serial;
293 struct key *key;
294 const u8 *ret;
295 int err;
296
297 if (optlen != sizeof(serial))
298 return -EINVAL;
299
300 if (copy_from_sockptr(&serial, optval, optlen))
301 return -EFAULT;
302
303 key = lookup_key(serial);
304 if (IS_ERR(key))
305 return PTR_ERR(key);
306
307 down_read(&key->sem);
308
309 ret = ERR_PTR(-ENOPROTOOPT);
310 if (!strcmp(key->type->name, "user") ||
311 !strcmp(key->type->name, "logon")) {
312 ret = key_data_ptr_user(key, &key_datalen);
313 } else if (IS_REACHABLE(CONFIG_ENCRYPTED_KEYS) &&
314 !strcmp(key->type->name, "encrypted")) {
315 ret = key_data_ptr_encrypted(key, &key_datalen);
316 } else if (IS_REACHABLE(CONFIG_TRUSTED_KEYS) &&
317 !strcmp(key->type->name, "trusted")) {
318 ret = key_data_ptr_trusted(key, &key_datalen);
319 }
320
321 if (IS_ERR(ret)) {
322 up_read(&key->sem);
323 key_put(key);
324 return PTR_ERR(ret);
325 }
326
327 key_data = sock_kmemdup(&ask->sk, ret, key_datalen, GFP_KERNEL);
328 if (!key_data) {
329 up_read(&key->sem);
330 key_put(key);
331 return -ENOMEM;
332 }
333
334 up_read(&key->sem);
335 key_put(key);
336
337 err = type->setkey(ask->private, key_data, key_datalen);
338
339 sock_kzfree_s(&ask->sk, key_data, key_datalen);
340
341 return err;
342 }
343
344 #else
345
alg_setkey_by_key_serial(struct alg_sock * ask,sockptr_t optval,unsigned int optlen)346 static inline int alg_setkey_by_key_serial(struct alg_sock *ask,
347 sockptr_t optval,
348 unsigned int optlen)
349 {
350 return -ENOPROTOOPT;
351 }
352
353 #endif
354
alg_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)355 static int alg_setsockopt(struct socket *sock, int level, int optname,
356 sockptr_t optval, unsigned int optlen)
357 {
358 struct sock *sk = sock->sk;
359 struct alg_sock *ask = alg_sk(sk);
360 const struct af_alg_type *type;
361 int err = -EBUSY;
362
363 lock_sock(sk);
364 if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
365 goto unlock;
366
367 type = ask->type;
368
369 err = -ENOPROTOOPT;
370 if (level != SOL_ALG || !type)
371 goto unlock;
372
373 switch (optname) {
374 case ALG_SET_KEY:
375 case ALG_SET_KEY_BY_KEY_SERIAL:
376 if (sock->state == SS_CONNECTED)
377 goto unlock;
378 if (!type->setkey)
379 goto unlock;
380
381 if (optname == ALG_SET_KEY_BY_KEY_SERIAL)
382 err = alg_setkey_by_key_serial(ask, optval, optlen);
383 else
384 err = alg_setkey(sk, optval, optlen);
385 break;
386 case ALG_SET_AEAD_AUTHSIZE:
387 if (sock->state == SS_CONNECTED)
388 goto unlock;
389 if (!type->setauthsize)
390 goto unlock;
391 err = type->setauthsize(ask->private, optlen);
392 break;
393 case ALG_SET_DRBG_ENTROPY:
394 if (sock->state == SS_CONNECTED)
395 goto unlock;
396 if (!type->setentropy)
397 goto unlock;
398
399 err = type->setentropy(ask->private, optval, optlen);
400 }
401
402 unlock:
403 release_sock(sk);
404
405 return err;
406 }
407
af_alg_accept(struct sock * sk,struct socket * newsock,struct proto_accept_arg * arg)408 int af_alg_accept(struct sock *sk, struct socket *newsock,
409 struct proto_accept_arg *arg)
410 {
411 struct alg_sock *ask = alg_sk(sk);
412 const struct af_alg_type *type;
413 struct sock *sk2;
414 unsigned int nokey;
415 int err;
416
417 lock_sock(sk);
418 type = ask->type;
419
420 err = -EINVAL;
421 if (!type)
422 goto unlock;
423
424 sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, arg->kern);
425 err = -ENOMEM;
426 if (!sk2)
427 goto unlock;
428
429 sock_init_data(newsock, sk2);
430 security_sock_graft(sk2, newsock);
431 security_sk_clone(sk, sk2);
432
433 /*
434 * newsock->ops assigned here to allow type->accept call to override
435 * them when required.
436 */
437 newsock->ops = type->ops;
438 err = type->accept(ask->private, sk2);
439
440 nokey = err == -ENOKEY;
441 if (nokey && type->accept_nokey)
442 err = type->accept_nokey(ask->private, sk2);
443
444 if (err)
445 goto unlock;
446
447 if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
448 sock_hold(sk);
449 if (nokey) {
450 atomic_inc(&ask->nokey_refcnt);
451 atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
452 }
453 alg_sk(sk2)->parent = sk;
454 alg_sk(sk2)->type = type;
455
456 newsock->state = SS_CONNECTED;
457
458 if (nokey)
459 newsock->ops = type->ops_nokey;
460
461 err = 0;
462
463 unlock:
464 release_sock(sk);
465
466 return err;
467 }
468 EXPORT_SYMBOL_GPL(af_alg_accept);
469
alg_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)470 static int alg_accept(struct socket *sock, struct socket *newsock,
471 struct proto_accept_arg *arg)
472 {
473 return af_alg_accept(sock->sk, newsock, arg);
474 }
475
476 static const struct proto_ops alg_proto_ops = {
477 .family = PF_ALG,
478 .owner = THIS_MODULE,
479
480 .connect = sock_no_connect,
481 .socketpair = sock_no_socketpair,
482 .getname = sock_no_getname,
483 .ioctl = sock_no_ioctl,
484 .listen = sock_no_listen,
485 .shutdown = sock_no_shutdown,
486 .mmap = sock_no_mmap,
487 .sendmsg = sock_no_sendmsg,
488 .recvmsg = sock_no_recvmsg,
489
490 .bind = alg_bind,
491 .release = af_alg_release,
492 .setsockopt = alg_setsockopt,
493 .accept = alg_accept,
494 };
495
alg_sock_destruct(struct sock * sk)496 static void alg_sock_destruct(struct sock *sk)
497 {
498 struct alg_sock *ask = alg_sk(sk);
499
500 alg_do_release(ask->type, ask->private);
501 }
502
alg_create(struct net * net,struct socket * sock,int protocol,int kern)503 static int alg_create(struct net *net, struct socket *sock, int protocol,
504 int kern)
505 {
506 struct sock *sk;
507 int err;
508
509 if (sock->type != SOCK_SEQPACKET)
510 return -ESOCKTNOSUPPORT;
511 if (protocol != 0)
512 return -EPROTONOSUPPORT;
513
514 err = -ENOMEM;
515 sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
516 if (!sk)
517 goto out;
518
519 sock->ops = &alg_proto_ops;
520 sock_init_data(sock, sk);
521
522 sk->sk_destruct = alg_sock_destruct;
523
524 return 0;
525 out:
526 return err;
527 }
528
529 static const struct net_proto_family alg_family = {
530 .family = PF_ALG,
531 .create = alg_create,
532 .owner = THIS_MODULE,
533 };
534
af_alg_link_sg(struct af_alg_sgl * sgl_prev,struct af_alg_sgl * sgl_new)535 static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
536 struct af_alg_sgl *sgl_new)
537 {
538 sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
539 sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
540 }
541
af_alg_free_sg(struct af_alg_sgl * sgl)542 void af_alg_free_sg(struct af_alg_sgl *sgl)
543 {
544 int i;
545
546 if (sgl->sgt.sgl) {
547 if (sgl->need_unpin)
548 for (i = 0; i < sgl->sgt.nents; i++)
549 unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
550 if (sgl->sgt.sgl != sgl->sgl)
551 kvfree(sgl->sgt.sgl);
552 sgl->sgt.sgl = NULL;
553 }
554 }
555 EXPORT_SYMBOL_GPL(af_alg_free_sg);
556
af_alg_cmsg_send(struct msghdr * msg,struct af_alg_control * con)557 static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
558 {
559 struct cmsghdr *cmsg;
560
561 for_each_cmsghdr(cmsg, msg) {
562 if (!CMSG_OK(msg, cmsg))
563 return -EINVAL;
564 if (cmsg->cmsg_level != SOL_ALG)
565 continue;
566
567 switch (cmsg->cmsg_type) {
568 case ALG_SET_IV:
569 if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
570 return -EINVAL;
571 con->iv = (void *)CMSG_DATA(cmsg);
572 if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
573 sizeof(*con->iv)))
574 return -EINVAL;
575 break;
576
577 case ALG_SET_OP:
578 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
579 return -EINVAL;
580 con->op = *(u32 *)CMSG_DATA(cmsg);
581 break;
582
583 case ALG_SET_AEAD_ASSOCLEN:
584 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
585 return -EINVAL;
586 con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
587 break;
588
589 default:
590 return -EINVAL;
591 }
592 }
593
594 return 0;
595 }
596
597 /**
598 * af_alg_alloc_tsgl - allocate the TX SGL
599 *
600 * @sk: socket of connection to user space
601 * Return: 0 upon success, < 0 upon error
602 */
af_alg_alloc_tsgl(struct sock * sk)603 static int af_alg_alloc_tsgl(struct sock *sk)
604 {
605 struct alg_sock *ask = alg_sk(sk);
606 struct af_alg_ctx *ctx = ask->private;
607 struct af_alg_tsgl *sgl;
608 struct scatterlist *sg = NULL;
609
610 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
611 if (!list_empty(&ctx->tsgl_list))
612 sg = sgl->sg;
613
614 if (!sg || sgl->cur >= MAX_SGL_ENTS) {
615 sgl = sock_kmalloc(sk,
616 struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
617 GFP_KERNEL);
618 if (!sgl)
619 return -ENOMEM;
620
621 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
622 sgl->cur = 0;
623
624 if (sg) {
625 sg_unmark_end(sg + MAX_SGL_ENTS - 1);
626 sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
627 }
628
629 list_add_tail(&sgl->list, &ctx->tsgl_list);
630 }
631
632 return 0;
633 }
634
635 /**
636 * af_alg_count_tsgl - Count number of TX SG entries
637 *
638 * The counting starts from the beginning of the SGL to @bytes.
639 *
640 * @sk: socket of connection to user space
641 * @bytes: Count the number of SG entries holding given number of bytes.
642 * Return: Number of TX SG entries found given the constraints
643 */
af_alg_count_tsgl(struct sock * sk,size_t bytes)644 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes)
645 {
646 const struct alg_sock *ask = alg_sk(sk);
647 const struct af_alg_ctx *ctx = ask->private;
648 const struct af_alg_tsgl *sgl;
649 unsigned int i;
650 unsigned int sgl_count = 0;
651
652 if (!bytes)
653 return 0;
654
655 list_for_each_entry(sgl, &ctx->tsgl_list, list) {
656 const struct scatterlist *sg = sgl->sg;
657
658 for (i = 0; i < sgl->cur; i++) {
659 sgl_count++;
660 if (sg[i].length >= bytes)
661 return sgl_count;
662
663 bytes -= sg[i].length;
664 }
665 }
666
667 return sgl_count;
668 }
669 EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
670
671 /**
672 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
673 *
674 * If @dst is non-null, reassign the pages to @dst. The caller must release
675 * the pages.
676 *
677 * @sk: socket of connection to user space
678 * @used: Number of bytes to pull from TX SGL
679 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
680 * caller must release the buffers in dst.
681 */
af_alg_pull_tsgl(struct sock * sk,size_t used,struct scatterlist * dst)682 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst)
683 {
684 struct alg_sock *ask = alg_sk(sk);
685 struct af_alg_ctx *ctx = ask->private;
686 struct af_alg_tsgl *sgl;
687 struct scatterlist *sg;
688 unsigned int i, j = 0;
689
690 while (!list_empty(&ctx->tsgl_list)) {
691 sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
692 list);
693 sg = sgl->sg;
694
695 for (i = 0; i < sgl->cur; i++) {
696 size_t plen = min_t(size_t, used, sg[i].length);
697 struct page *page = sg_page(sg + i);
698
699 if (!page)
700 continue;
701
702 /*
703 * Assumption: caller created af_alg_count_tsgl(len)
704 * SG entries in dst.
705 */
706 if (dst && plen) {
707 /* reassign page to dst */
708 get_page(page);
709 sg_set_page(dst + j, page, plen, sg[i].offset);
710 j++;
711 }
712
713 sg[i].length -= plen;
714 sg[i].offset += plen;
715
716 used -= plen;
717 ctx->used -= plen;
718
719 if (sg[i].length)
720 return;
721
722 put_page(page);
723 sg_assign_page(sg + i, NULL);
724 }
725
726 list_del(&sgl->list);
727 sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
728 }
729
730 if (!ctx->used)
731 ctx->merge = 0;
732 ctx->init = ctx->more;
733 }
734 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
735
736 /**
737 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
738 *
739 * @areq: Request holding the TX and RX SGL
740 */
af_alg_free_areq_sgls(struct af_alg_async_req * areq)741 static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
742 {
743 struct sock *sk = areq->sk;
744 struct alg_sock *ask = alg_sk(sk);
745 struct af_alg_ctx *ctx = ask->private;
746 struct af_alg_rsgl *rsgl, *tmp;
747 struct scatterlist *tsgl;
748 struct scatterlist *sg;
749 unsigned int i;
750
751 list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
752 atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
753 af_alg_free_sg(&rsgl->sgl);
754 list_del(&rsgl->list);
755 if (rsgl != &areq->first_rsgl)
756 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
757 }
758
759 tsgl = areq->tsgl;
760 if (tsgl) {
761 for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
762 if (!sg_page(sg))
763 continue;
764 put_page(sg_page(sg));
765 }
766
767 sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
768 }
769 }
770
771 /**
772 * af_alg_wait_for_wmem - wait for availability of writable memory
773 *
774 * @sk: socket of connection to user space
775 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
776 * Return: 0 when writable memory is available, < 0 upon error
777 */
af_alg_wait_for_wmem(struct sock * sk,unsigned int flags)778 static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
779 {
780 DEFINE_WAIT_FUNC(wait, woken_wake_function);
781 int err = -ERESTARTSYS;
782 long timeout;
783
784 if (flags & MSG_DONTWAIT)
785 return -EAGAIN;
786
787 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
788
789 add_wait_queue(sk_sleep(sk), &wait);
790 for (;;) {
791 if (signal_pending(current))
792 break;
793 timeout = MAX_SCHEDULE_TIMEOUT;
794 if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
795 err = 0;
796 break;
797 }
798 }
799 remove_wait_queue(sk_sleep(sk), &wait);
800
801 return err;
802 }
803
804 /**
805 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
806 *
807 * @sk: socket of connection to user space
808 */
af_alg_wmem_wakeup(struct sock * sk)809 void af_alg_wmem_wakeup(struct sock *sk)
810 {
811 struct socket_wq *wq;
812
813 if (!af_alg_writable(sk))
814 return;
815
816 rcu_read_lock();
817 wq = rcu_dereference(sk->sk_wq);
818 if (skwq_has_sleeper(wq))
819 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
820 EPOLLRDNORM |
821 EPOLLRDBAND);
822 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN);
823 rcu_read_unlock();
824 }
825 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
826
827 /**
828 * af_alg_wait_for_data - wait for availability of TX data
829 *
830 * @sk: socket of connection to user space
831 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
832 * @min: Set to minimum request size if partial requests are allowed.
833 * Return: 0 when writable memory is available, < 0 upon error
834 */
af_alg_wait_for_data(struct sock * sk,unsigned flags,unsigned min)835 int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
836 {
837 DEFINE_WAIT_FUNC(wait, woken_wake_function);
838 struct alg_sock *ask = alg_sk(sk);
839 struct af_alg_ctx *ctx = ask->private;
840 long timeout;
841 int err = -ERESTARTSYS;
842
843 if (flags & MSG_DONTWAIT)
844 return -EAGAIN;
845
846 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
847
848 add_wait_queue(sk_sleep(sk), &wait);
849 for (;;) {
850 if (signal_pending(current))
851 break;
852 timeout = MAX_SCHEDULE_TIMEOUT;
853 if (sk_wait_event(sk, &timeout,
854 ctx->init && (!ctx->more ||
855 (min && ctx->used >= min)),
856 &wait)) {
857 err = 0;
858 break;
859 }
860 }
861 remove_wait_queue(sk_sleep(sk), &wait);
862
863 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
864
865 return err;
866 }
867 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
868
869 /**
870 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
871 *
872 * @sk: socket of connection to user space
873 */
af_alg_data_wakeup(struct sock * sk)874 static void af_alg_data_wakeup(struct sock *sk)
875 {
876 struct alg_sock *ask = alg_sk(sk);
877 struct af_alg_ctx *ctx = ask->private;
878 struct socket_wq *wq;
879
880 if (!ctx->used)
881 return;
882
883 rcu_read_lock();
884 wq = rcu_dereference(sk->sk_wq);
885 if (skwq_has_sleeper(wq))
886 wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
887 EPOLLRDNORM |
888 EPOLLRDBAND);
889 sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT);
890 rcu_read_unlock();
891 }
892
893 /**
894 * af_alg_sendmsg - implementation of sendmsg system call handler
895 *
896 * The sendmsg system call handler obtains the user data and stores it
897 * in ctx->tsgl_list. This implies allocation of the required numbers of
898 * struct af_alg_tsgl.
899 *
900 * In addition, the ctx is filled with the information sent via CMSG.
901 *
902 * @sock: socket of connection to user space
903 * @msg: message from user space
904 * @size: size of message from user space
905 * @ivsize: the size of the IV for the cipher operation to verify that the
906 * user-space-provided IV has the right size
907 * Return: the number of copied data upon success, < 0 upon error
908 */
af_alg_sendmsg(struct socket * sock,struct msghdr * msg,size_t size,unsigned int ivsize)909 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
910 unsigned int ivsize)
911 {
912 struct sock *sk = sock->sk;
913 struct alg_sock *ask = alg_sk(sk);
914 struct af_alg_ctx *ctx = ask->private;
915 struct af_alg_tsgl *sgl;
916 struct af_alg_control con = {};
917 long copied = 0;
918 bool enc = false;
919 bool init = false;
920 int err = 0;
921
922 if (msg->msg_controllen) {
923 err = af_alg_cmsg_send(msg, &con);
924 if (err)
925 return err;
926
927 init = true;
928 switch (con.op) {
929 case ALG_OP_ENCRYPT:
930 enc = true;
931 break;
932 case ALG_OP_DECRYPT:
933 enc = false;
934 break;
935 default:
936 return -EINVAL;
937 }
938
939 if (con.iv && con.iv->ivlen != ivsize)
940 return -EINVAL;
941 }
942
943 lock_sock(sk);
944 if (ctx->write) {
945 release_sock(sk);
946 return -EBUSY;
947 }
948 ctx->write = true;
949
950 if (ctx->init && !ctx->more) {
951 if (ctx->used) {
952 err = -EINVAL;
953 goto unlock;
954 }
955
956 pr_info_once(
957 "%s sent an empty control message without MSG_MORE.\n",
958 current->comm);
959 }
960 ctx->init = true;
961
962 if (init) {
963 ctx->enc = enc;
964 if (con.iv)
965 memcpy(ctx->iv, con.iv->iv, ivsize);
966
967 ctx->aead_assoclen = con.aead_assoclen;
968 }
969
970 while (size) {
971 struct scatterlist *sg;
972 size_t len = size;
973 ssize_t plen;
974
975 /* use the existing memory in an allocated page */
976 if (ctx->merge && !(msg->msg_flags & MSG_SPLICE_PAGES)) {
977 sgl = list_entry(ctx->tsgl_list.prev,
978 struct af_alg_tsgl, list);
979 sg = sgl->sg + sgl->cur - 1;
980 len = min_t(size_t, len,
981 PAGE_SIZE - sg->offset - sg->length);
982
983 err = memcpy_from_msg(page_address(sg_page(sg)) +
984 sg->offset + sg->length,
985 msg, len);
986 if (err)
987 goto unlock;
988
989 sg->length += len;
990 ctx->merge = (sg->offset + sg->length) &
991 (PAGE_SIZE - 1);
992
993 ctx->used += len;
994 copied += len;
995 size -= len;
996 continue;
997 }
998
999 ctx->merge = 0;
1000
1001 if (!af_alg_writable(sk)) {
1002 err = af_alg_wait_for_wmem(sk, msg->msg_flags);
1003 if (err)
1004 goto unlock;
1005 }
1006
1007 /* allocate a new page */
1008 len = min_t(unsigned long, len, af_alg_sndbuf(sk));
1009
1010 err = af_alg_alloc_tsgl(sk);
1011 if (err)
1012 goto unlock;
1013
1014 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
1015 list);
1016 sg = sgl->sg;
1017 if (sgl->cur)
1018 sg_unmark_end(sg + sgl->cur - 1);
1019
1020 if (msg->msg_flags & MSG_SPLICE_PAGES) {
1021 struct sg_table sgtable = {
1022 .sgl = sg,
1023 .nents = sgl->cur,
1024 .orig_nents = sgl->cur,
1025 };
1026
1027 plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable,
1028 MAX_SGL_ENTS - sgl->cur, 0);
1029 if (plen < 0) {
1030 err = plen;
1031 goto unlock;
1032 }
1033
1034 for (; sgl->cur < sgtable.nents; sgl->cur++)
1035 get_page(sg_page(&sg[sgl->cur]));
1036 len -= plen;
1037 ctx->used += plen;
1038 copied += plen;
1039 size -= plen;
1040 } else {
1041 do {
1042 struct page *pg;
1043 unsigned int i = sgl->cur;
1044
1045 plen = min_t(size_t, len, PAGE_SIZE);
1046
1047 pg = alloc_page(GFP_KERNEL);
1048 if (!pg) {
1049 err = -ENOMEM;
1050 goto unlock;
1051 }
1052
1053 sg_assign_page(sg + i, pg);
1054
1055 err = memcpy_from_msg(
1056 page_address(sg_page(sg + i)),
1057 msg, plen);
1058 if (err) {
1059 __free_page(sg_page(sg + i));
1060 sg_assign_page(sg + i, NULL);
1061 goto unlock;
1062 }
1063
1064 sg[i].length = plen;
1065 len -= plen;
1066 ctx->used += plen;
1067 copied += plen;
1068 size -= plen;
1069 sgl->cur++;
1070 } while (len && sgl->cur < MAX_SGL_ENTS);
1071
1072 ctx->merge = plen & (PAGE_SIZE - 1);
1073 }
1074
1075 if (!size)
1076 sg_mark_end(sg + sgl->cur - 1);
1077 }
1078
1079 err = 0;
1080
1081 ctx->more = msg->msg_flags & MSG_MORE;
1082
1083 unlock:
1084 af_alg_data_wakeup(sk);
1085 ctx->write = false;
1086 release_sock(sk);
1087
1088 return copied ?: err;
1089 }
1090 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
1091
1092 /**
1093 * af_alg_free_resources - release resources required for crypto request
1094 * @areq: Request holding the TX and RX SGL
1095 */
af_alg_free_resources(struct af_alg_async_req * areq)1096 void af_alg_free_resources(struct af_alg_async_req *areq)
1097 {
1098 struct sock *sk = areq->sk;
1099 struct af_alg_ctx *ctx;
1100
1101 af_alg_free_areq_sgls(areq);
1102 sock_kfree_s(sk, areq, areq->areqlen);
1103
1104 ctx = alg_sk(sk)->private;
1105 ctx->inflight = false;
1106 }
1107 EXPORT_SYMBOL_GPL(af_alg_free_resources);
1108
1109 /**
1110 * af_alg_async_cb - AIO callback handler
1111 * @data: async request completion data
1112 * @err: if non-zero, error result to be returned via ki_complete();
1113 * otherwise return the AIO output length via ki_complete().
1114 *
1115 * This handler cleans up the struct af_alg_async_req upon completion of the
1116 * AIO operation.
1117 *
1118 * The number of bytes to be generated with the AIO operation must be set
1119 * in areq->outlen before the AIO callback handler is invoked.
1120 */
af_alg_async_cb(void * data,int err)1121 void af_alg_async_cb(void *data, int err)
1122 {
1123 struct af_alg_async_req *areq = data;
1124 struct sock *sk = areq->sk;
1125 struct kiocb *iocb = areq->iocb;
1126 unsigned int resultlen;
1127
1128 /* Buffer size written by crypto operation. */
1129 resultlen = areq->outlen;
1130
1131 af_alg_free_resources(areq);
1132 sock_put(sk);
1133
1134 iocb->ki_complete(iocb, err ? err : (int)resultlen);
1135 }
1136 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1137
1138 /**
1139 * af_alg_poll - poll system call handler
1140 * @file: file pointer
1141 * @sock: socket to poll
1142 * @wait: poll_table
1143 */
af_alg_poll(struct file * file,struct socket * sock,poll_table * wait)1144 __poll_t af_alg_poll(struct file *file, struct socket *sock,
1145 poll_table *wait)
1146 {
1147 struct sock *sk = sock->sk;
1148 struct alg_sock *ask = alg_sk(sk);
1149 struct af_alg_ctx *ctx = ask->private;
1150 __poll_t mask;
1151
1152 sock_poll_wait(file, sock, wait);
1153 mask = 0;
1154
1155 if (!ctx->more || ctx->used)
1156 mask |= EPOLLIN | EPOLLRDNORM;
1157
1158 if (af_alg_writable(sk))
1159 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1160
1161 return mask;
1162 }
1163 EXPORT_SYMBOL_GPL(af_alg_poll);
1164
1165 /**
1166 * af_alg_alloc_areq - allocate struct af_alg_async_req
1167 *
1168 * @sk: socket of connection to user space
1169 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1170 * Return: allocated data structure or ERR_PTR upon error
1171 */
af_alg_alloc_areq(struct sock * sk,unsigned int areqlen)1172 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1173 unsigned int areqlen)
1174 {
1175 struct af_alg_ctx *ctx = alg_sk(sk)->private;
1176 struct af_alg_async_req *areq;
1177
1178 /* Only one AIO request can be in flight. */
1179 if (ctx->inflight)
1180 return ERR_PTR(-EBUSY);
1181
1182 areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1183 if (unlikely(!areq))
1184 return ERR_PTR(-ENOMEM);
1185
1186 memset(areq, 0, areqlen);
1187
1188 ctx->inflight = true;
1189
1190 areq->areqlen = areqlen;
1191 areq->sk = sk;
1192 areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl;
1193 INIT_LIST_HEAD(&areq->rsgl_list);
1194
1195 return areq;
1196 }
1197 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1198
1199 /**
1200 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1201 * operation
1202 *
1203 * @sk: socket of connection to user space
1204 * @msg: user space message
1205 * @flags: flags used to invoke recvmsg with
1206 * @areq: instance of the cryptographic request that will hold the RX SGL
1207 * @maxsize: maximum number of bytes to be pulled from user space
1208 * @outlen: number of bytes in the RX SGL
1209 * Return: 0 on success, < 0 upon error
1210 */
af_alg_get_rsgl(struct sock * sk,struct msghdr * msg,int flags,struct af_alg_async_req * areq,size_t maxsize,size_t * outlen)1211 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1212 struct af_alg_async_req *areq, size_t maxsize,
1213 size_t *outlen)
1214 {
1215 struct alg_sock *ask = alg_sk(sk);
1216 struct af_alg_ctx *ctx = ask->private;
1217 size_t len = 0;
1218
1219 while (maxsize > len && msg_data_left(msg)) {
1220 struct af_alg_rsgl *rsgl;
1221 ssize_t err;
1222 size_t seglen;
1223
1224 /* limit the amount of readable buffers */
1225 if (!af_alg_readable(sk))
1226 break;
1227
1228 seglen = min_t(size_t, (maxsize - len),
1229 msg_data_left(msg));
1230 /* Never pin more pages than the remaining RX accounting budget. */
1231 seglen = min_t(size_t, seglen, af_alg_rcvbuf(sk));
1232
1233 if (list_empty(&areq->rsgl_list)) {
1234 rsgl = &areq->first_rsgl;
1235 } else {
1236 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1237 if (unlikely(!rsgl))
1238 return -ENOMEM;
1239 }
1240
1241 rsgl->sgl.need_unpin =
1242 iov_iter_extract_will_pin(&msg->msg_iter);
1243 rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
1244 rsgl->sgl.sgt.nents = 0;
1245 rsgl->sgl.sgt.orig_nents = 0;
1246 list_add_tail(&rsgl->list, &areq->rsgl_list);
1247
1248 sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
1249 err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
1250 ALG_MAX_PAGES, 0);
1251 if (err < 0) {
1252 rsgl->sg_num_bytes = 0;
1253 return err;
1254 }
1255
1256 sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
1257
1258 /* chain the new scatterlist with previous one */
1259 if (areq->last_rsgl)
1260 af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1261
1262 areq->last_rsgl = rsgl;
1263 len += err;
1264 atomic_add(err, &ctx->rcvused);
1265 rsgl->sg_num_bytes = err;
1266 }
1267
1268 *outlen = len;
1269 return 0;
1270 }
1271 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1272
af_alg_init(void)1273 static int __init af_alg_init(void)
1274 {
1275 int err = proto_register(&alg_proto, 0);
1276
1277 if (err)
1278 goto out;
1279
1280 err = sock_register(&alg_family);
1281 if (err != 0)
1282 goto out_unregister_proto;
1283
1284 out:
1285 return err;
1286
1287 out_unregister_proto:
1288 proto_unregister(&alg_proto);
1289 goto out;
1290 }
1291
af_alg_exit(void)1292 static void __exit af_alg_exit(void)
1293 {
1294 sock_unregister(PF_ALG);
1295 proto_unregister(&alg_proto);
1296 }
1297
1298 module_init(af_alg_init);
1299 module_exit(af_alg_exit);
1300 MODULE_DESCRIPTION("Crypto userspace interface");
1301 MODULE_LICENSE("GPL");
1302 MODULE_ALIAS_NETPROTO(AF_ALG);
1303