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
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
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(sizeof(*node), GFP_KERNEL);
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
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
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
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
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
148 static int alg_bind(struct socket *sock, struct sockaddr *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
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
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
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
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
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
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_kmalloc(&ask->sk, key_datalen, GFP_KERNEL);
328 if (!key_data) {
329 up_read(&key->sem);
330 key_put(key);
331 return -ENOMEM;
332 }
333
334 memcpy(key_data, ret, key_datalen);
335
336 up_read(&key->sem);
337 key_put(key);
338
339 err = type->setkey(ask->private, key_data, key_datalen);
340
341 sock_kzfree_s(&ask->sk, key_data, key_datalen);
342
343 return err;
344 }
345
346 #else
347
348 static inline int alg_setkey_by_key_serial(struct alg_sock *ask,
349 sockptr_t optval,
350 unsigned int optlen)
351 {
352 return -ENOPROTOOPT;
353 }
354
355 #endif
356
357 static int alg_setsockopt(struct socket *sock, int level, int optname,
358 sockptr_t optval, unsigned int optlen)
359 {
360 struct sock *sk = sock->sk;
361 struct alg_sock *ask = alg_sk(sk);
362 const struct af_alg_type *type;
363 int err = -EBUSY;
364
365 lock_sock(sk);
366 if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
367 goto unlock;
368
369 type = ask->type;
370
371 err = -ENOPROTOOPT;
372 if (level != SOL_ALG || !type)
373 goto unlock;
374
375 switch (optname) {
376 case ALG_SET_KEY:
377 case ALG_SET_KEY_BY_KEY_SERIAL:
378 if (sock->state == SS_CONNECTED)
379 goto unlock;
380 if (!type->setkey)
381 goto unlock;
382
383 if (optname == ALG_SET_KEY_BY_KEY_SERIAL)
384 err = alg_setkey_by_key_serial(ask, optval, optlen);
385 else
386 err = alg_setkey(sk, optval, optlen);
387 break;
388 case ALG_SET_AEAD_AUTHSIZE:
389 if (sock->state == SS_CONNECTED)
390 goto unlock;
391 if (!type->setauthsize)
392 goto unlock;
393 err = type->setauthsize(ask->private, optlen);
394 break;
395 case ALG_SET_DRBG_ENTROPY:
396 if (sock->state == SS_CONNECTED)
397 goto unlock;
398 if (!type->setentropy)
399 goto unlock;
400
401 err = type->setentropy(ask->private, optval, optlen);
402 }
403
404 unlock:
405 release_sock(sk);
406
407 return err;
408 }
409
410 int af_alg_accept(struct sock *sk, struct socket *newsock,
411 struct proto_accept_arg *arg)
412 {
413 struct alg_sock *ask = alg_sk(sk);
414 const struct af_alg_type *type;
415 struct sock *sk2;
416 unsigned int nokey;
417 int err;
418
419 lock_sock(sk);
420 type = ask->type;
421
422 err = -EINVAL;
423 if (!type)
424 goto unlock;
425
426 sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, arg->kern);
427 err = -ENOMEM;
428 if (!sk2)
429 goto unlock;
430
431 sock_init_data(newsock, sk2);
432 security_sock_graft(sk2, newsock);
433 security_sk_clone(sk, sk2);
434
435 /*
436 * newsock->ops assigned here to allow type->accept call to override
437 * them when required.
438 */
439 newsock->ops = type->ops;
440 err = type->accept(ask->private, sk2);
441
442 nokey = err == -ENOKEY;
443 if (nokey && type->accept_nokey)
444 err = type->accept_nokey(ask->private, sk2);
445
446 if (err)
447 goto unlock;
448
449 if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
450 sock_hold(sk);
451 if (nokey) {
452 atomic_inc(&ask->nokey_refcnt);
453 atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
454 }
455 alg_sk(sk2)->parent = sk;
456 alg_sk(sk2)->type = type;
457
458 newsock->state = SS_CONNECTED;
459
460 if (nokey)
461 newsock->ops = type->ops_nokey;
462
463 err = 0;
464
465 unlock:
466 release_sock(sk);
467
468 return err;
469 }
470 EXPORT_SYMBOL_GPL(af_alg_accept);
471
472 static int alg_accept(struct socket *sock, struct socket *newsock,
473 struct proto_accept_arg *arg)
474 {
475 return af_alg_accept(sock->sk, newsock, arg);
476 }
477
478 static const struct proto_ops alg_proto_ops = {
479 .family = PF_ALG,
480 .owner = THIS_MODULE,
481
482 .connect = sock_no_connect,
483 .socketpair = sock_no_socketpair,
484 .getname = sock_no_getname,
485 .ioctl = sock_no_ioctl,
486 .listen = sock_no_listen,
487 .shutdown = sock_no_shutdown,
488 .mmap = sock_no_mmap,
489 .sendmsg = sock_no_sendmsg,
490 .recvmsg = sock_no_recvmsg,
491
492 .bind = alg_bind,
493 .release = af_alg_release,
494 .setsockopt = alg_setsockopt,
495 .accept = alg_accept,
496 };
497
498 static void alg_sock_destruct(struct sock *sk)
499 {
500 struct alg_sock *ask = alg_sk(sk);
501
502 alg_do_release(ask->type, ask->private);
503 }
504
505 static int alg_create(struct net *net, struct socket *sock, int protocol,
506 int kern)
507 {
508 struct sock *sk;
509 int err;
510
511 if (sock->type != SOCK_SEQPACKET)
512 return -ESOCKTNOSUPPORT;
513 if (protocol != 0)
514 return -EPROTONOSUPPORT;
515
516 err = -ENOMEM;
517 sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
518 if (!sk)
519 goto out;
520
521 sock->ops = &alg_proto_ops;
522 sock_init_data(sock, sk);
523
524 sk->sk_destruct = alg_sock_destruct;
525
526 return 0;
527 out:
528 return err;
529 }
530
531 static const struct net_proto_family alg_family = {
532 .family = PF_ALG,
533 .create = alg_create,
534 .owner = THIS_MODULE,
535 };
536
537 static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
538 struct af_alg_sgl *sgl_new)
539 {
540 sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
541 sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
542 }
543
544 void af_alg_free_sg(struct af_alg_sgl *sgl)
545 {
546 int i;
547
548 if (sgl->sgt.sgl) {
549 if (sgl->need_unpin)
550 for (i = 0; i < sgl->sgt.nents; i++)
551 unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
552 if (sgl->sgt.sgl != sgl->sgl)
553 kvfree(sgl->sgt.sgl);
554 sgl->sgt.sgl = NULL;
555 }
556 }
557 EXPORT_SYMBOL_GPL(af_alg_free_sg);
558
559 static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
560 {
561 struct cmsghdr *cmsg;
562
563 for_each_cmsghdr(cmsg, msg) {
564 if (!CMSG_OK(msg, cmsg))
565 return -EINVAL;
566 if (cmsg->cmsg_level != SOL_ALG)
567 continue;
568
569 switch (cmsg->cmsg_type) {
570 case ALG_SET_IV:
571 if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
572 return -EINVAL;
573 con->iv = (void *)CMSG_DATA(cmsg);
574 if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
575 sizeof(*con->iv)))
576 return -EINVAL;
577 break;
578
579 case ALG_SET_OP:
580 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
581 return -EINVAL;
582 con->op = *(u32 *)CMSG_DATA(cmsg);
583 break;
584
585 case ALG_SET_AEAD_ASSOCLEN:
586 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
587 return -EINVAL;
588 con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
589 break;
590
591 default:
592 return -EINVAL;
593 }
594 }
595
596 return 0;
597 }
598
599 /**
600 * af_alg_alloc_tsgl - allocate the TX SGL
601 *
602 * @sk: socket of connection to user space
603 * Return: 0 upon success, < 0 upon error
604 */
605 static int af_alg_alloc_tsgl(struct sock *sk)
606 {
607 struct alg_sock *ask = alg_sk(sk);
608 struct af_alg_ctx *ctx = ask->private;
609 struct af_alg_tsgl *sgl;
610 struct scatterlist *sg = NULL;
611
612 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
613 if (!list_empty(&ctx->tsgl_list))
614 sg = sgl->sg;
615
616 if (!sg || sgl->cur >= MAX_SGL_ENTS) {
617 sgl = sock_kmalloc(sk,
618 struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
619 GFP_KERNEL);
620 if (!sgl)
621 return -ENOMEM;
622
623 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
624 sgl->cur = 0;
625
626 if (sg)
627 sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
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. If
639 * an @offset is provided, the counting of the SG entries starts at the @offset.
640 *
641 * @sk: socket of connection to user space
642 * @bytes: Count the number of SG entries holding given number of bytes.
643 * @offset: Start the counting of SG entries from the given offset.
644 * Return: Number of TX SG entries found given the constraints
645 */
646 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
647 {
648 const struct alg_sock *ask = alg_sk(sk);
649 const struct af_alg_ctx *ctx = ask->private;
650 const struct af_alg_tsgl *sgl;
651 unsigned int i;
652 unsigned int sgl_count = 0;
653
654 if (!bytes)
655 return 0;
656
657 list_for_each_entry(sgl, &ctx->tsgl_list, list) {
658 const struct scatterlist *sg = sgl->sg;
659
660 for (i = 0; i < sgl->cur; i++) {
661 size_t bytes_count;
662
663 /* Skip offset */
664 if (offset >= sg[i].length) {
665 offset -= sg[i].length;
666 bytes -= sg[i].length;
667 continue;
668 }
669
670 bytes_count = sg[i].length - offset;
671
672 offset = 0;
673 sgl_count++;
674
675 /* If we have seen requested number of bytes, stop */
676 if (bytes_count >= bytes)
677 return sgl_count;
678
679 bytes -= bytes_count;
680 }
681 }
682
683 return sgl_count;
684 }
685 EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
686
687 /**
688 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
689 *
690 * If @dst is non-null, reassign the pages to @dst. The caller must release
691 * the pages. If @dst_offset is given only reassign the pages to @dst starting
692 * at the @dst_offset (byte). The caller must ensure that @dst is large
693 * enough (e.g. by using af_alg_count_tsgl with the same offset).
694 *
695 * @sk: socket of connection to user space
696 * @used: Number of bytes to pull from TX SGL
697 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
698 * caller must release the buffers in dst.
699 * @dst_offset: Reassign the TX SGL from given offset. All buffers before
700 * reaching the offset is released.
701 */
702 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
703 size_t dst_offset)
704 {
705 struct alg_sock *ask = alg_sk(sk);
706 struct af_alg_ctx *ctx = ask->private;
707 struct af_alg_tsgl *sgl;
708 struct scatterlist *sg;
709 unsigned int i, j = 0;
710
711 while (!list_empty(&ctx->tsgl_list)) {
712 sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
713 list);
714 sg = sgl->sg;
715
716 for (i = 0; i < sgl->cur; i++) {
717 size_t plen = min_t(size_t, used, sg[i].length);
718 struct page *page = sg_page(sg + i);
719
720 if (!page)
721 continue;
722
723 /*
724 * Assumption: caller created af_alg_count_tsgl(len)
725 * SG entries in dst.
726 */
727 if (dst) {
728 if (dst_offset >= plen) {
729 /* discard page before offset */
730 dst_offset -= plen;
731 } else {
732 /* reassign page to dst after offset */
733 get_page(page);
734 sg_set_page(dst + j, page,
735 plen - dst_offset,
736 sg[i].offset + dst_offset);
737 dst_offset = 0;
738 j++;
739 }
740 }
741
742 sg[i].length -= plen;
743 sg[i].offset += plen;
744
745 used -= plen;
746 ctx->used -= plen;
747
748 if (sg[i].length)
749 return;
750
751 put_page(page);
752 sg_assign_page(sg + i, NULL);
753 }
754
755 list_del(&sgl->list);
756 sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
757 }
758
759 if (!ctx->used)
760 ctx->merge = 0;
761 ctx->init = ctx->more;
762 }
763 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
764
765 /**
766 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
767 *
768 * @areq: Request holding the TX and RX SGL
769 */
770 static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
771 {
772 struct sock *sk = areq->sk;
773 struct alg_sock *ask = alg_sk(sk);
774 struct af_alg_ctx *ctx = ask->private;
775 struct af_alg_rsgl *rsgl, *tmp;
776 struct scatterlist *tsgl;
777 struct scatterlist *sg;
778 unsigned int i;
779
780 list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
781 atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
782 af_alg_free_sg(&rsgl->sgl);
783 list_del(&rsgl->list);
784 if (rsgl != &areq->first_rsgl)
785 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
786 }
787
788 tsgl = areq->tsgl;
789 if (tsgl) {
790 for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
791 if (!sg_page(sg))
792 continue;
793 put_page(sg_page(sg));
794 }
795
796 sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
797 }
798 }
799
800 /**
801 * af_alg_wait_for_wmem - wait for availability of writable memory
802 *
803 * @sk: socket of connection to user space
804 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
805 * Return: 0 when writable memory is available, < 0 upon error
806 */
807 static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
808 {
809 DEFINE_WAIT_FUNC(wait, woken_wake_function);
810 int err = -ERESTARTSYS;
811 long timeout;
812
813 if (flags & MSG_DONTWAIT)
814 return -EAGAIN;
815
816 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
817
818 add_wait_queue(sk_sleep(sk), &wait);
819 for (;;) {
820 if (signal_pending(current))
821 break;
822 timeout = MAX_SCHEDULE_TIMEOUT;
823 if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
824 err = 0;
825 break;
826 }
827 }
828 remove_wait_queue(sk_sleep(sk), &wait);
829
830 return err;
831 }
832
833 /**
834 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
835 *
836 * @sk: socket of connection to user space
837 */
838 void af_alg_wmem_wakeup(struct sock *sk)
839 {
840 struct socket_wq *wq;
841
842 if (!af_alg_writable(sk))
843 return;
844
845 rcu_read_lock();
846 wq = rcu_dereference(sk->sk_wq);
847 if (skwq_has_sleeper(wq))
848 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
849 EPOLLRDNORM |
850 EPOLLRDBAND);
851 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN);
852 rcu_read_unlock();
853 }
854 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
855
856 /**
857 * af_alg_wait_for_data - wait for availability of TX data
858 *
859 * @sk: socket of connection to user space
860 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
861 * @min: Set to minimum request size if partial requests are allowed.
862 * Return: 0 when writable memory is available, < 0 upon error
863 */
864 int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
865 {
866 DEFINE_WAIT_FUNC(wait, woken_wake_function);
867 struct alg_sock *ask = alg_sk(sk);
868 struct af_alg_ctx *ctx = ask->private;
869 long timeout;
870 int err = -ERESTARTSYS;
871
872 if (flags & MSG_DONTWAIT)
873 return -EAGAIN;
874
875 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
876
877 add_wait_queue(sk_sleep(sk), &wait);
878 for (;;) {
879 if (signal_pending(current))
880 break;
881 timeout = MAX_SCHEDULE_TIMEOUT;
882 if (sk_wait_event(sk, &timeout,
883 ctx->init && (!ctx->more ||
884 (min && ctx->used >= min)),
885 &wait)) {
886 err = 0;
887 break;
888 }
889 }
890 remove_wait_queue(sk_sleep(sk), &wait);
891
892 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
893
894 return err;
895 }
896 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
897
898 /**
899 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
900 *
901 * @sk: socket of connection to user space
902 */
903 static void af_alg_data_wakeup(struct sock *sk)
904 {
905 struct alg_sock *ask = alg_sk(sk);
906 struct af_alg_ctx *ctx = ask->private;
907 struct socket_wq *wq;
908
909 if (!ctx->used)
910 return;
911
912 rcu_read_lock();
913 wq = rcu_dereference(sk->sk_wq);
914 if (skwq_has_sleeper(wq))
915 wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
916 EPOLLRDNORM |
917 EPOLLRDBAND);
918 sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT);
919 rcu_read_unlock();
920 }
921
922 /**
923 * af_alg_sendmsg - implementation of sendmsg system call handler
924 *
925 * The sendmsg system call handler obtains the user data and stores it
926 * in ctx->tsgl_list. This implies allocation of the required numbers of
927 * struct af_alg_tsgl.
928 *
929 * In addition, the ctx is filled with the information sent via CMSG.
930 *
931 * @sock: socket of connection to user space
932 * @msg: message from user space
933 * @size: size of message from user space
934 * @ivsize: the size of the IV for the cipher operation to verify that the
935 * user-space-provided IV has the right size
936 * Return: the number of copied data upon success, < 0 upon error
937 */
938 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
939 unsigned int ivsize)
940 {
941 struct sock *sk = sock->sk;
942 struct alg_sock *ask = alg_sk(sk);
943 struct af_alg_ctx *ctx = ask->private;
944 struct af_alg_tsgl *sgl;
945 struct af_alg_control con = {};
946 long copied = 0;
947 bool enc = false;
948 bool init = false;
949 int err = 0;
950
951 if (msg->msg_controllen) {
952 err = af_alg_cmsg_send(msg, &con);
953 if (err)
954 return err;
955
956 init = true;
957 switch (con.op) {
958 case ALG_OP_ENCRYPT:
959 enc = true;
960 break;
961 case ALG_OP_DECRYPT:
962 enc = false;
963 break;
964 default:
965 return -EINVAL;
966 }
967
968 if (con.iv && con.iv->ivlen != ivsize)
969 return -EINVAL;
970 }
971
972 lock_sock(sk);
973 if (ctx->init && !ctx->more) {
974 if (ctx->used) {
975 err = -EINVAL;
976 goto unlock;
977 }
978
979 pr_info_once(
980 "%s sent an empty control message without MSG_MORE.\n",
981 current->comm);
982 }
983 ctx->init = true;
984
985 if (init) {
986 ctx->enc = enc;
987 if (con.iv)
988 memcpy(ctx->iv, con.iv->iv, ivsize);
989
990 ctx->aead_assoclen = con.aead_assoclen;
991 }
992
993 while (size) {
994 struct scatterlist *sg;
995 size_t len = size;
996 ssize_t plen;
997
998 /* use the existing memory in an allocated page */
999 if (ctx->merge && !(msg->msg_flags & MSG_SPLICE_PAGES)) {
1000 sgl = list_entry(ctx->tsgl_list.prev,
1001 struct af_alg_tsgl, list);
1002 sg = sgl->sg + sgl->cur - 1;
1003 len = min_t(size_t, len,
1004 PAGE_SIZE - sg->offset - sg->length);
1005
1006 err = memcpy_from_msg(page_address(sg_page(sg)) +
1007 sg->offset + sg->length,
1008 msg, len);
1009 if (err)
1010 goto unlock;
1011
1012 sg->length += len;
1013 ctx->merge = (sg->offset + sg->length) &
1014 (PAGE_SIZE - 1);
1015
1016 ctx->used += len;
1017 copied += len;
1018 size -= len;
1019 continue;
1020 }
1021
1022 if (!af_alg_writable(sk)) {
1023 err = af_alg_wait_for_wmem(sk, msg->msg_flags);
1024 if (err)
1025 goto unlock;
1026 }
1027
1028 /* allocate a new page */
1029 len = min_t(unsigned long, len, af_alg_sndbuf(sk));
1030
1031 err = af_alg_alloc_tsgl(sk);
1032 if (err)
1033 goto unlock;
1034
1035 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
1036 list);
1037 sg = sgl->sg;
1038 if (sgl->cur)
1039 sg_unmark_end(sg + sgl->cur - 1);
1040
1041 if (msg->msg_flags & MSG_SPLICE_PAGES) {
1042 struct sg_table sgtable = {
1043 .sgl = sg,
1044 .nents = sgl->cur,
1045 .orig_nents = sgl->cur,
1046 };
1047
1048 plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable,
1049 MAX_SGL_ENTS - sgl->cur, 0);
1050 if (plen < 0) {
1051 err = plen;
1052 goto unlock;
1053 }
1054
1055 for (; sgl->cur < sgtable.nents; sgl->cur++)
1056 get_page(sg_page(&sg[sgl->cur]));
1057 len -= plen;
1058 ctx->used += plen;
1059 copied += plen;
1060 size -= plen;
1061 ctx->merge = 0;
1062 } else {
1063 do {
1064 struct page *pg;
1065 unsigned int i = sgl->cur;
1066
1067 plen = min_t(size_t, len, PAGE_SIZE);
1068
1069 pg = alloc_page(GFP_KERNEL);
1070 if (!pg) {
1071 err = -ENOMEM;
1072 goto unlock;
1073 }
1074
1075 sg_assign_page(sg + i, pg);
1076
1077 err = memcpy_from_msg(
1078 page_address(sg_page(sg + i)),
1079 msg, plen);
1080 if (err) {
1081 __free_page(sg_page(sg + i));
1082 sg_assign_page(sg + i, NULL);
1083 goto unlock;
1084 }
1085
1086 sg[i].length = plen;
1087 len -= plen;
1088 ctx->used += plen;
1089 copied += plen;
1090 size -= plen;
1091 sgl->cur++;
1092 } while (len && sgl->cur < MAX_SGL_ENTS);
1093
1094 ctx->merge = plen & (PAGE_SIZE - 1);
1095 }
1096
1097 if (!size)
1098 sg_mark_end(sg + sgl->cur - 1);
1099 }
1100
1101 err = 0;
1102
1103 ctx->more = msg->msg_flags & MSG_MORE;
1104
1105 unlock:
1106 af_alg_data_wakeup(sk);
1107 release_sock(sk);
1108
1109 return copied ?: err;
1110 }
1111 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
1112
1113 /**
1114 * af_alg_free_resources - release resources required for crypto request
1115 * @areq: Request holding the TX and RX SGL
1116 */
1117 void af_alg_free_resources(struct af_alg_async_req *areq)
1118 {
1119 struct sock *sk = areq->sk;
1120 struct af_alg_ctx *ctx;
1121
1122 af_alg_free_areq_sgls(areq);
1123 sock_kfree_s(sk, areq, areq->areqlen);
1124
1125 ctx = alg_sk(sk)->private;
1126 ctx->inflight = false;
1127 }
1128 EXPORT_SYMBOL_GPL(af_alg_free_resources);
1129
1130 /**
1131 * af_alg_async_cb - AIO callback handler
1132 * @data: async request completion data
1133 * @err: if non-zero, error result to be returned via ki_complete();
1134 * otherwise return the AIO output length via ki_complete().
1135 *
1136 * This handler cleans up the struct af_alg_async_req upon completion of the
1137 * AIO operation.
1138 *
1139 * The number of bytes to be generated with the AIO operation must be set
1140 * in areq->outlen before the AIO callback handler is invoked.
1141 */
1142 void af_alg_async_cb(void *data, int err)
1143 {
1144 struct af_alg_async_req *areq = data;
1145 struct sock *sk = areq->sk;
1146 struct kiocb *iocb = areq->iocb;
1147 unsigned int resultlen;
1148
1149 /* Buffer size written by crypto operation. */
1150 resultlen = areq->outlen;
1151
1152 af_alg_free_resources(areq);
1153 sock_put(sk);
1154
1155 iocb->ki_complete(iocb, err ? err : (int)resultlen);
1156 }
1157 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1158
1159 /**
1160 * af_alg_poll - poll system call handler
1161 * @file: file pointer
1162 * @sock: socket to poll
1163 * @wait: poll_table
1164 */
1165 __poll_t af_alg_poll(struct file *file, struct socket *sock,
1166 poll_table *wait)
1167 {
1168 struct sock *sk = sock->sk;
1169 struct alg_sock *ask = alg_sk(sk);
1170 struct af_alg_ctx *ctx = ask->private;
1171 __poll_t mask;
1172
1173 sock_poll_wait(file, sock, wait);
1174 mask = 0;
1175
1176 if (!ctx->more || ctx->used)
1177 mask |= EPOLLIN | EPOLLRDNORM;
1178
1179 if (af_alg_writable(sk))
1180 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1181
1182 return mask;
1183 }
1184 EXPORT_SYMBOL_GPL(af_alg_poll);
1185
1186 /**
1187 * af_alg_alloc_areq - allocate struct af_alg_async_req
1188 *
1189 * @sk: socket of connection to user space
1190 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1191 * Return: allocated data structure or ERR_PTR upon error
1192 */
1193 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1194 unsigned int areqlen)
1195 {
1196 struct af_alg_ctx *ctx = alg_sk(sk)->private;
1197 struct af_alg_async_req *areq;
1198
1199 /* Only one AIO request can be in flight. */
1200 if (ctx->inflight)
1201 return ERR_PTR(-EBUSY);
1202
1203 areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1204 if (unlikely(!areq))
1205 return ERR_PTR(-ENOMEM);
1206
1207 ctx->inflight = true;
1208
1209 areq->areqlen = areqlen;
1210 areq->sk = sk;
1211 areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl;
1212 areq->last_rsgl = NULL;
1213 INIT_LIST_HEAD(&areq->rsgl_list);
1214 areq->tsgl = NULL;
1215 areq->tsgl_entries = 0;
1216
1217 return areq;
1218 }
1219 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1220
1221 /**
1222 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1223 * operation
1224 *
1225 * @sk: socket of connection to user space
1226 * @msg: user space message
1227 * @flags: flags used to invoke recvmsg with
1228 * @areq: instance of the cryptographic request that will hold the RX SGL
1229 * @maxsize: maximum number of bytes to be pulled from user space
1230 * @outlen: number of bytes in the RX SGL
1231 * Return: 0 on success, < 0 upon error
1232 */
1233 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1234 struct af_alg_async_req *areq, size_t maxsize,
1235 size_t *outlen)
1236 {
1237 struct alg_sock *ask = alg_sk(sk);
1238 struct af_alg_ctx *ctx = ask->private;
1239 size_t len = 0;
1240
1241 while (maxsize > len && msg_data_left(msg)) {
1242 struct af_alg_rsgl *rsgl;
1243 ssize_t err;
1244 size_t seglen;
1245
1246 /* limit the amount of readable buffers */
1247 if (!af_alg_readable(sk))
1248 break;
1249
1250 seglen = min_t(size_t, (maxsize - len),
1251 msg_data_left(msg));
1252
1253 if (list_empty(&areq->rsgl_list)) {
1254 rsgl = &areq->first_rsgl;
1255 } else {
1256 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1257 if (unlikely(!rsgl))
1258 return -ENOMEM;
1259 }
1260
1261 rsgl->sgl.need_unpin =
1262 iov_iter_extract_will_pin(&msg->msg_iter);
1263 rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
1264 rsgl->sgl.sgt.nents = 0;
1265 rsgl->sgl.sgt.orig_nents = 0;
1266 list_add_tail(&rsgl->list, &areq->rsgl_list);
1267
1268 sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
1269 err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
1270 ALG_MAX_PAGES, 0);
1271 if (err < 0) {
1272 rsgl->sg_num_bytes = 0;
1273 return err;
1274 }
1275
1276 sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
1277
1278 /* chain the new scatterlist with previous one */
1279 if (areq->last_rsgl)
1280 af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1281
1282 areq->last_rsgl = rsgl;
1283 len += err;
1284 atomic_add(err, &ctx->rcvused);
1285 rsgl->sg_num_bytes = err;
1286 }
1287
1288 *outlen = len;
1289 return 0;
1290 }
1291 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1292
1293 static int __init af_alg_init(void)
1294 {
1295 int err = proto_register(&alg_proto, 0);
1296
1297 if (err)
1298 goto out;
1299
1300 err = sock_register(&alg_family);
1301 if (err != 0)
1302 goto out_unregister_proto;
1303
1304 out:
1305 return err;
1306
1307 out_unregister_proto:
1308 proto_unregister(&alg_proto);
1309 goto out;
1310 }
1311
1312 static void __exit af_alg_exit(void)
1313 {
1314 sock_unregister(PF_ALG);
1315 proto_unregister(&alg_proto);
1316 }
1317
1318 module_init(af_alg_init);
1319 module_exit(af_alg_exit);
1320 MODULE_DESCRIPTION("Crypto userspace interface");
1321 MODULE_LICENSE("GPL");
1322 MODULE_ALIAS_NETPROTO(AF_ALG);
1323
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.