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TOMOYO Linux Cross Reference
Linux/crypto/af_alg.c

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  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/list.h>
 16 #include <linux/module.h>
 17 #include <linux/net.h>
 18 #include <linux/rwsem.h>
 19 #include <linux/sched/signal.h>
 20 #include <linux/security.h>
 21 
 22 struct alg_type_list {
 23         const struct af_alg_type *type;
 24         struct list_head list;
 25 };
 26 
 27 static atomic_long_t alg_memory_allocated;
 28 
 29 static struct proto alg_proto = {
 30         .name                   = "ALG",
 31         .owner                  = THIS_MODULE,
 32         .memory_allocated       = &alg_memory_allocated,
 33         .obj_size               = sizeof(struct alg_sock),
 34 };
 35 
 36 static LIST_HEAD(alg_types);
 37 static DECLARE_RWSEM(alg_types_sem);
 38 
 39 static const struct af_alg_type *alg_get_type(const char *name)
 40 {
 41         const struct af_alg_type *type = ERR_PTR(-ENOENT);
 42         struct alg_type_list *node;
 43 
 44         down_read(&alg_types_sem);
 45         list_for_each_entry(node, &alg_types, list) {
 46                 if (strcmp(node->type->name, name))
 47                         continue;
 48 
 49                 if (try_module_get(node->type->owner))
 50                         type = node->type;
 51                 break;
 52         }
 53         up_read(&alg_types_sem);
 54 
 55         return type;
 56 }
 57 
 58 int af_alg_register_type(const struct af_alg_type *type)
 59 {
 60         struct alg_type_list *node;
 61         int err = -EEXIST;
 62 
 63         down_write(&alg_types_sem);
 64         list_for_each_entry(node, &alg_types, list) {
 65                 if (!strcmp(node->type->name, type->name))
 66                         goto unlock;
 67         }
 68 
 69         node = kmalloc(sizeof(*node), GFP_KERNEL);
 70         err = -ENOMEM;
 71         if (!node)
 72                 goto unlock;
 73 
 74         type->ops->owner = THIS_MODULE;
 75         if (type->ops_nokey)
 76                 type->ops_nokey->owner = THIS_MODULE;
 77         node->type = type;
 78         list_add(&node->list, &alg_types);
 79         err = 0;
 80 
 81 unlock:
 82         up_write(&alg_types_sem);
 83 
 84         return err;
 85 }
 86 EXPORT_SYMBOL_GPL(af_alg_register_type);
 87 
 88 int af_alg_unregister_type(const struct af_alg_type *type)
 89 {
 90         struct alg_type_list *node;
 91         int err = -ENOENT;
 92 
 93         down_write(&alg_types_sem);
 94         list_for_each_entry(node, &alg_types, list) {
 95                 if (strcmp(node->type->name, type->name))
 96                         continue;
 97 
 98                 list_del(&node->list);
 99                 kfree(node);
100                 err = 0;
101                 break;
102         }
103         up_write(&alg_types_sem);
104 
105         return err;
106 }
107 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
108 
109 static void alg_do_release(const struct af_alg_type *type, void *private)
110 {
111         if (!type)
112                 return;
113 
114         type->release(private);
115         module_put(type->owner);
116 }
117 
118 int af_alg_release(struct socket *sock)
119 {
120         if (sock->sk) {
121                 sock_put(sock->sk);
122                 sock->sk = NULL;
123         }
124         return 0;
125 }
126 EXPORT_SYMBOL_GPL(af_alg_release);
127 
128 void af_alg_release_parent(struct sock *sk)
129 {
130         struct alg_sock *ask = alg_sk(sk);
131         unsigned int nokey = ask->nokey_refcnt;
132         bool last = nokey && !ask->refcnt;
133 
134         sk = ask->parent;
135         ask = alg_sk(sk);
136 
137         lock_sock(sk);
138         ask->nokey_refcnt -= nokey;
139         if (!last)
140                 last = !--ask->refcnt;
141         release_sock(sk);
142 
143         if (last)
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 *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         if (addr_len < sizeof(*sa))
162                 return -EINVAL;
163 
164         /* If caller uses non-allowed flag, return error. */
165         if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
166                 return -EINVAL;
167 
168         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
169         sa->salg_name[sizeof(sa->salg_name) + addr_len - sizeof(*sa) - 1] = 0;
170 
171         type = alg_get_type(sa->salg_type);
172         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
173                 request_module("algif-%s", sa->salg_type);
174                 type = alg_get_type(sa->salg_type);
175         }
176 
177         if (IS_ERR(type))
178                 return PTR_ERR(type);
179 
180         private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
181         if (IS_ERR(private)) {
182                 module_put(type->owner);
183                 return PTR_ERR(private);
184         }
185 
186         err = -EBUSY;
187         lock_sock(sk);
188         if (ask->refcnt | ask->nokey_refcnt)
189                 goto unlock;
190 
191         swap(ask->type, type);
192         swap(ask->private, private);
193 
194         err = 0;
195 
196 unlock:
197         release_sock(sk);
198 
199         alg_do_release(type, private);
200 
201         return err;
202 }
203 
204 static int alg_setkey(struct sock *sk, char __user *ukey,
205                       unsigned int keylen)
206 {
207         struct alg_sock *ask = alg_sk(sk);
208         const struct af_alg_type *type = ask->type;
209         u8 *key;
210         int err;
211 
212         key = sock_kmalloc(sk, keylen, GFP_KERNEL);
213         if (!key)
214                 return -ENOMEM;
215 
216         err = -EFAULT;
217         if (copy_from_user(key, ukey, keylen))
218                 goto out;
219 
220         err = type->setkey(ask->private, key, keylen);
221 
222 out:
223         sock_kzfree_s(sk, key, keylen);
224 
225         return err;
226 }
227 
228 static int alg_setsockopt(struct socket *sock, int level, int optname,
229                           char __user *optval, unsigned int optlen)
230 {
231         struct sock *sk = sock->sk;
232         struct alg_sock *ask = alg_sk(sk);
233         const struct af_alg_type *type;
234         int err = -EBUSY;
235 
236         lock_sock(sk);
237         if (ask->refcnt)
238                 goto unlock;
239 
240         type = ask->type;
241 
242         err = -ENOPROTOOPT;
243         if (level != SOL_ALG || !type)
244                 goto unlock;
245 
246         switch (optname) {
247         case ALG_SET_KEY:
248                 if (sock->state == SS_CONNECTED)
249                         goto unlock;
250                 if (!type->setkey)
251                         goto unlock;
252 
253                 err = alg_setkey(sk, optval, optlen);
254                 break;
255         case ALG_SET_AEAD_AUTHSIZE:
256                 if (sock->state == SS_CONNECTED)
257                         goto unlock;
258                 if (!type->setauthsize)
259                         goto unlock;
260                 err = type->setauthsize(ask->private, optlen);
261         }
262 
263 unlock:
264         release_sock(sk);
265 
266         return err;
267 }
268 
269 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
270 {
271         struct alg_sock *ask = alg_sk(sk);
272         const struct af_alg_type *type;
273         struct sock *sk2;
274         unsigned int nokey;
275         int err;
276 
277         lock_sock(sk);
278         type = ask->type;
279 
280         err = -EINVAL;
281         if (!type)
282                 goto unlock;
283 
284         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
285         err = -ENOMEM;
286         if (!sk2)
287                 goto unlock;
288 
289         sock_init_data(newsock, sk2);
290         security_sock_graft(sk2, newsock);
291         security_sk_clone(sk, sk2);
292 
293         err = type->accept(ask->private, sk2);
294 
295         nokey = err == -ENOKEY;
296         if (nokey && type->accept_nokey)
297                 err = type->accept_nokey(ask->private, sk2);
298 
299         if (err)
300                 goto unlock;
301 
302         if (nokey || !ask->refcnt++)
303                 sock_hold(sk);
304         ask->nokey_refcnt += nokey;
305         alg_sk(sk2)->parent = sk;
306         alg_sk(sk2)->type = type;
307         alg_sk(sk2)->nokey_refcnt = nokey;
308 
309         newsock->ops = type->ops;
310         newsock->state = SS_CONNECTED;
311 
312         if (nokey)
313                 newsock->ops = type->ops_nokey;
314 
315         err = 0;
316 
317 unlock:
318         release_sock(sk);
319 
320         return err;
321 }
322 EXPORT_SYMBOL_GPL(af_alg_accept);
323 
324 static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
325                       bool kern)
326 {
327         return af_alg_accept(sock->sk, newsock, kern);
328 }
329 
330 static const struct proto_ops alg_proto_ops = {
331         .family         =       PF_ALG,
332         .owner          =       THIS_MODULE,
333 
334         .connect        =       sock_no_connect,
335         .socketpair     =       sock_no_socketpair,
336         .getname        =       sock_no_getname,
337         .ioctl          =       sock_no_ioctl,
338         .listen         =       sock_no_listen,
339         .shutdown       =       sock_no_shutdown,
340         .getsockopt     =       sock_no_getsockopt,
341         .mmap           =       sock_no_mmap,
342         .sendpage       =       sock_no_sendpage,
343         .sendmsg        =       sock_no_sendmsg,
344         .recvmsg        =       sock_no_recvmsg,
345 
346         .bind           =       alg_bind,
347         .release        =       af_alg_release,
348         .setsockopt     =       alg_setsockopt,
349         .accept         =       alg_accept,
350 };
351 
352 static void alg_sock_destruct(struct sock *sk)
353 {
354         struct alg_sock *ask = alg_sk(sk);
355 
356         alg_do_release(ask->type, ask->private);
357 }
358 
359 static int alg_create(struct net *net, struct socket *sock, int protocol,
360                       int kern)
361 {
362         struct sock *sk;
363         int err;
364 
365         if (sock->type != SOCK_SEQPACKET)
366                 return -ESOCKTNOSUPPORT;
367         if (protocol != 0)
368                 return -EPROTONOSUPPORT;
369 
370         err = -ENOMEM;
371         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
372         if (!sk)
373                 goto out;
374 
375         sock->ops = &alg_proto_ops;
376         sock_init_data(sock, sk);
377 
378         sk->sk_destruct = alg_sock_destruct;
379 
380         return 0;
381 out:
382         return err;
383 }
384 
385 static const struct net_proto_family alg_family = {
386         .family =       PF_ALG,
387         .create =       alg_create,
388         .owner  =       THIS_MODULE,
389 };
390 
391 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
392 {
393         size_t off;
394         ssize_t n;
395         int npages, i;
396 
397         n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
398         if (n < 0)
399                 return n;
400 
401         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
402         if (WARN_ON(npages == 0))
403                 return -EINVAL;
404         /* Add one extra for linking */
405         sg_init_table(sgl->sg, npages + 1);
406 
407         for (i = 0, len = n; i < npages; i++) {
408                 int plen = min_t(int, len, PAGE_SIZE - off);
409 
410                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
411 
412                 off = 0;
413                 len -= plen;
414         }
415         sg_mark_end(sgl->sg + npages - 1);
416         sgl->npages = npages;
417 
418         return n;
419 }
420 EXPORT_SYMBOL_GPL(af_alg_make_sg);
421 
422 static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
423                            struct af_alg_sgl *sgl_new)
424 {
425         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
426         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
427 }
428 
429 void af_alg_free_sg(struct af_alg_sgl *sgl)
430 {
431         int i;
432 
433         for (i = 0; i < sgl->npages; i++)
434                 put_page(sgl->pages[i]);
435 }
436 EXPORT_SYMBOL_GPL(af_alg_free_sg);
437 
438 static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
439 {
440         struct cmsghdr *cmsg;
441 
442         for_each_cmsghdr(cmsg, msg) {
443                 if (!CMSG_OK(msg, cmsg))
444                         return -EINVAL;
445                 if (cmsg->cmsg_level != SOL_ALG)
446                         continue;
447 
448                 switch (cmsg->cmsg_type) {
449                 case ALG_SET_IV:
450                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
451                                 return -EINVAL;
452                         con->iv = (void *)CMSG_DATA(cmsg);
453                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
454                                                       sizeof(*con->iv)))
455                                 return -EINVAL;
456                         break;
457 
458                 case ALG_SET_OP:
459                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
460                                 return -EINVAL;
461                         con->op = *(u32 *)CMSG_DATA(cmsg);
462                         break;
463 
464                 case ALG_SET_AEAD_ASSOCLEN:
465                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
466                                 return -EINVAL;
467                         con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
468                         break;
469 
470                 default:
471                         return -EINVAL;
472                 }
473         }
474 
475         return 0;
476 }
477 
478 /**
479  * af_alg_alloc_tsgl - allocate the TX SGL
480  *
481  * @sk socket of connection to user space
482  * @return: 0 upon success, < 0 upon error
483  */
484 static int af_alg_alloc_tsgl(struct sock *sk)
485 {
486         struct alg_sock *ask = alg_sk(sk);
487         struct af_alg_ctx *ctx = ask->private;
488         struct af_alg_tsgl *sgl;
489         struct scatterlist *sg = NULL;
490 
491         sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
492         if (!list_empty(&ctx->tsgl_list))
493                 sg = sgl->sg;
494 
495         if (!sg || sgl->cur >= MAX_SGL_ENTS) {
496                 sgl = sock_kmalloc(sk,
497                                    struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
498                                    GFP_KERNEL);
499                 if (!sgl)
500                         return -ENOMEM;
501 
502                 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
503                 sgl->cur = 0;
504 
505                 if (sg)
506                         sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
507 
508                 list_add_tail(&sgl->list, &ctx->tsgl_list);
509         }
510 
511         return 0;
512 }
513 
514 /**
515  * aead_count_tsgl - Count number of TX SG entries
516  *
517  * The counting starts from the beginning of the SGL to @bytes. If
518  * an offset is provided, the counting of the SG entries starts at the offset.
519  *
520  * @sk socket of connection to user space
521  * @bytes Count the number of SG entries holding given number of bytes.
522  * @offset Start the counting of SG entries from the given offset.
523  * @return Number of TX SG entries found given the constraints
524  */
525 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
526 {
527         const struct alg_sock *ask = alg_sk(sk);
528         const struct af_alg_ctx *ctx = ask->private;
529         const struct af_alg_tsgl *sgl;
530         unsigned int i;
531         unsigned int sgl_count = 0;
532 
533         if (!bytes)
534                 return 0;
535 
536         list_for_each_entry(sgl, &ctx->tsgl_list, list) {
537                 const struct scatterlist *sg = sgl->sg;
538 
539                 for (i = 0; i < sgl->cur; i++) {
540                         size_t bytes_count;
541 
542                         /* Skip offset */
543                         if (offset >= sg[i].length) {
544                                 offset -= sg[i].length;
545                                 bytes -= sg[i].length;
546                                 continue;
547                         }
548 
549                         bytes_count = sg[i].length - offset;
550 
551                         offset = 0;
552                         sgl_count++;
553 
554                         /* If we have seen requested number of bytes, stop */
555                         if (bytes_count >= bytes)
556                                 return sgl_count;
557 
558                         bytes -= bytes_count;
559                 }
560         }
561 
562         return sgl_count;
563 }
564 EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
565 
566 /**
567  * aead_pull_tsgl - Release the specified buffers from TX SGL
568  *
569  * If @dst is non-null, reassign the pages to dst. The caller must release
570  * the pages. If @dst_offset is given only reassign the pages to @dst starting
571  * at the @dst_offset (byte). The caller must ensure that @dst is large
572  * enough (e.g. by using af_alg_count_tsgl with the same offset).
573  *
574  * @sk socket of connection to user space
575  * @used Number of bytes to pull from TX SGL
576  * @dst If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
577  *      caller must release the buffers in dst.
578  * @dst_offset Reassign the TX SGL from given offset. All buffers before
579  *             reaching the offset is released.
580  */
581 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
582                       size_t dst_offset)
583 {
584         struct alg_sock *ask = alg_sk(sk);
585         struct af_alg_ctx *ctx = ask->private;
586         struct af_alg_tsgl *sgl;
587         struct scatterlist *sg;
588         unsigned int i, j = 0;
589 
590         while (!list_empty(&ctx->tsgl_list)) {
591                 sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
592                                        list);
593                 sg = sgl->sg;
594 
595                 for (i = 0; i < sgl->cur; i++) {
596                         size_t plen = min_t(size_t, used, sg[i].length);
597                         struct page *page = sg_page(sg + i);
598 
599                         if (!page)
600                                 continue;
601 
602                         /*
603                          * Assumption: caller created af_alg_count_tsgl(len)
604                          * SG entries in dst.
605                          */
606                         if (dst) {
607                                 if (dst_offset >= plen) {
608                                         /* discard page before offset */
609                                         dst_offset -= plen;
610                                 } else {
611                                         /* reassign page to dst after offset */
612                                         get_page(page);
613                                         sg_set_page(dst + j, page,
614                                                     plen - dst_offset,
615                                                     sg[i].offset + dst_offset);
616                                         dst_offset = 0;
617                                         j++;
618                                 }
619                         }
620 
621                         sg[i].length -= plen;
622                         sg[i].offset += plen;
623 
624                         used -= plen;
625                         ctx->used -= plen;
626 
627                         if (sg[i].length)
628                                 return;
629 
630                         put_page(page);
631                         sg_assign_page(sg + i, NULL);
632                 }
633 
634                 list_del(&sgl->list);
635                 sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
636         }
637 
638         if (!ctx->used)
639                 ctx->merge = 0;
640 }
641 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
642 
643 /**
644  * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
645  *
646  * @areq Request holding the TX and RX SGL
647  */
648 static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
649 {
650         struct sock *sk = areq->sk;
651         struct alg_sock *ask = alg_sk(sk);
652         struct af_alg_ctx *ctx = ask->private;
653         struct af_alg_rsgl *rsgl, *tmp;
654         struct scatterlist *tsgl;
655         struct scatterlist *sg;
656         unsigned int i;
657 
658         list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
659                 atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
660                 af_alg_free_sg(&rsgl->sgl);
661                 list_del(&rsgl->list);
662                 if (rsgl != &areq->first_rsgl)
663                         sock_kfree_s(sk, rsgl, sizeof(*rsgl));
664         }
665 
666         tsgl = areq->tsgl;
667         if (tsgl) {
668                 for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
669                         if (!sg_page(sg))
670                                 continue;
671                         put_page(sg_page(sg));
672                 }
673 
674                 sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
675         }
676 }
677 
678 /**
679  * af_alg_wait_for_wmem - wait for availability of writable memory
680  *
681  * @sk socket of connection to user space
682  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
683  * @return 0 when writable memory is available, < 0 upon error
684  */
685 static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
686 {
687         DEFINE_WAIT_FUNC(wait, woken_wake_function);
688         int err = -ERESTARTSYS;
689         long timeout;
690 
691         if (flags & MSG_DONTWAIT)
692                 return -EAGAIN;
693 
694         sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
695 
696         add_wait_queue(sk_sleep(sk), &wait);
697         for (;;) {
698                 if (signal_pending(current))
699                         break;
700                 timeout = MAX_SCHEDULE_TIMEOUT;
701                 if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
702                         err = 0;
703                         break;
704                 }
705         }
706         remove_wait_queue(sk_sleep(sk), &wait);
707 
708         return err;
709 }
710 
711 /**
712  * af_alg_wmem_wakeup - wakeup caller when writable memory is available
713  *
714  * @sk socket of connection to user space
715  */
716 void af_alg_wmem_wakeup(struct sock *sk)
717 {
718         struct socket_wq *wq;
719 
720         if (!af_alg_writable(sk))
721                 return;
722 
723         rcu_read_lock();
724         wq = rcu_dereference(sk->sk_wq);
725         if (skwq_has_sleeper(wq))
726                 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
727                                                            EPOLLRDNORM |
728                                                            EPOLLRDBAND);
729         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
730         rcu_read_unlock();
731 }
732 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
733 
734 /**
735  * af_alg_wait_for_data - wait for availability of TX data
736  *
737  * @sk socket of connection to user space
738  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
739  * @return 0 when writable memory is available, < 0 upon error
740  */
741 int af_alg_wait_for_data(struct sock *sk, unsigned flags)
742 {
743         DEFINE_WAIT_FUNC(wait, woken_wake_function);
744         struct alg_sock *ask = alg_sk(sk);
745         struct af_alg_ctx *ctx = ask->private;
746         long timeout;
747         int err = -ERESTARTSYS;
748 
749         if (flags & MSG_DONTWAIT)
750                 return -EAGAIN;
751 
752         sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
753 
754         add_wait_queue(sk_sleep(sk), &wait);
755         for (;;) {
756                 if (signal_pending(current))
757                         break;
758                 timeout = MAX_SCHEDULE_TIMEOUT;
759                 if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
760                                   &wait)) {
761                         err = 0;
762                         break;
763                 }
764         }
765         remove_wait_queue(sk_sleep(sk), &wait);
766 
767         sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
768 
769         return err;
770 }
771 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
772 
773 /**
774  * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
775  *
776  * @sk socket of connection to user space
777  */
778 static void af_alg_data_wakeup(struct sock *sk)
779 {
780         struct alg_sock *ask = alg_sk(sk);
781         struct af_alg_ctx *ctx = ask->private;
782         struct socket_wq *wq;
783 
784         if (!ctx->used)
785                 return;
786 
787         rcu_read_lock();
788         wq = rcu_dereference(sk->sk_wq);
789         if (skwq_has_sleeper(wq))
790                 wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
791                                                            EPOLLRDNORM |
792                                                            EPOLLRDBAND);
793         sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
794         rcu_read_unlock();
795 }
796 
797 /**
798  * af_alg_sendmsg - implementation of sendmsg system call handler
799  *
800  * The sendmsg system call handler obtains the user data and stores it
801  * in ctx->tsgl_list. This implies allocation of the required numbers of
802  * struct af_alg_tsgl.
803  *
804  * In addition, the ctx is filled with the information sent via CMSG.
805  *
806  * @sock socket of connection to user space
807  * @msg message from user space
808  * @size size of message from user space
809  * @ivsize the size of the IV for the cipher operation to verify that the
810  *         user-space-provided IV has the right size
811  * @return the number of copied data upon success, < 0 upon error
812  */
813 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
814                    unsigned int ivsize)
815 {
816         struct sock *sk = sock->sk;
817         struct alg_sock *ask = alg_sk(sk);
818         struct af_alg_ctx *ctx = ask->private;
819         struct af_alg_tsgl *sgl;
820         struct af_alg_control con = {};
821         long copied = 0;
822         bool enc = 0;
823         bool init = 0;
824         int err = 0;
825 
826         if (msg->msg_controllen) {
827                 err = af_alg_cmsg_send(msg, &con);
828                 if (err)
829                         return err;
830 
831                 init = 1;
832                 switch (con.op) {
833                 case ALG_OP_ENCRYPT:
834                         enc = 1;
835                         break;
836                 case ALG_OP_DECRYPT:
837                         enc = 0;
838                         break;
839                 default:
840                         return -EINVAL;
841                 }
842 
843                 if (con.iv && con.iv->ivlen != ivsize)
844                         return -EINVAL;
845         }
846 
847         lock_sock(sk);
848         if (!ctx->more && ctx->used) {
849                 err = -EINVAL;
850                 goto unlock;
851         }
852 
853         if (init) {
854                 ctx->enc = enc;
855                 if (con.iv)
856                         memcpy(ctx->iv, con.iv->iv, ivsize);
857 
858                 ctx->aead_assoclen = con.aead_assoclen;
859         }
860 
861         while (size) {
862                 struct scatterlist *sg;
863                 size_t len = size;
864                 size_t plen;
865 
866                 /* use the existing memory in an allocated page */
867                 if (ctx->merge) {
868                         sgl = list_entry(ctx->tsgl_list.prev,
869                                          struct af_alg_tsgl, list);
870                         sg = sgl->sg + sgl->cur - 1;
871                         len = min_t(size_t, len,
872                                     PAGE_SIZE - sg->offset - sg->length);
873 
874                         err = memcpy_from_msg(page_address(sg_page(sg)) +
875                                               sg->offset + sg->length,
876                                               msg, len);
877                         if (err)
878                                 goto unlock;
879 
880                         sg->length += len;
881                         ctx->merge = (sg->offset + sg->length) &
882                                      (PAGE_SIZE - 1);
883 
884                         ctx->used += len;
885                         copied += len;
886                         size -= len;
887                         continue;
888                 }
889 
890                 if (!af_alg_writable(sk)) {
891                         err = af_alg_wait_for_wmem(sk, msg->msg_flags);
892                         if (err)
893                                 goto unlock;
894                 }
895 
896                 /* allocate a new page */
897                 len = min_t(unsigned long, len, af_alg_sndbuf(sk));
898 
899                 err = af_alg_alloc_tsgl(sk);
900                 if (err)
901                         goto unlock;
902 
903                 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
904                                  list);
905                 sg = sgl->sg;
906                 if (sgl->cur)
907                         sg_unmark_end(sg + sgl->cur - 1);
908 
909                 do {
910                         unsigned int i = sgl->cur;
911 
912                         plen = min_t(size_t, len, PAGE_SIZE);
913 
914                         sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
915                         if (!sg_page(sg + i)) {
916                                 err = -ENOMEM;
917                                 goto unlock;
918                         }
919 
920                         err = memcpy_from_msg(page_address(sg_page(sg + i)),
921                                               msg, plen);
922                         if (err) {
923                                 __free_page(sg_page(sg + i));
924                                 sg_assign_page(sg + i, NULL);
925                                 goto unlock;
926                         }
927 
928                         sg[i].length = plen;
929                         len -= plen;
930                         ctx->used += plen;
931                         copied += plen;
932                         size -= plen;
933                         sgl->cur++;
934                 } while (len && sgl->cur < MAX_SGL_ENTS);
935 
936                 if (!size)
937                         sg_mark_end(sg + sgl->cur - 1);
938 
939                 ctx->merge = plen & (PAGE_SIZE - 1);
940         }
941 
942         err = 0;
943 
944         ctx->more = msg->msg_flags & MSG_MORE;
945 
946 unlock:
947         af_alg_data_wakeup(sk);
948         release_sock(sk);
949 
950         return copied ?: err;
951 }
952 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
953 
954 /**
955  * af_alg_sendpage - sendpage system call handler
956  *
957  * This is a generic implementation of sendpage to fill ctx->tsgl_list.
958  */
959 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
960                         int offset, size_t size, int flags)
961 {
962         struct sock *sk = sock->sk;
963         struct alg_sock *ask = alg_sk(sk);
964         struct af_alg_ctx *ctx = ask->private;
965         struct af_alg_tsgl *sgl;
966         int err = -EINVAL;
967 
968         if (flags & MSG_SENDPAGE_NOTLAST)
969                 flags |= MSG_MORE;
970 
971         lock_sock(sk);
972         if (!ctx->more && ctx->used)
973                 goto unlock;
974 
975         if (!size)
976                 goto done;
977 
978         if (!af_alg_writable(sk)) {
979                 err = af_alg_wait_for_wmem(sk, flags);
980                 if (err)
981                         goto unlock;
982         }
983 
984         err = af_alg_alloc_tsgl(sk);
985         if (err)
986                 goto unlock;
987 
988         ctx->merge = 0;
989         sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
990 
991         if (sgl->cur)
992                 sg_unmark_end(sgl->sg + sgl->cur - 1);
993 
994         sg_mark_end(sgl->sg + sgl->cur);
995 
996         get_page(page);
997         sg_set_page(sgl->sg + sgl->cur, page, size, offset);
998         sgl->cur++;
999         ctx->used += size;
1000 
1001 done:
1002         ctx->more = flags & MSG_MORE;
1003 
1004 unlock:
1005         af_alg_data_wakeup(sk);
1006         release_sock(sk);
1007 
1008         return err ?: size;
1009 }
1010 EXPORT_SYMBOL_GPL(af_alg_sendpage);
1011 
1012 /**
1013  * af_alg_free_resources - release resources required for crypto request
1014  */
1015 void af_alg_free_resources(struct af_alg_async_req *areq)
1016 {
1017         struct sock *sk = areq->sk;
1018 
1019         af_alg_free_areq_sgls(areq);
1020         sock_kfree_s(sk, areq, areq->areqlen);
1021 }
1022 EXPORT_SYMBOL_GPL(af_alg_free_resources);
1023 
1024 /**
1025  * af_alg_async_cb - AIO callback handler
1026  *
1027  * This handler cleans up the struct af_alg_async_req upon completion of the
1028  * AIO operation.
1029  *
1030  * The number of bytes to be generated with the AIO operation must be set
1031  * in areq->outlen before the AIO callback handler is invoked.
1032  */
1033 void af_alg_async_cb(struct crypto_async_request *_req, int err)
1034 {
1035         struct af_alg_async_req *areq = _req->data;
1036         struct sock *sk = areq->sk;
1037         struct kiocb *iocb = areq->iocb;
1038         unsigned int resultlen;
1039 
1040         /* Buffer size written by crypto operation. */
1041         resultlen = areq->outlen;
1042 
1043         af_alg_free_resources(areq);
1044         sock_put(sk);
1045 
1046         iocb->ki_complete(iocb, err ? err : resultlen, 0);
1047 }
1048 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1049 
1050 /**
1051  * af_alg_poll - poll system call handler
1052  */
1053 __poll_t af_alg_poll(struct file *file, struct socket *sock,
1054                          poll_table *wait)
1055 {
1056         struct sock *sk = sock->sk;
1057         struct alg_sock *ask = alg_sk(sk);
1058         struct af_alg_ctx *ctx = ask->private;
1059         __poll_t mask;
1060 
1061         sock_poll_wait(file, sock, wait);
1062         mask = 0;
1063 
1064         if (!ctx->more || ctx->used)
1065                 mask |= EPOLLIN | EPOLLRDNORM;
1066 
1067         if (af_alg_writable(sk))
1068                 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1069 
1070         return mask;
1071 }
1072 EXPORT_SYMBOL_GPL(af_alg_poll);
1073 
1074 /**
1075  * af_alg_alloc_areq - allocate struct af_alg_async_req
1076  *
1077  * @sk socket of connection to user space
1078  * @areqlen size of struct af_alg_async_req + crypto_*_reqsize
1079  * @return allocated data structure or ERR_PTR upon error
1080  */
1081 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1082                                            unsigned int areqlen)
1083 {
1084         struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1085 
1086         if (unlikely(!areq))
1087                 return ERR_PTR(-ENOMEM);
1088 
1089         areq->areqlen = areqlen;
1090         areq->sk = sk;
1091         areq->last_rsgl = NULL;
1092         INIT_LIST_HEAD(&areq->rsgl_list);
1093         areq->tsgl = NULL;
1094         areq->tsgl_entries = 0;
1095 
1096         return areq;
1097 }
1098 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1099 
1100 /**
1101  * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1102  *                   operation
1103  *
1104  * @sk socket of connection to user space
1105  * @msg user space message
1106  * @flags flags used to invoke recvmsg with
1107  * @areq instance of the cryptographic request that will hold the RX SGL
1108  * @maxsize maximum number of bytes to be pulled from user space
1109  * @outlen number of bytes in the RX SGL
1110  * @return 0 on success, < 0 upon error
1111  */
1112 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1113                     struct af_alg_async_req *areq, size_t maxsize,
1114                     size_t *outlen)
1115 {
1116         struct alg_sock *ask = alg_sk(sk);
1117         struct af_alg_ctx *ctx = ask->private;
1118         size_t len = 0;
1119 
1120         while (maxsize > len && msg_data_left(msg)) {
1121                 struct af_alg_rsgl *rsgl;
1122                 size_t seglen;
1123                 int err;
1124 
1125                 /* limit the amount of readable buffers */
1126                 if (!af_alg_readable(sk))
1127                         break;
1128 
1129                 seglen = min_t(size_t, (maxsize - len),
1130                                msg_data_left(msg));
1131 
1132                 if (list_empty(&areq->rsgl_list)) {
1133                         rsgl = &areq->first_rsgl;
1134                 } else {
1135                         rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1136                         if (unlikely(!rsgl))
1137                                 return -ENOMEM;
1138                 }
1139 
1140                 rsgl->sgl.npages = 0;
1141                 list_add_tail(&rsgl->list, &areq->rsgl_list);
1142 
1143                 /* make one iovec available as scatterlist */
1144                 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1145                 if (err < 0) {
1146                         rsgl->sg_num_bytes = 0;
1147                         return err;
1148                 }
1149 
1150                 /* chain the new scatterlist with previous one */
1151                 if (areq->last_rsgl)
1152                         af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1153 
1154                 areq->last_rsgl = rsgl;
1155                 len += err;
1156                 atomic_add(err, &ctx->rcvused);
1157                 rsgl->sg_num_bytes = err;
1158                 iov_iter_advance(&msg->msg_iter, err);
1159         }
1160 
1161         *outlen = len;
1162         return 0;
1163 }
1164 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1165 
1166 static int __init af_alg_init(void)
1167 {
1168         int err = proto_register(&alg_proto, 0);
1169 
1170         if (err)
1171                 goto out;
1172 
1173         err = sock_register(&alg_family);
1174         if (err != 0)
1175                 goto out_unregister_proto;
1176 
1177 out:
1178         return err;
1179 
1180 out_unregister_proto:
1181         proto_unregister(&alg_proto);
1182         goto out;
1183 }
1184 
1185 static void __exit af_alg_exit(void)
1186 {
1187         sock_unregister(PF_ALG);
1188         proto_unregister(&alg_proto);
1189 }
1190 
1191 module_init(af_alg_init);
1192 module_exit(af_alg_exit);
1193 MODULE_LICENSE("GPL");
1194 MODULE_ALIAS_NETPROTO(AF_ALG);
1195 

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