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TOMOYO Linux Cross Reference
Linux/crypto/algif_skcipher.c

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  1 /*
  2  * algif_skcipher: User-space interface for skcipher algorithms
  3  *
  4  * This file provides the user-space API for symmetric key ciphers.
  5  *
  6  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
  7  *
  8  * This program is free software; you can redistribute it and/or modify it
  9  * under the terms of the GNU General Public License as published by the Free
 10  * Software Foundation; either version 2 of the License, or (at your option)
 11  * any later version.
 12  *
 13  */
 14 
 15 #include <crypto/scatterwalk.h>
 16 #include <crypto/skcipher.h>
 17 #include <crypto/if_alg.h>
 18 #include <linux/init.h>
 19 #include <linux/list.h>
 20 #include <linux/kernel.h>
 21 #include <linux/mm.h>
 22 #include <linux/module.h>
 23 #include <linux/net.h>
 24 #include <net/sock.h>
 25 
 26 struct skcipher_sg_list {
 27         struct list_head list;
 28 
 29         int cur;
 30 
 31         struct scatterlist sg[0];
 32 };
 33 
 34 struct skcipher_ctx {
 35         struct list_head tsgl;
 36         struct af_alg_sgl rsgl;
 37 
 38         void *iv;
 39 
 40         struct af_alg_completion completion;
 41 
 42         unsigned used;
 43 
 44         unsigned int len;
 45         bool more;
 46         bool merge;
 47         bool enc;
 48 
 49         struct ablkcipher_request req;
 50 };
 51 
 52 #define MAX_SGL_ENTS ((PAGE_SIZE - sizeof(struct skcipher_sg_list)) / \
 53                       sizeof(struct scatterlist) - 1)
 54 
 55 static inline int skcipher_sndbuf(struct sock *sk)
 56 {
 57         struct alg_sock *ask = alg_sk(sk);
 58         struct skcipher_ctx *ctx = ask->private;
 59 
 60         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 61                           ctx->used, 0);
 62 }
 63 
 64 static inline bool skcipher_writable(struct sock *sk)
 65 {
 66         return PAGE_SIZE <= skcipher_sndbuf(sk);
 67 }
 68 
 69 static int skcipher_alloc_sgl(struct sock *sk)
 70 {
 71         struct alg_sock *ask = alg_sk(sk);
 72         struct skcipher_ctx *ctx = ask->private;
 73         struct skcipher_sg_list *sgl;
 74         struct scatterlist *sg = NULL;
 75 
 76         sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
 77         if (!list_empty(&ctx->tsgl))
 78                 sg = sgl->sg;
 79 
 80         if (!sg || sgl->cur >= MAX_SGL_ENTS) {
 81                 sgl = sock_kmalloc(sk, sizeof(*sgl) +
 82                                        sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
 83                                    GFP_KERNEL);
 84                 if (!sgl)
 85                         return -ENOMEM;
 86 
 87                 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
 88                 sgl->cur = 0;
 89 
 90                 if (sg)
 91                         scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
 92 
 93                 list_add_tail(&sgl->list, &ctx->tsgl);
 94         }
 95 
 96         return 0;
 97 }
 98 
 99 static void skcipher_pull_sgl(struct sock *sk, int used)
100 {
101         struct alg_sock *ask = alg_sk(sk);
102         struct skcipher_ctx *ctx = ask->private;
103         struct skcipher_sg_list *sgl;
104         struct scatterlist *sg;
105         int i;
106 
107         while (!list_empty(&ctx->tsgl)) {
108                 sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,
109                                        list);
110                 sg = sgl->sg;
111 
112                 for (i = 0; i < sgl->cur; i++) {
113                         int plen = min_t(int, used, sg[i].length);
114 
115                         if (!sg_page(sg + i))
116                                 continue;
117 
118                         sg[i].length -= plen;
119                         sg[i].offset += plen;
120 
121                         used -= plen;
122                         ctx->used -= plen;
123 
124                         if (sg[i].length)
125                                 return;
126 
127                         put_page(sg_page(sg + i));
128                         sg_assign_page(sg + i, NULL);
129                 }
130 
131                 list_del(&sgl->list);
132                 sock_kfree_s(sk, sgl,
133                              sizeof(*sgl) + sizeof(sgl->sg[0]) *
134                                             (MAX_SGL_ENTS + 1));
135         }
136 
137         if (!ctx->used)
138                 ctx->merge = 0;
139 }
140 
141 static void skcipher_free_sgl(struct sock *sk)
142 {
143         struct alg_sock *ask = alg_sk(sk);
144         struct skcipher_ctx *ctx = ask->private;
145 
146         skcipher_pull_sgl(sk, ctx->used);
147 }
148 
149 static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
150 {
151         long timeout;
152         DEFINE_WAIT(wait);
153         int err = -ERESTARTSYS;
154 
155         if (flags & MSG_DONTWAIT)
156                 return -EAGAIN;
157 
158         set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
159 
160         for (;;) {
161                 if (signal_pending(current))
162                         break;
163                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
164                 timeout = MAX_SCHEDULE_TIMEOUT;
165                 if (sk_wait_event(sk, &timeout, skcipher_writable(sk))) {
166                         err = 0;
167                         break;
168                 }
169         }
170         finish_wait(sk_sleep(sk), &wait);
171 
172         return err;
173 }
174 
175 static void skcipher_wmem_wakeup(struct sock *sk)
176 {
177         struct socket_wq *wq;
178 
179         if (!skcipher_writable(sk))
180                 return;
181 
182         rcu_read_lock();
183         wq = rcu_dereference(sk->sk_wq);
184         if (wq_has_sleeper(wq))
185                 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
186                                                            POLLRDNORM |
187                                                            POLLRDBAND);
188         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
189         rcu_read_unlock();
190 }
191 
192 static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
193 {
194         struct alg_sock *ask = alg_sk(sk);
195         struct skcipher_ctx *ctx = ask->private;
196         long timeout;
197         DEFINE_WAIT(wait);
198         int err = -ERESTARTSYS;
199 
200         if (flags & MSG_DONTWAIT) {
201                 return -EAGAIN;
202         }
203 
204         set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
205 
206         for (;;) {
207                 if (signal_pending(current))
208                         break;
209                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
210                 timeout = MAX_SCHEDULE_TIMEOUT;
211                 if (sk_wait_event(sk, &timeout, ctx->used)) {
212                         err = 0;
213                         break;
214                 }
215         }
216         finish_wait(sk_sleep(sk), &wait);
217 
218         clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
219 
220         return err;
221 }
222 
223 static void skcipher_data_wakeup(struct sock *sk)
224 {
225         struct alg_sock *ask = alg_sk(sk);
226         struct skcipher_ctx *ctx = ask->private;
227         struct socket_wq *wq;
228 
229         if (!ctx->used)
230                 return;
231 
232         rcu_read_lock();
233         wq = rcu_dereference(sk->sk_wq);
234         if (wq_has_sleeper(wq))
235                 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
236                                                            POLLRDNORM |
237                                                            POLLRDBAND);
238         sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
239         rcu_read_unlock();
240 }
241 
242 static int skcipher_sendmsg(struct kiocb *unused, struct socket *sock,
243                             struct msghdr *msg, size_t size)
244 {
245         struct sock *sk = sock->sk;
246         struct alg_sock *ask = alg_sk(sk);
247         struct skcipher_ctx *ctx = ask->private;
248         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
249         unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
250         struct skcipher_sg_list *sgl;
251         struct af_alg_control con = {};
252         long copied = 0;
253         bool enc = 0;
254         int err;
255         int i;
256 
257         if (msg->msg_controllen) {
258                 err = af_alg_cmsg_send(msg, &con);
259                 if (err)
260                         return err;
261 
262                 switch (con.op) {
263                 case ALG_OP_ENCRYPT:
264                         enc = 1;
265                         break;
266                 case ALG_OP_DECRYPT:
267                         enc = 0;
268                         break;
269                 default:
270                         return -EINVAL;
271                 }
272 
273                 if (con.iv && con.iv->ivlen != ivsize)
274                         return -EINVAL;
275         }
276 
277         err = -EINVAL;
278 
279         lock_sock(sk);
280         if (!ctx->more && ctx->used)
281                 goto unlock;
282 
283         if (!ctx->used) {
284                 ctx->enc = enc;
285                 if (con.iv)
286                         memcpy(ctx->iv, con.iv->iv, ivsize);
287         }
288 
289         while (size) {
290                 struct scatterlist *sg;
291                 unsigned long len = size;
292                 int plen;
293 
294                 if (ctx->merge) {
295                         sgl = list_entry(ctx->tsgl.prev,
296                                          struct skcipher_sg_list, list);
297                         sg = sgl->sg + sgl->cur - 1;
298                         len = min_t(unsigned long, len,
299                                     PAGE_SIZE - sg->offset - sg->length);
300 
301                         err = memcpy_fromiovec(page_address(sg_page(sg)) +
302                                                sg->offset + sg->length,
303                                                msg->msg_iov, len);
304                         if (err)
305                                 goto unlock;
306 
307                         sg->length += len;
308                         ctx->merge = (sg->offset + sg->length) &
309                                      (PAGE_SIZE - 1);
310 
311                         ctx->used += len;
312                         copied += len;
313                         size -= len;
314                         continue;
315                 }
316 
317                 if (!skcipher_writable(sk)) {
318                         err = skcipher_wait_for_wmem(sk, msg->msg_flags);
319                         if (err)
320                                 goto unlock;
321                 }
322 
323                 len = min_t(unsigned long, len, skcipher_sndbuf(sk));
324 
325                 err = skcipher_alloc_sgl(sk);
326                 if (err)
327                         goto unlock;
328 
329                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
330                 sg = sgl->sg;
331                 do {
332                         i = sgl->cur;
333                         plen = min_t(int, len, PAGE_SIZE);
334 
335                         sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
336                         err = -ENOMEM;
337                         if (!sg_page(sg + i))
338                                 goto unlock;
339 
340                         err = memcpy_fromiovec(page_address(sg_page(sg + i)),
341                                                msg->msg_iov, plen);
342                         if (err) {
343                                 __free_page(sg_page(sg + i));
344                                 sg_assign_page(sg + i, NULL);
345                                 goto unlock;
346                         }
347 
348                         sg[i].length = plen;
349                         len -= plen;
350                         ctx->used += plen;
351                         copied += plen;
352                         size -= plen;
353                         sgl->cur++;
354                 } while (len && sgl->cur < MAX_SGL_ENTS);
355 
356                 ctx->merge = plen & (PAGE_SIZE - 1);
357         }
358 
359         err = 0;
360 
361         ctx->more = msg->msg_flags & MSG_MORE;
362         if (!ctx->more && !list_empty(&ctx->tsgl))
363                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
364 
365 unlock:
366         skcipher_data_wakeup(sk);
367         release_sock(sk);
368 
369         return copied ?: err;
370 }
371 
372 static ssize_t skcipher_sendpage(struct socket *sock, struct page *page,
373                                  int offset, size_t size, int flags)
374 {
375         struct sock *sk = sock->sk;
376         struct alg_sock *ask = alg_sk(sk);
377         struct skcipher_ctx *ctx = ask->private;
378         struct skcipher_sg_list *sgl;
379         int err = -EINVAL;
380 
381         lock_sock(sk);
382         if (!ctx->more && ctx->used)
383                 goto unlock;
384 
385         if (!size)
386                 goto done;
387 
388         if (!skcipher_writable(sk)) {
389                 err = skcipher_wait_for_wmem(sk, flags);
390                 if (err)
391                         goto unlock;
392         }
393 
394         err = skcipher_alloc_sgl(sk);
395         if (err)
396                 goto unlock;
397 
398         ctx->merge = 0;
399         sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
400 
401         get_page(page);
402         sg_set_page(sgl->sg + sgl->cur, page, size, offset);
403         sgl->cur++;
404         ctx->used += size;
405 
406 done:
407         ctx->more = flags & MSG_MORE;
408         if (!ctx->more && !list_empty(&ctx->tsgl))
409                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
410 
411 unlock:
412         skcipher_data_wakeup(sk);
413         release_sock(sk);
414 
415         return err ?: size;
416 }
417 
418 static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
419                             struct msghdr *msg, size_t ignored, int flags)
420 {
421         struct sock *sk = sock->sk;
422         struct alg_sock *ask = alg_sk(sk);
423         struct skcipher_ctx *ctx = ask->private;
424         unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(
425                 &ctx->req));
426         struct skcipher_sg_list *sgl;
427         struct scatterlist *sg;
428         unsigned long iovlen;
429         struct iovec *iov;
430         int err = -EAGAIN;
431         int used;
432         long copied = 0;
433 
434         lock_sock(sk);
435         msg->msg_namelen = 0;
436         for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
437              iovlen--, iov++) {
438                 unsigned long seglen = iov->iov_len;
439                 char __user *from = iov->iov_base;
440 
441                 while (seglen) {
442                         sgl = list_first_entry(&ctx->tsgl,
443                                                struct skcipher_sg_list, list);
444                         sg = sgl->sg;
445 
446                         while (!sg->length)
447                                 sg++;
448 
449                         used = ctx->used;
450                         if (!used) {
451                                 err = skcipher_wait_for_data(sk, flags);
452                                 if (err)
453                                         goto unlock;
454                         }
455 
456                         used = min_t(unsigned long, used, seglen);
457 
458                         used = af_alg_make_sg(&ctx->rsgl, from, used, 1);
459                         err = used;
460                         if (err < 0)
461                                 goto unlock;
462 
463                         if (ctx->more || used < ctx->used)
464                                 used -= used % bs;
465 
466                         err = -EINVAL;
467                         if (!used)
468                                 goto free;
469 
470                         ablkcipher_request_set_crypt(&ctx->req, sg,
471                                                      ctx->rsgl.sg, used,
472                                                      ctx->iv);
473 
474                         err = af_alg_wait_for_completion(
475                                 ctx->enc ?
476                                         crypto_ablkcipher_encrypt(&ctx->req) :
477                                         crypto_ablkcipher_decrypt(&ctx->req),
478                                 &ctx->completion);
479 
480 free:
481                         af_alg_free_sg(&ctx->rsgl);
482 
483                         if (err)
484                                 goto unlock;
485 
486                         copied += used;
487                         from += used;
488                         seglen -= used;
489                         skcipher_pull_sgl(sk, used);
490                 }
491         }
492 
493         err = 0;
494 
495 unlock:
496         skcipher_wmem_wakeup(sk);
497         release_sock(sk);
498 
499         return copied ?: err;
500 }
501 
502 
503 static unsigned int skcipher_poll(struct file *file, struct socket *sock,
504                                   poll_table *wait)
505 {
506         struct sock *sk = sock->sk;
507         struct alg_sock *ask = alg_sk(sk);
508         struct skcipher_ctx *ctx = ask->private;
509         unsigned int mask;
510 
511         sock_poll_wait(file, sk_sleep(sk), wait);
512         mask = 0;
513 
514         if (ctx->used)
515                 mask |= POLLIN | POLLRDNORM;
516 
517         if (skcipher_writable(sk))
518                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
519 
520         return mask;
521 }
522 
523 static struct proto_ops algif_skcipher_ops = {
524         .family         =       PF_ALG,
525 
526         .connect        =       sock_no_connect,
527         .socketpair     =       sock_no_socketpair,
528         .getname        =       sock_no_getname,
529         .ioctl          =       sock_no_ioctl,
530         .listen         =       sock_no_listen,
531         .shutdown       =       sock_no_shutdown,
532         .getsockopt     =       sock_no_getsockopt,
533         .mmap           =       sock_no_mmap,
534         .bind           =       sock_no_bind,
535         .accept         =       sock_no_accept,
536         .setsockopt     =       sock_no_setsockopt,
537 
538         .release        =       af_alg_release,
539         .sendmsg        =       skcipher_sendmsg,
540         .sendpage       =       skcipher_sendpage,
541         .recvmsg        =       skcipher_recvmsg,
542         .poll           =       skcipher_poll,
543 };
544 
545 static void *skcipher_bind(const char *name, u32 type, u32 mask)
546 {
547         return crypto_alloc_ablkcipher(name, type, mask);
548 }
549 
550 static void skcipher_release(void *private)
551 {
552         crypto_free_ablkcipher(private);
553 }
554 
555 static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
556 {
557         return crypto_ablkcipher_setkey(private, key, keylen);
558 }
559 
560 static void skcipher_sock_destruct(struct sock *sk)
561 {
562         struct alg_sock *ask = alg_sk(sk);
563         struct skcipher_ctx *ctx = ask->private;
564         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
565 
566         skcipher_free_sgl(sk);
567         sock_kfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
568         sock_kfree_s(sk, ctx, ctx->len);
569         af_alg_release_parent(sk);
570 }
571 
572 static int skcipher_accept_parent(void *private, struct sock *sk)
573 {
574         struct skcipher_ctx *ctx;
575         struct alg_sock *ask = alg_sk(sk);
576         unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);
577 
578         ctx = sock_kmalloc(sk, len, GFP_KERNEL);
579         if (!ctx)
580                 return -ENOMEM;
581 
582         ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
583                                GFP_KERNEL);
584         if (!ctx->iv) {
585                 sock_kfree_s(sk, ctx, len);
586                 return -ENOMEM;
587         }
588 
589         memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));
590 
591         INIT_LIST_HEAD(&ctx->tsgl);
592         ctx->len = len;
593         ctx->used = 0;
594         ctx->more = 0;
595         ctx->merge = 0;
596         ctx->enc = 0;
597         af_alg_init_completion(&ctx->completion);
598 
599         ask->private = ctx;
600 
601         ablkcipher_request_set_tfm(&ctx->req, private);
602         ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
603                                         af_alg_complete, &ctx->completion);
604 
605         sk->sk_destruct = skcipher_sock_destruct;
606 
607         return 0;
608 }
609 
610 static const struct af_alg_type algif_type_skcipher = {
611         .bind           =       skcipher_bind,
612         .release        =       skcipher_release,
613         .setkey         =       skcipher_setkey,
614         .accept         =       skcipher_accept_parent,
615         .ops            =       &algif_skcipher_ops,
616         .name           =       "skcipher",
617         .owner          =       THIS_MODULE
618 };
619 
620 static int __init algif_skcipher_init(void)
621 {
622         return af_alg_register_type(&algif_type_skcipher);
623 }
624 
625 static void __exit algif_skcipher_exit(void)
626 {
627         int err = af_alg_unregister_type(&algif_type_skcipher);
628         BUG_ON(err);
629 }
630 
631 module_init(algif_skcipher_init);
632 module_exit(algif_skcipher_exit);
633 MODULE_LICENSE("GPL");
634 

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