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-rw-r--r--crypto/algif_aead.c666
1 files changed, 666 insertions, 0 deletions
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
new file mode 100644
index 000000000000..527d27b023ab
--- /dev/null
+++ b/crypto/algif_aead.c
@@ -0,0 +1,666 @@
1/*
2 * algif_aead: User-space interface for AEAD algorithms
3 *
4 * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
5 *
6 * This file provides the user-space API for AEAD ciphers.
7 *
8 * This file is derived from algif_skcipher.c.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 */
15
16#include <crypto/scatterwalk.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
26struct aead_sg_list {
27 unsigned int cur;
28 struct scatterlist sg[ALG_MAX_PAGES];
29};
30
31struct aead_ctx {
32 struct aead_sg_list tsgl;
33 /*
34 * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
35 * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
36 * bytes
37 */
38#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
39 struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
40
41 void *iv;
42
43 struct af_alg_completion completion;
44
45 unsigned long used;
46
47 unsigned int len;
48 bool more;
49 bool merge;
50 bool enc;
51
52 size_t aead_assoclen;
53 struct aead_request aead_req;
54};
55
56static inline int aead_sndbuf(struct sock *sk)
57{
58 struct alg_sock *ask = alg_sk(sk);
59 struct aead_ctx *ctx = ask->private;
60
61 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
62 ctx->used, 0);
63}
64
65static inline bool aead_writable(struct sock *sk)
66{
67 return PAGE_SIZE <= aead_sndbuf(sk);
68}
69
70static inline bool aead_sufficient_data(struct aead_ctx *ctx)
71{
72 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
73
74 return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ? 0 : as)));
75}
76
77static void aead_put_sgl(struct sock *sk)
78{
79 struct alg_sock *ask = alg_sk(sk);
80 struct aead_ctx *ctx = ask->private;
81 struct aead_sg_list *sgl = &ctx->tsgl;
82 struct scatterlist *sg = sgl->sg;
83 unsigned int i;
84
85 for (i = 0; i < sgl->cur; i++) {
86 if (!sg_page(sg + i))
87 continue;
88
89 put_page(sg_page(sg + i));
90 sg_assign_page(sg + i, NULL);
91 }
92 sgl->cur = 0;
93 ctx->used = 0;
94 ctx->more = 0;
95 ctx->merge = 0;
96}
97
98static void aead_wmem_wakeup(struct sock *sk)
99{
100 struct socket_wq *wq;
101
102 if (!aead_writable(sk))
103 return;
104
105 rcu_read_lock();
106 wq = rcu_dereference(sk->sk_wq);
107 if (wq_has_sleeper(wq))
108 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
109 POLLRDNORM |
110 POLLRDBAND);
111 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
112 rcu_read_unlock();
113}
114
115static int aead_wait_for_data(struct sock *sk, unsigned flags)
116{
117 struct alg_sock *ask = alg_sk(sk);
118 struct aead_ctx *ctx = ask->private;
119 long timeout;
120 DEFINE_WAIT(wait);
121 int err = -ERESTARTSYS;
122
123 if (flags & MSG_DONTWAIT)
124 return -EAGAIN;
125
126 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
127
128 for (;;) {
129 if (signal_pending(current))
130 break;
131 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
132 timeout = MAX_SCHEDULE_TIMEOUT;
133 if (sk_wait_event(sk, &timeout, !ctx->more)) {
134 err = 0;
135 break;
136 }
137 }
138 finish_wait(sk_sleep(sk), &wait);
139
140 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
141
142 return err;
143}
144
145static void aead_data_wakeup(struct sock *sk)
146{
147 struct alg_sock *ask = alg_sk(sk);
148 struct aead_ctx *ctx = ask->private;
149 struct socket_wq *wq;
150
151 if (ctx->more)
152 return;
153 if (!ctx->used)
154 return;
155
156 rcu_read_lock();
157 wq = rcu_dereference(sk->sk_wq);
158 if (wq_has_sleeper(wq))
159 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
160 POLLRDNORM |
161 POLLRDBAND);
162 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
163 rcu_read_unlock();
164}
165
166static int aead_sendmsg(struct kiocb *unused, struct socket *sock,
167 struct msghdr *msg, size_t size)
168{
169 struct sock *sk = sock->sk;
170 struct alg_sock *ask = alg_sk(sk);
171 struct aead_ctx *ctx = ask->private;
172 unsigned ivsize =
173 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
174 struct aead_sg_list *sgl = &ctx->tsgl;
175 struct af_alg_control con = {};
176 long copied = 0;
177 bool enc = 0;
178 bool init = 0;
179 int err = -EINVAL;
180
181 if (msg->msg_controllen) {
182 err = af_alg_cmsg_send(msg, &con);
183 if (err)
184 return err;
185
186 init = 1;
187 switch (con.op) {
188 case ALG_OP_ENCRYPT:
189 enc = 1;
190 break;
191 case ALG_OP_DECRYPT:
192 enc = 0;
193 break;
194 default:
195 return -EINVAL;
196 }
197
198 if (con.iv && con.iv->ivlen != ivsize)
199 return -EINVAL;
200 }
201
202 lock_sock(sk);
203 if (!ctx->more && ctx->used)
204 goto unlock;
205
206 if (init) {
207 ctx->enc = enc;
208 if (con.iv)
209 memcpy(ctx->iv, con.iv->iv, ivsize);
210
211 ctx->aead_assoclen = con.aead_assoclen;
212 }
213
214 while (size) {
215 unsigned long len = size;
216 struct scatterlist *sg = NULL;
217
218 /* use the existing memory in an allocated page */
219 if (ctx->merge) {
220 sg = sgl->sg + sgl->cur - 1;
221 len = min_t(unsigned long, len,
222 PAGE_SIZE - sg->offset - sg->length);
223 err = memcpy_from_msg(page_address(sg_page(sg)) +
224 sg->offset + sg->length,
225 msg, len);
226 if (err)
227 goto unlock;
228
229 sg->length += len;
230 ctx->merge = (sg->offset + sg->length) &
231 (PAGE_SIZE - 1);
232
233 ctx->used += len;
234 copied += len;
235 size -= len;
236 continue;
237 }
238
239 if (!aead_writable(sk)) {
240 /* user space sent too much data */
241 aead_put_sgl(sk);
242 err = -EMSGSIZE;
243 goto unlock;
244 }
245
246 /* allocate a new page */
247 len = min_t(unsigned long, size, aead_sndbuf(sk));
248 while (len) {
249 int plen = 0;
250
251 if (sgl->cur >= ALG_MAX_PAGES) {
252 aead_put_sgl(sk);
253 err = -E2BIG;
254 goto unlock;
255 }
256
257 sg = sgl->sg + sgl->cur;
258 plen = min_t(int, len, PAGE_SIZE);
259
260 sg_assign_page(sg, alloc_page(GFP_KERNEL));
261 err = -ENOMEM;
262 if (!sg_page(sg))
263 goto unlock;
264
265 err = memcpy_from_msg(page_address(sg_page(sg)),
266 msg, plen);
267 if (err) {
268 __free_page(sg_page(sg));
269 sg_assign_page(sg, NULL);
270 goto unlock;
271 }
272
273 sg->offset = 0;
274 sg->length = plen;
275 len -= plen;
276 ctx->used += plen;
277 copied += plen;
278 sgl->cur++;
279 size -= plen;
280 ctx->merge = plen & (PAGE_SIZE - 1);
281 }
282 }
283
284 err = 0;
285
286 ctx->more = msg->msg_flags & MSG_MORE;
287 if (!ctx->more && !aead_sufficient_data(ctx)) {
288 aead_put_sgl(sk);
289 err = -EMSGSIZE;
290 }
291
292unlock:
293 aead_data_wakeup(sk);
294 release_sock(sk);
295
296 return err ?: copied;
297}
298
299static ssize_t aead_sendpage(struct socket *sock, struct page *page,
300 int offset, size_t size, int flags)
301{
302 struct sock *sk = sock->sk;
303 struct alg_sock *ask = alg_sk(sk);
304 struct aead_ctx *ctx = ask->private;
305 struct aead_sg_list *sgl = &ctx->tsgl;
306 int err = -EINVAL;
307
308 if (flags & MSG_SENDPAGE_NOTLAST)
309 flags |= MSG_MORE;
310
311 if (sgl->cur >= ALG_MAX_PAGES)
312 return -E2BIG;
313
314 lock_sock(sk);
315 if (!ctx->more && ctx->used)
316 goto unlock;
317
318 if (!size)
319 goto done;
320
321 if (!aead_writable(sk)) {
322 /* user space sent too much data */
323 aead_put_sgl(sk);
324 err = -EMSGSIZE;
325 goto unlock;
326 }
327
328 ctx->merge = 0;
329
330 get_page(page);
331 sg_set_page(sgl->sg + sgl->cur, page, size, offset);
332 sgl->cur++;
333 ctx->used += size;
334
335 err = 0;
336
337done:
338 ctx->more = flags & MSG_MORE;
339 if (!ctx->more && !aead_sufficient_data(ctx)) {
340 aead_put_sgl(sk);
341 err = -EMSGSIZE;
342 }
343
344unlock:
345 aead_data_wakeup(sk);
346 release_sock(sk);
347
348 return err ?: size;
349}
350
351static int aead_recvmsg(struct kiocb *unused, struct socket *sock,
352 struct msghdr *msg, size_t ignored, int flags)
353{
354 struct sock *sk = sock->sk;
355 struct alg_sock *ask = alg_sk(sk);
356 struct aead_ctx *ctx = ask->private;
357 unsigned bs = crypto_aead_blocksize(crypto_aead_reqtfm(&ctx->aead_req));
358 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
359 struct aead_sg_list *sgl = &ctx->tsgl;
360 struct scatterlist *sg = NULL;
361 struct scatterlist assoc[ALG_MAX_PAGES];
362 size_t assoclen = 0;
363 unsigned int i = 0;
364 int err = -EINVAL;
365 unsigned long used = 0;
366 size_t outlen = 0;
367 size_t usedpages = 0;
368 unsigned int cnt = 0;
369
370 /* Limit number of IOV blocks to be accessed below */
371 if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
372 return -ENOMSG;
373
374 lock_sock(sk);
375
376 /*
377 * AEAD memory structure: For encryption, the tag is appended to the
378 * ciphertext which implies that the memory allocated for the ciphertext
379 * must be increased by the tag length. For decryption, the tag
380 * is expected to be concatenated to the ciphertext. The plaintext
381 * therefore has a memory size of the ciphertext minus the tag length.
382 *
383 * The memory structure for cipher operation has the following
384 * structure:
385 * AEAD encryption input: assoc data || plaintext
386 * AEAD encryption output: cipherntext || auth tag
387 * AEAD decryption input: assoc data || ciphertext || auth tag
388 * AEAD decryption output: plaintext
389 */
390
391 if (ctx->more) {
392 err = aead_wait_for_data(sk, flags);
393 if (err)
394 goto unlock;
395 }
396
397 used = ctx->used;
398
399 /*
400 * Make sure sufficient data is present -- note, the same check is
401 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
402 * shall provide an information to the data sender that something is
403 * wrong, but they are irrelevant to maintain the kernel integrity.
404 * We need this check here too in case user space decides to not honor
405 * the error message in sendmsg/sendpage and still call recvmsg. This
406 * check here protects the kernel integrity.
407 */
408 if (!aead_sufficient_data(ctx))
409 goto unlock;
410
411 /*
412 * The cipher operation input data is reduced by the associated data
413 * length as this data is processed separately later on.
414 */
415 used -= ctx->aead_assoclen;
416
417 if (ctx->enc) {
418 /* round up output buffer to multiple of block size */
419 outlen = ((used + bs - 1) / bs * bs);
420 /* add the size needed for the auth tag to be created */
421 outlen += as;
422 } else {
423 /* output data size is input without the authentication tag */
424 outlen = used - as;
425 /* round up output buffer to multiple of block size */
426 outlen = ((outlen + bs - 1) / bs * bs);
427 }
428
429 /* convert iovecs of output buffers into scatterlists */
430 while (iov_iter_count(&msg->msg_iter)) {
431 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
432 (outlen - usedpages));
433
434 /* make one iovec available as scatterlist */
435 err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
436 seglen);
437 if (err < 0)
438 goto unlock;
439 usedpages += err;
440 /* chain the new scatterlist with initial list */
441 if (cnt)
442 scatterwalk_crypto_chain(ctx->rsgl[0].sg,
443 ctx->rsgl[cnt].sg, 1,
444 sg_nents(ctx->rsgl[cnt-1].sg));
445 /* we do not need more iovecs as we have sufficient memory */
446 if (outlen <= usedpages)
447 break;
448 iov_iter_advance(&msg->msg_iter, err);
449 cnt++;
450 }
451
452 err = -EINVAL;
453 /* ensure output buffer is sufficiently large */
454 if (usedpages < outlen)
455 goto unlock;
456
457 sg_init_table(assoc, ALG_MAX_PAGES);
458 assoclen = ctx->aead_assoclen;
459 /*
460 * Split scatterlist into two: first part becomes AD, second part
461 * is plaintext / ciphertext. The first part is assigned to assoc
462 * scatterlist. When this loop finishes, sg points to the start of the
463 * plaintext / ciphertext.
464 */
465 for (i = 0; i < ctx->tsgl.cur; i++) {
466 sg = sgl->sg + i;
467 if (sg->length <= assoclen) {
468 /* AD is larger than one page */
469 sg_set_page(assoc + i, sg_page(sg),
470 sg->length, sg->offset);
471 assoclen -= sg->length;
472 if (i >= ctx->tsgl.cur)
473 goto unlock;
474 } else if (!assoclen) {
475 /* current page is to start of plaintext / ciphertext */
476 if (i)
477 /* AD terminates at page boundary */
478 sg_mark_end(assoc + i - 1);
479 else
480 /* AD size is zero */
481 sg_mark_end(assoc);
482 break;
483 } else {
484 /* AD does not terminate at page boundary */
485 sg_set_page(assoc + i, sg_page(sg),
486 assoclen, sg->offset);
487 sg_mark_end(assoc + i);
488 /* plaintext / ciphertext starts after AD */
489 sg->length -= assoclen;
490 sg->offset += assoclen;
491 break;
492 }
493 }
494
495 aead_request_set_assoc(&ctx->aead_req, assoc, ctx->aead_assoclen);
496 aead_request_set_crypt(&ctx->aead_req, sg, ctx->rsgl[0].sg, used,
497 ctx->iv);
498
499 err = af_alg_wait_for_completion(ctx->enc ?
500 crypto_aead_encrypt(&ctx->aead_req) :
501 crypto_aead_decrypt(&ctx->aead_req),
502 &ctx->completion);
503
504 if (err) {
505 /* EBADMSG implies a valid cipher operation took place */
506 if (err == -EBADMSG)
507 aead_put_sgl(sk);
508 goto unlock;
509 }
510
511 aead_put_sgl(sk);
512
513 err = 0;
514
515unlock:
516 for (i = 0; i < cnt; i++)
517 af_alg_free_sg(&ctx->rsgl[i]);
518
519 aead_wmem_wakeup(sk);
520 release_sock(sk);
521
522 return err ? err : outlen;
523}
524
525static unsigned int aead_poll(struct file *file, struct socket *sock,
526 poll_table *wait)
527{
528 struct sock *sk = sock->sk;
529 struct alg_sock *ask = alg_sk(sk);
530 struct aead_ctx *ctx = ask->private;
531 unsigned int mask;
532
533 sock_poll_wait(file, sk_sleep(sk), wait);
534 mask = 0;
535
536 if (!ctx->more)
537 mask |= POLLIN | POLLRDNORM;
538
539 if (aead_writable(sk))
540 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
541
542 return mask;
543}
544
545static struct proto_ops algif_aead_ops = {
546 .family = PF_ALG,
547
548 .connect = sock_no_connect,
549 .socketpair = sock_no_socketpair,
550 .getname = sock_no_getname,
551 .ioctl = sock_no_ioctl,
552 .listen = sock_no_listen,
553 .shutdown = sock_no_shutdown,
554 .getsockopt = sock_no_getsockopt,
555 .mmap = sock_no_mmap,
556 .bind = sock_no_bind,
557 .accept = sock_no_accept,
558 .setsockopt = sock_no_setsockopt,
559
560 .release = af_alg_release,
561 .sendmsg = aead_sendmsg,
562 .sendpage = aead_sendpage,
563 .recvmsg = aead_recvmsg,
564 .poll = aead_poll,
565};
566
567static void *aead_bind(const char *name, u32 type, u32 mask)
568{
569 return crypto_alloc_aead(name, type, mask);
570}
571
572static void aead_release(void *private)
573{
574 crypto_free_aead(private);
575}
576
577static int aead_setauthsize(void *private, unsigned int authsize)
578{
579 return crypto_aead_setauthsize(private, authsize);
580}
581
582static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
583{
584 return crypto_aead_setkey(private, key, keylen);
585}
586
587static void aead_sock_destruct(struct sock *sk)
588{
589 struct alg_sock *ask = alg_sk(sk);
590 struct aead_ctx *ctx = ask->private;
591 unsigned int ivlen = crypto_aead_ivsize(
592 crypto_aead_reqtfm(&ctx->aead_req));
593
594 aead_put_sgl(sk);
595 sock_kzfree_s(sk, ctx->iv, ivlen);
596 sock_kfree_s(sk, ctx, ctx->len);
597 af_alg_release_parent(sk);
598}
599
600static int aead_accept_parent(void *private, struct sock *sk)
601{
602 struct aead_ctx *ctx;
603 struct alg_sock *ask = alg_sk(sk);
604 unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
605 unsigned int ivlen = crypto_aead_ivsize(private);
606
607 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
608 if (!ctx)
609 return -ENOMEM;
610 memset(ctx, 0, len);
611
612 ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
613 if (!ctx->iv) {
614 sock_kfree_s(sk, ctx, len);
615 return -ENOMEM;
616 }
617 memset(ctx->iv, 0, ivlen);
618
619 ctx->len = len;
620 ctx->used = 0;
621 ctx->more = 0;
622 ctx->merge = 0;
623 ctx->enc = 0;
624 ctx->tsgl.cur = 0;
625 ctx->aead_assoclen = 0;
626 af_alg_init_completion(&ctx->completion);
627 sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
628
629 ask->private = ctx;
630
631 aead_request_set_tfm(&ctx->aead_req, private);
632 aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
633 af_alg_complete, &ctx->completion);
634
635 sk->sk_destruct = aead_sock_destruct;
636
637 return 0;
638}
639
640static const struct af_alg_type algif_type_aead = {
641 .bind = aead_bind,
642 .release = aead_release,
643 .setkey = aead_setkey,
644 .setauthsize = aead_setauthsize,
645 .accept = aead_accept_parent,
646 .ops = &algif_aead_ops,
647 .name = "aead",
648 .owner = THIS_MODULE
649};
650
651static int __init algif_aead_init(void)
652{
653 return af_alg_register_type(&algif_type_aead);
654}
655
656static void __exit algif_aead_exit(void)
657{
658 int err = af_alg_unregister_type(&algif_type_aead);
659 BUG_ON(err);
660}
661
662module_init(algif_aead_init);
663module_exit(algif_aead_exit);
664MODULE_LICENSE("GPL");
665MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
666MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-17 04:39:59 -0400