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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * algif_aead: User-space interface for AEAD algorithms
4 *
5 * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
6 *
7 * This file provides the user-space API for AEAD ciphers.
8 *
9 * The following concept of the memory management is used:
10 *
11 * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is
12 * filled by user space with the data submitted via sendmsg (maybe with
13 * MSG_SPLICE_PAGES). Filling up the TX SGL does not cause a crypto operation
14 * -- the data will only be tracked by the kernel. Upon receipt of one recvmsg
15 * call, the caller must provide a buffer which is tracked with the RX SGL.
16 *
17 * During the processing of the recvmsg operation, the cipher request is
18 * allocated and prepared. As part of the recvmsg operation, the processed
19 * TX buffers are extracted from the TX SGL into a separate SGL.
20 *
21 * After the completion of the crypto operation, the RX SGL and the cipher
22 * request is released. The extracted TX SGL parts are released together with
23 * the RX SGL release.
24 */
25
26#include <crypto/internal/aead.h>
27#include <crypto/scatterwalk.h>
28#include <crypto/if_alg.h>
29#include <crypto/skcipher.h>
30#include <crypto/null.h>
31#include <linux/init.h>
32#include <linux/list.h>
33#include <linux/kernel.h>
34#include <linux/mm.h>
35#include <linux/module.h>
36#include <linux/net.h>
37#include <net/sock.h>
38
39struct aead_tfm {
40 struct crypto_aead *aead;
41 struct crypto_sync_skcipher *null_tfm;
42};
43
44static inline bool aead_sufficient_data(struct sock *sk)
45{
46 struct alg_sock *ask = alg_sk(sk);
47 struct sock *psk = ask->parent;
48 struct alg_sock *pask = alg_sk(psk);
49 struct af_alg_ctx *ctx = ask->private;
50 struct aead_tfm *aeadc = pask->private;
51 struct crypto_aead *tfm = aeadc->aead;
52 unsigned int as = crypto_aead_authsize(tfm);
53
54 /*
55 * The minimum amount of memory needed for an AEAD cipher is
56 * the AAD and in case of decryption the tag.
57 */
58 return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as);
59}
60
61static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
62{
63 struct sock *sk = sock->sk;
64 struct alg_sock *ask = alg_sk(sk);
65 struct sock *psk = ask->parent;
66 struct alg_sock *pask = alg_sk(psk);
67 struct aead_tfm *aeadc = pask->private;
68 struct crypto_aead *tfm = aeadc->aead;
69 unsigned int ivsize = crypto_aead_ivsize(tfm);
70
71 return af_alg_sendmsg(sock, msg, size, ivsize);
72}
73
74static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
75 struct scatterlist *src,
76 struct scatterlist *dst, unsigned int len)
77{
78 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
79
80 skcipher_request_set_sync_tfm(skreq, null_tfm);
81 skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_SLEEP,
82 NULL, NULL);
83 skcipher_request_set_crypt(skreq, src, dst, len, NULL);
84
85 return crypto_skcipher_encrypt(skreq);
86}
87
88static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
89 size_t ignored, int flags)
90{
91 struct sock *sk = sock->sk;
92 struct alg_sock *ask = alg_sk(sk);
93 struct sock *psk = ask->parent;
94 struct alg_sock *pask = alg_sk(psk);
95 struct af_alg_ctx *ctx = ask->private;
96 struct aead_tfm *aeadc = pask->private;
97 struct crypto_aead *tfm = aeadc->aead;
98 struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
99 unsigned int i, as = crypto_aead_authsize(tfm);
100 struct af_alg_async_req *areq;
101 struct af_alg_tsgl *tsgl, *tmp;
102 struct scatterlist *rsgl_src, *tsgl_src = NULL;
103 int err = 0;
104 size_t used = 0; /* [in] TX bufs to be en/decrypted */
105 size_t outlen = 0; /* [out] RX bufs produced by kernel */
106 size_t usedpages = 0; /* [in] RX bufs to be used from user */
107 size_t processed = 0; /* [in] TX bufs to be consumed */
108
109 if (!ctx->init || ctx->more) {
110 err = af_alg_wait_for_data(sk, flags, 0);
111 if (err)
112 return err;
113 }
114
115 /*
116 * Data length provided by caller via sendmsg that has not yet been
117 * processed.
118 */
119 used = ctx->used;
120
121 /*
122 * Make sure sufficient data is present -- note, the same check is also
123 * present in sendmsg. The checks in sendmsg shall provide an
124 * information to the data sender that something is wrong, but they are
125 * irrelevant to maintain the kernel integrity. We need this check
126 * here too in case user space decides to not honor the error message
127 * in sendmsg and still call recvmsg. This check here protects the
128 * kernel integrity.
129 */
130 if (!aead_sufficient_data(sk))
131 return -EINVAL;
132
133 /*
134 * Calculate the minimum output buffer size holding the result of the
135 * cipher operation. When encrypting data, the receiving buffer is
136 * larger by the tag length compared to the input buffer as the
137 * encryption operation generates the tag. For decryption, the input
138 * buffer provides the tag which is consumed resulting in only the
139 * plaintext without a buffer for the tag returned to the caller.
140 */
141 if (ctx->enc)
142 outlen = used + as;
143 else
144 outlen = used - as;
145
146 /*
147 * The cipher operation input data is reduced by the associated data
148 * length as this data is processed separately later on.
149 */
150 used -= ctx->aead_assoclen;
151
152 /* Allocate cipher request for current operation. */
153 areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +
154 crypto_aead_reqsize(tfm));
155 if (IS_ERR(areq))
156 return PTR_ERR(areq);
157
158 /* convert iovecs of output buffers into RX SGL */
159 err = af_alg_get_rsgl(sk, msg, flags, areq, outlen, &usedpages);
160 if (err)
161 goto free;
162
163 /*
164 * Ensure output buffer is sufficiently large. If the caller provides
165 * less buffer space, only use the relative required input size. This
166 * allows AIO operation where the caller sent all data to be processed
167 * and the AIO operation performs the operation on the different chunks
168 * of the input data.
169 */
170 if (usedpages < outlen) {
171 size_t less = outlen - usedpages;
172
173 if (used < less) {
174 err = -EINVAL;
175 goto free;
176 }
177 used -= less;
178 outlen -= less;
179 }
180
181 processed = used + ctx->aead_assoclen;
182 list_for_each_entry_safe(tsgl, tmp, &ctx->tsgl_list, list) {
183 for (i = 0; i < tsgl->cur; i++) {
184 struct scatterlist *process_sg = tsgl->sg + i;
185
186 if (!(process_sg->length) || !sg_page(process_sg))
187 continue;
188 tsgl_src = process_sg;
189 break;
190 }
191 if (tsgl_src)
192 break;
193 }
194 if (processed && !tsgl_src) {
195 err = -EFAULT;
196 goto free;
197 }
198
199 /*
200 * Copy of AAD from source to destination
201 *
202 * The AAD is copied to the destination buffer without change. Even
203 * when user space uses an in-place cipher operation, the kernel
204 * will copy the data as it does not see whether such in-place operation
205 * is initiated.
206 *
207 * To ensure efficiency, the following implementation ensure that the
208 * ciphers are invoked to perform a crypto operation in-place. This
209 * is achieved by memory management specified as follows.
210 */
211
212 /* Use the RX SGL as source (and destination) for crypto op. */
213 rsgl_src = areq->first_rsgl.sgl.sgt.sgl;
214
215 if (ctx->enc) {
216 /*
217 * Encryption operation - The in-place cipher operation is
218 * achieved by the following operation:
219 *
220 * TX SGL: AAD || PT
221 * | |
222 * | copy |
223 * v v
224 * RX SGL: AAD || PT || Tag
225 */
226 err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
227 areq->first_rsgl.sgl.sgt.sgl,
228 processed);
229 if (err)
230 goto free;
231 af_alg_pull_tsgl(sk, processed, NULL, 0);
232 } else {
233 /*
234 * Decryption operation - To achieve an in-place cipher
235 * operation, the following SGL structure is used:
236 *
237 * TX SGL: AAD || CT || Tag
238 * | | ^
239 * | copy | | Create SGL link.
240 * v v |
241 * RX SGL: AAD || CT ----+
242 */
243
244 /* Copy AAD || CT to RX SGL buffer for in-place operation. */
245 err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
246 areq->first_rsgl.sgl.sgt.sgl,
247 outlen);
248 if (err)
249 goto free;
250
251 /* Create TX SGL for tag and chain it to RX SGL. */
252 areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
253 processed - as);
254 if (!areq->tsgl_entries)
255 areq->tsgl_entries = 1;
256 areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
257 areq->tsgl_entries),
258 GFP_KERNEL);
259 if (!areq->tsgl) {
260 err = -ENOMEM;
261 goto free;
262 }
263 sg_init_table(areq->tsgl, areq->tsgl_entries);
264
265 /* Release TX SGL, except for tag data and reassign tag data. */
266 af_alg_pull_tsgl(sk, processed, areq->tsgl, processed - as);
267
268 /* chain the areq TX SGL holding the tag with RX SGL */
269 if (usedpages) {
270 /* RX SGL present */
271 struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
272 struct scatterlist *sg = sgl_prev->sgt.sgl;
273
274 sg_unmark_end(sg + sgl_prev->sgt.nents - 1);
275 sg_chain(sg, sgl_prev->sgt.nents + 1, areq->tsgl);
276 } else
277 /* no RX SGL present (e.g. authentication only) */
278 rsgl_src = areq->tsgl;
279 }
280
281 /* Initialize the crypto operation */
282 aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
283 areq->first_rsgl.sgl.sgt.sgl, used, ctx->iv);
284 aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
285 aead_request_set_tfm(&areq->cra_u.aead_req, tfm);
286
287 if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {
288 /* AIO operation */
289 sock_hold(sk);
290 areq->iocb = msg->msg_iocb;
291
292 /* Remember output size that will be generated. */
293 areq->outlen = outlen;
294
295 aead_request_set_callback(&areq->cra_u.aead_req,
296 CRYPTO_TFM_REQ_MAY_SLEEP,
297 af_alg_async_cb, areq);
298 err = ctx->enc ? crypto_aead_encrypt(&areq->cra_u.aead_req) :
299 crypto_aead_decrypt(&areq->cra_u.aead_req);
300
301 /* AIO operation in progress */
302 if (err == -EINPROGRESS)
303 return -EIOCBQUEUED;
304
305 sock_put(sk);
306 } else {
307 /* Synchronous operation */
308 aead_request_set_callback(&areq->cra_u.aead_req,
309 CRYPTO_TFM_REQ_MAY_SLEEP |
310 CRYPTO_TFM_REQ_MAY_BACKLOG,
311 crypto_req_done, &ctx->wait);
312 err = crypto_wait_req(ctx->enc ?
313 crypto_aead_encrypt(&areq->cra_u.aead_req) :
314 crypto_aead_decrypt(&areq->cra_u.aead_req),
315 &ctx->wait);
316 }
317
318
319free:
320 af_alg_free_resources(areq);
321
322 return err ? err : outlen;
323}
324
325static int aead_recvmsg(struct socket *sock, struct msghdr *msg,
326 size_t ignored, int flags)
327{
328 struct sock *sk = sock->sk;
329 int ret = 0;
330
331 lock_sock(sk);
332 while (msg_data_left(msg)) {
333 int err = _aead_recvmsg(sock, msg, ignored, flags);
334
335 /*
336 * This error covers -EIOCBQUEUED which implies that we can
337 * only handle one AIO request. If the caller wants to have
338 * multiple AIO requests in parallel, he must make multiple
339 * separate AIO calls.
340 *
341 * Also return the error if no data has been processed so far.
342 */
343 if (err <= 0) {
344 if (err == -EIOCBQUEUED || err == -EBADMSG || !ret)
345 ret = err;
346 goto out;
347 }
348
349 ret += err;
350 }
351
352out:
353 af_alg_wmem_wakeup(sk);
354 release_sock(sk);
355 return ret;
356}
357
358static struct proto_ops algif_aead_ops = {
359 .family = PF_ALG,
360
361 .connect = sock_no_connect,
362 .socketpair = sock_no_socketpair,
363 .getname = sock_no_getname,
364 .ioctl = sock_no_ioctl,
365 .listen = sock_no_listen,
366 .shutdown = sock_no_shutdown,
367 .mmap = sock_no_mmap,
368 .bind = sock_no_bind,
369 .accept = sock_no_accept,
370
371 .release = af_alg_release,
372 .sendmsg = aead_sendmsg,
373 .recvmsg = aead_recvmsg,
374 .poll = af_alg_poll,
375};
376
377static int aead_check_key(struct socket *sock)
378{
379 int err = 0;
380 struct sock *psk;
381 struct alg_sock *pask;
382 struct aead_tfm *tfm;
383 struct sock *sk = sock->sk;
384 struct alg_sock *ask = alg_sk(sk);
385
386 lock_sock(sk);
387 if (!atomic_read(&ask->nokey_refcnt))
388 goto unlock_child;
389
390 psk = ask->parent;
391 pask = alg_sk(ask->parent);
392 tfm = pask->private;
393
394 err = -ENOKEY;
395 lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
396 if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
397 goto unlock;
398
399 atomic_dec(&pask->nokey_refcnt);
400 atomic_set(&ask->nokey_refcnt, 0);
401
402 err = 0;
403
404unlock:
405 release_sock(psk);
406unlock_child:
407 release_sock(sk);
408
409 return err;
410}
411
412static int aead_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
413 size_t size)
414{
415 int err;
416
417 err = aead_check_key(sock);
418 if (err)
419 return err;
420
421 return aead_sendmsg(sock, msg, size);
422}
423
424static int aead_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
425 size_t ignored, int flags)
426{
427 int err;
428
429 err = aead_check_key(sock);
430 if (err)
431 return err;
432
433 return aead_recvmsg(sock, msg, ignored, flags);
434}
435
436static struct proto_ops algif_aead_ops_nokey = {
437 .family = PF_ALG,
438
439 .connect = sock_no_connect,
440 .socketpair = sock_no_socketpair,
441 .getname = sock_no_getname,
442 .ioctl = sock_no_ioctl,
443 .listen = sock_no_listen,
444 .shutdown = sock_no_shutdown,
445 .mmap = sock_no_mmap,
446 .bind = sock_no_bind,
447 .accept = sock_no_accept,
448
449 .release = af_alg_release,
450 .sendmsg = aead_sendmsg_nokey,
451 .recvmsg = aead_recvmsg_nokey,
452 .poll = af_alg_poll,
453};
454
455static void *aead_bind(const char *name, u32 type, u32 mask)
456{
457 struct aead_tfm *tfm;
458 struct crypto_aead *aead;
459 struct crypto_sync_skcipher *null_tfm;
460
461 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
462 if (!tfm)
463 return ERR_PTR(-ENOMEM);
464
465 aead = crypto_alloc_aead(name, type, mask);
466 if (IS_ERR(aead)) {
467 kfree(tfm);
468 return ERR_CAST(aead);
469 }
470
471 null_tfm = crypto_get_default_null_skcipher();
472 if (IS_ERR(null_tfm)) {
473 crypto_free_aead(aead);
474 kfree(tfm);
475 return ERR_CAST(null_tfm);
476 }
477
478 tfm->aead = aead;
479 tfm->null_tfm = null_tfm;
480
481 return tfm;
482}
483
484static void aead_release(void *private)
485{
486 struct aead_tfm *tfm = private;
487
488 crypto_free_aead(tfm->aead);
489 crypto_put_default_null_skcipher();
490 kfree(tfm);
491}
492
493static int aead_setauthsize(void *private, unsigned int authsize)
494{
495 struct aead_tfm *tfm = private;
496
497 return crypto_aead_setauthsize(tfm->aead, authsize);
498}
499
500static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
501{
502 struct aead_tfm *tfm = private;
503
504 return crypto_aead_setkey(tfm->aead, key, keylen);
505}
506
507static void aead_sock_destruct(struct sock *sk)
508{
509 struct alg_sock *ask = alg_sk(sk);
510 struct af_alg_ctx *ctx = ask->private;
511 struct sock *psk = ask->parent;
512 struct alg_sock *pask = alg_sk(psk);
513 struct aead_tfm *aeadc = pask->private;
514 struct crypto_aead *tfm = aeadc->aead;
515 unsigned int ivlen = crypto_aead_ivsize(tfm);
516
517 af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
518 sock_kzfree_s(sk, ctx->iv, ivlen);
519 sock_kfree_s(sk, ctx, ctx->len);
520 af_alg_release_parent(sk);
521}
522
523static int aead_accept_parent_nokey(void *private, struct sock *sk)
524{
525 struct af_alg_ctx *ctx;
526 struct alg_sock *ask = alg_sk(sk);
527 struct aead_tfm *tfm = private;
528 struct crypto_aead *aead = tfm->aead;
529 unsigned int len = sizeof(*ctx);
530 unsigned int ivlen = crypto_aead_ivsize(aead);
531
532 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
533 if (!ctx)
534 return -ENOMEM;
535 memset(ctx, 0, len);
536
537 ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
538 if (!ctx->iv) {
539 sock_kfree_s(sk, ctx, len);
540 return -ENOMEM;
541 }
542 memset(ctx->iv, 0, ivlen);
543
544 INIT_LIST_HEAD(&ctx->tsgl_list);
545 ctx->len = len;
546 crypto_init_wait(&ctx->wait);
547
548 ask->private = ctx;
549
550 sk->sk_destruct = aead_sock_destruct;
551
552 return 0;
553}
554
555static int aead_accept_parent(void *private, struct sock *sk)
556{
557 struct aead_tfm *tfm = private;
558
559 if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
560 return -ENOKEY;
561
562 return aead_accept_parent_nokey(private, sk);
563}
564
565static const struct af_alg_type algif_type_aead = {
566 .bind = aead_bind,
567 .release = aead_release,
568 .setkey = aead_setkey,
569 .setauthsize = aead_setauthsize,
570 .accept = aead_accept_parent,
571 .accept_nokey = aead_accept_parent_nokey,
572 .ops = &algif_aead_ops,
573 .ops_nokey = &algif_aead_ops_nokey,
574 .name = "aead",
575 .owner = THIS_MODULE
576};
577
578static int __init algif_aead_init(void)
579{
580 return af_alg_register_type(&algif_type_aead);
581}
582
583static void __exit algif_aead_exit(void)
584{
585 int err = af_alg_unregister_type(&algif_type_aead);
586 BUG_ON(err);
587}
588
589module_init(algif_aead_init);
590module_exit(algif_aead_exit);
591MODULE_LICENSE("GPL");
592MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
593MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");
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/internal/aead.h>
17#include <crypto/scatterwalk.h>
18#include <crypto/if_alg.h>
19#include <linux/init.h>
20#include <linux/list.h>
21#include <linux/kernel.h>
22#include <linux/mm.h>
23#include <linux/module.h>
24#include <linux/net.h>
25#include <net/sock.h>
26
27struct aead_sg_list {
28 unsigned int cur;
29 struct scatterlist sg[ALG_MAX_PAGES];
30};
31
32struct aead_async_rsgl {
33 struct af_alg_sgl sgl;
34 struct list_head list;
35};
36
37struct aead_async_req {
38 struct scatterlist *tsgl;
39 struct aead_async_rsgl first_rsgl;
40 struct list_head list;
41 struct kiocb *iocb;
42 unsigned int tsgls;
43 char iv[];
44};
45
46struct aead_ctx {
47 struct aead_sg_list tsgl;
48 struct aead_async_rsgl first_rsgl;
49 struct list_head list;
50
51 void *iv;
52
53 struct af_alg_completion completion;
54
55 unsigned long used;
56
57 unsigned int len;
58 bool more;
59 bool merge;
60 bool enc;
61
62 size_t aead_assoclen;
63 struct aead_request aead_req;
64};
65
66static inline int aead_sndbuf(struct sock *sk)
67{
68 struct alg_sock *ask = alg_sk(sk);
69 struct aead_ctx *ctx = ask->private;
70
71 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
72 ctx->used, 0);
73}
74
75static inline bool aead_writable(struct sock *sk)
76{
77 return PAGE_SIZE <= aead_sndbuf(sk);
78}
79
80static inline bool aead_sufficient_data(struct aead_ctx *ctx)
81{
82 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
83
84 /*
85 * The minimum amount of memory needed for an AEAD cipher is
86 * the AAD and in case of decryption the tag.
87 */
88 return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as);
89}
90
91static void aead_reset_ctx(struct aead_ctx *ctx)
92{
93 struct aead_sg_list *sgl = &ctx->tsgl;
94
95 sg_init_table(sgl->sg, ALG_MAX_PAGES);
96 sgl->cur = 0;
97 ctx->used = 0;
98 ctx->more = 0;
99 ctx->merge = 0;
100}
101
102static void aead_put_sgl(struct sock *sk)
103{
104 struct alg_sock *ask = alg_sk(sk);
105 struct aead_ctx *ctx = ask->private;
106 struct aead_sg_list *sgl = &ctx->tsgl;
107 struct scatterlist *sg = sgl->sg;
108 unsigned int i;
109
110 for (i = 0; i < sgl->cur; i++) {
111 if (!sg_page(sg + i))
112 continue;
113
114 put_page(sg_page(sg + i));
115 sg_assign_page(sg + i, NULL);
116 }
117 aead_reset_ctx(ctx);
118}
119
120static void aead_wmem_wakeup(struct sock *sk)
121{
122 struct socket_wq *wq;
123
124 if (!aead_writable(sk))
125 return;
126
127 rcu_read_lock();
128 wq = rcu_dereference(sk->sk_wq);
129 if (skwq_has_sleeper(wq))
130 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
131 POLLRDNORM |
132 POLLRDBAND);
133 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
134 rcu_read_unlock();
135}
136
137static int aead_wait_for_data(struct sock *sk, unsigned flags)
138{
139 DEFINE_WAIT_FUNC(wait, woken_wake_function);
140 struct alg_sock *ask = alg_sk(sk);
141 struct aead_ctx *ctx = ask->private;
142 long timeout;
143 int err = -ERESTARTSYS;
144
145 if (flags & MSG_DONTWAIT)
146 return -EAGAIN;
147
148 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
149 add_wait_queue(sk_sleep(sk), &wait);
150 for (;;) {
151 if (signal_pending(current))
152 break;
153 timeout = MAX_SCHEDULE_TIMEOUT;
154 if (sk_wait_event(sk, &timeout, !ctx->more, &wait)) {
155 err = 0;
156 break;
157 }
158 }
159 remove_wait_queue(sk_sleep(sk), &wait);
160
161 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
162
163 return err;
164}
165
166static void aead_data_wakeup(struct sock *sk)
167{
168 struct alg_sock *ask = alg_sk(sk);
169 struct aead_ctx *ctx = ask->private;
170 struct socket_wq *wq;
171
172 if (ctx->more)
173 return;
174 if (!ctx->used)
175 return;
176
177 rcu_read_lock();
178 wq = rcu_dereference(sk->sk_wq);
179 if (skwq_has_sleeper(wq))
180 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
181 POLLRDNORM |
182 POLLRDBAND);
183 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
184 rcu_read_unlock();
185}
186
187static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
188{
189 struct sock *sk = sock->sk;
190 struct alg_sock *ask = alg_sk(sk);
191 struct aead_ctx *ctx = ask->private;
192 unsigned ivsize =
193 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
194 struct aead_sg_list *sgl = &ctx->tsgl;
195 struct af_alg_control con = {};
196 long copied = 0;
197 bool enc = 0;
198 bool init = 0;
199 int err = -EINVAL;
200
201 if (msg->msg_controllen) {
202 err = af_alg_cmsg_send(msg, &con);
203 if (err)
204 return err;
205
206 init = 1;
207 switch (con.op) {
208 case ALG_OP_ENCRYPT:
209 enc = 1;
210 break;
211 case ALG_OP_DECRYPT:
212 enc = 0;
213 break;
214 default:
215 return -EINVAL;
216 }
217
218 if (con.iv && con.iv->ivlen != ivsize)
219 return -EINVAL;
220 }
221
222 lock_sock(sk);
223 if (!ctx->more && ctx->used)
224 goto unlock;
225
226 if (init) {
227 ctx->enc = enc;
228 if (con.iv)
229 memcpy(ctx->iv, con.iv->iv, ivsize);
230
231 ctx->aead_assoclen = con.aead_assoclen;
232 }
233
234 while (size) {
235 size_t len = size;
236 struct scatterlist *sg = NULL;
237
238 /* use the existing memory in an allocated page */
239 if (ctx->merge) {
240 sg = sgl->sg + sgl->cur - 1;
241 len = min_t(unsigned long, len,
242 PAGE_SIZE - sg->offset - sg->length);
243 err = memcpy_from_msg(page_address(sg_page(sg)) +
244 sg->offset + sg->length,
245 msg, len);
246 if (err)
247 goto unlock;
248
249 sg->length += len;
250 ctx->merge = (sg->offset + sg->length) &
251 (PAGE_SIZE - 1);
252
253 ctx->used += len;
254 copied += len;
255 size -= len;
256 continue;
257 }
258
259 if (!aead_writable(sk)) {
260 /* user space sent too much data */
261 aead_put_sgl(sk);
262 err = -EMSGSIZE;
263 goto unlock;
264 }
265
266 /* allocate a new page */
267 len = min_t(unsigned long, size, aead_sndbuf(sk));
268 while (len) {
269 size_t plen = 0;
270
271 if (sgl->cur >= ALG_MAX_PAGES) {
272 aead_put_sgl(sk);
273 err = -E2BIG;
274 goto unlock;
275 }
276
277 sg = sgl->sg + sgl->cur;
278 plen = min_t(size_t, len, PAGE_SIZE);
279
280 sg_assign_page(sg, alloc_page(GFP_KERNEL));
281 err = -ENOMEM;
282 if (!sg_page(sg))
283 goto unlock;
284
285 err = memcpy_from_msg(page_address(sg_page(sg)),
286 msg, plen);
287 if (err) {
288 __free_page(sg_page(sg));
289 sg_assign_page(sg, NULL);
290 goto unlock;
291 }
292
293 sg->offset = 0;
294 sg->length = plen;
295 len -= plen;
296 ctx->used += plen;
297 copied += plen;
298 sgl->cur++;
299 size -= plen;
300 ctx->merge = plen & (PAGE_SIZE - 1);
301 }
302 }
303
304 err = 0;
305
306 ctx->more = msg->msg_flags & MSG_MORE;
307 if (!ctx->more && !aead_sufficient_data(ctx)) {
308 aead_put_sgl(sk);
309 err = -EMSGSIZE;
310 }
311
312unlock:
313 aead_data_wakeup(sk);
314 release_sock(sk);
315
316 return err ?: copied;
317}
318
319static ssize_t aead_sendpage(struct socket *sock, struct page *page,
320 int offset, size_t size, int flags)
321{
322 struct sock *sk = sock->sk;
323 struct alg_sock *ask = alg_sk(sk);
324 struct aead_ctx *ctx = ask->private;
325 struct aead_sg_list *sgl = &ctx->tsgl;
326 int err = -EINVAL;
327
328 if (flags & MSG_SENDPAGE_NOTLAST)
329 flags |= MSG_MORE;
330
331 if (sgl->cur >= ALG_MAX_PAGES)
332 return -E2BIG;
333
334 lock_sock(sk);
335 if (!ctx->more && ctx->used)
336 goto unlock;
337
338 if (!size)
339 goto done;
340
341 if (!aead_writable(sk)) {
342 /* user space sent too much data */
343 aead_put_sgl(sk);
344 err = -EMSGSIZE;
345 goto unlock;
346 }
347
348 ctx->merge = 0;
349
350 get_page(page);
351 sg_set_page(sgl->sg + sgl->cur, page, size, offset);
352 sgl->cur++;
353 ctx->used += size;
354
355 err = 0;
356
357done:
358 ctx->more = flags & MSG_MORE;
359 if (!ctx->more && !aead_sufficient_data(ctx)) {
360 aead_put_sgl(sk);
361 err = -EMSGSIZE;
362 }
363
364unlock:
365 aead_data_wakeup(sk);
366 release_sock(sk);
367
368 return err ?: size;
369}
370
371#define GET_ASYM_REQ(req, tfm) (struct aead_async_req *) \
372 ((char *)req + sizeof(struct aead_request) + \
373 crypto_aead_reqsize(tfm))
374
375 #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
376 crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
377 sizeof(struct aead_request)
378
379static void aead_async_cb(struct crypto_async_request *_req, int err)
380{
381 struct sock *sk = _req->data;
382 struct alg_sock *ask = alg_sk(sk);
383 struct aead_ctx *ctx = ask->private;
384 struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
385 struct aead_request *req = aead_request_cast(_req);
386 struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
387 struct scatterlist *sg = areq->tsgl;
388 struct aead_async_rsgl *rsgl;
389 struct kiocb *iocb = areq->iocb;
390 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
391
392 list_for_each_entry(rsgl, &areq->list, list) {
393 af_alg_free_sg(&rsgl->sgl);
394 if (rsgl != &areq->first_rsgl)
395 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
396 }
397
398 for (i = 0; i < areq->tsgls; i++)
399 put_page(sg_page(sg + i));
400
401 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
402 sock_kfree_s(sk, req, reqlen);
403 __sock_put(sk);
404 iocb->ki_complete(iocb, err, err);
405}
406
407static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
408 int flags)
409{
410 struct sock *sk = sock->sk;
411 struct alg_sock *ask = alg_sk(sk);
412 struct aead_ctx *ctx = ask->private;
413 struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
414 struct aead_async_req *areq;
415 struct aead_request *req = NULL;
416 struct aead_sg_list *sgl = &ctx->tsgl;
417 struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
418 unsigned int as = crypto_aead_authsize(tfm);
419 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
420 int err = -ENOMEM;
421 unsigned long used;
422 size_t outlen = 0;
423 size_t usedpages = 0;
424
425 lock_sock(sk);
426 if (ctx->more) {
427 err = aead_wait_for_data(sk, flags);
428 if (err)
429 goto unlock;
430 }
431
432 if (!aead_sufficient_data(ctx))
433 goto unlock;
434
435 used = ctx->used;
436 if (ctx->enc)
437 outlen = used + as;
438 else
439 outlen = used - as;
440
441 req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
442 if (unlikely(!req))
443 goto unlock;
444
445 areq = GET_ASYM_REQ(req, tfm);
446 memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
447 INIT_LIST_HEAD(&areq->list);
448 areq->iocb = msg->msg_iocb;
449 memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
450 aead_request_set_tfm(req, tfm);
451 aead_request_set_ad(req, ctx->aead_assoclen);
452 aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
453 aead_async_cb, sk);
454 used -= ctx->aead_assoclen;
455
456 /* take over all tx sgls from ctx */
457 areq->tsgl = sock_kmalloc(sk,
458 sizeof(*areq->tsgl) * max_t(u32, sgl->cur, 1),
459 GFP_KERNEL);
460 if (unlikely(!areq->tsgl))
461 goto free;
462
463 sg_init_table(areq->tsgl, max_t(u32, sgl->cur, 1));
464 for (i = 0; i < sgl->cur; i++)
465 sg_set_page(&areq->tsgl[i], sg_page(&sgl->sg[i]),
466 sgl->sg[i].length, sgl->sg[i].offset);
467
468 areq->tsgls = sgl->cur;
469
470 /* create rx sgls */
471 while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) {
472 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
473 (outlen - usedpages));
474
475 if (list_empty(&areq->list)) {
476 rsgl = &areq->first_rsgl;
477
478 } else {
479 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
480 if (unlikely(!rsgl)) {
481 err = -ENOMEM;
482 goto free;
483 }
484 }
485 rsgl->sgl.npages = 0;
486 list_add_tail(&rsgl->list, &areq->list);
487
488 /* make one iovec available as scatterlist */
489 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
490 if (err < 0)
491 goto free;
492
493 usedpages += err;
494
495 /* chain the new scatterlist with previous one */
496 if (last_rsgl)
497 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
498
499 last_rsgl = rsgl;
500
501 iov_iter_advance(&msg->msg_iter, err);
502 }
503
504 /* ensure output buffer is sufficiently large */
505 if (usedpages < outlen) {
506 err = -EINVAL;
507 goto unlock;
508 }
509
510 aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
511 areq->iv);
512 err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
513 if (err) {
514 if (err == -EINPROGRESS) {
515 sock_hold(sk);
516 err = -EIOCBQUEUED;
517 aead_reset_ctx(ctx);
518 goto unlock;
519 } else if (err == -EBADMSG) {
520 aead_put_sgl(sk);
521 }
522 goto free;
523 }
524 aead_put_sgl(sk);
525
526free:
527 list_for_each_entry(rsgl, &areq->list, list) {
528 af_alg_free_sg(&rsgl->sgl);
529 if (rsgl != &areq->first_rsgl)
530 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
531 }
532 if (areq->tsgl)
533 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
534 if (req)
535 sock_kfree_s(sk, req, reqlen);
536unlock:
537 aead_wmem_wakeup(sk);
538 release_sock(sk);
539 return err ? err : outlen;
540}
541
542static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags)
543{
544 struct sock *sk = sock->sk;
545 struct alg_sock *ask = alg_sk(sk);
546 struct aead_ctx *ctx = ask->private;
547 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
548 struct aead_sg_list *sgl = &ctx->tsgl;
549 struct aead_async_rsgl *last_rsgl = NULL;
550 struct aead_async_rsgl *rsgl, *tmp;
551 int err = -EINVAL;
552 unsigned long used = 0;
553 size_t outlen = 0;
554 size_t usedpages = 0;
555
556 lock_sock(sk);
557
558 /*
559 * Please see documentation of aead_request_set_crypt for the
560 * description of the AEAD memory structure expected from the caller.
561 */
562
563 if (ctx->more) {
564 err = aead_wait_for_data(sk, flags);
565 if (err)
566 goto unlock;
567 }
568
569 /* data length provided by caller via sendmsg/sendpage */
570 used = ctx->used;
571
572 /*
573 * Make sure sufficient data is present -- note, the same check is
574 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
575 * shall provide an information to the data sender that something is
576 * wrong, but they are irrelevant to maintain the kernel integrity.
577 * We need this check here too in case user space decides to not honor
578 * the error message in sendmsg/sendpage and still call recvmsg. This
579 * check here protects the kernel integrity.
580 */
581 if (!aead_sufficient_data(ctx))
582 goto unlock;
583
584 /*
585 * Calculate the minimum output buffer size holding the result of the
586 * cipher operation. When encrypting data, the receiving buffer is
587 * larger by the tag length compared to the input buffer as the
588 * encryption operation generates the tag. For decryption, the input
589 * buffer provides the tag which is consumed resulting in only the
590 * plaintext without a buffer for the tag returned to the caller.
591 */
592 if (ctx->enc)
593 outlen = used + as;
594 else
595 outlen = used - as;
596
597 /*
598 * The cipher operation input data is reduced by the associated data
599 * length as this data is processed separately later on.
600 */
601 used -= ctx->aead_assoclen;
602
603 /* convert iovecs of output buffers into scatterlists */
604 while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) {
605 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
606 (outlen - usedpages));
607
608 if (list_empty(&ctx->list)) {
609 rsgl = &ctx->first_rsgl;
610 } else {
611 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
612 if (unlikely(!rsgl)) {
613 err = -ENOMEM;
614 goto unlock;
615 }
616 }
617 rsgl->sgl.npages = 0;
618 list_add_tail(&rsgl->list, &ctx->list);
619
620 /* make one iovec available as scatterlist */
621 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
622 if (err < 0)
623 goto unlock;
624 usedpages += err;
625 /* chain the new scatterlist with previous one */
626 if (last_rsgl)
627 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
628
629 last_rsgl = rsgl;
630
631 iov_iter_advance(&msg->msg_iter, err);
632 }
633
634 /* ensure output buffer is sufficiently large */
635 if (usedpages < outlen) {
636 err = -EINVAL;
637 goto unlock;
638 }
639
640 sg_mark_end(sgl->sg + sgl->cur - 1);
641 aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg,
642 used, ctx->iv);
643 aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
644
645 err = af_alg_wait_for_completion(ctx->enc ?
646 crypto_aead_encrypt(&ctx->aead_req) :
647 crypto_aead_decrypt(&ctx->aead_req),
648 &ctx->completion);
649
650 if (err) {
651 /* EBADMSG implies a valid cipher operation took place */
652 if (err == -EBADMSG)
653 aead_put_sgl(sk);
654
655 goto unlock;
656 }
657
658 aead_put_sgl(sk);
659 err = 0;
660
661unlock:
662 list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
663 af_alg_free_sg(&rsgl->sgl);
664 list_del(&rsgl->list);
665 if (rsgl != &ctx->first_rsgl)
666 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
667 }
668 INIT_LIST_HEAD(&ctx->list);
669 aead_wmem_wakeup(sk);
670 release_sock(sk);
671
672 return err ? err : outlen;
673}
674
675static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
676 int flags)
677{
678 return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
679 aead_recvmsg_async(sock, msg, flags) :
680 aead_recvmsg_sync(sock, msg, flags);
681}
682
683static unsigned int aead_poll(struct file *file, struct socket *sock,
684 poll_table *wait)
685{
686 struct sock *sk = sock->sk;
687 struct alg_sock *ask = alg_sk(sk);
688 struct aead_ctx *ctx = ask->private;
689 unsigned int mask;
690
691 sock_poll_wait(file, sk_sleep(sk), wait);
692 mask = 0;
693
694 if (!ctx->more)
695 mask |= POLLIN | POLLRDNORM;
696
697 if (aead_writable(sk))
698 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
699
700 return mask;
701}
702
703static struct proto_ops algif_aead_ops = {
704 .family = PF_ALG,
705
706 .connect = sock_no_connect,
707 .socketpair = sock_no_socketpair,
708 .getname = sock_no_getname,
709 .ioctl = sock_no_ioctl,
710 .listen = sock_no_listen,
711 .shutdown = sock_no_shutdown,
712 .getsockopt = sock_no_getsockopt,
713 .mmap = sock_no_mmap,
714 .bind = sock_no_bind,
715 .accept = sock_no_accept,
716 .setsockopt = sock_no_setsockopt,
717
718 .release = af_alg_release,
719 .sendmsg = aead_sendmsg,
720 .sendpage = aead_sendpage,
721 .recvmsg = aead_recvmsg,
722 .poll = aead_poll,
723};
724
725static void *aead_bind(const char *name, u32 type, u32 mask)
726{
727 return crypto_alloc_aead(name, type, mask);
728}
729
730static void aead_release(void *private)
731{
732 crypto_free_aead(private);
733}
734
735static int aead_setauthsize(void *private, unsigned int authsize)
736{
737 return crypto_aead_setauthsize(private, authsize);
738}
739
740static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
741{
742 return crypto_aead_setkey(private, key, keylen);
743}
744
745static void aead_sock_destruct(struct sock *sk)
746{
747 struct alg_sock *ask = alg_sk(sk);
748 struct aead_ctx *ctx = ask->private;
749 unsigned int ivlen = crypto_aead_ivsize(
750 crypto_aead_reqtfm(&ctx->aead_req));
751
752 WARN_ON(atomic_read(&sk->sk_refcnt) != 0);
753 aead_put_sgl(sk);
754 sock_kzfree_s(sk, ctx->iv, ivlen);
755 sock_kfree_s(sk, ctx, ctx->len);
756 af_alg_release_parent(sk);
757}
758
759static int aead_accept_parent(void *private, struct sock *sk)
760{
761 struct aead_ctx *ctx;
762 struct alg_sock *ask = alg_sk(sk);
763 unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
764 unsigned int ivlen = crypto_aead_ivsize(private);
765
766 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
767 if (!ctx)
768 return -ENOMEM;
769 memset(ctx, 0, len);
770
771 ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
772 if (!ctx->iv) {
773 sock_kfree_s(sk, ctx, len);
774 return -ENOMEM;
775 }
776 memset(ctx->iv, 0, ivlen);
777
778 ctx->len = len;
779 ctx->used = 0;
780 ctx->more = 0;
781 ctx->merge = 0;
782 ctx->enc = 0;
783 ctx->tsgl.cur = 0;
784 ctx->aead_assoclen = 0;
785 af_alg_init_completion(&ctx->completion);
786 sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
787 INIT_LIST_HEAD(&ctx->list);
788
789 ask->private = ctx;
790
791 aead_request_set_tfm(&ctx->aead_req, private);
792 aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
793 af_alg_complete, &ctx->completion);
794
795 sk->sk_destruct = aead_sock_destruct;
796
797 return 0;
798}
799
800static const struct af_alg_type algif_type_aead = {
801 .bind = aead_bind,
802 .release = aead_release,
803 .setkey = aead_setkey,
804 .setauthsize = aead_setauthsize,
805 .accept = aead_accept_parent,
806 .ops = &algif_aead_ops,
807 .name = "aead",
808 .owner = THIS_MODULE
809};
810
811static int __init algif_aead_init(void)
812{
813 return af_alg_register_type(&algif_type_aead);
814}
815
816static void __exit algif_aead_exit(void)
817{
818 int err = af_alg_unregister_type(&algif_type_aead);
819 BUG_ON(err);
820}
821
822module_init(algif_aead_init);
823module_exit(algif_aead_exit);
824MODULE_LICENSE("GPL");
825MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
826MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");