2 * algif_aead: User-space interface for AEAD algorithms
4 * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
6 * This file provides the user-space API for AEAD ciphers.
8 * This file is derived from algif_skcipher.c.
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)
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>
22 #include <linux/module.h>
23 #include <linux/net.h>
28 struct scatterlist sg
[ALG_MAX_PAGES
];
32 struct aead_sg_list tsgl
;
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
38 #define RSGL_MAX_ENTRIES ALG_MAX_PAGES
39 struct af_alg_sgl rsgl
[RSGL_MAX_ENTRIES
];
43 struct af_alg_completion completion
;
53 struct aead_request aead_req
;
56 static inline int aead_sndbuf(struct sock
*sk
)
58 struct alg_sock
*ask
= alg_sk(sk
);
59 struct aead_ctx
*ctx
= ask
->private;
61 return max_t(int, max_t(int, sk
->sk_sndbuf
& PAGE_MASK
, PAGE_SIZE
) -
65 static inline bool aead_writable(struct sock
*sk
)
67 return PAGE_SIZE
<= aead_sndbuf(sk
);
70 static inline bool aead_sufficient_data(struct aead_ctx
*ctx
)
72 unsigned as
= crypto_aead_authsize(crypto_aead_reqtfm(&ctx
->aead_req
));
74 return (ctx
->used
>= (ctx
->aead_assoclen
+ (ctx
->enc
? 0 : as
)));
77 static void aead_put_sgl(struct sock
*sk
)
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
;
85 for (i
= 0; i
< sgl
->cur
; i
++) {
89 put_page(sg_page(sg
+ i
));
90 sg_assign_page(sg
+ i
, NULL
);
98 static void aead_wmem_wakeup(struct sock
*sk
)
100 struct socket_wq
*wq
;
102 if (!aead_writable(sk
))
106 wq
= rcu_dereference(sk
->sk_wq
);
107 if (wq_has_sleeper(wq
))
108 wake_up_interruptible_sync_poll(&wq
->wait
, POLLIN
|
111 sk_wake_async(sk
, SOCK_WAKE_WAITD
, POLL_IN
);
115 static int aead_wait_for_data(struct sock
*sk
, unsigned flags
)
117 struct alg_sock
*ask
= alg_sk(sk
);
118 struct aead_ctx
*ctx
= ask
->private;
121 int err
= -ERESTARTSYS
;
123 if (flags
& MSG_DONTWAIT
)
126 set_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
129 if (signal_pending(current
))
131 prepare_to_wait(sk_sleep(sk
), &wait
, TASK_INTERRUPTIBLE
);
132 timeout
= MAX_SCHEDULE_TIMEOUT
;
133 if (sk_wait_event(sk
, &timeout
, !ctx
->more
)) {
138 finish_wait(sk_sleep(sk
), &wait
);
140 clear_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
145 static void aead_data_wakeup(struct sock
*sk
)
147 struct alg_sock
*ask
= alg_sk(sk
);
148 struct aead_ctx
*ctx
= ask
->private;
149 struct socket_wq
*wq
;
157 wq
= rcu_dereference(sk
->sk_wq
);
158 if (wq_has_sleeper(wq
))
159 wake_up_interruptible_sync_poll(&wq
->wait
, POLLOUT
|
162 sk_wake_async(sk
, SOCK_WAKE_SPACE
, POLL_OUT
);
166 static int aead_sendmsg(struct socket
*sock
, struct msghdr
*msg
, size_t size
)
168 struct sock
*sk
= sock
->sk
;
169 struct alg_sock
*ask
= alg_sk(sk
);
170 struct aead_ctx
*ctx
= ask
->private;
172 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx
->aead_req
));
173 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
174 struct af_alg_control con
= {};
180 if (msg
->msg_controllen
) {
181 err
= af_alg_cmsg_send(msg
, &con
);
197 if (con
.iv
&& con
.iv
->ivlen
!= ivsize
)
202 if (!ctx
->more
&& ctx
->used
)
208 memcpy(ctx
->iv
, con
.iv
->iv
, ivsize
);
210 ctx
->aead_assoclen
= con
.aead_assoclen
;
214 unsigned long len
= size
;
215 struct scatterlist
*sg
= NULL
;
217 /* use the existing memory in an allocated page */
219 sg
= sgl
->sg
+ sgl
->cur
- 1;
220 len
= min_t(unsigned long, len
,
221 PAGE_SIZE
- sg
->offset
- sg
->length
);
222 err
= memcpy_from_msg(page_address(sg_page(sg
)) +
223 sg
->offset
+ sg
->length
,
229 ctx
->merge
= (sg
->offset
+ sg
->length
) &
238 if (!aead_writable(sk
)) {
239 /* user space sent too much data */
245 /* allocate a new page */
246 len
= min_t(unsigned long, size
, aead_sndbuf(sk
));
250 if (sgl
->cur
>= ALG_MAX_PAGES
) {
256 sg
= sgl
->sg
+ sgl
->cur
;
257 plen
= min_t(int, len
, PAGE_SIZE
);
259 sg_assign_page(sg
, alloc_page(GFP_KERNEL
));
264 err
= memcpy_from_msg(page_address(sg_page(sg
)),
267 __free_page(sg_page(sg
));
268 sg_assign_page(sg
, NULL
);
279 ctx
->merge
= plen
& (PAGE_SIZE
- 1);
285 ctx
->more
= msg
->msg_flags
& MSG_MORE
;
286 if (!ctx
->more
&& !aead_sufficient_data(ctx
)) {
292 aead_data_wakeup(sk
);
295 return err
?: copied
;
298 static ssize_t
aead_sendpage(struct socket
*sock
, struct page
*page
,
299 int offset
, size_t size
, int flags
)
301 struct sock
*sk
= sock
->sk
;
302 struct alg_sock
*ask
= alg_sk(sk
);
303 struct aead_ctx
*ctx
= ask
->private;
304 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
307 if (flags
& MSG_SENDPAGE_NOTLAST
)
310 if (sgl
->cur
>= ALG_MAX_PAGES
)
314 if (!ctx
->more
&& ctx
->used
)
320 if (!aead_writable(sk
)) {
321 /* user space sent too much data */
330 sg_set_page(sgl
->sg
+ sgl
->cur
, page
, size
, offset
);
337 ctx
->more
= flags
& MSG_MORE
;
338 if (!ctx
->more
&& !aead_sufficient_data(ctx
)) {
344 aead_data_wakeup(sk
);
350 static int aead_recvmsg(struct socket
*sock
, struct msghdr
*msg
, size_t ignored
, int flags
)
352 struct sock
*sk
= sock
->sk
;
353 struct alg_sock
*ask
= alg_sk(sk
);
354 struct aead_ctx
*ctx
= ask
->private;
355 unsigned bs
= crypto_aead_blocksize(crypto_aead_reqtfm(&ctx
->aead_req
));
356 unsigned as
= crypto_aead_authsize(crypto_aead_reqtfm(&ctx
->aead_req
));
357 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
358 struct scatterlist
*sg
= NULL
;
359 struct scatterlist assoc
[ALG_MAX_PAGES
];
363 unsigned long used
= 0;
365 size_t usedpages
= 0;
366 unsigned int cnt
= 0;
368 /* Limit number of IOV blocks to be accessed below */
369 if (msg
->msg_iter
.nr_segs
> RSGL_MAX_ENTRIES
)
375 * AEAD memory structure: For encryption, the tag is appended to the
376 * ciphertext which implies that the memory allocated for the ciphertext
377 * must be increased by the tag length. For decryption, the tag
378 * is expected to be concatenated to the ciphertext. The plaintext
379 * therefore has a memory size of the ciphertext minus the tag length.
381 * The memory structure for cipher operation has the following
383 * AEAD encryption input: assoc data || plaintext
384 * AEAD encryption output: cipherntext || auth tag
385 * AEAD decryption input: assoc data || ciphertext || auth tag
386 * AEAD decryption output: plaintext
390 err
= aead_wait_for_data(sk
, flags
);
398 * Make sure sufficient data is present -- note, the same check is
399 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
400 * shall provide an information to the data sender that something is
401 * wrong, but they are irrelevant to maintain the kernel integrity.
402 * We need this check here too in case user space decides to not honor
403 * the error message in sendmsg/sendpage and still call recvmsg. This
404 * check here protects the kernel integrity.
406 if (!aead_sufficient_data(ctx
))
410 * The cipher operation input data is reduced by the associated data
411 * length as this data is processed separately later on.
413 used
-= ctx
->aead_assoclen
;
416 /* round up output buffer to multiple of block size */
417 outlen
= ((used
+ bs
- 1) / bs
* bs
);
418 /* add the size needed for the auth tag to be created */
421 /* output data size is input without the authentication tag */
423 /* round up output buffer to multiple of block size */
424 outlen
= ((outlen
+ bs
- 1) / bs
* bs
);
427 /* convert iovecs of output buffers into scatterlists */
428 while (iov_iter_count(&msg
->msg_iter
)) {
429 size_t seglen
= min_t(size_t, iov_iter_count(&msg
->msg_iter
),
430 (outlen
- usedpages
));
432 /* make one iovec available as scatterlist */
433 err
= af_alg_make_sg(&ctx
->rsgl
[cnt
], &msg
->msg_iter
,
438 /* chain the new scatterlist with previous one */
440 af_alg_link_sg(&ctx
->rsgl
[cnt
-1], &ctx
->rsgl
[cnt
]);
442 /* we do not need more iovecs as we have sufficient memory */
443 if (outlen
<= usedpages
)
445 iov_iter_advance(&msg
->msg_iter
, err
);
450 /* ensure output buffer is sufficiently large */
451 if (usedpages
< outlen
)
454 sg_init_table(assoc
, ALG_MAX_PAGES
);
455 assoclen
= ctx
->aead_assoclen
;
457 * Split scatterlist into two: first part becomes AD, second part
458 * is plaintext / ciphertext. The first part is assigned to assoc
459 * scatterlist. When this loop finishes, sg points to the start of the
460 * plaintext / ciphertext.
462 for (i
= 0; i
< ctx
->tsgl
.cur
; i
++) {
464 if (sg
->length
<= assoclen
) {
465 /* AD is larger than one page */
466 sg_set_page(assoc
+ i
, sg_page(sg
),
467 sg
->length
, sg
->offset
);
468 assoclen
-= sg
->length
;
469 if (i
>= ctx
->tsgl
.cur
)
471 } else if (!assoclen
) {
472 /* current page is to start of plaintext / ciphertext */
474 /* AD terminates at page boundary */
475 sg_mark_end(assoc
+ i
- 1);
477 /* AD size is zero */
481 /* AD does not terminate at page boundary */
482 sg_set_page(assoc
+ i
, sg_page(sg
),
483 assoclen
, sg
->offset
);
484 sg_mark_end(assoc
+ i
);
485 /* plaintext / ciphertext starts after AD */
486 sg
->length
-= assoclen
;
487 sg
->offset
+= assoclen
;
492 aead_request_set_assoc(&ctx
->aead_req
, assoc
, ctx
->aead_assoclen
);
493 aead_request_set_crypt(&ctx
->aead_req
, sg
, ctx
->rsgl
[0].sg
, used
,
496 err
= af_alg_wait_for_completion(ctx
->enc
?
497 crypto_aead_encrypt(&ctx
->aead_req
) :
498 crypto_aead_decrypt(&ctx
->aead_req
),
502 /* EBADMSG implies a valid cipher operation took place */
513 for (i
= 0; i
< cnt
; i
++)
514 af_alg_free_sg(&ctx
->rsgl
[i
]);
516 aead_wmem_wakeup(sk
);
519 return err
? err
: outlen
;
522 static unsigned int aead_poll(struct file
*file
, struct socket
*sock
,
525 struct sock
*sk
= sock
->sk
;
526 struct alg_sock
*ask
= alg_sk(sk
);
527 struct aead_ctx
*ctx
= ask
->private;
530 sock_poll_wait(file
, sk_sleep(sk
), wait
);
534 mask
|= POLLIN
| POLLRDNORM
;
536 if (aead_writable(sk
))
537 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
542 static struct proto_ops algif_aead_ops
= {
545 .connect
= sock_no_connect
,
546 .socketpair
= sock_no_socketpair
,
547 .getname
= sock_no_getname
,
548 .ioctl
= sock_no_ioctl
,
549 .listen
= sock_no_listen
,
550 .shutdown
= sock_no_shutdown
,
551 .getsockopt
= sock_no_getsockopt
,
552 .mmap
= sock_no_mmap
,
553 .bind
= sock_no_bind
,
554 .accept
= sock_no_accept
,
555 .setsockopt
= sock_no_setsockopt
,
557 .release
= af_alg_release
,
558 .sendmsg
= aead_sendmsg
,
559 .sendpage
= aead_sendpage
,
560 .recvmsg
= aead_recvmsg
,
564 static void *aead_bind(const char *name
, u32 type
, u32 mask
)
566 return crypto_alloc_aead(name
, type
, mask
);
569 static void aead_release(void *private)
571 crypto_free_aead(private);
574 static int aead_setauthsize(void *private, unsigned int authsize
)
576 return crypto_aead_setauthsize(private, authsize
);
579 static int aead_setkey(void *private, const u8
*key
, unsigned int keylen
)
581 return crypto_aead_setkey(private, key
, keylen
);
584 static void aead_sock_destruct(struct sock
*sk
)
586 struct alg_sock
*ask
= alg_sk(sk
);
587 struct aead_ctx
*ctx
= ask
->private;
588 unsigned int ivlen
= crypto_aead_ivsize(
589 crypto_aead_reqtfm(&ctx
->aead_req
));
592 sock_kzfree_s(sk
, ctx
->iv
, ivlen
);
593 sock_kfree_s(sk
, ctx
, ctx
->len
);
594 af_alg_release_parent(sk
);
597 static int aead_accept_parent(void *private, struct sock
*sk
)
599 struct aead_ctx
*ctx
;
600 struct alg_sock
*ask
= alg_sk(sk
);
601 unsigned int len
= sizeof(*ctx
) + crypto_aead_reqsize(private);
602 unsigned int ivlen
= crypto_aead_ivsize(private);
604 ctx
= sock_kmalloc(sk
, len
, GFP_KERNEL
);
609 ctx
->iv
= sock_kmalloc(sk
, ivlen
, GFP_KERNEL
);
611 sock_kfree_s(sk
, ctx
, len
);
614 memset(ctx
->iv
, 0, ivlen
);
622 ctx
->aead_assoclen
= 0;
623 af_alg_init_completion(&ctx
->completion
);
624 sg_init_table(ctx
->tsgl
.sg
, ALG_MAX_PAGES
);
628 aead_request_set_tfm(&ctx
->aead_req
, private);
629 aead_request_set_callback(&ctx
->aead_req
, CRYPTO_TFM_REQ_MAY_BACKLOG
,
630 af_alg_complete
, &ctx
->completion
);
632 sk
->sk_destruct
= aead_sock_destruct
;
637 static const struct af_alg_type algif_type_aead
= {
639 .release
= aead_release
,
640 .setkey
= aead_setkey
,
641 .setauthsize
= aead_setauthsize
,
642 .accept
= aead_accept_parent
,
643 .ops
= &algif_aead_ops
,
648 static int __init
algif_aead_init(void)
650 return af_alg_register_type(&algif_type_aead
);
653 static void __exit
algif_aead_exit(void)
655 int err
= af_alg_unregister_type(&algif_type_aead
);
659 module_init(algif_aead_init
);
660 module_exit(algif_aead_exit
);
661 MODULE_LICENSE("GPL");
662 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
663 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");