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/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>
23 #include <linux/module.h>
24 #include <linux/net.h>
29 struct scatterlist sg
[ALG_MAX_PAGES
];
33 struct aead_sg_list tsgl
;
35 * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
36 * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
39 #define RSGL_MAX_ENTRIES ALG_MAX_PAGES
40 struct af_alg_sgl rsgl
[RSGL_MAX_ENTRIES
];
44 struct af_alg_completion completion
;
54 struct aead_request aead_req
;
57 static inline int aead_sndbuf(struct sock
*sk
)
59 struct alg_sock
*ask
= alg_sk(sk
);
60 struct aead_ctx
*ctx
= ask
->private;
62 return max_t(int, max_t(int, sk
->sk_sndbuf
& PAGE_MASK
, PAGE_SIZE
) -
66 static inline bool aead_writable(struct sock
*sk
)
68 return PAGE_SIZE
<= aead_sndbuf(sk
);
71 static inline bool aead_sufficient_data(struct aead_ctx
*ctx
)
73 unsigned as
= crypto_aead_authsize(crypto_aead_reqtfm(&ctx
->aead_req
));
75 return (ctx
->used
>= (ctx
->aead_assoclen
+ (ctx
->enc
? 0 : as
)));
78 static void aead_put_sgl(struct sock
*sk
)
80 struct alg_sock
*ask
= alg_sk(sk
);
81 struct aead_ctx
*ctx
= ask
->private;
82 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
83 struct scatterlist
*sg
= sgl
->sg
;
86 for (i
= 0; i
< sgl
->cur
; i
++) {
90 put_page(sg_page(sg
+ i
));
91 sg_assign_page(sg
+ i
, NULL
);
99 static void aead_wmem_wakeup(struct sock
*sk
)
101 struct socket_wq
*wq
;
103 if (!aead_writable(sk
))
107 wq
= rcu_dereference(sk
->sk_wq
);
108 if (wq_has_sleeper(wq
))
109 wake_up_interruptible_sync_poll(&wq
->wait
, POLLIN
|
112 sk_wake_async(sk
, SOCK_WAKE_WAITD
, POLL_IN
);
116 static int aead_wait_for_data(struct sock
*sk
, unsigned flags
)
118 struct alg_sock
*ask
= alg_sk(sk
);
119 struct aead_ctx
*ctx
= ask
->private;
122 int err
= -ERESTARTSYS
;
124 if (flags
& MSG_DONTWAIT
)
127 set_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
130 if (signal_pending(current
))
132 prepare_to_wait(sk_sleep(sk
), &wait
, TASK_INTERRUPTIBLE
);
133 timeout
= MAX_SCHEDULE_TIMEOUT
;
134 if (sk_wait_event(sk
, &timeout
, !ctx
->more
)) {
139 finish_wait(sk_sleep(sk
), &wait
);
141 clear_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
146 static void aead_data_wakeup(struct sock
*sk
)
148 struct alg_sock
*ask
= alg_sk(sk
);
149 struct aead_ctx
*ctx
= ask
->private;
150 struct socket_wq
*wq
;
158 wq
= rcu_dereference(sk
->sk_wq
);
159 if (wq_has_sleeper(wq
))
160 wake_up_interruptible_sync_poll(&wq
->wait
, POLLOUT
|
163 sk_wake_async(sk
, SOCK_WAKE_SPACE
, POLL_OUT
);
167 static int aead_sendmsg(struct socket
*sock
, struct msghdr
*msg
, size_t size
)
169 struct sock
*sk
= sock
->sk
;
170 struct alg_sock
*ask
= alg_sk(sk
);
171 struct aead_ctx
*ctx
= ask
->private;
173 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx
->aead_req
));
174 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
175 struct af_alg_control con
= {};
181 if (msg
->msg_controllen
) {
182 err
= af_alg_cmsg_send(msg
, &con
);
198 if (con
.iv
&& con
.iv
->ivlen
!= ivsize
)
203 if (!ctx
->more
&& ctx
->used
)
209 memcpy(ctx
->iv
, con
.iv
->iv
, ivsize
);
211 ctx
->aead_assoclen
= con
.aead_assoclen
;
215 unsigned long len
= size
;
216 struct scatterlist
*sg
= NULL
;
218 /* use the existing memory in an allocated page */
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
,
230 ctx
->merge
= (sg
->offset
+ sg
->length
) &
239 if (!aead_writable(sk
)) {
240 /* user space sent too much data */
246 /* allocate a new page */
247 len
= min_t(unsigned long, size
, aead_sndbuf(sk
));
251 if (sgl
->cur
>= ALG_MAX_PAGES
) {
257 sg
= sgl
->sg
+ sgl
->cur
;
258 plen
= min_t(int, len
, PAGE_SIZE
);
260 sg_assign_page(sg
, alloc_page(GFP_KERNEL
));
265 err
= memcpy_from_msg(page_address(sg_page(sg
)),
268 __free_page(sg_page(sg
));
269 sg_assign_page(sg
, NULL
);
280 ctx
->merge
= plen
& (PAGE_SIZE
- 1);
286 ctx
->more
= msg
->msg_flags
& MSG_MORE
;
287 if (!ctx
->more
&& !aead_sufficient_data(ctx
)) {
293 aead_data_wakeup(sk
);
296 return err
?: copied
;
299 static ssize_t
aead_sendpage(struct socket
*sock
, struct page
*page
,
300 int offset
, size_t size
, int flags
)
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
;
308 if (flags
& MSG_SENDPAGE_NOTLAST
)
311 if (sgl
->cur
>= ALG_MAX_PAGES
)
315 if (!ctx
->more
&& ctx
->used
)
321 if (!aead_writable(sk
)) {
322 /* user space sent too much data */
331 sg_set_page(sgl
->sg
+ sgl
->cur
, page
, size
, offset
);
338 ctx
->more
= flags
& MSG_MORE
;
339 if (!ctx
->more
&& !aead_sufficient_data(ctx
)) {
345 aead_data_wakeup(sk
);
351 static int aead_recvmsg(struct socket
*sock
, struct msghdr
*msg
, size_t ignored
, int flags
)
353 struct sock
*sk
= sock
->sk
;
354 struct alg_sock
*ask
= alg_sk(sk
);
355 struct aead_ctx
*ctx
= ask
->private;
356 unsigned bs
= crypto_aead_blocksize(crypto_aead_reqtfm(&ctx
->aead_req
));
357 unsigned as
= crypto_aead_authsize(crypto_aead_reqtfm(&ctx
->aead_req
));
358 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
359 struct scatterlist
*sg
= NULL
;
360 struct scatterlist assoc
[ALG_MAX_PAGES
];
364 unsigned long used
= 0;
366 size_t usedpages
= 0;
367 unsigned int cnt
= 0;
369 /* Limit number of IOV blocks to be accessed below */
370 if (msg
->msg_iter
.nr_segs
> RSGL_MAX_ENTRIES
)
376 * AEAD memory structure: For encryption, the tag is appended to the
377 * ciphertext which implies that the memory allocated for the ciphertext
378 * must be increased by the tag length. For decryption, the tag
379 * is expected to be concatenated to the ciphertext. The plaintext
380 * therefore has a memory size of the ciphertext minus the tag length.
382 * The memory structure for cipher operation has the following
384 * AEAD encryption input: assoc data || plaintext
385 * AEAD encryption output: cipherntext || auth tag
386 * AEAD decryption input: assoc data || ciphertext || auth tag
387 * AEAD decryption output: plaintext
391 err
= aead_wait_for_data(sk
, flags
);
399 * Make sure sufficient data is present -- note, the same check is
400 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
401 * shall provide an information to the data sender that something is
402 * wrong, but they are irrelevant to maintain the kernel integrity.
403 * We need this check here too in case user space decides to not honor
404 * the error message in sendmsg/sendpage and still call recvmsg. This
405 * check here protects the kernel integrity.
407 if (!aead_sufficient_data(ctx
))
411 * The cipher operation input data is reduced by the associated data
412 * length as this data is processed separately later on.
414 used
-= ctx
->aead_assoclen
;
417 /* round up output buffer to multiple of block size */
418 outlen
= ((used
+ bs
- 1) / bs
* bs
);
419 /* add the size needed for the auth tag to be created */
422 /* output data size is input without the authentication tag */
424 /* round up output buffer to multiple of block size */
425 outlen
= ((outlen
+ bs
- 1) / bs
* bs
);
428 /* convert iovecs of output buffers into scatterlists */
429 while (iov_iter_count(&msg
->msg_iter
)) {
430 size_t seglen
= min_t(size_t, iov_iter_count(&msg
->msg_iter
),
431 (outlen
- usedpages
));
433 /* make one iovec available as scatterlist */
434 err
= af_alg_make_sg(&ctx
->rsgl
[cnt
], &msg
->msg_iter
,
439 /* chain the new scatterlist with previous one */
441 af_alg_link_sg(&ctx
->rsgl
[cnt
-1], &ctx
->rsgl
[cnt
]);
443 /* we do not need more iovecs as we have sufficient memory */
444 if (outlen
<= usedpages
)
446 iov_iter_advance(&msg
->msg_iter
, err
);
451 /* ensure output buffer is sufficiently large */
452 if (usedpages
< outlen
)
455 sg_init_table(assoc
, ALG_MAX_PAGES
);
456 assoclen
= ctx
->aead_assoclen
;
458 * Split scatterlist into two: first part becomes AD, second part
459 * is plaintext / ciphertext. The first part is assigned to assoc
460 * scatterlist. When this loop finishes, sg points to the start of the
461 * plaintext / ciphertext.
463 for (i
= 0; i
< ctx
->tsgl
.cur
; i
++) {
465 if (sg
->length
<= assoclen
) {
466 /* AD is larger than one page */
467 sg_set_page(assoc
+ i
, sg_page(sg
),
468 sg
->length
, sg
->offset
);
469 assoclen
-= sg
->length
;
470 if (i
>= ctx
->tsgl
.cur
)
472 } else if (!assoclen
) {
473 /* current page is to start of plaintext / ciphertext */
475 /* AD terminates at page boundary */
476 sg_mark_end(assoc
+ i
- 1);
478 /* AD size is zero */
482 /* AD does not terminate at page boundary */
483 sg_set_page(assoc
+ i
, sg_page(sg
),
484 assoclen
, sg
->offset
);
485 sg_mark_end(assoc
+ i
);
486 /* plaintext / ciphertext starts after AD */
487 sg
->length
-= assoclen
;
488 sg
->offset
+= assoclen
;
493 aead_request_set_assoc(&ctx
->aead_req
, assoc
, ctx
->aead_assoclen
);
494 aead_request_set_crypt(&ctx
->aead_req
, sg
, ctx
->rsgl
[0].sg
, used
,
497 err
= af_alg_wait_for_completion(ctx
->enc
?
498 crypto_aead_encrypt(&ctx
->aead_req
) :
499 crypto_aead_decrypt(&ctx
->aead_req
),
503 /* EBADMSG implies a valid cipher operation took place */
514 for (i
= 0; i
< cnt
; i
++)
515 af_alg_free_sg(&ctx
->rsgl
[i
]);
517 aead_wmem_wakeup(sk
);
520 return err
? err
: outlen
;
523 static unsigned int aead_poll(struct file
*file
, struct socket
*sock
,
526 struct sock
*sk
= sock
->sk
;
527 struct alg_sock
*ask
= alg_sk(sk
);
528 struct aead_ctx
*ctx
= ask
->private;
531 sock_poll_wait(file
, sk_sleep(sk
), wait
);
535 mask
|= POLLIN
| POLLRDNORM
;
537 if (aead_writable(sk
))
538 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
543 static struct proto_ops algif_aead_ops
= {
546 .connect
= sock_no_connect
,
547 .socketpair
= sock_no_socketpair
,
548 .getname
= sock_no_getname
,
549 .ioctl
= sock_no_ioctl
,
550 .listen
= sock_no_listen
,
551 .shutdown
= sock_no_shutdown
,
552 .getsockopt
= sock_no_getsockopt
,
553 .mmap
= sock_no_mmap
,
554 .bind
= sock_no_bind
,
555 .accept
= sock_no_accept
,
556 .setsockopt
= sock_no_setsockopt
,
558 .release
= af_alg_release
,
559 .sendmsg
= aead_sendmsg
,
560 .sendpage
= aead_sendpage
,
561 .recvmsg
= aead_recvmsg
,
565 static void *aead_bind(const char *name
, u32 type
, u32 mask
)
567 return crypto_alloc_aead(name
, type
, mask
);
570 static void aead_release(void *private)
572 crypto_free_aead(private);
575 static int aead_setauthsize(void *private, unsigned int authsize
)
577 return crypto_aead_setauthsize(private, authsize
);
580 static int aead_setkey(void *private, const u8
*key
, unsigned int keylen
)
582 return crypto_aead_setkey(private, key
, keylen
);
585 static void aead_sock_destruct(struct sock
*sk
)
587 struct alg_sock
*ask
= alg_sk(sk
);
588 struct aead_ctx
*ctx
= ask
->private;
589 unsigned int ivlen
= crypto_aead_ivsize(
590 crypto_aead_reqtfm(&ctx
->aead_req
));
593 sock_kzfree_s(sk
, ctx
->iv
, ivlen
);
594 sock_kfree_s(sk
, ctx
, ctx
->len
);
595 af_alg_release_parent(sk
);
598 static int aead_accept_parent(void *private, struct sock
*sk
)
600 struct aead_ctx
*ctx
;
601 struct alg_sock
*ask
= alg_sk(sk
);
602 unsigned int len
= sizeof(*ctx
) + crypto_aead_reqsize(private);
603 unsigned int ivlen
= crypto_aead_ivsize(private);
605 ctx
= sock_kmalloc(sk
, len
, GFP_KERNEL
);
610 ctx
->iv
= sock_kmalloc(sk
, ivlen
, GFP_KERNEL
);
612 sock_kfree_s(sk
, ctx
, len
);
615 memset(ctx
->iv
, 0, ivlen
);
623 ctx
->aead_assoclen
= 0;
624 af_alg_init_completion(&ctx
->completion
);
625 sg_init_table(ctx
->tsgl
.sg
, ALG_MAX_PAGES
);
629 aead_request_set_tfm(&ctx
->aead_req
, private);
630 aead_request_set_callback(&ctx
->aead_req
, CRYPTO_TFM_REQ_MAY_BACKLOG
,
631 af_alg_complete
, &ctx
->completion
);
633 sk
->sk_destruct
= aead_sock_destruct
;
638 static const struct af_alg_type algif_type_aead
= {
640 .release
= aead_release
,
641 .setkey
= aead_setkey
,
642 .setauthsize
= aead_setauthsize
,
643 .accept
= aead_accept_parent
,
644 .ops
= &algif_aead_ops
,
649 static int __init
algif_aead_init(void)
651 return af_alg_register_type(&algif_type_aead
);
654 static void __exit
algif_aead_exit(void)
656 int err
= af_alg_unregister_type(&algif_type_aead
);
660 module_init(algif_aead_init
);
661 module_exit(algif_aead_exit
);
662 MODULE_LICENSE("GPL");
663 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
664 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");