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 kiocb
*unused
, struct socket
*sock
,
167 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 kiocb
*unused
, struct socket
*sock
,
352 struct msghdr
*msg
, size_t ignored
, int flags
)
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
];
365 unsigned long used
= 0;
367 size_t usedpages
= 0;
368 unsigned int cnt
= 0;
370 /* Limit number of IOV blocks to be accessed below */
371 if (msg
->msg_iter
.nr_segs
> RSGL_MAX_ENTRIES
)
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.
383 * The memory structure for cipher operation has the following
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
392 err
= aead_wait_for_data(sk
, flags
);
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.
408 if (!aead_sufficient_data(ctx
))
412 * The cipher operation input data is reduced by the associated data
413 * length as this data is processed separately later on.
415 used
-= ctx
->aead_assoclen
;
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 */
423 /* output data size is input without the authentication tag */
425 /* round up output buffer to multiple of block size */
426 outlen
= ((outlen
+ bs
- 1) / bs
* bs
);
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
));
434 /* make one iovec available as scatterlist */
435 err
= af_alg_make_sg(&ctx
->rsgl
[cnt
], &msg
->msg_iter
,
440 /* chain the new scatterlist with initial list */
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
)
448 iov_iter_advance(&msg
->msg_iter
, err
);
453 /* ensure output buffer is sufficiently large */
454 if (usedpages
< outlen
)
457 sg_init_table(assoc
, ALG_MAX_PAGES
);
458 assoclen
= ctx
->aead_assoclen
;
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.
465 for (i
= 0; i
< ctx
->tsgl
.cur
; 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
)
474 } else if (!assoclen
) {
475 /* current page is to start of plaintext / ciphertext */
477 /* AD terminates at page boundary */
478 sg_mark_end(assoc
+ i
- 1);
480 /* AD size is zero */
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
;
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
,
499 err
= af_alg_wait_for_completion(ctx
->enc
?
500 crypto_aead_encrypt(&ctx
->aead_req
) :
501 crypto_aead_decrypt(&ctx
->aead_req
),
505 /* EBADMSG implies a valid cipher operation took place */
516 for (i
= 0; i
< cnt
; i
++)
517 af_alg_free_sg(&ctx
->rsgl
[i
]);
519 aead_wmem_wakeup(sk
);
522 return err
? err
: outlen
;
525 static unsigned int aead_poll(struct file
*file
, struct socket
*sock
,
528 struct sock
*sk
= sock
->sk
;
529 struct alg_sock
*ask
= alg_sk(sk
);
530 struct aead_ctx
*ctx
= ask
->private;
533 sock_poll_wait(file
, sk_sleep(sk
), wait
);
537 mask
|= POLLIN
| POLLRDNORM
;
539 if (aead_writable(sk
))
540 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
545 static struct proto_ops algif_aead_ops
= {
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
,
560 .release
= af_alg_release
,
561 .sendmsg
= aead_sendmsg
,
562 .sendpage
= aead_sendpage
,
563 .recvmsg
= aead_recvmsg
,
567 static void *aead_bind(const char *name
, u32 type
, u32 mask
)
569 return crypto_alloc_aead(name
, type
, mask
);
572 static void aead_release(void *private)
574 crypto_free_aead(private);
577 static int aead_setauthsize(void *private, unsigned int authsize
)
579 return crypto_aead_setauthsize(private, authsize
);
582 static int aead_setkey(void *private, const u8
*key
, unsigned int keylen
)
584 return crypto_aead_setkey(private, key
, keylen
);
587 static void aead_sock_destruct(struct sock
*sk
)
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
));
595 sock_kzfree_s(sk
, ctx
->iv
, ivlen
);
596 sock_kfree_s(sk
, ctx
, ctx
->len
);
597 af_alg_release_parent(sk
);
600 static int aead_accept_parent(void *private, struct sock
*sk
)
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);
607 ctx
= sock_kmalloc(sk
, len
, GFP_KERNEL
);
612 ctx
->iv
= sock_kmalloc(sk
, ivlen
, GFP_KERNEL
);
614 sock_kfree_s(sk
, ctx
, len
);
617 memset(ctx
->iv
, 0, ivlen
);
625 ctx
->aead_assoclen
= 0;
626 af_alg_init_completion(&ctx
->completion
);
627 sg_init_table(ctx
->tsgl
.sg
, ALG_MAX_PAGES
);
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
);
635 sk
->sk_destruct
= aead_sock_destruct
;
640 static const struct af_alg_type algif_type_aead
= {
642 .release
= aead_release
,
643 .setkey
= aead_setkey
,
644 .setauthsize
= aead_setauthsize
,
645 .accept
= aead_accept_parent
,
646 .ops
= &algif_aead_ops
,
651 static int __init
algif_aead_init(void)
653 return af_alg_register_type(&algif_type_aead
);
656 static void __exit
algif_aead_exit(void)
658 int err
= af_alg_unregister_type(&algif_type_aead
);
662 module_init(algif_aead_init
);
663 module_exit(algif_aead_exit
);
664 MODULE_LICENSE("GPL");
665 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
666 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");