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
+ 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 as
= crypto_aead_authsize(crypto_aead_reqtfm(&ctx
->aead_req
));
357 struct aead_sg_list
*sgl
= &ctx
->tsgl
;
360 unsigned long used
= 0;
362 size_t usedpages
= 0;
363 unsigned int cnt
= 0;
365 /* Limit number of IOV blocks to be accessed below */
366 if (msg
->msg_iter
.nr_segs
> RSGL_MAX_ENTRIES
)
372 * AEAD memory structure: For encryption, the tag is appended to the
373 * ciphertext which implies that the memory allocated for the ciphertext
374 * must be increased by the tag length. For decryption, the tag
375 * is expected to be concatenated to the ciphertext. The plaintext
376 * therefore has a memory size of the ciphertext minus the tag length.
378 * The memory structure for cipher operation has the following
380 * AEAD encryption input: assoc data || plaintext
381 * AEAD encryption output: cipherntext || auth tag
382 * AEAD decryption input: assoc data || ciphertext || auth tag
383 * AEAD decryption output: plaintext
387 err
= aead_wait_for_data(sk
, flags
);
395 * Make sure sufficient data is present -- note, the same check is
396 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
397 * shall provide an information to the data sender that something is
398 * wrong, but they are irrelevant to maintain the kernel integrity.
399 * We need this check here too in case user space decides to not honor
400 * the error message in sendmsg/sendpage and still call recvmsg. This
401 * check here protects the kernel integrity.
403 if (!aead_sufficient_data(ctx
))
409 * The cipher operation input data is reduced by the associated data
410 * length as this data is processed separately later on.
412 used
-= ctx
->aead_assoclen
+ (ctx
->enc
? as
: 0);
414 /* convert iovecs of output buffers into scatterlists */
415 while (iov_iter_count(&msg
->msg_iter
)) {
416 size_t seglen
= min_t(size_t, iov_iter_count(&msg
->msg_iter
),
417 (outlen
- usedpages
));
419 /* make one iovec available as scatterlist */
420 err
= af_alg_make_sg(&ctx
->rsgl
[cnt
], &msg
->msg_iter
,
425 /* chain the new scatterlist with previous one */
427 af_alg_link_sg(&ctx
->rsgl
[cnt
-1], &ctx
->rsgl
[cnt
]);
429 /* we do not need more iovecs as we have sufficient memory */
430 if (outlen
<= usedpages
)
432 iov_iter_advance(&msg
->msg_iter
, err
);
437 /* ensure output buffer is sufficiently large */
438 if (usedpages
< outlen
)
441 sg_mark_end(sgl
->sg
+ sgl
->cur
- 1);
443 aead_request_set_crypt(&ctx
->aead_req
, sgl
->sg
, ctx
->rsgl
[0].sg
,
445 aead_request_set_ad(&ctx
->aead_req
, ctx
->aead_assoclen
);
447 err
= af_alg_wait_for_completion(ctx
->enc
?
448 crypto_aead_encrypt(&ctx
->aead_req
) :
449 crypto_aead_decrypt(&ctx
->aead_req
),
453 /* EBADMSG implies a valid cipher operation took place */
464 for (i
= 0; i
< cnt
; i
++)
465 af_alg_free_sg(&ctx
->rsgl
[i
]);
467 aead_wmem_wakeup(sk
);
470 return err
? err
: outlen
;
473 static unsigned int aead_poll(struct file
*file
, struct socket
*sock
,
476 struct sock
*sk
= sock
->sk
;
477 struct alg_sock
*ask
= alg_sk(sk
);
478 struct aead_ctx
*ctx
= ask
->private;
481 sock_poll_wait(file
, sk_sleep(sk
), wait
);
485 mask
|= POLLIN
| POLLRDNORM
;
487 if (aead_writable(sk
))
488 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
493 static struct proto_ops algif_aead_ops
= {
496 .connect
= sock_no_connect
,
497 .socketpair
= sock_no_socketpair
,
498 .getname
= sock_no_getname
,
499 .ioctl
= sock_no_ioctl
,
500 .listen
= sock_no_listen
,
501 .shutdown
= sock_no_shutdown
,
502 .getsockopt
= sock_no_getsockopt
,
503 .mmap
= sock_no_mmap
,
504 .bind
= sock_no_bind
,
505 .accept
= sock_no_accept
,
506 .setsockopt
= sock_no_setsockopt
,
508 .release
= af_alg_release
,
509 .sendmsg
= aead_sendmsg
,
510 .sendpage
= aead_sendpage
,
511 .recvmsg
= aead_recvmsg
,
515 static void *aead_bind(const char *name
, u32 type
, u32 mask
)
517 return crypto_alloc_aead(name
, type
| CRYPTO_ALG_AEAD_NEW
,
518 mask
| CRYPTO_ALG_AEAD_NEW
);
521 static void aead_release(void *private)
523 crypto_free_aead(private);
526 static int aead_setauthsize(void *private, unsigned int authsize
)
528 return crypto_aead_setauthsize(private, authsize
);
531 static int aead_setkey(void *private, const u8
*key
, unsigned int keylen
)
533 return crypto_aead_setkey(private, key
, keylen
);
536 static void aead_sock_destruct(struct sock
*sk
)
538 struct alg_sock
*ask
= alg_sk(sk
);
539 struct aead_ctx
*ctx
= ask
->private;
540 unsigned int ivlen
= crypto_aead_ivsize(
541 crypto_aead_reqtfm(&ctx
->aead_req
));
544 sock_kzfree_s(sk
, ctx
->iv
, ivlen
);
545 sock_kfree_s(sk
, ctx
, ctx
->len
);
546 af_alg_release_parent(sk
);
549 static int aead_accept_parent(void *private, struct sock
*sk
)
551 struct aead_ctx
*ctx
;
552 struct alg_sock
*ask
= alg_sk(sk
);
553 unsigned int len
= sizeof(*ctx
) + crypto_aead_reqsize(private);
554 unsigned int ivlen
= crypto_aead_ivsize(private);
556 ctx
= sock_kmalloc(sk
, len
, GFP_KERNEL
);
561 ctx
->iv
= sock_kmalloc(sk
, ivlen
, GFP_KERNEL
);
563 sock_kfree_s(sk
, ctx
, len
);
566 memset(ctx
->iv
, 0, ivlen
);
574 ctx
->aead_assoclen
= 0;
575 af_alg_init_completion(&ctx
->completion
);
576 sg_init_table(ctx
->tsgl
.sg
, ALG_MAX_PAGES
);
580 aead_request_set_tfm(&ctx
->aead_req
, private);
581 aead_request_set_callback(&ctx
->aead_req
, CRYPTO_TFM_REQ_MAY_BACKLOG
,
582 af_alg_complete
, &ctx
->completion
);
584 sk
->sk_destruct
= aead_sock_destruct
;
589 static const struct af_alg_type algif_type_aead
= {
591 .release
= aead_release
,
592 .setkey
= aead_setkey
,
593 .setauthsize
= aead_setauthsize
,
594 .accept
= aead_accept_parent
,
595 .ops
= &algif_aead_ops
,
600 static int __init
algif_aead_init(void)
602 return af_alg_register_type(&algif_type_aead
);
605 static void __exit
algif_aead_exit(void)
607 int err
= af_alg_unregister_type(&algif_type_aead
);
611 module_init(algif_aead_init
);
612 module_exit(algif_aead_exit
);
613 MODULE_LICENSE("GPL");
614 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
615 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");