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/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>
23 #include <linux/module.h>
24 #include <linux/net.h>
29 struct scatterlist sg[ALG_MAX_PAGES];
32 struct aead_async_rsgl {
33 struct af_alg_sgl sgl;
34 struct list_head list;
37 struct aead_async_req {
38 struct scatterlist *tsgl;
39 struct aead_async_rsgl first_rsgl;
40 struct list_head list;
47 struct aead_sg_list tsgl;
48 struct aead_async_rsgl first_rsgl;
49 struct list_head list;
53 struct af_alg_completion completion;
63 struct aead_request aead_req;
66 static inline int aead_sndbuf(struct sock *sk)
68 struct alg_sock *ask = alg_sk(sk);
69 struct aead_ctx *ctx = ask->private;
71 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
75 static inline bool aead_writable(struct sock *sk)
77 return PAGE_SIZE <= aead_sndbuf(sk);
80 static inline bool aead_sufficient_data(struct aead_ctx *ctx)
82 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
85 * The minimum amount of memory needed for an AEAD cipher is
86 * the AAD and in case of decryption the tag.
88 return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as);
91 static void aead_reset_ctx(struct aead_ctx *ctx)
93 struct aead_sg_list *sgl = &ctx->tsgl;
95 sg_init_table(sgl->sg, ALG_MAX_PAGES);
102 static void aead_put_sgl(struct sock *sk)
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;
110 for (i = 0; i < sgl->cur; i++) {
111 if (!sg_page(sg + i))
114 put_page(sg_page(sg + i));
115 sg_assign_page(sg + i, NULL);
120 static void aead_wmem_wakeup(struct sock *sk)
122 struct socket_wq *wq;
124 if (!aead_writable(sk))
128 wq = rcu_dereference(sk->sk_wq);
129 if (skwq_has_sleeper(wq))
130 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
133 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
137 static int aead_wait_for_data(struct sock *sk, unsigned flags)
139 struct alg_sock *ask = alg_sk(sk);
140 struct aead_ctx *ctx = ask->private;
143 int err = -ERESTARTSYS;
145 if (flags & MSG_DONTWAIT)
148 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
151 if (signal_pending(current))
153 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
154 timeout = MAX_SCHEDULE_TIMEOUT;
155 if (sk_wait_event(sk, &timeout, !ctx->more)) {
160 finish_wait(sk_sleep(sk), &wait);
162 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
167 static void aead_data_wakeup(struct sock *sk)
169 struct alg_sock *ask = alg_sk(sk);
170 struct aead_ctx *ctx = ask->private;
171 struct socket_wq *wq;
179 wq = rcu_dereference(sk->sk_wq);
180 if (skwq_has_sleeper(wq))
181 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
184 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
188 static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
190 struct sock *sk = sock->sk;
191 struct alg_sock *ask = alg_sk(sk);
192 struct aead_ctx *ctx = ask->private;
194 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
195 struct aead_sg_list *sgl = &ctx->tsgl;
196 struct af_alg_control con = {};
202 if (msg->msg_controllen) {
203 err = af_alg_cmsg_send(msg, &con);
219 if (con.iv && con.iv->ivlen != ivsize)
224 if (!ctx->more && ctx->used)
230 memcpy(ctx->iv, con.iv->iv, ivsize);
232 ctx->aead_assoclen = con.aead_assoclen;
237 struct scatterlist *sg = NULL;
239 /* use the existing memory in an allocated page */
241 sg = sgl->sg + sgl->cur - 1;
242 len = min_t(unsigned long, len,
243 PAGE_SIZE - sg->offset - sg->length);
244 err = memcpy_from_msg(page_address(sg_page(sg)) +
245 sg->offset + sg->length,
251 ctx->merge = (sg->offset + sg->length) &
260 if (!aead_writable(sk)) {
261 /* user space sent too much data */
267 /* allocate a new page */
268 len = min_t(unsigned long, size, aead_sndbuf(sk));
272 if (sgl->cur >= ALG_MAX_PAGES) {
278 sg = sgl->sg + sgl->cur;
279 plen = min_t(size_t, len, PAGE_SIZE);
281 sg_assign_page(sg, alloc_page(GFP_KERNEL));
286 err = memcpy_from_msg(page_address(sg_page(sg)),
289 __free_page(sg_page(sg));
290 sg_assign_page(sg, NULL);
301 ctx->merge = plen & (PAGE_SIZE - 1);
307 ctx->more = msg->msg_flags & MSG_MORE;
308 if (!ctx->more && !aead_sufficient_data(ctx)) {
314 aead_data_wakeup(sk);
317 return err ?: copied;
320 static ssize_t aead_sendpage(struct socket *sock, struct page *page,
321 int offset, size_t size, int flags)
323 struct sock *sk = sock->sk;
324 struct alg_sock *ask = alg_sk(sk);
325 struct aead_ctx *ctx = ask->private;
326 struct aead_sg_list *sgl = &ctx->tsgl;
329 if (flags & MSG_SENDPAGE_NOTLAST)
332 if (sgl->cur >= ALG_MAX_PAGES)
336 if (!ctx->more && ctx->used)
342 if (!aead_writable(sk)) {
343 /* user space sent too much data */
352 sg_set_page(sgl->sg + sgl->cur, page, size, offset);
359 ctx->more = flags & MSG_MORE;
360 if (!ctx->more && !aead_sufficient_data(ctx)) {
366 aead_data_wakeup(sk);
372 #define GET_ASYM_REQ(req, tfm) (struct aead_async_req *) \
373 ((char *)req + sizeof(struct aead_request) + \
374 crypto_aead_reqsize(tfm))
376 #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
377 crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
378 sizeof(struct aead_request)
380 static void aead_async_cb(struct crypto_async_request *_req, int err)
382 struct sock *sk = _req->data;
383 struct alg_sock *ask = alg_sk(sk);
384 struct aead_ctx *ctx = ask->private;
385 struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
386 struct aead_request *req = aead_request_cast(_req);
387 struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
388 struct scatterlist *sg = areq->tsgl;
389 struct aead_async_rsgl *rsgl;
390 struct kiocb *iocb = areq->iocb;
391 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
393 list_for_each_entry(rsgl, &areq->list, list) {
394 af_alg_free_sg(&rsgl->sgl);
395 if (rsgl != &areq->first_rsgl)
396 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
399 for (i = 0; i < areq->tsgls; i++)
400 put_page(sg_page(sg + i));
402 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
403 sock_kfree_s(sk, req, reqlen);
405 iocb->ki_complete(iocb, err, err);
408 static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
411 struct sock *sk = sock->sk;
412 struct alg_sock *ask = alg_sk(sk);
413 struct aead_ctx *ctx = ask->private;
414 struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
415 struct aead_async_req *areq;
416 struct aead_request *req = NULL;
417 struct aead_sg_list *sgl = &ctx->tsgl;
418 struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
419 unsigned int as = crypto_aead_authsize(tfm);
420 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
424 size_t usedpages = 0;
428 err = aead_wait_for_data(sk, flags);
433 if (!aead_sufficient_data(ctx))
442 req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
446 areq = GET_ASYM_REQ(req, tfm);
447 memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
448 INIT_LIST_HEAD(&areq->list);
449 areq->iocb = msg->msg_iocb;
450 memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
451 aead_request_set_tfm(req, tfm);
452 aead_request_set_ad(req, ctx->aead_assoclen);
453 aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
455 used -= ctx->aead_assoclen;
457 /* take over all tx sgls from ctx */
458 areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur,
460 if (unlikely(!areq->tsgl))
463 sg_init_table(areq->tsgl, sgl->cur);
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);
468 areq->tsgls = sgl->cur;
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));
475 if (list_empty(&areq->list)) {
476 rsgl = &areq->first_rsgl;
479 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
480 if (unlikely(!rsgl)) {
485 rsgl->sgl.npages = 0;
486 list_add_tail(&rsgl->list, &areq->list);
488 /* make one iovec available as scatterlist */
489 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
495 /* chain the new scatterlist with previous one */
497 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
501 iov_iter_advance(&msg->msg_iter, err);
504 /* ensure output buffer is sufficiently large */
505 if (usedpages < outlen) {
510 aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
512 err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
514 if (err == -EINPROGRESS) {
519 } else if (err == -EBADMSG) {
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));
533 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
535 sock_kfree_s(sk, req, reqlen);
537 aead_wmem_wakeup(sk);
539 return err ? err : outlen;
542 static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags)
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;
552 unsigned long used = 0;
554 size_t usedpages = 0;
559 * AEAD memory structure: For encryption, the tag is appended to the
560 * ciphertext which implies that the memory allocated for the ciphertext
561 * must be increased by the tag length. For decryption, the tag
562 * is expected to be concatenated to the ciphertext. The plaintext
563 * therefore has a memory size of the ciphertext minus the tag length.
565 * The memory structure for cipher operation has the following
567 * AEAD encryption input: assoc data || plaintext
568 * AEAD encryption output: cipherntext || auth tag
569 * AEAD decryption input: assoc data || ciphertext || auth tag
570 * AEAD decryption output: plaintext
574 err = aead_wait_for_data(sk, flags);
579 /* data length provided by caller via sendmsg/sendpage */
583 * Make sure sufficient data is present -- note, the same check is
584 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
585 * shall provide an information to the data sender that something is
586 * wrong, but they are irrelevant to maintain the kernel integrity.
587 * We need this check here too in case user space decides to not honor
588 * the error message in sendmsg/sendpage and still call recvmsg. This
589 * check here protects the kernel integrity.
591 if (!aead_sufficient_data(ctx))
595 * Calculate the minimum output buffer size holding the result of the
596 * cipher operation. When encrypting data, the receiving buffer is
597 * larger by the tag length compared to the input buffer as the
598 * encryption operation generates the tag. For decryption, the input
599 * buffer provides the tag which is consumed resulting in only the
600 * plaintext without a buffer for the tag returned to the caller.
608 * The cipher operation input data is reduced by the associated data
609 * length as this data is processed separately later on.
611 used -= ctx->aead_assoclen;
613 /* convert iovecs of output buffers into scatterlists */
614 while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) {
615 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
616 (outlen - usedpages));
618 if (list_empty(&ctx->list)) {
619 rsgl = &ctx->first_rsgl;
621 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
622 if (unlikely(!rsgl)) {
627 rsgl->sgl.npages = 0;
628 list_add_tail(&rsgl->list, &ctx->list);
630 /* make one iovec available as scatterlist */
631 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
635 /* chain the new scatterlist with previous one */
637 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
641 iov_iter_advance(&msg->msg_iter, err);
644 /* ensure output buffer is sufficiently large */
645 if (usedpages < outlen) {
650 sg_mark_end(sgl->sg + sgl->cur - 1);
651 aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg,
653 aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
655 err = af_alg_wait_for_completion(ctx->enc ?
656 crypto_aead_encrypt(&ctx->aead_req) :
657 crypto_aead_decrypt(&ctx->aead_req),
661 /* EBADMSG implies a valid cipher operation took place */
672 list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
673 af_alg_free_sg(&rsgl->sgl);
674 list_del(&rsgl->list);
675 if (rsgl != &ctx->first_rsgl)
676 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
678 INIT_LIST_HEAD(&ctx->list);
679 aead_wmem_wakeup(sk);
682 return err ? err : outlen;
685 static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
688 return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
689 aead_recvmsg_async(sock, msg, flags) :
690 aead_recvmsg_sync(sock, msg, flags);
693 static unsigned int aead_poll(struct file *file, struct socket *sock,
696 struct sock *sk = sock->sk;
697 struct alg_sock *ask = alg_sk(sk);
698 struct aead_ctx *ctx = ask->private;
701 sock_poll_wait(file, sk_sleep(sk), wait);
705 mask |= POLLIN | POLLRDNORM;
707 if (aead_writable(sk))
708 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
713 static struct proto_ops algif_aead_ops = {
716 .connect = sock_no_connect,
717 .socketpair = sock_no_socketpair,
718 .getname = sock_no_getname,
719 .ioctl = sock_no_ioctl,
720 .listen = sock_no_listen,
721 .shutdown = sock_no_shutdown,
722 .getsockopt = sock_no_getsockopt,
723 .mmap = sock_no_mmap,
724 .bind = sock_no_bind,
725 .accept = sock_no_accept,
726 .setsockopt = sock_no_setsockopt,
728 .release = af_alg_release,
729 .sendmsg = aead_sendmsg,
730 .sendpage = aead_sendpage,
731 .recvmsg = aead_recvmsg,
735 static void *aead_bind(const char *name, u32 type, u32 mask)
737 return crypto_alloc_aead(name, type, mask);
740 static void aead_release(void *private)
742 crypto_free_aead(private);
745 static int aead_setauthsize(void *private, unsigned int authsize)
747 return crypto_aead_setauthsize(private, authsize);
750 static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
752 return crypto_aead_setkey(private, key, keylen);
755 static void aead_sock_destruct(struct sock *sk)
757 struct alg_sock *ask = alg_sk(sk);
758 struct aead_ctx *ctx = ask->private;
759 unsigned int ivlen = crypto_aead_ivsize(
760 crypto_aead_reqtfm(&ctx->aead_req));
762 WARN_ON(atomic_read(&sk->sk_refcnt) != 0);
764 sock_kzfree_s(sk, ctx->iv, ivlen);
765 sock_kfree_s(sk, ctx, ctx->len);
766 af_alg_release_parent(sk);
769 static int aead_accept_parent(void *private, struct sock *sk)
771 struct aead_ctx *ctx;
772 struct alg_sock *ask = alg_sk(sk);
773 unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
774 unsigned int ivlen = crypto_aead_ivsize(private);
776 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
781 ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
783 sock_kfree_s(sk, ctx, len);
786 memset(ctx->iv, 0, ivlen);
794 ctx->aead_assoclen = 0;
795 af_alg_init_completion(&ctx->completion);
796 sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
797 INIT_LIST_HEAD(&ctx->list);
801 aead_request_set_tfm(&ctx->aead_req, private);
802 aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
803 af_alg_complete, &ctx->completion);
805 sk->sk_destruct = aead_sock_destruct;
810 static const struct af_alg_type algif_type_aead = {
812 .release = aead_release,
813 .setkey = aead_setkey,
814 .setauthsize = aead_setauthsize,
815 .accept = aead_accept_parent,
816 .ops = &algif_aead_ops,
821 static int __init algif_aead_init(void)
823 return af_alg_register_type(&algif_type_aead);
826 static void __exit algif_aead_exit(void)
828 int err = af_alg_unregister_type(&algif_type_aead);
832 module_init(algif_aead_init);
833 module_exit(algif_aead_exit);
834 MODULE_LICENSE("GPL");
835 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
836 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");