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;
48 struct crypto_aead *aead;
53 struct aead_sg_list tsgl;
54 struct aead_async_rsgl first_rsgl;
55 struct list_head list;
59 struct af_alg_completion completion;
69 struct aead_request aead_req;
72 static inline int aead_sndbuf(struct sock *sk)
74 struct alg_sock *ask = alg_sk(sk);
75 struct aead_ctx *ctx = ask->private;
77 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
81 static inline bool aead_writable(struct sock *sk)
83 return PAGE_SIZE <= aead_sndbuf(sk);
86 static inline bool aead_sufficient_data(struct aead_ctx *ctx)
88 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
91 * The minimum amount of memory needed for an AEAD cipher is
92 * the AAD and in case of decryption the tag.
94 return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as);
97 static void aead_reset_ctx(struct aead_ctx *ctx)
99 struct aead_sg_list *sgl = &ctx->tsgl;
101 sg_init_table(sgl->sg, ALG_MAX_PAGES);
108 static void aead_put_sgl(struct sock *sk)
110 struct alg_sock *ask = alg_sk(sk);
111 struct aead_ctx *ctx = ask->private;
112 struct aead_sg_list *sgl = &ctx->tsgl;
113 struct scatterlist *sg = sgl->sg;
116 for (i = 0; i < sgl->cur; i++) {
117 if (!sg_page(sg + i))
120 put_page(sg_page(sg + i));
121 sg_assign_page(sg + i, NULL);
126 static void aead_wmem_wakeup(struct sock *sk)
128 struct socket_wq *wq;
130 if (!aead_writable(sk))
134 wq = rcu_dereference(sk->sk_wq);
135 if (skwq_has_sleeper(wq))
136 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
139 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
143 static int aead_wait_for_data(struct sock *sk, unsigned flags)
145 struct alg_sock *ask = alg_sk(sk);
146 struct aead_ctx *ctx = ask->private;
149 int err = -ERESTARTSYS;
151 if (flags & MSG_DONTWAIT)
154 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
157 if (signal_pending(current))
159 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
160 timeout = MAX_SCHEDULE_TIMEOUT;
161 if (sk_wait_event(sk, &timeout, !ctx->more)) {
166 finish_wait(sk_sleep(sk), &wait);
168 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
173 static void aead_data_wakeup(struct sock *sk)
175 struct alg_sock *ask = alg_sk(sk);
176 struct aead_ctx *ctx = ask->private;
177 struct socket_wq *wq;
185 wq = rcu_dereference(sk->sk_wq);
186 if (skwq_has_sleeper(wq))
187 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
190 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
194 static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
196 struct sock *sk = sock->sk;
197 struct alg_sock *ask = alg_sk(sk);
198 struct aead_ctx *ctx = ask->private;
200 crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
201 struct aead_sg_list *sgl = &ctx->tsgl;
202 struct af_alg_control con = {};
208 if (msg->msg_controllen) {
209 err = af_alg_cmsg_send(msg, &con);
225 if (con.iv && con.iv->ivlen != ivsize)
230 if (!ctx->more && ctx->used)
236 memcpy(ctx->iv, con.iv->iv, ivsize);
238 ctx->aead_assoclen = con.aead_assoclen;
243 struct scatterlist *sg = NULL;
245 /* use the existing memory in an allocated page */
247 sg = sgl->sg + sgl->cur - 1;
248 len = min_t(unsigned long, len,
249 PAGE_SIZE - sg->offset - sg->length);
250 err = memcpy_from_msg(page_address(sg_page(sg)) +
251 sg->offset + sg->length,
257 ctx->merge = (sg->offset + sg->length) &
266 if (!aead_writable(sk)) {
267 /* user space sent too much data */
273 /* allocate a new page */
274 len = min_t(unsigned long, size, aead_sndbuf(sk));
278 if (sgl->cur >= ALG_MAX_PAGES) {
284 sg = sgl->sg + sgl->cur;
285 plen = min_t(size_t, len, PAGE_SIZE);
287 sg_assign_page(sg, alloc_page(GFP_KERNEL));
292 err = memcpy_from_msg(page_address(sg_page(sg)),
295 __free_page(sg_page(sg));
296 sg_assign_page(sg, NULL);
307 ctx->merge = plen & (PAGE_SIZE - 1);
313 ctx->more = msg->msg_flags & MSG_MORE;
314 if (!ctx->more && !aead_sufficient_data(ctx)) {
320 aead_data_wakeup(sk);
323 return err ?: copied;
326 static ssize_t aead_sendpage(struct socket *sock, struct page *page,
327 int offset, size_t size, int flags)
329 struct sock *sk = sock->sk;
330 struct alg_sock *ask = alg_sk(sk);
331 struct aead_ctx *ctx = ask->private;
332 struct aead_sg_list *sgl = &ctx->tsgl;
335 if (flags & MSG_SENDPAGE_NOTLAST)
338 if (sgl->cur >= ALG_MAX_PAGES)
342 if (!ctx->more && ctx->used)
348 if (!aead_writable(sk)) {
349 /* user space sent too much data */
358 sg_set_page(sgl->sg + sgl->cur, page, size, offset);
365 ctx->more = flags & MSG_MORE;
366 if (!ctx->more && !aead_sufficient_data(ctx)) {
372 aead_data_wakeup(sk);
378 #define GET_ASYM_REQ(req, tfm) (struct aead_async_req *) \
379 ((char *)req + sizeof(struct aead_request) + \
380 crypto_aead_reqsize(tfm))
382 #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
383 crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
384 sizeof(struct aead_request)
386 static void aead_async_cb(struct crypto_async_request *_req, int err)
388 struct aead_request *req = _req->data;
389 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
390 struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
391 struct sock *sk = areq->sk;
392 struct scatterlist *sg = areq->tsgl;
393 struct aead_async_rsgl *rsgl;
394 struct kiocb *iocb = areq->iocb;
395 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
397 list_for_each_entry(rsgl, &areq->list, list) {
398 af_alg_free_sg(&rsgl->sgl);
399 if (rsgl != &areq->first_rsgl)
400 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
403 for (i = 0; i < areq->tsgls; i++)
404 put_page(sg_page(sg + i));
406 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
407 sock_kfree_s(sk, req, reqlen);
409 iocb->ki_complete(iocb, err, err);
412 static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
415 struct sock *sk = sock->sk;
416 struct alg_sock *ask = alg_sk(sk);
417 struct aead_ctx *ctx = ask->private;
418 struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
419 struct aead_async_req *areq;
420 struct aead_request *req = NULL;
421 struct aead_sg_list *sgl = &ctx->tsgl;
422 struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
423 unsigned int as = crypto_aead_authsize(tfm);
424 unsigned int i, reqlen = GET_REQ_SIZE(tfm);
428 size_t usedpages = 0;
432 err = aead_wait_for_data(sk, flags);
437 if (!aead_sufficient_data(ctx))
446 req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
450 areq = GET_ASYM_REQ(req, tfm);
451 memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
452 INIT_LIST_HEAD(&areq->list);
453 areq->iocb = msg->msg_iocb;
455 memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
456 aead_request_set_tfm(req, tfm);
457 aead_request_set_ad(req, ctx->aead_assoclen);
458 aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
460 used -= ctx->aead_assoclen;
462 /* take over all tx sgls from ctx */
463 areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur,
465 if (unlikely(!areq->tsgl))
468 sg_init_table(areq->tsgl, sgl->cur);
469 for (i = 0; i < sgl->cur; i++)
470 sg_set_page(&areq->tsgl[i], sg_page(&sgl->sg[i]),
471 sgl->sg[i].length, sgl->sg[i].offset);
473 areq->tsgls = sgl->cur;
476 while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) {
477 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
478 (outlen - usedpages));
480 if (list_empty(&areq->list)) {
481 rsgl = &areq->first_rsgl;
484 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
485 if (unlikely(!rsgl)) {
490 rsgl->sgl.npages = 0;
491 list_add_tail(&rsgl->list, &areq->list);
493 /* make one iovec available as scatterlist */
494 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
500 /* chain the new scatterlist with previous one */
502 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
506 iov_iter_advance(&msg->msg_iter, err);
509 /* ensure output buffer is sufficiently large */
510 if (usedpages < outlen) {
515 aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
517 err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
519 if (err == -EINPROGRESS) {
524 } else if (err == -EBADMSG) {
532 list_for_each_entry(rsgl, &areq->list, list) {
533 af_alg_free_sg(&rsgl->sgl);
534 if (rsgl != &areq->first_rsgl)
535 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
538 sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
540 sock_kfree_s(sk, req, reqlen);
542 aead_wmem_wakeup(sk);
544 return err ? err : outlen;
547 static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags)
549 struct sock *sk = sock->sk;
550 struct alg_sock *ask = alg_sk(sk);
551 struct aead_ctx *ctx = ask->private;
552 unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
553 struct aead_sg_list *sgl = &ctx->tsgl;
554 struct aead_async_rsgl *last_rsgl = NULL;
555 struct aead_async_rsgl *rsgl, *tmp;
557 unsigned long used = 0;
559 size_t usedpages = 0;
564 * AEAD memory structure: For encryption, the tag is appended to the
565 * ciphertext which implies that the memory allocated for the ciphertext
566 * must be increased by the tag length. For decryption, the tag
567 * is expected to be concatenated to the ciphertext. The plaintext
568 * therefore has a memory size of the ciphertext minus the tag length.
570 * The memory structure for cipher operation has the following
572 * AEAD encryption input: assoc data || plaintext
573 * AEAD encryption output: cipherntext || auth tag
574 * AEAD decryption input: assoc data || ciphertext || auth tag
575 * AEAD decryption output: plaintext
579 err = aead_wait_for_data(sk, flags);
584 /* data length provided by caller via sendmsg/sendpage */
588 * Make sure sufficient data is present -- note, the same check is
589 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
590 * shall provide an information to the data sender that something is
591 * wrong, but they are irrelevant to maintain the kernel integrity.
592 * We need this check here too in case user space decides to not honor
593 * the error message in sendmsg/sendpage and still call recvmsg. This
594 * check here protects the kernel integrity.
596 if (!aead_sufficient_data(ctx))
600 * Calculate the minimum output buffer size holding the result of the
601 * cipher operation. When encrypting data, the receiving buffer is
602 * larger by the tag length compared to the input buffer as the
603 * encryption operation generates the tag. For decryption, the input
604 * buffer provides the tag which is consumed resulting in only the
605 * plaintext without a buffer for the tag returned to the caller.
613 * The cipher operation input data is reduced by the associated data
614 * length as this data is processed separately later on.
616 used -= ctx->aead_assoclen;
618 /* convert iovecs of output buffers into scatterlists */
619 while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) {
620 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
621 (outlen - usedpages));
623 if (list_empty(&ctx->list)) {
624 rsgl = &ctx->first_rsgl;
626 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
627 if (unlikely(!rsgl)) {
632 rsgl->sgl.npages = 0;
633 list_add_tail(&rsgl->list, &ctx->list);
635 /* make one iovec available as scatterlist */
636 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
640 /* chain the new scatterlist with previous one */
642 af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
646 iov_iter_advance(&msg->msg_iter, err);
649 /* ensure output buffer is sufficiently large */
650 if (usedpages < outlen) {
655 sg_mark_end(sgl->sg + sgl->cur - 1);
656 aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg,
658 aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
660 err = af_alg_wait_for_completion(ctx->enc ?
661 crypto_aead_encrypt(&ctx->aead_req) :
662 crypto_aead_decrypt(&ctx->aead_req),
666 /* EBADMSG implies a valid cipher operation took place */
677 list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
678 af_alg_free_sg(&rsgl->sgl);
679 list_del(&rsgl->list);
680 if (rsgl != &ctx->first_rsgl)
681 sock_kfree_s(sk, rsgl, sizeof(*rsgl));
683 INIT_LIST_HEAD(&ctx->list);
684 aead_wmem_wakeup(sk);
687 return err ? err : outlen;
690 static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
693 return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
694 aead_recvmsg_async(sock, msg, flags) :
695 aead_recvmsg_sync(sock, msg, flags);
698 static unsigned int aead_poll(struct file *file, struct socket *sock,
701 struct sock *sk = sock->sk;
702 struct alg_sock *ask = alg_sk(sk);
703 struct aead_ctx *ctx = ask->private;
706 sock_poll_wait(file, sk_sleep(sk), wait);
710 mask |= POLLIN | POLLRDNORM;
712 if (aead_writable(sk))
713 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
718 static struct proto_ops algif_aead_ops = {
721 .connect = sock_no_connect,
722 .socketpair = sock_no_socketpair,
723 .getname = sock_no_getname,
724 .ioctl = sock_no_ioctl,
725 .listen = sock_no_listen,
726 .shutdown = sock_no_shutdown,
727 .getsockopt = sock_no_getsockopt,
728 .mmap = sock_no_mmap,
729 .bind = sock_no_bind,
730 .accept = sock_no_accept,
731 .setsockopt = sock_no_setsockopt,
733 .release = af_alg_release,
734 .sendmsg = aead_sendmsg,
735 .sendpage = aead_sendpage,
736 .recvmsg = aead_recvmsg,
740 static int aead_check_key(struct socket *sock)
744 struct alg_sock *pask;
745 struct aead_tfm *tfm;
746 struct sock *sk = sock->sk;
747 struct alg_sock *ask = alg_sk(sk);
750 if (!atomic_read(&ask->nokey_refcnt))
754 pask = alg_sk(ask->parent);
758 lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
762 atomic_dec(&pask->nokey_refcnt);
763 atomic_set(&ask->nokey_refcnt, 0);
775 static int aead_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
780 err = aead_check_key(sock);
784 return aead_sendmsg(sock, msg, size);
787 static ssize_t aead_sendpage_nokey(struct socket *sock, struct page *page,
788 int offset, size_t size, int flags)
792 err = aead_check_key(sock);
796 return aead_sendpage(sock, page, offset, size, flags);
799 static int aead_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
800 size_t ignored, int flags)
804 err = aead_check_key(sock);
808 return aead_recvmsg(sock, msg, ignored, flags);
811 static struct proto_ops algif_aead_ops_nokey = {
814 .connect = sock_no_connect,
815 .socketpair = sock_no_socketpair,
816 .getname = sock_no_getname,
817 .ioctl = sock_no_ioctl,
818 .listen = sock_no_listen,
819 .shutdown = sock_no_shutdown,
820 .getsockopt = sock_no_getsockopt,
821 .mmap = sock_no_mmap,
822 .bind = sock_no_bind,
823 .accept = sock_no_accept,
824 .setsockopt = sock_no_setsockopt,
826 .release = af_alg_release,
827 .sendmsg = aead_sendmsg_nokey,
828 .sendpage = aead_sendpage_nokey,
829 .recvmsg = aead_recvmsg_nokey,
833 static void *aead_bind(const char *name, u32 type, u32 mask)
835 struct aead_tfm *tfm;
836 struct crypto_aead *aead;
838 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
840 return ERR_PTR(-ENOMEM);
842 aead = crypto_alloc_aead(name, type, mask);
845 return ERR_CAST(aead);
853 static void aead_release(void *private)
855 struct aead_tfm *tfm = private;
857 crypto_free_aead(tfm->aead);
861 static int aead_setauthsize(void *private, unsigned int authsize)
863 struct aead_tfm *tfm = private;
865 return crypto_aead_setauthsize(tfm->aead, authsize);
868 static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
870 struct aead_tfm *tfm = private;
873 err = crypto_aead_setkey(tfm->aead, key, keylen);
879 static void aead_sock_destruct(struct sock *sk)
881 struct alg_sock *ask = alg_sk(sk);
882 struct aead_ctx *ctx = ask->private;
883 unsigned int ivlen = crypto_aead_ivsize(
884 crypto_aead_reqtfm(&ctx->aead_req));
886 WARN_ON(atomic_read(&sk->sk_refcnt) != 0);
888 sock_kzfree_s(sk, ctx->iv, ivlen);
889 sock_kfree_s(sk, ctx, ctx->len);
890 af_alg_release_parent(sk);
893 static int aead_accept_parent_nokey(void *private, struct sock *sk)
895 struct aead_ctx *ctx;
896 struct alg_sock *ask = alg_sk(sk);
897 struct aead_tfm *tfm = private;
898 struct crypto_aead *aead = tfm->aead;
899 unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(aead);
900 unsigned int ivlen = crypto_aead_ivsize(aead);
902 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
907 ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
909 sock_kfree_s(sk, ctx, len);
912 memset(ctx->iv, 0, ivlen);
920 ctx->aead_assoclen = 0;
921 af_alg_init_completion(&ctx->completion);
922 sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
923 INIT_LIST_HEAD(&ctx->list);
927 aead_request_set_tfm(&ctx->aead_req, aead);
928 aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_SLEEP,
929 af_alg_complete, &ctx->completion);
931 sk->sk_destruct = aead_sock_destruct;
936 static int aead_accept_parent(void *private, struct sock *sk)
938 struct aead_tfm *tfm = private;
943 return aead_accept_parent_nokey(private, sk);
946 static const struct af_alg_type algif_type_aead = {
948 .release = aead_release,
949 .setkey = aead_setkey,
950 .setauthsize = aead_setauthsize,
951 .accept = aead_accept_parent,
952 .accept_nokey = aead_accept_parent_nokey,
953 .ops = &algif_aead_ops,
954 .ops_nokey = &algif_aead_ops_nokey,
959 static int __init algif_aead_init(void)
961 return af_alg_register_type(&algif_type_aead);
964 static void __exit algif_aead_exit(void)
966 int err = af_alg_unregister_type(&algif_type_aead);
970 module_init(algif_aead_init);
971 module_exit(algif_aead_exit);
972 MODULE_LICENSE("GPL");
973 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
974 MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");