1 files changed, 666 insertions, 0 deletions

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
new file mode 100644
index 000000000000..527d27b023ab
--- /dev/null
+++ b/crypto/algif_aead.c
@@ -0,0 +1,666 @@
+/*
+ * algif_aead: User-space interface for AEAD algorithms
+ *
+ * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
+ *
+ * This file provides the user-space API for AEAD ciphers.
+ *
+ * This file is derived from algif_skcipher.c.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <crypto/scatterwalk.h>
+#include <crypto/if_alg.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <net/sock.h>
+
+struct aead_sg_list {
+	unsigned int cur;
+	struct scatterlist sg[ALG_MAX_PAGES];
+};
+
+struct aead_ctx {
+	struct aead_sg_list tsgl;
+	/*
+	 * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
+	 * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
+	 * bytes
+	 */
+#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
+	struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
+
+	void *iv;
+
+	struct af_alg_completion completion;
+
+	unsigned long used;
+
+	unsigned int len;
+	bool more;
+	bool merge;
+	bool enc;
+
+	size_t aead_assoclen;
+	struct aead_request aead_req;
+};
+
+static inline int aead_sndbuf(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+
+	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
+			  ctx->used, 0);
+}
+
+static inline bool aead_writable(struct sock *sk)
+{
+	return PAGE_SIZE <= aead_sndbuf(sk);
+}
+
+static inline bool aead_sufficient_data(struct aead_ctx *ctx)
+{
+	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
+
+	return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ? 0 : as)));
+}
+
+static void aead_put_sgl(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	struct aead_sg_list *sgl = &ctx->tsgl;
+	struct scatterlist *sg = sgl->sg;
+	unsigned int i;
+
+	for (i = 0; i < sgl->cur; i++) {
+		if (!sg_page(sg + i))
+			continue;
+
+		put_page(sg_page(sg + i));
+		sg_assign_page(sg + i, NULL);
+	}
+	sgl->cur = 0;
+	ctx->used = 0;
+	ctx->more = 0;
+	ctx->merge = 0;
+}
+
+static void aead_wmem_wakeup(struct sock *sk)
+{
+	struct socket_wq *wq;
+
+	if (!aead_writable(sk))
+		return;
+
+	rcu_read_lock();
+	wq = rcu_dereference(sk->sk_wq);
+	if (wq_has_sleeper(wq))
+		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
+							   POLLRDNORM |
+							   POLLRDBAND);
+	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+	rcu_read_unlock();
+}
+
+static int aead_wait_for_data(struct sock *sk, unsigned flags)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	long timeout;
+	DEFINE_WAIT(wait);
+	int err = -ERESTARTSYS;
+
+	if (flags & MSG_DONTWAIT)
+		return -EAGAIN;
+
+	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	for (;;) {
+		if (signal_pending(current))
+			break;
+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+		timeout = MAX_SCHEDULE_TIMEOUT;
+		if (sk_wait_event(sk, &timeout, !ctx->more)) {
+			err = 0;
+			break;
+		}
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	return err;
+}
+
+static void aead_data_wakeup(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	struct socket_wq *wq;
+
+	if (ctx->more)
+		return;
+	if (!ctx->used)
+		return;
+
+	rcu_read_lock();
+	wq = rcu_dereference(sk->sk_wq);
+	if (wq_has_sleeper(wq))
+		wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
+							   POLLRDNORM |
+							   POLLRDBAND);
+	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
+	rcu_read_unlock();
+}
+
+static int aead_sendmsg(struct kiocb *unused, struct socket *sock,
+			struct msghdr *msg, size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	unsigned ivsize =
+		crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
+	struct aead_sg_list *sgl = &ctx->tsgl;
+	struct af_alg_control con = {};
+	long copied = 0;
+	bool enc = 0;
+	bool init = 0;
+	int err = -EINVAL;
+
+	if (msg->msg_controllen) {
+		err = af_alg_cmsg_send(msg, &con);
+		if (err)
+			return err;
+
+		init = 1;
+		switch (con.op) {
+		case ALG_OP_ENCRYPT:
+			enc = 1;
+			break;
+		case ALG_OP_DECRYPT:
+			enc = 0;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		if (con.iv && con.iv->ivlen != ivsize)
+			return -EINVAL;
+	}
+
+	lock_sock(sk);
+	if (!ctx->more && ctx->used)
+		goto unlock;
+
+	if (init) {
+		ctx->enc = enc;
+		if (con.iv)
+			memcpy(ctx->iv, con.iv->iv, ivsize);
+
+		ctx->aead_assoclen = con.aead_assoclen;
+	}
+
+	while (size) {
+		unsigned long len = size;
+		struct scatterlist *sg = NULL;
+
+		/* use the existing memory in an allocated page */
+		if (ctx->merge) {
+			sg = sgl->sg + sgl->cur - 1;
+			len = min_t(unsigned long, len,
+				    PAGE_SIZE - sg->offset - sg->length);
+			err = memcpy_from_msg(page_address(sg_page(sg)) +
+					      sg->offset + sg->length,
+					      msg, len);
+			if (err)
+				goto unlock;
+
+			sg->length += len;
+			ctx->merge = (sg->offset + sg->length) &
+				     (PAGE_SIZE - 1);
+
+			ctx->used += len;
+			copied += len;
+			size -= len;
+			continue;
+		}
+
+		if (!aead_writable(sk)) {
+			/* user space sent too much data */
+			aead_put_sgl(sk);
+			err = -EMSGSIZE;
+			goto unlock;
+		}
+
+		/* allocate a new page */
+		len = min_t(unsigned long, size, aead_sndbuf(sk));
+		while (len) {
+			int plen = 0;
+
+			if (sgl->cur >= ALG_MAX_PAGES) {
+				aead_put_sgl(sk);
+				err = -E2BIG;
+				goto unlock;
+			}
+
+			sg = sgl->sg + sgl->cur;
+			plen = min_t(int, len, PAGE_SIZE);
+
+			sg_assign_page(sg, alloc_page(GFP_KERNEL));
+			err = -ENOMEM;
+			if (!sg_page(sg))
+				goto unlock;
+
+			err = memcpy_from_msg(page_address(sg_page(sg)),
+					      msg, plen);
+			if (err) {
+				__free_page(sg_page(sg));
+				sg_assign_page(sg, NULL);
+				goto unlock;
+			}
+
+			sg->offset = 0;
+			sg->length = plen;
+			len -= plen;
+			ctx->used += plen;
+			copied += plen;
+			sgl->cur++;
+			size -= plen;
+			ctx->merge = plen & (PAGE_SIZE - 1);
+		}
+	}
+
+	err = 0;
+
+	ctx->more = msg->msg_flags & MSG_MORE;
+	if (!ctx->more && !aead_sufficient_data(ctx)) {
+		aead_put_sgl(sk);
+		err = -EMSGSIZE;
+	}
+
+unlock:
+	aead_data_wakeup(sk);
+	release_sock(sk);
+
+	return err ?: copied;
+}
+
+static ssize_t aead_sendpage(struct socket *sock, struct page *page,
+			     int offset, size_t size, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	struct aead_sg_list *sgl = &ctx->tsgl;
+	int err = -EINVAL;
+
+	if (flags & MSG_SENDPAGE_NOTLAST)
+		flags |= MSG_MORE;
+
+	if (sgl->cur >= ALG_MAX_PAGES)
+		return -E2BIG;
+
+	lock_sock(sk);
+	if (!ctx->more && ctx->used)
+		goto unlock;
+
+	if (!size)
+		goto done;
+
+	if (!aead_writable(sk)) {
+		/* user space sent too much data */
+		aead_put_sgl(sk);
+		err = -EMSGSIZE;
+		goto unlock;
+	}
+
+	ctx->merge = 0;
+
+	get_page(page);
+	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
+	sgl->cur++;
+	ctx->used += size;
+
+	err = 0;
+
+done:
+	ctx->more = flags & MSG_MORE;
+	if (!ctx->more && !aead_sufficient_data(ctx)) {
+		aead_put_sgl(sk);
+		err = -EMSGSIZE;
+	}
+
+unlock:
+	aead_data_wakeup(sk);
+	release_sock(sk);
+
+	return err ?: size;
+}
+
+static int aead_recvmsg(struct kiocb *unused, struct socket *sock,
+			struct msghdr *msg, size_t ignored, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	unsigned bs = crypto_aead_blocksize(crypto_aead_reqtfm(&ctx->aead_req));
+	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
+	struct aead_sg_list *sgl = &ctx->tsgl;
+	struct scatterlist *sg = NULL;
+	struct scatterlist assoc[ALG_MAX_PAGES];
+	size_t assoclen = 0;
+	unsigned int i = 0;
+	int err = -EINVAL;
+	unsigned long used = 0;
+	size_t outlen = 0;
+	size_t usedpages = 0;
+	unsigned int cnt = 0;
+
+	/* Limit number of IOV blocks to be accessed below */
+	if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
+		return -ENOMSG;
+
+	lock_sock(sk);
+
+	/*
+	 * AEAD memory structure: For encryption, the tag is appended to the
+	 * ciphertext which implies that the memory allocated for the ciphertext
+	 * must be increased by the tag length. For decryption, the tag
+	 * is expected to be concatenated to the ciphertext. The plaintext
+	 * therefore has a memory size of the ciphertext minus the tag length.
+	 *
+	 * The memory structure for cipher operation has the following
+	 * structure:
+	 *	AEAD encryption input:  assoc data || plaintext
+	 *	AEAD encryption output: cipherntext || auth tag
+	 *	AEAD decryption input:  assoc data || ciphertext || auth tag
+	 *	AEAD decryption output: plaintext
+	 */
+
+	if (ctx->more) {
+		err = aead_wait_for_data(sk, flags);
+		if (err)
+			goto unlock;
+	}
+
+	used = ctx->used;
+
+	/*
+	 * Make sure sufficient data is present -- note, the same check is
+	 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
+	 * shall provide an information to the data sender that something is
+	 * wrong, but they are irrelevant to maintain the kernel integrity.
+	 * We need this check here too in case user space decides to not honor
+	 * the error message in sendmsg/sendpage and still call recvmsg. This
+	 * check here protects the kernel integrity.
+	 */
+	if (!aead_sufficient_data(ctx))
+		goto unlock;
+
+	/*
+	 * The cipher operation input data is reduced by the associated data
+	 * length as this data is processed separately later on.
+	 */
+	used -= ctx->aead_assoclen;
+
+	if (ctx->enc) {
+		/* round up output buffer to multiple of block size */
+		outlen = ((used + bs - 1) / bs * bs);
+		/* add the size needed for the auth tag to be created */
+		outlen += as;
+	} else {
+		/* output data size is input without the authentication tag */
+		outlen = used - as;
+		/* round up output buffer to multiple of block size */
+		outlen = ((outlen + bs - 1) / bs * bs);
+	}
+
+	/* convert iovecs of output buffers into scatterlists */
+	while (iov_iter_count(&msg->msg_iter)) {
+		size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
+				      (outlen - usedpages));
+
+		/* make one iovec available as scatterlist */
+		err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
+				     seglen);
+		if (err < 0)
+			goto unlock;
+		usedpages += err;
+		/* chain the new scatterlist with initial list */
+		if (cnt)
+			scatterwalk_crypto_chain(ctx->rsgl[0].sg,
+					ctx->rsgl[cnt].sg, 1,
+					sg_nents(ctx->rsgl[cnt-1].sg));
+		/* we do not need more iovecs as we have sufficient memory */
+		if (outlen <= usedpages)
+			break;
+		iov_iter_advance(&msg->msg_iter, err);
+		cnt++;
+	}
+
+	err = -EINVAL;
+	/* ensure output buffer is sufficiently large */
+	if (usedpages < outlen)
+		goto unlock;
+
+	sg_init_table(assoc, ALG_MAX_PAGES);
+	assoclen = ctx->aead_assoclen;
+	/*
+	 * Split scatterlist into two: first part becomes AD, second part
+	 * is plaintext / ciphertext. The first part is assigned to assoc
+	 * scatterlist. When this loop finishes, sg points to the start of the
+	 * plaintext / ciphertext.
+	 */
+	for (i = 0; i < ctx->tsgl.cur; i++) {
+		sg = sgl->sg + i;
+		if (sg->length <= assoclen) {
+			/* AD is larger than one page */
+			sg_set_page(assoc + i, sg_page(sg),
+				    sg->length, sg->offset);
+			assoclen -= sg->length;
+			if (i >= ctx->tsgl.cur)
+				goto unlock;
+		} else if (!assoclen) {
+			/* current page is to start of plaintext / ciphertext */
+			if (i)
+				/* AD terminates at page boundary */
+				sg_mark_end(assoc + i - 1);
+			else
+				/* AD size is zero */
+				sg_mark_end(assoc);
+			break;
+		} else {
+			/* AD does not terminate at page boundary */
+			sg_set_page(assoc + i, sg_page(sg),
+				    assoclen, sg->offset);
+			sg_mark_end(assoc + i);
+			/* plaintext / ciphertext starts after AD */
+			sg->length -= assoclen;
+			sg->offset += assoclen;
+			break;
+		}
+	}
+
+	aead_request_set_assoc(&ctx->aead_req, assoc, ctx->aead_assoclen);
+	aead_request_set_crypt(&ctx->aead_req, sg, ctx->rsgl[0].sg, used,
+			       ctx->iv);
+
+	err = af_alg_wait_for_completion(ctx->enc ?
+					 crypto_aead_encrypt(&ctx->aead_req) :
+					 crypto_aead_decrypt(&ctx->aead_req),
+					 &ctx->completion);
+
+	if (err) {
+		/* EBADMSG implies a valid cipher operation took place */
+		if (err == -EBADMSG)
+			aead_put_sgl(sk);
+		goto unlock;
+	}
+
+	aead_put_sgl(sk);
+
+	err = 0;
+
+unlock:
+	for (i = 0; i < cnt; i++)
+		af_alg_free_sg(&ctx->rsgl[i]);
+
+	aead_wmem_wakeup(sk);
+	release_sock(sk);
+
+	return err ? err : outlen;
+}
+
+static unsigned int aead_poll(struct file *file, struct socket *sock,
+			      poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	unsigned int mask;
+
+	sock_poll_wait(file, sk_sleep(sk), wait);
+	mask = 0;
+
+	if (!ctx->more)
+		mask |= POLLIN | POLLRDNORM;
+
+	if (aead_writable(sk))
+		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
+
+	return mask;
+}
+
+static struct proto_ops algif_aead_ops = {
+	.family		=	PF_ALG,
+
+	.connect	=	sock_no_connect,
+	.socketpair	=	sock_no_socketpair,
+	.getname	=	sock_no_getname,
+	.ioctl		=	sock_no_ioctl,
+	.listen		=	sock_no_listen,
+	.shutdown	=	sock_no_shutdown,
+	.getsockopt	=	sock_no_getsockopt,
+	.mmap		=	sock_no_mmap,
+	.bind		=	sock_no_bind,
+	.accept		=	sock_no_accept,
+	.setsockopt	=	sock_no_setsockopt,
+
+	.release	=	af_alg_release,
+	.sendmsg	=	aead_sendmsg,
+	.sendpage	=	aead_sendpage,
+	.recvmsg	=	aead_recvmsg,
+	.poll		=	aead_poll,
+};
+
+static void *aead_bind(const char *name, u32 type, u32 mask)
+{
+	return crypto_alloc_aead(name, type, mask);
+}
+
+static void aead_release(void *private)
+{
+	crypto_free_aead(private);
+}
+
+static int aead_setauthsize(void *private, unsigned int authsize)
+{
+	return crypto_aead_setauthsize(private, authsize);
+}
+
+static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
+{
+	return crypto_aead_setkey(private, key, keylen);
+}
+
+static void aead_sock_destruct(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct aead_ctx *ctx = ask->private;
+	unsigned int ivlen = crypto_aead_ivsize(
+				crypto_aead_reqtfm(&ctx->aead_req));
+
+	aead_put_sgl(sk);
+	sock_kzfree_s(sk, ctx->iv, ivlen);
+	sock_kfree_s(sk, ctx, ctx->len);
+	af_alg_release_parent(sk);
+}
+
+static int aead_accept_parent(void *private, struct sock *sk)
+{
+	struct aead_ctx *ctx;
+	struct alg_sock *ask = alg_sk(sk);
+	unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
+	unsigned int ivlen = crypto_aead_ivsize(private);
+
+	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	memset(ctx, 0, len);
+
+	ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
+	if (!ctx->iv) {
+		sock_kfree_s(sk, ctx, len);
+		return -ENOMEM;
+	}
+	memset(ctx->iv, 0, ivlen);
+
+	ctx->len = len;
+	ctx->used = 0;
+	ctx->more = 0;
+	ctx->merge = 0;
+	ctx->enc = 0;
+	ctx->tsgl.cur = 0;
+	ctx->aead_assoclen = 0;
+	af_alg_init_completion(&ctx->completion);
+	sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
+
+	ask->private = ctx;
+
+	aead_request_set_tfm(&ctx->aead_req, private);
+	aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  af_alg_complete, &ctx->completion);
+
+	sk->sk_destruct = aead_sock_destruct;
+
+	return 0;
+}
+
+static const struct af_alg_type algif_type_aead = {
+	.bind		=	aead_bind,
+	.release	=	aead_release,
+	.setkey		=	aead_setkey,
+	.setauthsize	=	aead_setauthsize,
+	.accept		=	aead_accept_parent,
+	.ops		=	&algif_aead_ops,
+	.name		=	"aead",
+	.owner		=	THIS_MODULE
+};
+
+static int __init algif_aead_init(void)
+{
+	return af_alg_register_type(&algif_type_aead);
+}
+
+static void __exit algif_aead_exit(void)
+{
+	int err = af_alg_unregister_type(&algif_type_aead);
+	BUG_ON(err);
+}
+
+module_init(algif_aead_init);
+module_exit(algif_aead_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");