/* * algif_skcipher: User-space interface for skcipher algorithms * * This file provides the user-space API for symmetric key ciphers. * * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> * * 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/skcipher.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 skcipher_sg_list {	struct list_head list; 	int cur; 	struct scatterlist sg[0];}; struct skcipher_ctx {	struct list_head tsgl;	struct af_alg_sgl rsgl; 	void *iv; 	struct af_alg_completion completion; 	unsigned used; 	unsigned int len;	bool more;	bool merge;	bool enc; 	struct ablkcipher_request req;}; #define MAX_SGL_ENTS ((PAGE_SIZE - sizeof(struct skcipher_sg_list)) / \		      sizeof(struct scatterlist) - 1) static inline int skcipher_sndbuf(struct sock *sk){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_ctx *ctx = ask->private; 	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -			  ctx->used, 0);} static inline bool skcipher_writable(struct sock *sk){	return PAGE_SIZE <= skcipher_sndbuf(sk);} static int skcipher_alloc_sgl(struct sock *sk){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_ctx *ctx = ask->private;	struct skcipher_sg_list *sgl;	struct scatterlist *sg = NULL; 	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);	if (!list_empty(&ctx->tsgl))		sg = sgl->sg; 	if (!sg || sgl->cur >= MAX_SGL_ENTS) {		sgl = sock_kmalloc(sk, sizeof(*sgl) +				       sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),				   GFP_KERNEL);		if (!sgl)			return -ENOMEM; 		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);		sgl->cur = 0; 		if (sg)			scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg); 		list_add_tail(&sgl->list, &ctx->tsgl);	} 	return 0;} static void skcipher_pull_sgl(struct sock *sk, int used){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_ctx *ctx = ask->private;	struct skcipher_sg_list *sgl;	struct scatterlist *sg;	int i; 	while (!list_empty(&ctx->tsgl)) {		sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,				       list);		sg = sgl->sg; 		for (i = 0; i < sgl->cur; i++) {			int plen = min_t(int, used, sg[i].length); 			if (!sg_page(sg + i))				continue; 			sg[i].length -= plen;			sg[i].offset += plen; 			used -= plen;			ctx->used -= plen; 			if (sg[i].length)				return; 			put_page(sg_page(sg + i));			sg_assign_page(sg + i, NULL);		} 		list_del(&sgl->list);		sock_kfree_s(sk, sgl,			     sizeof(*sgl) + sizeof(sgl->sg[0]) *					    (MAX_SGL_ENTS + 1));	} 	if (!ctx->used)		ctx->merge = 0;} static void skcipher_free_sgl(struct sock *sk){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_ctx *ctx = ask->private; 	skcipher_pull_sgl(sk, ctx->used);} static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags){	long timeout;	DEFINE_WAIT(wait);	int err = -ERESTARTSYS; 	if (flags & MSG_DONTWAIT)		return -EAGAIN; 	set_bit(SOCK_ASYNC_NOSPACE, &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, skcipher_writable(sk))) {			err = 0;			break;		}	}	finish_wait(sk_sleep(sk), &wait); 	return err;} static void skcipher_wmem_wakeup(struct sock *sk){	struct socket_wq *wq; 	if (!skcipher_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 skcipher_wait_for_data(struct sock *sk, unsigned flags){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_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->used)) {			err = 0;			break;		}	}	finish_wait(sk_sleep(sk), &wait); 	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 	return err;} static void skcipher_data_wakeup(struct sock *sk){	struct alg_sock *ask = alg_sk(sk);	struct skcipher_ctx *ctx = ask->private;	struct socket_wq *wq; 	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 skcipher_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 skcipher_ctx *ctx = ask->private;	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);	unsigned ivsize = crypto_ablkcipher_ivsize(tfm);	struct skcipher_sg_list *sgl;	struct af_alg_control con = {};	long copied = 0;	bool enc = 0;	int err;	int i; 	if (msg->msg_controllen) {		err = af_alg_cmsg_send(msg, &con);		if (err)			return err; 		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;	} 	err = -EINVAL; 	lock_sock(sk);	if (!ctx->more && ctx->used)		goto unlock; 	if (!ctx->used) {		ctx->enc = enc;		if (con.iv)			memcpy(ctx->iv, con.iv->iv, ivsize);	} 	while (size) {		struct scatterlist *sg;		unsigned long len = size;		int plen; 		if (ctx->merge) {			sgl = list_entry(ctx->tsgl.prev,					 struct skcipher_sg_list, list);			sg = sgl->sg + sgl->cur - 1;			len = min_t(unsigned long, len,				    PAGE_SIZE - sg->offset - sg->length); 			err = memcpy_fromiovec(page_address(sg_page(sg)) +					       sg->offset + sg->length,					       msg->msg_iov, 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 (!skcipher_writable(sk)) {			err = skcipher_wait_for_wmem(sk, msg->msg_flags);			if (err)				goto unlock;		} 		len = min_t(unsigned long, len, skcipher_sndbuf(sk)); 		err = skcipher_alloc_sgl(sk);		if (err)			goto unlock; 		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);		sg = sgl->sg;		do {			i = sgl->cur;			plen = min_t(int, len, PAGE_SIZE); 			sg_assign_page(sg + i, alloc_page(GFP_KERNEL));			err = -ENOMEM;			if (!sg_page(sg + i))				goto unlock; 			err = memcpy_fromiovec(page_address(sg_page(sg + i)),					       msg->msg_iov, plen);			if (err) {				__free_page(sg_page(sg + i));				sg_assign_page(sg + i, NULL);				goto unlock;			} 			sg[i].length = plen;			len -= plen;			ctx->used += plen;			copied += plen;			size -= plen;			sgl->cur++;		} while (len && sgl->cur < MAX_SGL_ENTS); 		ctx->merge = plen & (PAGE_SIZE - 1);	} 	err = 0; 	ctx->more = msg->msg_flags & MSG_MORE;	if (!ctx->more && !list_empty(&ctx->tsgl))		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); unlock:	skcipher_data_wakeup(sk);	release_sock(sk); 	return copied ?: err;} static ssize_t skcipher_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 skcipher_ctx *ctx = ask->private;	struct skcipher_sg_list *sgl;	int err = -EINVAL; 	lock_sock(sk);	if (!ctx->more && ctx->used)		goto unlock; 	if (!size)		goto done; 	if (!skcipher_writable(sk)) {		err = skcipher_wait_for_wmem(sk, flags);		if (err)			goto unlock;	} 	err = skcipher_alloc_sgl(sk);	if (err)		goto unlock; 	ctx->merge = 0;	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); 	get_page(page);	sg_set_page(sgl->sg + sgl->cur, page, size, offset);	sgl->cur++;	ctx->used += size; done:	ctx->more = flags & MSG_MORE;	if (!ctx->more && !list_empty(&ctx->tsgl))		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); unlock:	skcipher_data_wakeup(sk);	release_sock(sk); 	return err ?: size;} static int skcipher_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 skcipher_ctx *ctx = ask->private;	unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(		&ctx->req));	struct skcipher_sg_list *sgl;	struct scatterlist *sg;	unsigned long iovlen;	struct iovec *iov;	int err = -EAGAIN;	int used;	long copied = 0; 	lock_sock(sk);	for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;	     iovlen--, iov++) {		unsigned long seglen = iov->iov_len;		char __user *from = iov->iov_base; 		while (seglen) {			sgl = list_first_entry(&ctx->tsgl,					       struct skcipher_sg_list, list);			sg = sgl->sg; 			while (!sg->length)				sg++; 			used = ctx->used;			if (!used) {				err = skcipher_wait_for_data(sk, flags);				if (err)					goto unlock;			} 			used = min_t(unsigned long, used, seglen); 			used = af_alg_make_sg(&ctx->rsgl, from, used, 1);			err = used;			if (err < 0)				goto unlock; 			if (ctx->more || used < ctx->used)				used -= used % bs; 			err = -EINVAL;			if (!used)				goto free; 			ablkcipher_request_set_crypt(&ctx->req, sg,						     ctx->rsgl.sg, used,						     ctx->iv); 			err = af_alg_wait_for_completion(				ctx->enc ?					crypto_ablkcipher_encrypt(&ctx->req) :					crypto_ablkcipher_decrypt(&ctx->req),				&ctx->completion); free:			af_alg_free_sg(&ctx->rsgl); 			if (err)				goto unlock; 			copied += used;			from += used;			seglen -= used;			skcipher_pull_sgl(sk, used);		}	} 	err = 0; unlock:	skcipher_wmem_wakeup(sk);	release_sock(sk); 	return copied ?: err;} 

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