/*
   * af_alg: User-space algorithm interface
   *
   * This file provides the user-space API for algorithms.
   *
   * 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 <linux/atomic.h>

  #include <crypto/if_alg.h>
  #include <linux/crypto.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/list.h>
  #include <linux/module.h>
  #include <linux/net.h>
  #include <linux/rwsem.h>

  #include <linux/security.h>

  
  struct alg_type_list {
  	const struct af_alg_type *type;
  	struct list_head list;
  };

  static atomic_long_t alg_memory_allocated;

  
  static struct proto alg_proto = {
  	.name			= "ALG",
  	.owner			= THIS_MODULE,
  	.memory_allocated	= &alg_memory_allocated,
  	.obj_size		= sizeof(struct alg_sock),
  };
  
  static LIST_HEAD(alg_types);
  static DECLARE_RWSEM(alg_types_sem);
  
  static const struct af_alg_type *alg_get_type(const char *name)
  {
  	const struct af_alg_type *type = ERR_PTR(-ENOENT);
  	struct alg_type_list *node;
  
  	down_read(&alg_types_sem);
  	list_for_each_entry(node, &alg_types, list) {
  		if (strcmp(node->type->name, name))
  			continue;
  
  		if (try_module_get(node->type->owner))
  			type = node->type;
  		break;
  	}
  	up_read(&alg_types_sem);
  
  	return type;
  }
  
  int af_alg_register_type(const struct af_alg_type *type)
  {
  	struct alg_type_list *node;
  	int err = -EEXIST;
  
  	down_write(&alg_types_sem);
  	list_for_each_entry(node, &alg_types, list) {
  		if (!strcmp(node->type->name, type->name))
  			goto unlock;
  	}
  
  	node = kmalloc(sizeof(*node), GFP_KERNEL);
  	err = -ENOMEM;
  	if (!node)
  		goto unlock;
  
  	type->ops->owner = THIS_MODULE;

  	if (type->ops_nokey)
  		type->ops_nokey->owner = THIS_MODULE;

  	node->type = type;
  	list_add(&node->list, &alg_types);
  	err = 0;
  
  unlock:
  	up_write(&alg_types_sem);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(af_alg_register_type);
  
  int af_alg_unregister_type(const struct af_alg_type *type)
  {
  	struct alg_type_list *node;
  	int err = -ENOENT;
  
  	down_write(&alg_types_sem);
  	list_for_each_entry(node, &alg_types, list) {
  		if (strcmp(node->type->name, type->name))
  			continue;
  
  		list_del(&node->list);
  		kfree(node);
  		err = 0;
  		break;
  	}
  	up_write(&alg_types_sem);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(af_alg_unregister_type);
  
  static void alg_do_release(const struct af_alg_type *type, void *private)
  {
  	if (!type)
  		return;
  
  	type->release(private);
  	module_put(type->owner);
  }
  
  int af_alg_release(struct socket *sock)
  {
  	if (sock->sk)
  		sock_put(sock->sk);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(af_alg_release);

  void af_alg_release_parent(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);

  	unsigned int nokey = ask->nokey_refcnt;
  	bool last = nokey && !ask->refcnt;

  
  	sk = ask->parent;
  	ask = alg_sk(sk);
  
  	lock_sock(sk);

  	ask->nokey_refcnt -= nokey;
  	if (!last)
  		last = !--ask->refcnt;

  	release_sock(sk);
  
  	if (last)
  		sock_put(sk);
  }
  EXPORT_SYMBOL_GPL(af_alg_release_parent);

  static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {

  	const u32 forbidden = CRYPTO_ALG_INTERNAL;

  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	struct sockaddr_alg *sa = (void *)uaddr;
  	const struct af_alg_type *type;
  	void *private;

  	int err;

  
  	if (sock->state == SS_CONNECTED)
  		return -EINVAL;
  
  	if (addr_len != sizeof(*sa))
  		return -EINVAL;
  
  	sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
  	sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
  
  	type = alg_get_type(sa->salg_type);
  	if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
  		request_module("algif-%s", sa->salg_type);
  		type = alg_get_type(sa->salg_type);
  	}
  
  	if (IS_ERR(type))
  		return PTR_ERR(type);

  	private = type->bind(sa->salg_name,
  			     sa->salg_feat & ~forbidden,
  			     sa->salg_mask & ~forbidden);

  	if (IS_ERR(private)) {
  		module_put(type->owner);
  		return PTR_ERR(private);
  	}

  	err = -EBUSY;

  	lock_sock(sk);

  	if (ask->refcnt | ask->nokey_refcnt)

  		goto unlock;

  
  	swap(ask->type, type);
  	swap(ask->private, private);

  	err = 0;
  
  unlock:

  	release_sock(sk);
  
  	alg_do_release(type, private);

  	return err;

  }
  
  static int alg_setkey(struct sock *sk, char __user *ukey,
  		      unsigned int keylen)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	const struct af_alg_type *type = ask->type;
  	u8 *key;
  	int err;
  
  	key = sock_kmalloc(sk, keylen, GFP_KERNEL);
  	if (!key)
  		return -ENOMEM;
  
  	err = -EFAULT;
  	if (copy_from_user(key, ukey, keylen))
  		goto out;
  
  	err = type->setkey(ask->private, key, keylen);
  
  out:

  	sock_kzfree_s(sk, key, keylen);

  
  	return err;
  }
  
  static int alg_setsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, unsigned int optlen)
  {
  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	const struct af_alg_type *type;

  	int err = -EBUSY;

  
  	lock_sock(sk);

  	if (ask->refcnt)
  		goto unlock;

  	type = ask->type;

  	err = -ENOPROTOOPT;

  	if (level != SOL_ALG || !type)
  		goto unlock;
  
  	switch (optname) {
  	case ALG_SET_KEY:
  		if (sock->state == SS_CONNECTED)
  			goto unlock;
  		if (!type->setkey)
  			goto unlock;
  
  		err = alg_setkey(sk, optval, optlen);

  		break;
  	case ALG_SET_AEAD_AUTHSIZE:
  		if (sock->state == SS_CONNECTED)
  			goto unlock;
  		if (!type->setauthsize)
  			goto unlock;
  		err = type->setauthsize(ask->private, optlen);

  	}
  
  unlock:
  	release_sock(sk);
  
  	return err;
  }
  
  int af_alg_accept(struct sock *sk, struct socket *newsock)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	const struct af_alg_type *type;
  	struct sock *sk2;

  	unsigned int nokey;

  	int err;
  
  	lock_sock(sk);
  	type = ask->type;
  
  	err = -EINVAL;
  	if (!type)
  		goto unlock;

  	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, 0);

  	err = -ENOMEM;
  	if (!sk2)
  		goto unlock;
  
  	sock_init_data(newsock, sk2);

  	sock_graft(sk2, newsock);

  	security_sk_clone(sk, sk2);

  
  	err = type->accept(ask->private, sk2);

  
  	nokey = err == -ENOKEY;
  	if (nokey && type->accept_nokey)
  		err = type->accept_nokey(ask->private, sk2);

  	if (err)

  		goto unlock;

  
  	sk2->sk_family = PF_ALG;

  	if (nokey || !ask->refcnt++)

  		sock_hold(sk);

  	ask->nokey_refcnt += nokey;

  	alg_sk(sk2)->parent = sk;
  	alg_sk(sk2)->type = type;

  	alg_sk(sk2)->nokey_refcnt = nokey;

  
  	newsock->ops = type->ops;
  	newsock->state = SS_CONNECTED;

  	if (nokey)
  		newsock->ops = type->ops_nokey;

  	err = 0;
  
  unlock:
  	release_sock(sk);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(af_alg_accept);
  
  static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
  {
  	return af_alg_accept(sock->sk, newsock);
  }
  
  static const struct proto_ops alg_proto_ops = {
  	.family		=	PF_ALG,
  	.owner		=	THIS_MODULE,
  
  	.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,
  	.sendpage	=	sock_no_sendpage,
  	.sendmsg	=	sock_no_sendmsg,
  	.recvmsg	=	sock_no_recvmsg,
  	.poll		=	sock_no_poll,
  
  	.bind		=	alg_bind,
  	.release	=	af_alg_release,
  	.setsockopt	=	alg_setsockopt,
  	.accept		=	alg_accept,
  };
  
  static void alg_sock_destruct(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);
  
  	alg_do_release(ask->type, ask->private);
  }
  
  static int alg_create(struct net *net, struct socket *sock, int protocol,
  		      int kern)
  {
  	struct sock *sk;
  	int err;
  
  	if (sock->type != SOCK_SEQPACKET)
  		return -ESOCKTNOSUPPORT;
  	if (protocol != 0)
  		return -EPROTONOSUPPORT;
  
  	err = -ENOMEM;

  	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);

  	if (!sk)
  		goto out;
  
  	sock->ops = &alg_proto_ops;
  	sock_init_data(sock, sk);
  
  	sk->sk_family = PF_ALG;
  	sk->sk_destruct = alg_sock_destruct;
  
  	return 0;
  out:
  	return err;
  }
  
  static const struct net_proto_family alg_family = {
  	.family	=	PF_ALG,
  	.create	=	alg_create,
  	.owner	=	THIS_MODULE,
  };

  int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)

  {

  	size_t off;
  	ssize_t n;
  	int npages, i;

  	n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
  	if (n < 0)
  		return n;

  	npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;

  	if (WARN_ON(npages == 0))

  		return -EINVAL;

  	/* Add one extra for linking */
  	sg_init_table(sgl->sg, npages + 1);

  	for (i = 0, len = n; i < npages; i++) {

  		int plen = min_t(int, len, PAGE_SIZE - off);
  
  		sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
  
  		off = 0;
  		len -= plen;

  	}

  	sg_mark_end(sgl->sg + npages - 1);
  	sgl->npages = npages;

  	return n;

  }
  EXPORT_SYMBOL_GPL(af_alg_make_sg);

  void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
  {
  	sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
  	sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
  }

  EXPORT_SYMBOL_GPL(af_alg_link_sg);

  void af_alg_free_sg(struct af_alg_sgl *sgl)
  {
  	int i;

  	for (i = 0; i < sgl->npages; i++)

  		put_page(sgl->pages[i]);

  }
  EXPORT_SYMBOL_GPL(af_alg_free_sg);
  
  int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
  {
  	struct cmsghdr *cmsg;

  	for_each_cmsghdr(cmsg, msg) {

  		if (!CMSG_OK(msg, cmsg))
  			return -EINVAL;
  		if (cmsg->cmsg_level != SOL_ALG)
  			continue;

  		switch (cmsg->cmsg_type) {

  		case ALG_SET_IV:
  			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
  				return -EINVAL;
  			con->iv = (void *)CMSG_DATA(cmsg);
  			if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
  						      sizeof(*con->iv)))
  				return -EINVAL;
  			break;
  
  		case ALG_SET_OP:
  			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
  				return -EINVAL;
  			con->op = *(u32 *)CMSG_DATA(cmsg);
  			break;

  		case ALG_SET_AEAD_ASSOCLEN:
  			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
  				return -EINVAL;
  			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
  			break;

  		default:
  			return -EINVAL;
  		}
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
  
  int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
  {
  	switch (err) {
  	case -EINPROGRESS:
  	case -EBUSY:
  		wait_for_completion(&completion->completion);

  		reinit_completion(&completion->completion);

  		err = completion->err;
  		break;
  	};
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
  
  void af_alg_complete(struct crypto_async_request *req, int err)
  {
  	struct af_alg_completion *completion = req->data;

  	if (err == -EINPROGRESS)
  		return;

  	completion->err = err;
  	complete(&completion->completion);
  }
  EXPORT_SYMBOL_GPL(af_alg_complete);
  
  static int __init af_alg_init(void)
  {
  	int err = proto_register(&alg_proto, 0);
  
  	if (err)
  		goto out;
  
  	err = sock_register(&alg_family);
  	if (err != 0)
  		goto out_unregister_proto;
  
  out:
  	return err;
  
  out_unregister_proto:
  	proto_unregister(&alg_proto);
  	goto out;
  }
  
  static void __exit af_alg_exit(void)
  {
  	sock_unregister(PF_ALG);
  	proto_unregister(&alg_proto);
  }
  
  module_init(af_alg_init);
  module_exit(af_alg_exit);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NETPROTO(AF_ALG);