/*

* algif_hash: User-space interface for hash algorithms

*

* This file provides the user-space API for hash 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 <crypto/hash.h>

#include <crypto/if_alg.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <linux/net.h>

#include <net/sock.h>

struct hash_ctx {

};

static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)

{

unsigned ds;

if (ctx->result)

return 0;

ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);

if (!ctx->result)

return -ENOMEM;

memset(ctx->result, 0, ds);

return 0;

}

static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)

{

unsigned ds;

if (!ctx->result)

return;

ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

sock_kzfree_s(sk, ctx->result, ds);

ctx->result = NULL;

}

static int hash_sendmsg(struct socket *sock, struct msghdr *msg,

size_t ignored)

{

int limit = ALG_MAX_PAGES * PAGE_SIZE;

struct sock *sk = sock->sk;

struct alg_sock *ask = alg_sk(sk);

struct hash_ctx *ctx = ask->private;

long copied = 0;

int err;

if (limit > sk->sk_sndbuf)

limit = sk->sk_sndbuf;

lock_sock(sk);

if (!ctx->more) {

if ((msg->msg_flags & MSG_MORE))

hash_free_result(sk, ctx);

err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),

&ctx->completion);

if (err)

goto unlock;

}

ctx->more = 0;

while (msg_data_left(msg)) {

int len = msg_data_left(msg);

if (len > limit)

len = limit;

len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);

if (len < 0) {

err = copied ? 0 : len;

goto unlock;

}

ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);

err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),

&ctx->completion);

af_alg_free_sg(&ctx->sgl);

if (err)

goto unlock;

copied += len;

iov_iter_advance(&msg->msg_iter, len);

}

err = 0;

ctx->more = msg->msg_flags & MSG_MORE;

if (!ctx->more) {

err = hash_alloc_result(sk, ctx);

if (err)

goto unlock;

ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);

err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),

&ctx->completion);

}

unlock:

release_sock(sk);

return err ?: copied;

}

static ssize_t hash_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 hash_ctx *ctx = ask->private;

int err;

if (flags & MSG_SENDPAGE_NOTLAST)

flags |= MSG_MORE;

lock_sock(sk);

sg_init_table(ctx->sgl.sg, 1);

sg_set_page(ctx->sgl.sg, page, size, offset);

if (!(flags & MSG_MORE)) {

err = hash_alloc_result(sk, ctx);

if (err)

goto unlock;

} else if (!ctx->more)

hash_free_result(sk, ctx);

ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);

if (!(flags & MSG_MORE)) {

if (ctx->more)

err = crypto_ahash_finup(&ctx->req);

else

err = crypto_ahash_digest(&ctx->req);

} else {

if (!ctx->more) {

err = crypto_ahash_init(&ctx->req);

err = af_alg_wait_for_completion(err, &ctx->completion);

if (err)

goto unlock;

}

err = crypto_ahash_update(&ctx->req);

}

err = af_alg_wait_for_completion(err, &ctx->completion);

if (err)

goto unlock;

ctx->more = flags & MSG_MORE;

unlock:

release_sock(sk);

return err ?: size;

}

static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,

int flags)

{

struct sock *sk = sock->sk;

struct alg_sock *ask = alg_sk(sk);

struct hash_ctx *ctx = ask->private;

unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

bool result;

int err;

if (len > ds)

len = ds;

else if (len < ds)

msg->msg_flags |= MSG_TRUNC;

lock_sock(sk);

result = ctx->result;

err = hash_alloc_result(sk, ctx);

if (err)

goto unlock;

ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);

if (!result && !ctx->more) {

err = af_alg_wait_for_completion(

crypto_ahash_init(&ctx->req),

&ctx->completion);

if (err)

goto unlock;

}

if (!result || ctx->more) {

ctx->more = 0;

err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),

&ctx->completion);

if (err)

goto unlock;

}

err = memcpy_to_msg(msg, ctx->result, len);

unlock:

hash_free_result(sk, ctx);

release_sock(sk);

return err ?: len;

}

static int hash_accept(struct socket *sock, struct socket *newsock, int flags)

{

struct sock *sk = sock->sk;

struct alg_sock *ask = alg_sk(sk);

struct hash_ctx *ctx = ask->private;

struct ahash_request *req = &ctx->req;

char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1];

struct sock *sk2;

struct alg_sock *ask2;

struct hash_ctx *ctx2;

bool more;

int err;

lock_sock(sk);

more = ctx->more;

err = more ? crypto_ahash_export(req, state) : 0;

release_sock(sk);

if (err)

return err;

err = af_alg_accept(ask->parent, newsock);

if (err)

return err;

sk2 = newsock->sk;

ask2 = alg_sk(sk2);

ctx2 = ask2->private;

ctx2->more = more;

if (!more)

return err;

err = crypto_ahash_import(&ctx2->req, state);

if (err) {

sock_orphan(sk2);

sock_put(sk2);

}

return err;

}

static struct proto_ops algif_hash_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,

.setsockopt = sock_no_setsockopt,

.poll = sock_no_poll,

.release = af_alg_release,

.sendmsg = hash_sendmsg,

.sendpage = hash_sendpage,

.recvmsg = hash_recvmsg,

.accept = hash_accept,

};

static int hash_check_key(struct socket *sock)

{

int err = 0;

struct sock *psk;

struct alg_sock *pask;

struct crypto_ahash *tfm;

struct sock *sk = sock->sk;

struct alg_sock *ask = alg_sk(sk);

lock_sock(sk);

if (ask->refcnt)

goto unlock_child;

psk = ask->parent;

pask = alg_sk(ask->parent);

tfm = pask->private;

err = -ENOKEY;

lock_sock_nested(psk, SINGLE_DEPTH_NESTING);

if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)

goto unlock;

if (!pask->refcnt++)

sock_hold(psk);

ask->refcnt = 1;

sock_put(psk);

err = 0;

unlock:

release_sock(psk);

unlock_child:

release_sock(sk);

return err;

}

static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,

size_t size)

{

int err;

err = hash_check_key(sock);

if (err)

return err;

return hash_sendmsg(sock, msg, size);

}

static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,

int offset, size_t size, int flags)

{

int err;

err = hash_check_key(sock);

if (err)

return err;

return hash_sendpage(sock, page, offset, size, flags);

}

static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,

size_t ignored, int flags)

{

int err;

err = hash_check_key(sock);

if (err)

return err;

return hash_recvmsg(sock, msg, ignored, flags);

}

static int hash_accept_nokey(struct socket *sock, struct socket *newsock,

int flags)

{

int err;

err = hash_check_key(sock);

if (err)

return err;

return hash_accept(sock, newsock, flags);

}

static struct proto_ops algif_hash_ops_nokey = {

.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,

.setsockopt = sock_no_setsockopt,

.poll = sock_no_poll,

.release = af_alg_release,

.sendmsg = hash_sendmsg_nokey,

.sendpage = hash_sendpage_nokey,

.recvmsg = hash_recvmsg_nokey,

.accept = hash_accept_nokey,

};

static void *hash_bind(const char *name, u32 type, u32 mask)

{

return crypto_alloc_ahash(name, type, mask);

}

static void hash_release(void *private)

{

crypto_free_ahash(private);

}

static int hash_setkey(void *private, const u8 *key, unsigned int keylen)

{

return crypto_ahash_setkey(private, key, keylen);

}

static void hash_sock_destruct(struct sock *sk)

{

struct alg_sock *ask = alg_sk(sk);

struct hash_ctx *ctx = ask->private;

hash_free_result(sk, ctx);

sock_kfree_s(sk, ctx, ctx->len);

af_alg_release_parent(sk);

}

static int hash_accept_parent_nokey(void *private, struct sock *sk)

{

struct crypto_ahash *tfm = private;

struct alg_sock *ask = alg_sk(sk);

struct hash_ctx *ctx;

unsigned int len = sizeof(*ctx) + crypto_ahash_reqsize(tfm);

ctx = sock_kmalloc(sk, len, GFP_KERNEL);

if (!ctx)

return -ENOMEM;

ctx->result = NULL;

ctx->len = len;

ctx->more = 0;

af_alg_init_completion(&ctx->completion);

ask->private = ctx;

ahash_request_set_tfm(&ctx->req, tfm);

ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,

af_alg_complete, &ctx->completion);

sk->sk_destruct = hash_sock_destruct;

return 0;

}

static int hash_accept_parent(void *private, struct sock *sk)

{

struct crypto_ahash *tfm = private;

if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)

return -ENOKEY;

return hash_accept_parent_nokey(private, sk);

}

static const struct af_alg_type algif_type_hash = {

.bind = hash_bind,

.release = hash_release,

.setkey = hash_setkey,

.accept = hash_accept_parent,

.accept_nokey = hash_accept_parent_nokey,

.ops = &algif_hash_ops,

.ops_nokey = &algif_hash_ops_nokey,

.name = "hash",

.owner = THIS_MODULE

};

static int __init algif_hash_init(void)

{

return af_alg_register_type(&algif_type_hash);

}

static void __exit algif_hash_exit(void)

{

int err = af_alg_unregister_type(&algif_type_hash);

BUG_ON(err);

}

module_init(algif_hash_init);

module_exit(algif_hash_exit);

MODULE_LICENSE("GPL");