path: root/drivers/staging/pohmelfs/crypto.c

/*
 * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
 * All rights reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/crypto.h>
#include <linux/highmem.h>
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/slab.h>

#include "netfs.h"

static struct crypto_hash *pohmelfs_init_hash(struct pohmelfs_sb *psb)
{
	int err;
	struct crypto_hash *hash;

	hash = crypto_alloc_hash(psb->hash_string, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(hash)) {
		err = PTR_ERR(hash);
		dprintk("%s: idx: %u: failed to allocate hash '%s', err: %d.\n",
				__func__, psb->idx, psb->hash_string, err);
		goto err_out_exit;
	}

	psb->crypto_attached_size = crypto_hash_digestsize(hash);

	if (!psb->hash_keysize)
		return hash;

	err = crypto_hash_setkey(hash, psb->hash_key, psb->hash_keysize);
	if (err) {
		dprintk("%s: idx: %u: failed to set key for hash '%s', err: %d.\n",
				__func__, psb->idx, psb->hash_string, err);
		goto err_out_free;
	}

	return hash;

err_out_free:
	crypto_free_hash(hash);
err_out_exit:
	return ERR_PTR(err);
}

static struct crypto_ablkcipher *pohmelfs_init_cipher(struct pohmelfs_sb *psb)
{
	int err = -EINVAL;
	struct crypto_ablkcipher *cipher;

	if (!psb->cipher_keysize)
		goto err_out_exit;

	cipher = crypto_alloc_ablkcipher(psb->cipher_string, 0, 0);
	if (IS_ERR(cipher)) {
		err = PTR_ERR(cipher);
		dprintk("%s: idx: %u: failed to allocate cipher '%s', err: %d.\n",
				__func__, psb->idx, psb->cipher_string, err);
		goto err_out_exit;
	}

	crypto_ablkcipher_clear_flags(cipher, ~0);

	err = crypto_ablkcipher_setkey(cipher, psb->cipher_key, psb->cipher_keysize);
	if (err) {
		dprintk("%s: idx: %u: failed to set key for cipher '%s', err: %d.\n",
				__func__, psb->idx, psb->cipher_string, err);
		goto err_out_free;
	}

	return cipher;

err_out_free:
	crypto_free_ablkcipher(cipher);
err_out_exit:
	return ERR_PTR(err);
}

int pohmelfs_crypto_engine_init(struct pohmelfs_crypto_engine *e, struct pohmelfs_sb *psb)
{
	int err;

	e->page_num = 0;

	e->size = PAGE_SIZE;
	e->data = kmalloc(e->size, GFP_KERNEL);
	if (!e->data) {
		err = -ENOMEM;
		goto err_out_exit;
	}

	if (psb->hash_string) {
		e->hash = pohmelfs_init_hash(psb);
		if (IS_ERR(e->hash)) {
			err = PTR_ERR(e->hash);
			e->hash = NULL;
			goto err_out_free;
		}
	}

	if (psb->cipher_string) {
		e->cipher = pohmelfs_init_cipher(psb);
		if (IS_ERR(e->cipher)) {
			err = PTR_ERR(e->cipher);
			e->cipher = NULL;
			goto err_out_free_hash;
		}
	}

	return 0;

err_out_free_hash:
	crypto_free_hash(e->hash);
err_out_free:
	kfree(e->data);
err_out_exit:
	return err;
}

void pohmelfs_crypto_engine_exit(struct pohmelfs_crypto_engine *e)
{
	crypto_free_hash(e->hash);
	crypto_free_ablkcipher(e->cipher);
	kfree(e->data);
}

static void pohmelfs_crypto_complete(struct crypto_async_request *req, int err)
{
	struct pohmelfs_crypto_completion *c = req->data;

	if (err == -EINPROGRESS)
		return;

	dprintk("%s: req: %p, err: %d.\n", __func__, req, err);
	c->error = err;
	complete(&c->complete);
}

static int pohmelfs_crypto_process(struct ablkcipher_request *req,
		struct scatterlist *sg_dst, struct scatterlist *sg_src,
		void *iv, int enc, unsigned long timeout)
{
	struct pohmelfs_crypto_completion complete;
	int err;

	init_completion(&complete.complete);
	complete.error = -EINPROGRESS;

	ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
					pohmelfs_crypto_complete, &complete);

	ablkcipher_request_set_crypt(req, sg_src, sg_dst, sg_src->length, iv);

	if (enc)
		err = crypto_ablkcipher_encrypt(req);
	else
		err = crypto_ablkcipher_decrypt(req);

	switch (err) {
	case -EINPROGRESS:
	case -EBUSY:
		err = wait_for_completion_interruptible_timeout(&complete.complete,
					timeout);
		if (!err)
			err = -ETIMEDOUT;
		else if (err > 0)
			err = complete.error;
		break;
	default:
		break;
	}