blob: 351295c97a4b89a50f65cbd841b3a50e5f91e665 [file] [log] [blame]
/*
* 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/bio.h>
#include <linux/crypto.h>
#include <linux/dst.h>
#include <linux/kernel.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
/*
* Tricky bastard, but IV can be more complex with time...
*/
static inline u64 dst_gen_iv(struct dst_trans *t)
{
return t->gen;
}
/*
* Crypto machinery: hash/cipher support for the given crypto controls.
*/
static struct crypto_hash *dst_init_hash(struct dst_crypto_ctl *ctl, u8 *key)
{
int err;
struct crypto_hash *hash;
hash = crypto_alloc_hash(ctl->hash_algo, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hash)) {
err = PTR_ERR(hash);
dprintk("%s: failed to allocate hash '%s', err: %d.\n",
__func__, ctl->hash_algo, err);
goto err_out_exit;
}
ctl->crypto_attached_size = crypto_hash_digestsize(hash);
if (!ctl->hash_keysize)
return hash;
err = crypto_hash_setkey(hash, key, ctl->hash_keysize);
if (err) {
dprintk("%s: failed to set key for hash '%s', err: %d.\n",
__func__, ctl->hash_algo, 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 *dst_init_cipher(struct dst_crypto_ctl *ctl,
u8 *key)
{
int err = -EINVAL;
struct crypto_ablkcipher *cipher;
if (!ctl->cipher_keysize)
goto err_out_exit;
cipher = crypto_alloc_ablkcipher(ctl->cipher_algo, 0, 0);
if (IS_ERR(cipher)) {
err = PTR_ERR(cipher);
dprintk("%s: failed to allocate cipher '%s', err: %d.\n",
__func__, ctl->cipher_algo, err);
goto err_out_exit;
}
crypto_ablkcipher_clear_flags(cipher, ~0);
err = crypto_ablkcipher_setkey(cipher, key, ctl->cipher_keysize);
if (err) {
dprintk("%s: failed to set key for cipher '%s', err: %d.\n",
__func__, ctl->cipher_algo, err);
goto err_out_free;
}
return cipher;
err_out_free:
crypto_free_ablkcipher(cipher);
err_out_exit:
return ERR_PTR(err);
}
/*
* Crypto engine has a pool of pages to encrypt data into before sending
* it over the network. This pool is freed/allocated here.
*/
static void dst_crypto_pages_free(struct dst_crypto_engine *e)
{
unsigned int i;
for (i = 0; i < e->page_num; ++i)
__free_page(e->pages[i]);
kfree(e->pages);
}
static int dst_crypto_pages_alloc(struct dst_crypto_engine *e, int num)
{
int i;
e->pages = kmalloc(num * sizeof(struct page **), GFP_KERNEL);
if (!e->pages)
return -ENOMEM;
for (i = 0; i < num; ++i) {
e->pages[i] = alloc_page(GFP_KERNEL);
if (!e->pages[i])
goto err_out_free_pages;
}
e->page_num = num;
return 0;
err_out_free_pages:
while (--i >= 0)
__free_page(e->pages[i]);
kfree(e->pages);
return -ENOMEM;
}
/*
* Initialize crypto engine for given node.
* Setup cipher/hash, keys, pool of threads and private data.
*/
static int dst_crypto_engine_init(struct dst_crypto_engine *e,
struct dst_node *n)
{
int err;
struct dst_crypto_ctl *ctl = &n->crypto;
err = dst_crypto_pages_alloc(e, n->max_pages);
if (err)
goto err_out_exit;
e->size = PAGE_SIZE;
e->data = kmalloc(e->size, GFP_KERNEL);
if (!e->data) {
err = -ENOMEM;
goto err_out_free_pages;
}
if (ctl->hash_algo[0]) {
e->hash = dst_init_hash(ctl, n->hash_key);
if (IS_ERR(e->hash)) {
err = PTR_ERR(e->hash);
e->hash = NULL;
goto err_out_free;
}
}
if (ctl->cipher_algo[0]) {
e->cipher = dst_init_cipher(ctl, n->cipher_key);
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_free_pages:
dst_crypto_pages_free(e);
err_out_exit:
return err;
}
static void dst_crypto_engine_exit(struct dst_crypto_engine *e)
{
if (e->hash)
crypto_free_hash(e->hash);
if (e->cipher)
crypto_free_ablkcipher(e->cipher);
dst_crypto_pages_free(e);
kfree(e->data);
}
/*
* Waiting for cipher processing to be completed.
*/
struct dst_crypto_completion {
struct completion complete;
int error;
};
static void dst_crypto_complete(struct crypto_async_request *req, int err)
{
struct dst_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 dst_crypto_process(struct ablkcipher_request *req,
struct scatterlist *sg_dst, struct scatterlist *sg_src,
void *iv, int enc, unsigned long timeout)
{
struct dst_crypto_completion c;
int err;
init_completion(&c.complete);
c.error = -EINPROGRESS;
ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
dst_crypto_complete, &c);
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(&c.complete,
timeout);
if (!err)
err = -ETIMEDOUT;
else
err = c.error;
break;
default:
break;
}
return err;
}
/*
* DST uses generic iteration approach for data crypto processing.
* Single block IO request is switched into array of scatterlists,
* which are submitted to the crypto processing iterator.
*
* Input and output iterator initialization are different, since
* in output case we can not encrypt data in-place and need a
* temporary storage, which is then being sent to the remote peer.
*/
static int dst_trans_iter_out(struct bio *bio, struct dst_crypto_engine *e,
int (*iterator) (struct dst_crypto_engine *e,
struct scatterlist *dst,
struct scatterlist *src))
{
struct bio_vec *bv;
int err, i;
sg_init_table(e->src, bio->bi_vcnt);
sg_init_table(e->dst, bio->bi_vcnt);
bio_for_each_segment(bv, bio, i) {
sg_set_page(&e->src[i], bv->bv_page, bv->bv_len, bv->bv_offset);
sg_set_page(&e->dst[i], e->pages[i], bv->bv_len, bv->bv_offset);
err = iterator(e, &e->dst[i], &e->src[i]);
if (err)
return err;
}
return 0;
}
static int dst_trans_iter_in(struct bio *bio, struct dst_crypto_engine *e,
int (*iterator) (struct dst_crypto_engine *e,
struct scatterlist *dst,
struct scatterlist *src))
{
struct bio_vec *bv;
int err, i;
sg_init_table(e->src, bio->bi_vcnt);
sg_init_table(e->dst, bio->bi_vcnt);
bio_for_each_segment(bv, bio, i) {
sg_set_page(&e->src[i], bv->bv_page, bv->bv_len, bv->bv_offset);
sg_set_page(&e->dst[i], bv->bv_page, bv->bv_len, bv->bv_offset);
err = iterator(e, &e->dst[i], &e->src[i]);
if (err)
return err;
}
return 0;
}
static int dst_crypt_iterator(struct dst_crypto_engine *e,
struct scatterlist *sg_dst, struct scatterlist *sg_src)
{
struct ablkcipher_request *req = e->data;
u8 iv[32];
memset(iv, 0, sizeof(iv));
memcpy(iv, &e->iv, sizeof(e->iv));
return dst_crypto_process(req, sg_dst, sg_src, iv, e->enc, e->timeout);
}
static int dst_crypt(struct dst_crypto_engine *e, struct bio *bio)
{
struct ablkcipher_request *req = e->data;
memset(req, 0, sizeof(struct ablkcipher_request));
ablkcipher_request_set_tfm(req, e->cipher);
if (e->enc)
return dst_trans_iter_out(bio, e, dst_crypt_iterator);
else
return dst_trans_iter_in(bio, e, dst_crypt_iterator);
}
static int dst_hash_iterator(struct dst_crypto_engine *e,
struct scatterlist *sg_dst, struct scatterlist *sg_src)
{
return crypto_hash_update(e->data, sg_src, sg_src->length);
}
static int dst_hash(struct dst_crypto_engine *e, struct bio *bio, void *dst)
{
struct hash_desc *desc = e->data;
int err;
desc->tfm = e->hash;
desc->flags = 0;
err = crypto_hash_init(desc);
if (err)
return err;
err = dst_trans_iter_in(bio, e, dst_hash_iterator);
if (err)
return err;
err = crypto_hash_final(desc, dst);
if (err)
return err;
return 0;
}
/*
* Initialize/cleanup a crypto thread. The only thing it should
* do is to allocate a pool of pages as temporary storage.
* And to setup cipher and/or hash.
*/
static void *dst_crypto_thread_init(void *data)
{
struct dst_node *n = data;
struct dst_crypto_engine *e;
int err = -ENOMEM;
e = kzalloc(sizeof(struct dst_crypto_engine), GFP_KERNEL);
if (!e)
goto err_out_exit;
e->src = kcalloc(2 * n->max_pages, sizeof(struct scatterlist),
GFP_KERNEL);
if (!e->src)
goto err_out_free;
e->dst = e->src + n->max_pages;
err = dst_crypto_engine_init(e, n);
if (err)
goto err_out_free_all;
return e;
err_out_free_all:
kfree(e->src);
err_out_free:
kfree(e);
err_out_exit:
return ERR_PTR(err);
}
static void dst_crypto_thread_cleanup(void *private)
{
struct dst_crypto_engine *e = private;
dst_crypto_engine_exit(e);
kfree(e->src);
kfree(e);
}
/*
* Initialize crypto engine for given node: store keys, create pool
* of threads, initialize each one.
*
* Each thread has unique ID, but 0 and 1 are reserved for receiving and
* accepting threads (if export node), so IDs could start from 2, but starting
* them from 10 allows easily understand what this thread is for.
*/
int dst_node_crypto_init(struct dst_node *n, struct dst_crypto_ctl *ctl)
{
void *key = (ctl + 1);
int err = -ENOMEM, i;
char name[32];
if (ctl->hash_keysize) {
n->hash_key = kmalloc(ctl->hash_keysize, GFP_KERNEL);
if (!n->hash_key)
goto err_out_exit;
memcpy(n->hash_key, key, ctl->hash_keysize);
}
if (ctl->cipher_keysize) {
n->cipher_key = kmalloc(ctl->cipher_keysize, GFP_KERNEL);
if (!n->cipher_key)
goto err_out_free_hash;
memcpy(n->cipher_key, key, ctl->cipher_keysize);
}
memcpy(&n->crypto, ctl, sizeof(struct dst_crypto_ctl));
for (i = 0; i < ctl->thread_num; ++i) {
snprintf(name, sizeof(name), "%s-crypto-%d", n->name, i);
/* Unique ids... */
err = thread_pool_add_worker(n->pool, name, i + 10,
dst_crypto_thread_init, dst_crypto_thread_cleanup, n);
if (err)
goto err_out_free_threads;
}
return 0;
err_out_free_threads:
while (--i >= 0)
thread_pool_del_worker_id(n->pool, i+10);
if (ctl->cipher_keysize)
kfree(n->cipher_key);
ctl->cipher_keysize = 0;
err_out_free_hash:
if (ctl->hash_keysize)
kfree(n->hash_key);
ctl->hash_keysize = 0;
err_out_exit:
return err;
}
void dst_node_crypto_exit(struct dst_node *n)
{
struct dst_crypto_ctl *ctl = &n->crypto;
if (ctl->cipher_algo[0] || ctl->hash_algo[0]) {
kfree(n->hash_key);
kfree(n->cipher_key);
}
}
/*
* Thrad pool setup callback. Just stores a transaction in private data.
*/
static int dst_trans_crypto_setup(void *crypto_engine, void *trans)
{
struct dst_crypto_engine *e = crypto_engine;
e->private = trans;
return 0;
}
#if 0
static void dst_dump_bio(struct bio *bio)
{
u8 *p;
struct bio_vec *bv;
int i;
bio_for_each_segment(bv, bio, i) {
dprintk("%s: %llu/%u: size: %u, offset: %u, data: ",
__func__, bio->bi_sector, bio->bi_size,
bv->bv_len, bv->bv_offset);
p = kmap(bv->bv_page) + bv->bv_offset;
for (i = 0; i < bv->bv_len; ++i)
printk(KERN_DEBUG "%02x ", p[i]);
kunmap(bv->bv_page);
printk("\n");
}
}
#endif
/*
* Encrypt/hash data and send it to the network.
*/
static int dst_crypto_process_sending(struct dst_crypto_engine *e,
struct bio *bio, u8 *hash)
{
int err;
if (e->cipher) {
err = dst_crypt(e, bio);
if (err)
goto err_out_exit;
}
if (e->hash) {
err = dst_hash(e, bio, hash);
if (err)
goto err_out_exit;
#ifdef CONFIG_DST_DEBUG
{
unsigned int i;
/* dst_dump_bio(bio); */
printk(KERN_DEBUG "%s: bio: %llu/%u, rw: %lu, hash: ",
__func__, (u64)bio->bi_sector,
bio->bi_size, bio_data_dir(bio));
for (i = 0; i < crypto_hash_digestsize(e->hash); ++i)
printk("%02x ", hash[i]);
printk("\n");
}
#endif
}
return 0;
err_out_exit:
return err;
}
/*
* Check if received data is valid. Decipher if it is.
*/
static int dst_crypto_process_receiving(struct dst_crypto_engine *e,
struct bio *bio, u8 *hash, u8 *recv_hash)
{
int err;
if (e->hash) {
int mismatch;
err = dst_hash(e, bio, hash);
if (err)
goto err_out_exit;
mismatch = !!memcmp(recv_hash, hash,
crypto_hash_digestsize(e->hash));
#ifdef CONFIG_DST_DEBUG
/* dst_dump_bio(bio); */
printk(KERN_DEBUG "%s: bio: %llu/%u, rw: %lu, hash mismatch: %d",
__func__, (u64)bio->bi_sector, bio->bi_size,
bio_data_dir(bio), mismatch);
if (mismatch) {
unsigned int i;
printk(", recv/calc: ");
for (i = 0; i < crypto_hash_digestsize(e->hash); ++i)
printk("%02x/%02x ", recv_hash[i], hash[i]);
}
printk("\n");
#endif
err = -1;
if (mismatch)
goto err_out_exit;
}
if (e->cipher) {
err = dst_crypt(e, bio);
if (err)
goto err_out_exit;
}
return 0;
err_out_exit:
return err;
}
/*
* Thread pool callback to encrypt data and send it to the netowork.
*/
static int dst_trans_crypto_action(void *crypto_engine, void *schedule_data)
{
struct dst_crypto_engine *e = crypto_engine;
struct dst_trans *t = schedule_data;
struct bio *bio = t->bio;
int err;
dprintk("%s: t: %p, gen: %llu, cipher: %p, hash: %p.\n",
__func__, t, t->gen, e->cipher, e->hash);
e->enc = t->enc;
e->iv = dst_gen_iv(t);
if (bio_data_dir(bio) == WRITE) {
err = dst_crypto_process_sending(e, bio, t->cmd.hash);
if (err)
goto err_out_exit;
if (e->hash) {
t->cmd.csize = crypto_hash_digestsize(e->hash);
t->cmd.size += t->cmd.csize;
}
return dst_trans_send(t);
} else {
u8 *hash = e->data + e->size/2;
err = dst_crypto_process_receiving(e, bio, hash, t->cmd.hash);
if (err)
goto err_out_exit;
dst_trans_remove(t);
dst_trans_put(t);
}
return 0;
err_out_exit:
t->error = err;
dst_trans_put(t);
return err;
}
/*
* Schedule crypto processing for given transaction.
*/
int dst_trans_crypto(struct dst_trans *t)
{
struct dst_node *n = t->n;
int err;
err = thread_pool_schedule(n->pool,
dst_trans_crypto_setup, dst_trans_crypto_action,
t, MAX_SCHEDULE_TIMEOUT);
if (err)
goto err_out_exit;
return 0;
err_out_exit:
dst_trans_put(t);
return err;
}
/*
* Crypto machinery for the export node.
*/
static int dst_export_crypto_setup(void *crypto_engine, void *bio)
{
struct dst_crypto_engine *e = crypto_engine;
e->private = bio;
return 0;
}
static int dst_export_crypto_action(void *crypto_engine, void *schedule_data)
{
struct dst_crypto_engine *e = crypto_engine;
struct bio *bio = schedule_data;
struct dst_export_priv *p = bio->bi_private;
int err;
dprintk("%s: e: %p, data: %p, bio: %llu/%u, dir: %lu.\n",
__func__, e, e->data, (u64)bio->bi_sector,
bio->bi_size, bio_data_dir(bio));
e->enc = (bio_data_dir(bio) == READ);
e->iv = p->cmd.id;
if (bio_data_dir(bio) == WRITE) {
u8 *hash = e->data + e->size/2;
err = dst_crypto_process_receiving(e, bio, hash, p->cmd.hash);
if (err)
goto err_out_exit;
generic_make_request(bio);
} else {
err = dst_crypto_process_sending(e, bio, p->cmd.hash);
if (err)
goto err_out_exit;
if (e->hash) {
p->cmd.csize = crypto_hash_digestsize(e->hash);
p->cmd.size += p->cmd.csize;
}
err = dst_export_send_bio(bio);
}
return 0;
err_out_exit:
bio_put(bio);
return err;
}
int dst_export_crypto(struct dst_node *n, struct bio *bio)
{
int err;
err = thread_pool_schedule(n->pool,
dst_export_crypto_setup, dst_export_crypto_action,
bio, MAX_SCHEDULE_TIMEOUT);
if (err)
goto err_out_exit;
return 0;
err_out_exit:
bio_put(bio);
return err;
}