[linux.git] / crypto / chainiv.c

/*
 * chainiv: Chain IV Generator
 *
 * Generate IVs simply be using the last block of the previous encryption.
 * This is mainly useful for CBC with a synchronous algorithm.
 *
 * Copyright (c) 2007 Herbert Xu <[email protected]>
 *
 * 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/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/workqueue.h>

enum {
	CHAINIV_STATE_INUSE = 0,
};

struct chainiv_ctx {
	spinlock_t lock;
	char iv[];
};

struct async_chainiv_ctx {
	unsigned long state;

	spinlock_t lock;
	int err;

	struct crypto_queue queue;
	struct work_struct postponed;

	char iv[];
};

static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	unsigned int ivsize;
	int err;

	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	ablkcipher_request_set_callback(subreq, req->creq.base.flags &
						~CRYPTO_TFM_REQ_MAY_SLEEP,
					req->creq.base.complete,
					req->creq.base.data);
	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
				     req->creq.nbytes, req->creq.info);

	spin_lock_bh(&ctx->lock);

	ivsize = crypto_ablkcipher_ivsize(geniv);

	memcpy(req->giv, ctx->iv, ivsize);
	memcpy(subreq->info, ctx->iv, ivsize);

	err = crypto_ablkcipher_encrypt(subreq);
	if (err)
		goto unlock;

	memcpy(ctx->iv, subreq->info, ivsize);

unlock:
	spin_unlock_bh(&ctx->lock);

	return err;
}

static int chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);

	spin_lock_bh(&ctx->lock);
	if (crypto_ablkcipher_crt(geniv)->givencrypt !=
	    chainiv_givencrypt_first)
		goto unlock;

	crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
	get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));

unlock:
	spin_unlock_bh(&ctx->lock);

	return chainiv_givencrypt(req);
}

static int chainiv_init_common(struct crypto_tfm *tfm)
{
	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);

	return skcipher_geniv_init(tfm);
}

static int chainiv_init(struct crypto_tfm *tfm)
{
	struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	spin_lock_init(&ctx->lock);

	return chainiv_init_common(tfm);
}

static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
{
	int queued;
	int err = ctx->err;

	if (!ctx->queue.qlen) {
		smp_mb__before_clear_bit();
		clear_bit(CHAINIV_STATE_INUSE, &ctx->state);

		if (!ctx->queue.qlen ||
		    test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
			goto out;
	}

	queued = schedule_work(&ctx->postponed);
	BUG_ON(!queued);

out:
	return err;
}

static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	int err;

	spin_lock_bh(&ctx->lock);
	err = skcipher_enqueue_givcrypt(&ctx->queue, req);
	spin_unlock_bh(&ctx->lock);

	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
		return err;

	ctx->err = err;
	return async_chainiv_schedule_work(ctx);
}

static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);

	memcpy(req->giv, ctx->iv, ivsize);
	memcpy(subreq->info, ctx->iv, ivsize);

	ctx->err = crypto_ablkcipher_encrypt(subreq);
	if (ctx->err)
		goto out;

	memcpy(ctx->iv, subreq->info, ivsize);

out:
	return async_chainiv_schedule_work(ctx);
}

static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);

	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	ablkcipher_request_set_callback(subreq, req->creq.base.flags,
					req->creq.base.complete,
					req->creq.base.data);
	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
				     req->creq.nbytes, req->creq.info);

	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
		goto postpone;

	if (ctx->queue.qlen) {
		clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
		goto postpone;
	}

	return async_chainiv_givencrypt_tail(req);

postpone:
	return async_chainiv_postpone_request(req);
}

static int async_chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);

	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
		goto out;

	if (crypto_ablkcipher_crt(geniv)->givencrypt !=
	    async_chainiv_givencrypt_first)
		goto unlock;

	crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
	get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));

unlock:
	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);

out:
	return async_chainiv_givencrypt(req);
}

static void async_chainiv_do_postponed(struct work_struct *work)
{
	struct async_chainiv_ctx *ctx = container_of(work,
						     struct async_chainiv_ctx,
						     postponed);
	struct skcipher_givcrypt_request *req;
	struct ablkcipher_request *subreq;
	int err;

	/* Only handle one request at a time to avoid hogging keventd. */
	spin_lock_bh(&ctx->lock);
	req = skcipher_dequeue_givcrypt(&ctx->queue);
	spin_unlock_bh(&ctx->lock);

	if (!req) {
		async_chainiv_schedule_work(ctx);
		return;
	}

	subreq = skcipher_givcrypt_reqctx(req);
	subreq->base.flags |= CRYPTO_TFM_REQ_MAY_SLEEP;

	err = async_chainiv_givencrypt_tail(req);

	local_bh_disable();
	skcipher_givcrypt_complete(req, err);
	local_bh_enable();
}

static int async_chainiv_init(struct crypto_tfm *tfm)
{
	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	spin_lock_init(&ctx->lock);

	crypto_init_queue(&ctx->queue, 100);
	INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);

	return chainiv_init_common(tfm);
}

static void async_chainiv_exit(struct crypto_tfm *tfm)
{
	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) || ctx->queue.qlen);

	skcipher_geniv_exit(tfm);
}

static struct crypto_template chainiv_tmpl;

static struct crypto_instance *chainiv_alloc(struct rtattr **tb)
{
	struct crypto_attr_type *algt;
	struct crypto_instance *inst;
	int err;

	algt = crypto_get_attr_type(tb);
	err = PTR_ERR(algt);
	if (IS_ERR(algt))
		return ERR_PTR(err);

	inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
	if (IS_ERR(inst))
		goto out;

	inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;

	inst->alg.cra_init = chainiv_init;
	inst->alg.cra_exit = skcipher_geniv_exit;

	inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);

	if (!crypto_requires_sync(algt->type, algt->mask)) {
		inst->alg.cra_flags |= CRYPTO_ALG_ASYNC;

		inst->alg.cra_ablkcipher.givencrypt =
			async_chainiv_givencrypt_first;

		inst->alg.cra_init = async_chainiv_init;
		inst->alg.cra_exit = async_chainiv_exit;

		inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
	}

	inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;

out:
	return inst;
}

static struct crypto_template chainiv_tmpl = {
	.name = "chainiv",
	.alloc = chainiv_alloc,
	.free = skcipher_geniv_free,
	.module = THIS_MODULE,
};

static int __init chainiv_module_init(void)
{
	return crypto_register_template(&chainiv_tmpl);
}

static void chainiv_module_exit(void)
{
	crypto_unregister_template(&chainiv_tmpl);
}

module_init(chainiv_module_init);
module_exit(chainiv_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Chain IV Generator");
Commit	Line	Data
7f470739 HX	1	/*
	2	* chainiv: Chain IV Generator
	3	*
	4	* Generate IVs simply be using the last block of the previous encryption.
	5	* This is mainly useful for CBC with a synchronous algorithm.
	6	*
	7	* Copyright (c) 2007 Herbert Xu <[email protected]>
	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms of the GNU General Public License as published by the Free
	11	* Software Foundation; either version 2 of the License, or (at your option)
	12	* any later version.
	13	*
	14	*/
	15
	16	#include <crypto/internal/skcipher.h>
	17	#include <linux/err.h>
	18	#include <linux/init.h>
e7cd2514	19	#include <linux/kernel.h>
7f470739 HX	20	#include <linux/module.h>
	21	#include <linux/random.h>
	22	#include <linux/spinlock.h>
	23	#include <linux/string.h>
e7cd2514 HX	24	#include <linux/workqueue.h>
	25
	26	enum {
	27	CHAINIV_STATE_INUSE = 0,
	28	};
7f470739 HX	29
	30	struct chainiv_ctx {
	31	spinlock_t lock;
	32	char iv[];
	33	};
	34
e7cd2514 HX	35	struct async_chainiv_ctx {
	36	unsigned long state;
	37
	38	spinlock_t lock;
	39	int err;
	40
	41	struct crypto_queue queue;
	42	struct work_struct postponed;
	43
	44	char iv[];
	45	};
	46
7f470739 HX	47	static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
	48	{
	49	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	50	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	51	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	52	unsigned int ivsize;
	53	int err;
	54
	55	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	56	ablkcipher_request_set_callback(subreq, req->creq.base.flags &
	57	~CRYPTO_TFM_REQ_MAY_SLEEP,
	58	req->creq.base.complete,
	59	req->creq.base.data);
	60	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
	61	req->creq.nbytes, req->creq.info);
	62
	63	spin_lock_bh(&ctx->lock);
	64
	65	ivsize = crypto_ablkcipher_ivsize(geniv);
	66
	67	memcpy(req->giv, ctx->iv, ivsize);
	68	memcpy(subreq->info, ctx->iv, ivsize);
	69
	70	err = crypto_ablkcipher_encrypt(subreq);
	71	if (err)
	72	goto unlock;
	73
	74	memcpy(ctx->iv, subreq->info, ivsize);
	75
	76	unlock:
	77	spin_unlock_bh(&ctx->lock);
	78
	79	return err;
	80	}
	81
	82	static int chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
	83	{
	84	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	85	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	86
	87	spin_lock_bh(&ctx->lock);
	88	if (crypto_ablkcipher_crt(geniv)->givencrypt !=
	89	chainiv_givencrypt_first)
	90	goto unlock;
	91
	92	crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
	93	get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
	94
	95	unlock:
	96	spin_unlock_bh(&ctx->lock);
	97
	98	return chainiv_givencrypt(req);
	99	}
	100
e7cd2514 HX	101	static int chainiv_init_common(struct crypto_tfm *tfm)
	102	{
	103	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
	104
	105	return skcipher_geniv_init(tfm);
	106	}
	107
7f470739 HX	108	static int chainiv_init(struct crypto_tfm *tfm)
7f470739 HX	109	{
e7cd2514	110	struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
7f470739 HX	111
	112	spin_lock_init(&ctx->lock);
	113
e7cd2514 HX	114	return chainiv_init_common(tfm);
e7cd2514 HX	115	}
7f470739	116
e7cd2514 HX	117	static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
	118	{
	119	int queued;
872ac874	120	int err = ctx->err;
e7cd2514 HX	121
	122	if (!ctx->queue.qlen) {
	123	smp_mb__before_clear_bit();
	124	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
	125
	126	if (!ctx->queue.qlen \|\|
	127	test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	128	goto out;
	129	}
	130
	131	queued = schedule_work(&ctx->postponed);
	132	BUG_ON(!queued);
	133
	134	out:
872ac874	135	return err;
e7cd2514 HX	136	}
	137
	138	static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
	139	{
	140	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	141	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	142	int err;
	143
	144	spin_lock_bh(&ctx->lock);
	145	err = skcipher_enqueue_givcrypt(&ctx->queue, req);
	146	spin_unlock_bh(&ctx->lock);
	147
	148	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	149	return err;
	150
	151	ctx->err = err;
	152	return async_chainiv_schedule_work(ctx);
	153	}
	154
	155	static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
	156	{
	157	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	158	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	159	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	160	unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
	161
	162	memcpy(req->giv, ctx->iv, ivsize);
	163	memcpy(subreq->info, ctx->iv, ivsize);
	164
	165	ctx->err = crypto_ablkcipher_encrypt(subreq);
	166	if (ctx->err)
	167	goto out;
	168
	169	memcpy(ctx->iv, subreq->info, ivsize);
	170
	171	out:
	172	return async_chainiv_schedule_work(ctx);
	173	}
	174
	175	static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
	176	{
	177	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	178	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	179	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	180
	181	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	182	ablkcipher_request_set_callback(subreq, req->creq.base.flags,
	183	req->creq.base.complete,
	184	req->creq.base.data);
	185	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
	186	req->creq.nbytes, req->creq.info);
	187
	188	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	189	goto postpone;
	190
	191	if (ctx->queue.qlen) {
	192	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
	193	goto postpone;
	194	}
	195
	196	return async_chainiv_givencrypt_tail(req);
	197
	198	postpone:
	199	return async_chainiv_postpone_request(req);
200	}
201
202	static int async_chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
203	{
204	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
205	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
206
207	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
208	goto out;
209
210	if (crypto_ablkcipher_crt(geniv)->givencrypt !=
211	async_chainiv_givencrypt_first)
212	goto unlock;
213
214	crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
215	get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
216
217	unlock:
218	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
219
220	out:
221	return async_chainiv_givencrypt(req);
222	}
223
224	static void async_chainiv_do_postponed(struct work_struct *work)
225	{
226	struct async_chainiv_ctx *ctx = container_of(work,
227	struct async_chainiv_ctx,
228	postponed);
229	struct skcipher_givcrypt_request *req;
230	struct ablkcipher_request *subreq;
872ac874	231	int err;
e7cd2514 HX	232
	233	/* Only handle one request at a time to avoid hogging keventd. */
	234	spin_lock_bh(&ctx->lock);
	235	req = skcipher_dequeue_givcrypt(&ctx->queue);
	236	spin_unlock_bh(&ctx->lock);
	237
	238	if (!req) {
	239	async_chainiv_schedule_work(ctx);
	240	return;
	241	}
	242
	243	subreq = skcipher_givcrypt_reqctx(req);
	244	subreq->base.flags \|= CRYPTO_TFM_REQ_MAY_SLEEP;
	245
872ac874 HX	246	err = async_chainiv_givencrypt_tail(req);
	247
	248	local_bh_disable();
	249	skcipher_givcrypt_complete(req, err);
	250	local_bh_enable();
e7cd2514 HX	251	}
	252
	253	static int async_chainiv_init(struct crypto_tfm *tfm)
	254	{
	255	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	256
	257	spin_lock_init(&ctx->lock);
	258
	259	crypto_init_queue(&ctx->queue, 100);
	260	INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
	261
	262	return chainiv_init_common(tfm);
	263	}
	264
	265	static void async_chainiv_exit(struct crypto_tfm *tfm)
	266	{
	267	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	268
	269	BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) \|\| ctx->queue.qlen);
	270
	271	skcipher_geniv_exit(tfm);
7f470739 HX	272	}
	273
	274	static struct crypto_template chainiv_tmpl;
	275
	276	static struct crypto_instance chainiv_alloc(struct rtattr *tb)
	277	{
e7cd2514	278	struct crypto_attr_type *algt;
7f470739	279	struct crypto_instance *inst;
e7cd2514	280	int err;
7f470739	281
e7cd2514 HX	282	algt = crypto_get_attr_type(tb);
	283	err = PTR_ERR(algt);
	284	if (IS_ERR(algt))
	285	return ERR_PTR(err);
	286
	287	inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
7f470739 HX	288	if (IS_ERR(inst))
	289	goto out;
	290
	291	inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;
	292
	293	inst->alg.cra_init = chainiv_init;
	294	inst->alg.cra_exit = skcipher_geniv_exit;
	295
e7cd2514 HX	296	inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
	297
	298	if (!crypto_requires_sync(algt->type, algt->mask)) {
	299	inst->alg.cra_flags \|= CRYPTO_ALG_ASYNC;
	300
	301	inst->alg.cra_ablkcipher.givencrypt =
	302	async_chainiv_givencrypt_first;
	303
	304	inst->alg.cra_init = async_chainiv_init;
	305	inst->alg.cra_exit = async_chainiv_exit;
	306
	307	inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
	308	}
	309
	310	inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
7f470739 HX	311
	312	out:
	313	return inst;
	314	}
	315
	316	static struct crypto_template chainiv_tmpl = {
	317	.name = "chainiv",
	318	.alloc = chainiv_alloc,
	319	.free = skcipher_geniv_free,
	320	.module = THIS_MODULE,
	321	};
	322
5be5e667	323	static int __init chainiv_module_init(void)
7f470739 HX	324	{
	325	return crypto_register_template(&chainiv_tmpl);
	326	}
	327
5be5e667	328	static void chainiv_module_exit(void)
7f470739 HX	329	{
	330	crypto_unregister_template(&chainiv_tmpl);
	331	}
5be5e667 HX	332
	333	module_init(chainiv_module_init);
	334	module_exit(chainiv_module_exit);
	335
	336	MODULE_LICENSE("GPL");
	337	MODULE_DESCRIPTION("Chain IV Generator");