[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 <crypto/rng.h>
#include <crypto/crypto_wq.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.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_init_common(struct crypto_tfm *tfm, char iv[])
{
	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
	int err = 0;

	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);

	if (iv) {
		err = crypto_rng_get_bytes(crypto_default_rng, iv,
					   crypto_ablkcipher_ivsize(geniv));
		crypto_put_default_rng();
	}

	return err ?: skcipher_geniv_init(tfm);
}

static int chainiv_init(struct crypto_tfm *tfm)
{
	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
	struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	char *iv;

	spin_lock_init(&ctx->lock);

	iv = NULL;
	if (!crypto_get_default_rng()) {
		crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
		iv = ctx->iv;
	}

	return chainiv_init_common(tfm, iv);
}

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

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

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

	queued = queue_work(kcrypto_wq, &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 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 crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	char *iv;

	spin_lock_init(&ctx->lock);

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

	iv = NULL;
	if (!crypto_get_default_rng()) {
		crypto_ablkcipher_crt(geniv)->givencrypt =
			async_chainiv_givencrypt;
		iv = ctx->iv;
	}

	return chainiv_init_common(tfm, iv);
}

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;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return ERR_CAST(algt);

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

	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_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");
MODULE_ALIAS_CRYPTO("chainiv");
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>
a0f000ec	17	#include <crypto/rng.h>
0a2e821d	18	#include <crypto/crypto_wq.h>
7f470739 HX	19	#include <linux/err.h>
7f470739 HX	20	#include <linux/init.h>
e7cd2514	21	#include <linux/kernel.h>
7f470739	22	#include <linux/module.h>
7f470739 HX	23	#include <linux/spinlock.h>
7f470739 HX	24	#include <linux/string.h>
e7cd2514 HX	25	#include <linux/workqueue.h>
	26
	27	enum {
	28	CHAINIV_STATE_INUSE = 0,
	29	};
7f470739 HX	30
	31	struct chainiv_ctx {
	32	spinlock_t lock;
	33	char iv[];
	34	};
	35
e7cd2514 HX	36	struct async_chainiv_ctx {
	37	unsigned long state;
	38
	39	spinlock_t lock;
	40	int err;
	41
	42	struct crypto_queue queue;
	43	struct work_struct postponed;
	44
	45	char iv[];
	46	};
	47
7f470739 HX	48	static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
	49	{
	50	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	51	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	52	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	53	unsigned int ivsize;
	54	int err;
	55
	56	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	57	ablkcipher_request_set_callback(subreq, req->creq.base.flags &
	58	~CRYPTO_TFM_REQ_MAY_SLEEP,
	59	req->creq.base.complete,
	60	req->creq.base.data);
	61	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
	62	req->creq.nbytes, req->creq.info);
	63
	64	spin_lock_bh(&ctx->lock);
	65
	66	ivsize = crypto_ablkcipher_ivsize(geniv);
	67
	68	memcpy(req->giv, ctx->iv, ivsize);
	69	memcpy(subreq->info, ctx->iv, ivsize);
	70
	71	err = crypto_ablkcipher_encrypt(subreq);
	72	if (err)
	73	goto unlock;
	74
	75	memcpy(ctx->iv, subreq->info, ivsize);
	76
	77	unlock:
	78	spin_unlock_bh(&ctx->lock);
	79
	80	return err;
	81	}
	82
65fe6740	83	static int chainiv_init_common(struct crypto_tfm *tfm, char iv[])
7f470739	84	{
65fe6740	85	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
341476d6	86	int err = 0;
7f470739	87
e7cd2514 HX	88	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
e7cd2514 HX	89
341476d6 HX	90	if (iv) {
	91	err = crypto_rng_get_bytes(crypto_default_rng, iv,
	92	crypto_ablkcipher_ivsize(geniv));
	93	crypto_put_default_rng();
	94	}
	95
	96	return err ?: skcipher_geniv_init(tfm);
e7cd2514 HX	97	}
e7cd2514 HX	98
7f470739 HX	99	static int chainiv_init(struct crypto_tfm *tfm)
7f470739 HX	100	{
341476d6	101	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
e7cd2514	102	struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
341476d6	103	char *iv;
7f470739 HX	104
	105	spin_lock_init(&ctx->lock);
	106
341476d6 HX	107	iv = NULL;
	108	if (!crypto_get_default_rng()) {
	109	crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
	110	iv = ctx->iv;
	111	}
	112
	113	return chainiv_init_common(tfm, iv);
e7cd2514	114	}
7f470739	115
e7cd2514 HX	116	static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
	117	{
	118	int queued;
872ac874	119	int err = ctx->err;
e7cd2514 HX	120
e7cd2514 HX	121	if (!ctx->queue.qlen) {
4e857c58	122	smp_mb__before_atomic();
e7cd2514 HX	123	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
	124
	125	if (!ctx->queue.qlen \|\|
	126	test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	127	goto out;
	128	}
	129
0a2e821d	130	queued = queue_work(kcrypto_wq, &ctx->postponed);
e7cd2514 HX	131	BUG_ON(!queued);
	132
	133	out:
872ac874	134	return err;
e7cd2514 HX	135	}
	136
	137	static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
	138	{
	139	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	140	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	141	int err;
	142
	143	spin_lock_bh(&ctx->lock);
	144	err = skcipher_enqueue_givcrypt(&ctx->queue, req);
	145	spin_unlock_bh(&ctx->lock);
	146
	147	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	148	return err;
	149
	150	ctx->err = err;
	151	return async_chainiv_schedule_work(ctx);
	152	}
	153
	154	static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
	155	{
	156	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	157	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	158	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	159	unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
	160
	161	memcpy(req->giv, ctx->iv, ivsize);
	162	memcpy(subreq->info, ctx->iv, ivsize);
	163
	164	ctx->err = crypto_ablkcipher_encrypt(subreq);
	165	if (ctx->err)
	166	goto out;
	167
	168	memcpy(ctx->iv, subreq->info, ivsize);
	169
	170	out:
	171	return async_chainiv_schedule_work(ctx);
	172	}
	173
	174	static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
	175	{
	176	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	177	struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	178	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	179
	180	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
	181	ablkcipher_request_set_callback(subreq, req->creq.base.flags,
	182	req->creq.base.complete,
	183	req->creq.base.data);
	184	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
	185	req->creq.nbytes, req->creq.info);
	186
	187	if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
	188	goto postpone;
	189
	190	if (ctx->queue.qlen) {
	191	clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
	192	goto postpone;
	193	}
	194
	195	return async_chainiv_givencrypt_tail(req);
	196
	197	postpone:
	198	return async_chainiv_postpone_request(req);
199	}
200
e7cd2514 HX	201	static void async_chainiv_do_postponed(struct work_struct *work)
	202	{
	203	struct async_chainiv_ctx *ctx = container_of(work,
	204	struct async_chainiv_ctx,
	205	postponed);
	206	struct skcipher_givcrypt_request *req;
	207	struct ablkcipher_request *subreq;
872ac874	208	int err;
e7cd2514 HX	209
	210	/* Only handle one request at a time to avoid hogging keventd. */
	211	spin_lock_bh(&ctx->lock);
	212	req = skcipher_dequeue_givcrypt(&ctx->queue);
	213	spin_unlock_bh(&ctx->lock);
	214
	215	if (!req) {
	216	async_chainiv_schedule_work(ctx);
	217	return;
	218	}
	219
	220	subreq = skcipher_givcrypt_reqctx(req);
	221	subreq->base.flags \|= CRYPTO_TFM_REQ_MAY_SLEEP;
	222
872ac874 HX	223	err = async_chainiv_givencrypt_tail(req);
	224
	225	local_bh_disable();
	226	skcipher_givcrypt_complete(req, err);
	227	local_bh_enable();
e7cd2514 HX	228	}
	229
	230	static int async_chainiv_init(struct crypto_tfm *tfm)
	231	{
341476d6	232	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
e7cd2514	233	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
341476d6	234	char *iv;
e7cd2514 HX	235
	236	spin_lock_init(&ctx->lock);
	237
	238	crypto_init_queue(&ctx->queue, 100);
	239	INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
	240
341476d6 HX	241	iv = NULL;
	242	if (!crypto_get_default_rng()) {
	243	crypto_ablkcipher_crt(geniv)->givencrypt =
	244	async_chainiv_givencrypt;
	245	iv = ctx->iv;
	246	}
	247
	248	return chainiv_init_common(tfm, iv);
e7cd2514 HX	249	}
	250
	251	static void async_chainiv_exit(struct crypto_tfm *tfm)
	252	{
	253	struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	254
	255	BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) \|\| ctx->queue.qlen);
	256
	257	skcipher_geniv_exit(tfm);
7f470739 HX	258	}
	259
	260	static struct crypto_template chainiv_tmpl;
	261
	262	static struct crypto_instance chainiv_alloc(struct rtattr *tb)
	263	{
e7cd2514	264	struct crypto_attr_type *algt;
7f470739 HX	265	struct crypto_instance *inst;
7f470739 HX	266
e7cd2514	267	algt = crypto_get_attr_type(tb);
e7cd2514	268	if (IS_ERR(algt))
3e8afe35	269	return ERR_CAST(algt);
e7cd2514 HX	270
e7cd2514 HX	271	inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
7f470739	272	if (IS_ERR(inst))
341476d6	273	goto out;
7f470739 HX	274
	275	inst->alg.cra_init = chainiv_init;
	276	inst->alg.cra_exit = skcipher_geniv_exit;
	277
e7cd2514 HX	278	inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
	279
	280	if (!crypto_requires_sync(algt->type, algt->mask)) {
	281	inst->alg.cra_flags \|= CRYPTO_ALG_ASYNC;
	282
e7cd2514 HX	283	inst->alg.cra_init = async_chainiv_init;
	284	inst->alg.cra_exit = async_chainiv_exit;
	285
	286	inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
	287	}
	288
	289	inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
7f470739 HX	290
	291	out:
	292	return inst;
	293	}
	294
	295	static struct crypto_template chainiv_tmpl = {
	296	.name = "chainiv",
	297	.alloc = chainiv_alloc,
341476d6	298	.free = skcipher_geniv_free,
7f470739 HX	299	.module = THIS_MODULE,
	300	};
	301
5be5e667	302	static int __init chainiv_module_init(void)
7f470739 HX	303	{
	304	return crypto_register_template(&chainiv_tmpl);
	305	}
	306
5be5e667	307	static void chainiv_module_exit(void)
7f470739 HX	308	{
	309	crypto_unregister_template(&chainiv_tmpl);
	310	}
5be5e667 HX	311
	312	module_init(chainiv_module_init);
	313	module_exit(chainiv_module_exit);
	314
	315	MODULE_LICENSE("GPL");
	316	MODULE_DESCRIPTION("Chain IV Generator");
4943ba16	317	MODULE_ALIAS_CRYPTO("chainiv");