crypto/chainiv.c - kernel/common - Git at Google

 /*
  * 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_givencrypt_first(struct skcipher_givcrypt_request *req)
 {
 	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
 	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
 	int err = 0;

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

 	crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
 	err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
 				   crypto_ablkcipher_ivsize(geniv));

 unlock:
 	spin_unlock_bh(&ctx->lock);

 	if (err)
 		return err;

 	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 = 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 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);
 	int err = 0;

 	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;
 	err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
 				   crypto_ablkcipher_ivsize(geniv));

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

 	if (err)
 		return err;

 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);

 	err = crypto_get_default_rng();
 	if (err)
 		return ERR_PTR(err);

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

 	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;

 put_rng:
 	crypto_put_default_rng();
 	goto out;
 }

 static void chainiv_free(struct crypto_instance *inst)
 {
 	skcipher_geniv_free(inst);
 	crypto_put_default_rng();
 }

 static struct crypto_template chainiv_tmpl = {
 	.name = "chainiv",
 	.alloc = chainiv_alloc,
 	.free = chainiv_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");
	/*
	* 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_givencrypt_first(struct skcipher_givcrypt_request *req)
	{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	int err = 0;

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

	crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
	err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
	crypto_ablkcipher_ivsize(geniv));

	unlock:
	spin_unlock_bh(&ctx->lock);

	if (err)
	return err;

	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 = 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 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);
	int err = 0;

	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;
	err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
	crypto_ablkcipher_ivsize(geniv));

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

	if (err)
	return err;

	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);

	err = crypto_get_default_rng();
	if (err)
	return ERR_PTR(err);

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

	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;

	put_rng:
	crypto_put_default_rng();
	goto out;
	}

	static void chainiv_free(struct crypto_instance *inst)
	{
	skcipher_geniv_free(inst);
	crypto_put_default_rng();
	}

	static struct crypto_template chainiv_tmpl = {
	.name = "chainiv",
	.alloc = chainiv_alloc,
	.free = chainiv_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");