[mirror_ubuntu-hirsute-kernel.git] / crypto / echainiv.c

/*
 * echainiv: Encrypted Chain IV Generator
 *
 * This generator generates an IV based on a sequence number by xoring it
 * with a salt and then encrypting it with the same key as used to encrypt
 * the plain text.  This algorithm requires that the block size be equal
 * to the IV size.  It is mainly useful for CBC.
 *
 * This generator can only be used by algorithms where authentication
 * is performed after encryption (i.e., authenc).
 *
 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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/aead.h>
#include <crypto/null.h>
#include <crypto/rng.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/string.h>

#define MAX_IV_SIZE 16

struct echainiv_request_ctx {
	struct scatterlist src[2];
	struct scatterlist dst[2];
	struct scatterlist ivbuf[2];
	struct scatterlist *ivsg;
	struct aead_givcrypt_request subreq;
};

struct echainiv_ctx {
	struct crypto_aead *child;
	spinlock_t lock;
	struct crypto_blkcipher *null;
	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
};

static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);

static int echainiv_setkey(struct crypto_aead *tfm,
			      const u8 *key, unsigned int keylen)
{
	struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);

	return crypto_aead_setkey(ctx->child, key, keylen);
}

static int echainiv_setauthsize(struct crypto_aead *tfm,
				  unsigned int authsize)
{
	struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);

	return crypto_aead_setauthsize(ctx->child, authsize);
}

/* We don't care if we get preempted and read/write IVs from the next CPU. */
static void echainiv_read_iv(u8 *dst, unsigned size)
{
	u32 *a = (u32 *)dst;
	u32 __percpu *b = echainiv_iv;

	for (; size >= 4; size -= 4) {
		*a++ = this_cpu_read(*b);
		b++;
	}
}

static void echainiv_write_iv(const u8 *src, unsigned size)
{
	const u32 *a = (const u32 *)src;
	u32 __percpu *b = echainiv_iv;

	for (; size >= 4; size -= 4) {
		this_cpu_write(*b, *a);
		a++;
		b++;
	}
}

static void echainiv_encrypt_compat_complete2(struct aead_request *req,
						 int err)
{
	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
	struct aead_givcrypt_request *subreq = &rctx->subreq;
	struct crypto_aead *geniv;

	if (err == -EINPROGRESS)
		return;

	if (err)
		goto out;

	geniv = crypto_aead_reqtfm(req);
	scatterwalk_map_and_copy(subreq->giv, rctx->ivsg, 0,
				 crypto_aead_ivsize(geniv), 1);

out:
	kzfree(subreq->giv);
}

static void echainiv_encrypt_compat_complete(
	struct crypto_async_request *base, int err)
{
	struct aead_request *req = base->data;

	echainiv_encrypt_compat_complete2(req, err);
	aead_request_complete(req, err);
}

static void echainiv_encrypt_complete2(struct aead_request *req, int err)
{
	struct aead_request *subreq = aead_request_ctx(req);
	struct crypto_aead *geniv;
	unsigned int ivsize;

	if (err == -EINPROGRESS)
		return;

	if (err)
		goto out;

	geniv = crypto_aead_reqtfm(req);
	ivsize = crypto_aead_ivsize(geniv);

	echainiv_write_iv(subreq->iv, ivsize);

	if (req->iv != subreq->iv)
		memcpy(req->iv, subreq->iv, ivsize);

out:
	if (req->iv != subreq->iv)
		kzfree(subreq->iv);
}

static void echainiv_encrypt_complete(struct crypto_async_request *base,
					 int err)
{
	struct aead_request *req = base->data;

	echainiv_encrypt_complete2(req, err);
	aead_request_complete(req, err);
}

static int echainiv_encrypt_compat(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
	struct aead_givcrypt_request *subreq = &rctx->subreq;
	unsigned int ivsize = crypto_aead_ivsize(geniv);
	crypto_completion_t compl;
	void *data;
	u8 *info;
	__be64 seq;
	int err;

	if (req->cryptlen < ivsize)
		return -EINVAL;

	compl = req->base.complete;
	data = req->base.data;

	rctx->ivsg = scatterwalk_ffwd(rctx->ivbuf, req->dst, req->assoclen);
	info = PageHighMem(sg_page(rctx->ivsg)) ? NULL : sg_virt(rctx->ivsg);

	if (!info) {
		info = kmalloc(ivsize, req->base.flags &
				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
								  GFP_ATOMIC);
		if (!info)
			return -ENOMEM;

		compl = echainiv_encrypt_compat_complete;
		data = req;
	}

	memcpy(&seq, req->iv + ivsize - sizeof(seq), sizeof(seq));

	aead_givcrypt_set_tfm(subreq, ctx->child);
	aead_givcrypt_set_callback(subreq, req->base.flags,
				   req->base.complete, req->base.data);
	aead_givcrypt_set_crypt(subreq,
				scatterwalk_ffwd(rctx->src, req->src,
						 req->assoclen + ivsize),
				scatterwalk_ffwd(rctx->dst, rctx->ivsg,
						 ivsize),
				req->cryptlen - ivsize, req->iv);
	aead_givcrypt_set_assoc(subreq, req->src, req->assoclen);
	aead_givcrypt_set_giv(subreq, info, be64_to_cpu(seq));

	err = crypto_aead_givencrypt(subreq);
	if (unlikely(PageHighMem(sg_page(rctx->ivsg))))
		echainiv_encrypt_compat_complete2(req, err);
	return err;
}

static int echainiv_encrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	u8 *info;
	unsigned int ivsize = crypto_aead_ivsize(geniv);
	int err;

	if (req->cryptlen < ivsize)
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = echainiv_encrypt_complete;
	data = req;
	info = req->iv;

	if (req->src != req->dst) {
		struct blkcipher_desc desc = {
			.tfm = ctx->null,
		};

		err = crypto_blkcipher_encrypt(
			&desc, req->dst, req->src,
			req->assoclen + req->cryptlen);
		if (err)
			return err;
	}

	if (unlikely(!IS_ALIGNED((unsigned long)info,
				 crypto_aead_alignmask(geniv) + 1))) {
		info = kmalloc(ivsize, req->base.flags &
				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
								  GFP_ATOMIC);
		if (!info)
			return -ENOMEM;

		memcpy(info, req->iv, ivsize);
	}

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->dst, req->dst,
			       req->cryptlen - ivsize, info);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	crypto_xor(info, ctx->salt, ivsize);
	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
	echainiv_read_iv(info, ivsize);

	err = crypto_aead_encrypt(subreq);
	echainiv_encrypt_complete2(req, err);
	return err;
}

static int echainiv_decrypt_compat(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
	struct aead_request *subreq = &rctx->subreq.areq;
	crypto_completion_t compl;
	void *data;
	unsigned int ivsize = crypto_aead_ivsize(geniv);

	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = req->base.complete;
	data = req->base.data;

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq,
			       scatterwalk_ffwd(rctx->src, req->src,
						req->assoclen + ivsize),
			       scatterwalk_ffwd(rctx->dst, req->dst,
						req->assoclen + ivsize),
			       req->cryptlen - ivsize, req->iv);
	aead_request_set_assoc(subreq, req->src, req->assoclen);

	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);

	return crypto_aead_decrypt(subreq);
}

static int echainiv_decrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	unsigned int ivsize = crypto_aead_ivsize(geniv);

	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = req->base.complete;
	data = req->base.data;

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->src, req->dst,
			       req->cryptlen - ivsize, req->iv);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
	if (req->src != req->dst)
		scatterwalk_map_and_copy(req->iv, req->dst,
					 req->assoclen, ivsize, 1);

	return crypto_aead_decrypt(subreq);
}

static int echainiv_encrypt_compat_first(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err = 0;

	spin_lock_bh(&ctx->lock);
	if (geniv->encrypt != echainiv_encrypt_compat_first)
		goto unlock;

	geniv->encrypt = echainiv_encrypt_compat;
	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
				   crypto_aead_ivsize(geniv));

unlock:
	spin_unlock_bh(&ctx->lock);

	if (err)
		return err;

	return echainiv_encrypt_compat(req);
}

static int echainiv_encrypt_first(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err = 0;

	spin_lock_bh(&ctx->lock);
	if (geniv->encrypt != echainiv_encrypt_first)
		goto unlock;

	geniv->encrypt = echainiv_encrypt;
	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
				   crypto_aead_ivsize(geniv));

unlock:
	spin_unlock_bh(&ctx->lock);

	if (err)
		return err;

	return echainiv_encrypt(req);
}

static int echainiv_compat_init(struct crypto_tfm *tfm)
{
	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err;

	spin_lock_init(&ctx->lock);

	crypto_aead_set_reqsize(geniv, sizeof(struct echainiv_request_ctx));

	err = aead_geniv_init(tfm);

	ctx->child = geniv->child;
	geniv->child = geniv;

	return err;
}

static int echainiv_init(struct crypto_tfm *tfm)
{
	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err;

	spin_lock_init(&ctx->lock);

	crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));

	ctx->null = crypto_get_default_null_skcipher();
	err = PTR_ERR(ctx->null);
	if (IS_ERR(ctx->null))
		goto out;

	err = aead_geniv_init(tfm);
	if (err)
		goto drop_null;

	ctx->child = geniv->child;
	geniv->child = geniv;

out:
	return err;

drop_null:
	crypto_put_default_null_skcipher();
	goto out;
}

static void echainiv_compat_exit(struct crypto_tfm *tfm)
{
	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	crypto_free_aead(ctx->child);
}

static void echainiv_exit(struct crypto_tfm *tfm)
{
	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	crypto_free_aead(ctx->child);
	crypto_put_default_null_skcipher();
}

static int echainiv_aead_create(struct crypto_template *tmpl,
				struct rtattr **tb)
{
	struct aead_instance *inst;
	struct crypto_aead_spawn *spawn;
	struct aead_alg *alg;
	int err;

	inst = aead_geniv_alloc(tmpl, tb, 0, 0);

	if (IS_ERR(inst))
		return PTR_ERR(inst);

	err = -EINVAL;
	if (inst->alg.ivsize < sizeof(u64) ||
	    inst->alg.ivsize & (sizeof(u32) - 1) ||
	    inst->alg.ivsize > MAX_IV_SIZE)
		goto free_inst;

	spawn = aead_instance_ctx(inst);
	alg = crypto_spawn_aead_alg(spawn);

	inst->alg.setkey = echainiv_setkey;
	inst->alg.setauthsize = echainiv_setauthsize;
	inst->alg.encrypt = echainiv_encrypt_first;
	inst->alg.decrypt = echainiv_decrypt;

	inst->alg.base.cra_init = echainiv_init;
	inst->alg.base.cra_exit = echainiv_exit;

	inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
	inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx);
	inst->alg.base.cra_ctxsize += inst->alg.base.cra_aead.ivsize;

	if (alg->base.cra_aead.encrypt) {
		inst->alg.encrypt = echainiv_encrypt_compat_first;
		inst->alg.decrypt = echainiv_decrypt_compat;

		inst->alg.base.cra_init = echainiv_compat_init;
		inst->alg.base.cra_exit = echainiv_compat_exit;
	}

	err = aead_register_instance(tmpl, inst);
	if (err)
		goto free_inst;

out:
	return err;

free_inst:
	aead_geniv_free(inst);
	goto out;
}

static int echainiv_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	int err;

	err = crypto_get_default_rng();
	if (err)
		goto out;

	err = echainiv_aead_create(tmpl, tb);
	if (err)
		goto put_rng;

out:
	return err;

put_rng:
	crypto_put_default_rng();
	goto out;
}

static void echainiv_free(struct crypto_instance *inst)
{
	aead_geniv_free(aead_instance(inst));
	crypto_put_default_rng();
}

static struct crypto_template echainiv_tmpl = {
	.name = "echainiv",
	.create = echainiv_create,
	.free = echainiv_free,
	.module = THIS_MODULE,
};

static int __init echainiv_module_init(void)
{
	return crypto_register_template(&echainiv_tmpl);
}

static void __exit echainiv_module_exit(void)
{
	crypto_unregister_template(&echainiv_tmpl);
}

module_init(echainiv_module_init);
module_exit(echainiv_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Encrypted Chain IV Generator");
MODULE_ALIAS_CRYPTO("echainiv");
Commit	Line	Data
a10f554f HX	1	/*
	2	* echainiv: Encrypted Chain IV Generator
	3	*
	4	* This generator generates an IV based on a sequence number by xoring it
	5	* with a salt and then encrypting it with the same key as used to encrypt
	6	* the plain text. This algorithm requires that the block size be equal
	7	* to the IV size. It is mainly useful for CBC.
	8	*
	9	* This generator can only be used by algorithms where authentication
	10	* is performed after encryption (i.e., authenc).
	11	*
	12	* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
	13	*
	14	* This program is free software; you can redistribute it and/or modify it
	15	* under the terms of the GNU General Public License as published by the Free
	16	* Software Foundation; either version 2 of the License, or (at your option)
	17	* any later version.
	18	*
	19	*/
	20
	21	#include <crypto/internal/aead.h>
	22	#include <crypto/null.h>
	23	#include <crypto/rng.h>
	24	#include <crypto/scatterwalk.h>
	25	#include <linux/err.h>
	26	#include <linux/init.h>
	27	#include <linux/kernel.h>
	28	#include <linux/mm.h>
	29	#include <linux/module.h>
	30	#include <linux/percpu.h>
	31	#include <linux/spinlock.h>
	32	#include <linux/string.h>
	33
	34	#define MAX_IV_SIZE 16
	35
	36	struct echainiv_request_ctx {
	37	struct scatterlist src[2];
	38	struct scatterlist dst[2];
	39	struct scatterlist ivbuf[2];
	40	struct scatterlist *ivsg;
	41	struct aead_givcrypt_request subreq;
	42	};
	43
	44	struct echainiv_ctx {
	45	struct crypto_aead *child;
	46	spinlock_t lock;
	47	struct crypto_blkcipher *null;
	48	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
	49	};
	50
	51	static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);
	52
	53	static int echainiv_setkey(struct crypto_aead *tfm,
	54	const u8 *key, unsigned int keylen)
	55	{
	56	struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);
	57
	58	return crypto_aead_setkey(ctx->child, key, keylen);
	59	}
	60
	61	static int echainiv_setauthsize(struct crypto_aead *tfm,
	62	unsigned int authsize)
	63	{
	64	struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);
65
66	return crypto_aead_setauthsize(ctx->child, authsize);
67	}
68
69	/* We don't care if we get preempted and read/write IVs from the next CPU. */
622ff875	70	static void echainiv_read_iv(u8 *dst, unsigned size)
a10f554f HX	71	{
	72	u32 a = (u32 )dst;
	73	u32 __percpu *b = echainiv_iv;
	74
	75	for (; size >= 4; size -= 4) {
	76	a++ = this_cpu_read(b);
	77	b++;
	78	}
	79	}
	80
622ff875	81	static void echainiv_write_iv(const u8 *src, unsigned size)
a10f554f HX	82	{
	83	const u32 a = (const u32 )src;
	84	u32 __percpu *b = echainiv_iv;
	85
	86	for (; size >= 4; size -= 4) {
	87	this_cpu_write(b, a);
	88	a++;
	89	b++;
	90	}
	91	}
	92
	93	static void echainiv_encrypt_compat_complete2(struct aead_request *req,
	94	int err)
	95	{
	96	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
	97	struct aead_givcrypt_request *subreq = &rctx->subreq;
	98	struct crypto_aead *geniv;
	99
	100	if (err == -EINPROGRESS)
	101	return;
	102
	103	if (err)
	104	goto out;
	105
	106	geniv = crypto_aead_reqtfm(req);
	107	scatterwalk_map_and_copy(subreq->giv, rctx->ivsg, 0,
	108	crypto_aead_ivsize(geniv), 1);
	109
	110	out:
	111	kzfree(subreq->giv);
	112	}
	113
	114	static void echainiv_encrypt_compat_complete(
	115	struct crypto_async_request *base, int err)
	116	{
	117	struct aead_request *req = base->data;
	118
	119	echainiv_encrypt_compat_complete2(req, err);
	120	aead_request_complete(req, err);
	121	}
	122
	123	static void echainiv_encrypt_complete2(struct aead_request *req, int err)
	124	{
	125	struct aead_request *subreq = aead_request_ctx(req);
	126	struct crypto_aead *geniv;
	127	unsigned int ivsize;
	128
	129	if (err == -EINPROGRESS)
	130	return;
	131
	132	if (err)
	133	goto out;
	134
	135	geniv = crypto_aead_reqtfm(req);
	136	ivsize = crypto_aead_ivsize(geniv);
	137
	138	echainiv_write_iv(subreq->iv, ivsize);
	139
	140	if (req->iv != subreq->iv)
	141	memcpy(req->iv, subreq->iv, ivsize);
	142
	143	out:
	144	if (req->iv != subreq->iv)
	145	kzfree(subreq->iv);
146	}
147
148	static void echainiv_encrypt_complete(struct crypto_async_request *base,
149	int err)
150	{
151	struct aead_request *req = base->data;
152
153	echainiv_encrypt_complete2(req, err);
154	aead_request_complete(req, err);
155	}
156
157	static int echainiv_encrypt_compat(struct aead_request *req)
158	{
159	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
160	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
161	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
162	struct aead_givcrypt_request *subreq = &rctx->subreq;
163	unsigned int ivsize = crypto_aead_ivsize(geniv);
164	crypto_completion_t compl;
165	void *data;
166	u8 *info;
167	__be64 seq;
168	int err;
169
823655c9 HX	170	if (req->cryptlen < ivsize)
	171	return -EINVAL;
	172
a10f554f HX	173	compl = req->base.complete;
	174	data = req->base.data;
	175
	176	rctx->ivsg = scatterwalk_ffwd(rctx->ivbuf, req->dst, req->assoclen);
	177	info = PageHighMem(sg_page(rctx->ivsg)) ? NULL : sg_virt(rctx->ivsg);
	178
	179	if (!info) {
	180	info = kmalloc(ivsize, req->base.flags &
	181	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
	182	GFP_ATOMIC);
	183	if (!info)
	184	return -ENOMEM;
	185
	186	compl = echainiv_encrypt_compat_complete;
	187	data = req;
	188	}
	189
	190	memcpy(&seq, req->iv + ivsize - sizeof(seq), sizeof(seq));
	191
	192	aead_givcrypt_set_tfm(subreq, ctx->child);
	193	aead_givcrypt_set_callback(subreq, req->base.flags,
	194	req->base.complete, req->base.data);
	195	aead_givcrypt_set_crypt(subreq,
	196	scatterwalk_ffwd(rctx->src, req->src,
	197	req->assoclen + ivsize),
	198	scatterwalk_ffwd(rctx->dst, rctx->ivsg,
	199	ivsize),
	200	req->cryptlen - ivsize, req->iv);
	201	aead_givcrypt_set_assoc(subreq, req->src, req->assoclen);
	202	aead_givcrypt_set_giv(subreq, info, be64_to_cpu(seq));
	203
	204	err = crypto_aead_givencrypt(subreq);
	205	if (unlikely(PageHighMem(sg_page(rctx->ivsg))))
	206	echainiv_encrypt_compat_complete2(req, err);
	207	return err;
	208	}
	209
	210	static int echainiv_encrypt(struct aead_request *req)
	211	{
	212	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	213	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	214	struct aead_request *subreq = aead_request_ctx(req);
	215	crypto_completion_t compl;
	216	void *data;
	217	u8 *info;
823655c9	218	unsigned int ivsize = crypto_aead_ivsize(geniv);
a10f554f HX	219	int err;
a10f554f HX	220
823655c9 HX	221	if (req->cryptlen < ivsize)
	222	return -EINVAL;
	223
a10f554f HX	224	aead_request_set_tfm(subreq, ctx->child);
	225
	226	compl = echainiv_encrypt_complete;
	227	data = req;
	228	info = req->iv;
	229
a10f554f	230	if (req->src != req->dst) {
a10f554f HX	231	struct blkcipher_desc desc = {
	232	.tfm = ctx->null,
	233	};
	234
	235	err = crypto_blkcipher_encrypt(
838c9d56 HX	236	&desc, req->dst, req->src,
838c9d56 HX	237	req->assoclen + req->cryptlen);
a10f554f HX	238	if (err)
	239	return err;
	240	}
	241
	242	if (unlikely(!IS_ALIGNED((unsigned long)info,
	243	crypto_aead_alignmask(geniv) + 1))) {
	244	info = kmalloc(ivsize, req->base.flags &
	245	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
	246	GFP_ATOMIC);
	247	if (!info)
	248	return -ENOMEM;
	249
	250	memcpy(info, req->iv, ivsize);
	251	}
	252
	253	aead_request_set_callback(subreq, req->base.flags, compl, data);
	254	aead_request_set_crypt(subreq, req->dst, req->dst,
	255	req->cryptlen - ivsize, info);
374d4ad1	256	aead_request_set_ad(subreq, req->assoclen + ivsize);
a10f554f HX	257
	258	crypto_xor(info, ctx->salt, ivsize);
	259	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
	260	echainiv_read_iv(info, ivsize);
	261
	262	err = crypto_aead_encrypt(subreq);
	263	echainiv_encrypt_complete2(req, err);
	264	return err;
	265	}
	266
	267	static int echainiv_decrypt_compat(struct aead_request *req)
	268	{
	269	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	270	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
823655c9 HX	271	struct echainiv_request_ctx *rctx = aead_request_ctx(req);
823655c9 HX	272	struct aead_request *subreq = &rctx->subreq.areq;
a10f554f HX	273	crypto_completion_t compl;
a10f554f HX	274	void *data;
823655c9 HX	275	unsigned int ivsize = crypto_aead_ivsize(geniv);
	276
	277	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
	278	return -EINVAL;
a10f554f HX	279
	280	aead_request_set_tfm(subreq, ctx->child);
	281
	282	compl = req->base.complete;
	283	data = req->base.data;
	284
a10f554f	285	aead_request_set_callback(subreq, req->base.flags, compl, data);
823655c9 HX	286	aead_request_set_crypt(subreq,
	287	scatterwalk_ffwd(rctx->src, req->src,
	288	req->assoclen + ivsize),
	289	scatterwalk_ffwd(rctx->dst, req->dst,
	290	req->assoclen + ivsize),
a10f554f	291	req->cryptlen - ivsize, req->iv);
823655c9	292	aead_request_set_assoc(subreq, req->src, req->assoclen);
a10f554f HX	293
	294	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
	295
	296	return crypto_aead_decrypt(subreq);
	297	}
	298
	299	static int echainiv_decrypt(struct aead_request *req)
	300	{
	301	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	302	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	303	struct aead_request *subreq = aead_request_ctx(req);
	304	crypto_completion_t compl;
	305	void *data;
823655c9 HX	306	unsigned int ivsize = crypto_aead_ivsize(geniv);
	307
	308	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
	309	return -EINVAL;
a10f554f HX	310
	311	aead_request_set_tfm(subreq, ctx->child);
	312
	313	compl = req->base.complete;
	314	data = req->base.data;
	315
a10f554f HX	316	aead_request_set_callback(subreq, req->base.flags, compl, data);
	317	aead_request_set_crypt(subreq, req->src, req->dst,
	318	req->cryptlen - ivsize, req->iv);
374d4ad1	319	aead_request_set_ad(subreq, req->assoclen + ivsize);
a10f554f HX	320
	321	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
	322	if (req->src != req->dst)
	323	scatterwalk_map_and_copy(req->iv, req->dst,
	324	req->assoclen, ivsize, 1);
	325
	326	return crypto_aead_decrypt(subreq);
	327	}
	328
	329	static int echainiv_encrypt_compat_first(struct aead_request *req)
	330	{
	331	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	332	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	333	int err = 0;
	334
	335	spin_lock_bh(&ctx->lock);
	336	if (geniv->encrypt != echainiv_encrypt_compat_first)
	337	goto unlock;
	338
	339	geniv->encrypt = echainiv_encrypt_compat;
	340	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
	341	crypto_aead_ivsize(geniv));
	342
	343	unlock:
	344	spin_unlock_bh(&ctx->lock);
	345
	346	if (err)
	347	return err;
	348
	349	return echainiv_encrypt_compat(req);
	350	}
	351
	352	static int echainiv_encrypt_first(struct aead_request *req)
	353	{
	354	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	355	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	356	int err = 0;
	357
	358	spin_lock_bh(&ctx->lock);
	359	if (geniv->encrypt != echainiv_encrypt_first)
	360	goto unlock;
	361
	362	geniv->encrypt = echainiv_encrypt;
	363	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
	364	crypto_aead_ivsize(geniv));
	365
	366	unlock:
	367	spin_unlock_bh(&ctx->lock);
	368
	369	if (err)
	370	return err;
	371
	372	return echainiv_encrypt(req);
	373	}
	374
	375	static int echainiv_compat_init(struct crypto_tfm *tfm)
	376	{
	377	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
	378	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	379	int err;
	380
	381	spin_lock_init(&ctx->lock);
	382
	383	crypto_aead_set_reqsize(geniv, sizeof(struct echainiv_request_ctx));
384
385	err = aead_geniv_init(tfm);
386
387	ctx->child = geniv->child;
388	geniv->child = geniv;
389
390	return err;
391	}
392
393	static int echainiv_init(struct crypto_tfm *tfm)
394	{
395	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
396	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
397	int err;
398
399	spin_lock_init(&ctx->lock);
400
401	crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));
402
403	ctx->null = crypto_get_default_null_skcipher();
404	err = PTR_ERR(ctx->null);
405	if (IS_ERR(ctx->null))
406	goto out;
407
408	err = aead_geniv_init(tfm);
409	if (err)
410	goto drop_null;
411
412	ctx->child = geniv->child;
413	geniv->child = geniv;
414
415	out:
416	return err;
417
418	drop_null:
419	crypto_put_default_null_skcipher();
420	goto out;
421	}
422
423	static void echainiv_compat_exit(struct crypto_tfm *tfm)
424	{
425	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
426
427	crypto_free_aead(ctx->child);
428	}
429
430	static void echainiv_exit(struct crypto_tfm *tfm)
431	{
432	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
433
434	crypto_free_aead(ctx->child);
435	crypto_put_default_null_skcipher();
436	}
437
1e419c79 HX	438	static int echainiv_aead_create(struct crypto_template *tmpl,
1e419c79 HX	439	struct rtattr **tb)
a10f554f HX	440	{
	441	struct aead_instance *inst;
	442	struct crypto_aead_spawn *spawn;
	443	struct aead_alg *alg;
1e419c79	444	int err;
a10f554f	445
1e419c79	446	inst = aead_geniv_alloc(tmpl, tb, 0, 0);
a10f554f HX	447
a10f554f HX	448	if (IS_ERR(inst))
1e419c79	449	return PTR_ERR(inst);
a10f554f	450
1e419c79	451	err = -EINVAL;
a10f554f HX	452	if (inst->alg.ivsize < sizeof(u64) \|\|
a10f554f HX	453	inst->alg.ivsize & (sizeof(u32) - 1) \|\|
1e419c79 HX	454	inst->alg.ivsize > MAX_IV_SIZE)
1e419c79 HX	455	goto free_inst;
a10f554f HX	456
	457	spawn = aead_instance_ctx(inst);
	458	alg = crypto_spawn_aead_alg(spawn);
	459
	460	inst->alg.setkey = echainiv_setkey;
	461	inst->alg.setauthsize = echainiv_setauthsize;
	462	inst->alg.encrypt = echainiv_encrypt_first;
	463	inst->alg.decrypt = echainiv_decrypt;
	464
	465	inst->alg.base.cra_init = echainiv_init;
	466	inst->alg.base.cra_exit = echainiv_exit;
	467
	468	inst->alg.base.cra_alignmask \|= __alignof__(u32) - 1;
	469	inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx);
	470	inst->alg.base.cra_ctxsize += inst->alg.base.cra_aead.ivsize;
	471
	472	if (alg->base.cra_aead.encrypt) {
	473	inst->alg.encrypt = echainiv_encrypt_compat_first;
	474	inst->alg.decrypt = echainiv_decrypt_compat;
	475
	476	inst->alg.base.cra_init = echainiv_compat_init;
	477	inst->alg.base.cra_exit = echainiv_compat_exit;
	478	}
	479
1e419c79 HX	480	err = aead_register_instance(tmpl, inst);
	481	if (err)
	482	goto free_inst;
	483
a10f554f	484	out:
1e419c79 HX	485	return err;
	486
	487	free_inst:
	488	aead_geniv_free(inst);
	489	goto out;
a10f554f HX	490	}
a10f554f HX	491
1e419c79	492	static int echainiv_create(struct crypto_template tmpl, struct rtattr *tb)
a10f554f	493	{
a10f554f HX	494	int err;
	495
	496	err = crypto_get_default_rng();
	497	if (err)
1e419c79	498	goto out;
a10f554f	499
1e419c79 HX	500	err = echainiv_aead_create(tmpl, tb);
1e419c79 HX	501	if (err)
a10f554f HX	502	goto put_rng;
	503
	504	out:
1e419c79	505	return err;
a10f554f HX	506
	507	put_rng:
	508	crypto_put_default_rng();
	509	goto out;
	510	}
	511
	512	static void echainiv_free(struct crypto_instance *inst)
	513	{
	514	aead_geniv_free(aead_instance(inst));
	515	crypto_put_default_rng();
	516	}
	517
	518	static struct crypto_template echainiv_tmpl = {
	519	.name = "echainiv",
1e419c79	520	.create = echainiv_create,
a10f554f HX	521	.free = echainiv_free,
	522	.module = THIS_MODULE,
	523	};
	524
	525	static int __init echainiv_module_init(void)
	526	{
	527	return crypto_register_template(&echainiv_tmpl);
	528	}
	529
	530	static void __exit echainiv_module_exit(void)
	531	{
	532	crypto_unregister_template(&echainiv_tmpl);
	533	}
	534
	535	module_init(echainiv_module_init);
	536	module_exit(echainiv_module_exit);
	537
	538	MODULE_LICENSE("GPL");
	539	MODULE_DESCRIPTION("Encrypted Chain IV Generator");
	540	MODULE_ALIAS_CRYPTO("echainiv");