[linux.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 <[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/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;

	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;
	int err;

	aead_request_set_tfm(subreq, ctx->child);

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

	ivsize = crypto_aead_ivsize(geniv);

	if (req->src != req->dst) {
		struct scatterlist src[2];
		struct scatterlist dst[2];
		struct blkcipher_desc desc = {
			.tfm = ctx->null,
		};

		err = crypto_blkcipher_encrypt(
			&desc,
			scatterwalk_ffwd(dst, req->dst,
					 req->assoclen + ivsize),
			scatterwalk_ffwd(src, req->src,
					 req->assoclen + ivsize),
			req->cryptlen - ivsize);
		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, 0);

	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 aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	unsigned int ivsize;

	aead_request_set_tfm(subreq, ctx->child);

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

	ivsize = crypto_aead_ivsize(geniv);

	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);

	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;

	aead_request_set_tfm(subreq, ctx->child);

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

	ivsize = crypto_aead_ivsize(geniv);

	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, 0);

	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 <[email protected]>
	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
170	compl = req->base.complete;
171	data = req->base.data;
172
173	rctx->ivsg = scatterwalk_ffwd(rctx->ivbuf, req->dst, req->assoclen);
174	info = PageHighMem(sg_page(rctx->ivsg)) ? NULL : sg_virt(rctx->ivsg);
175
176	if (!info) {
177	info = kmalloc(ivsize, req->base.flags &
178	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
179	GFP_ATOMIC);
180	if (!info)
181	return -ENOMEM;
182
183	compl = echainiv_encrypt_compat_complete;
184	data = req;
185	}
186
187	memcpy(&seq, req->iv + ivsize - sizeof(seq), sizeof(seq));
188
189	aead_givcrypt_set_tfm(subreq, ctx->child);
190	aead_givcrypt_set_callback(subreq, req->base.flags,
191	req->base.complete, req->base.data);
192	aead_givcrypt_set_crypt(subreq,
193	scatterwalk_ffwd(rctx->src, req->src,
194	req->assoclen + ivsize),
195	scatterwalk_ffwd(rctx->dst, rctx->ivsg,
196	ivsize),
197	req->cryptlen - ivsize, req->iv);
198	aead_givcrypt_set_assoc(subreq, req->src, req->assoclen);
199	aead_givcrypt_set_giv(subreq, info, be64_to_cpu(seq));
200
201	err = crypto_aead_givencrypt(subreq);
202	if (unlikely(PageHighMem(sg_page(rctx->ivsg))))
203	echainiv_encrypt_compat_complete2(req, err);
204	return err;
205	}
206
207	static int echainiv_encrypt(struct aead_request *req)
208	{
209	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
210	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
211	struct aead_request *subreq = aead_request_ctx(req);
212	crypto_completion_t compl;
213	void *data;
214	u8 *info;
215	unsigned int ivsize;
216	int err;
217
218	aead_request_set_tfm(subreq, ctx->child);
219
220	compl = echainiv_encrypt_complete;
221	data = req;
222	info = req->iv;
223
224	ivsize = crypto_aead_ivsize(geniv);
225
226	if (req->src != req->dst) {
227	struct scatterlist src[2];
228	struct scatterlist dst[2];
229	struct blkcipher_desc desc = {
230	.tfm = ctx->null,
231	};
232
233	err = crypto_blkcipher_encrypt(
234	&desc,
235	scatterwalk_ffwd(dst, req->dst,
236	req->assoclen + ivsize),
237	scatterwalk_ffwd(src, req->src,
238	req->assoclen + ivsize),
239	req->cryptlen - ivsize);
240	if (err)
241	return err;
242	}
243
244	if (unlikely(!IS_ALIGNED((unsigned long)info,
245	crypto_aead_alignmask(geniv) + 1))) {
246	info = kmalloc(ivsize, req->base.flags &
247	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
248	GFP_ATOMIC);
249	if (!info)
250	return -ENOMEM;
251
252	memcpy(info, req->iv, ivsize);
253	}
254
255	aead_request_set_callback(subreq, req->base.flags, compl, data);
256	aead_request_set_crypt(subreq, req->dst, req->dst,
257	req->cryptlen - ivsize, info);
258	aead_request_set_ad(subreq, req->assoclen + ivsize, 0);
259
260	crypto_xor(info, ctx->salt, ivsize);
261	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
262	echainiv_read_iv(info, ivsize);
263
264	err = crypto_aead_encrypt(subreq);
265	echainiv_encrypt_complete2(req, err);
266	return err;
267	}
268
269	static int echainiv_decrypt_compat(struct aead_request *req)
270	{
271	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
272	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
273	struct aead_request *subreq = aead_request_ctx(req);
274	crypto_completion_t compl;
275	void *data;
276	unsigned int ivsize;
277
278	aead_request_set_tfm(subreq, ctx->child);
279
280	compl = req->base.complete;
281	data = req->base.data;
282
283	ivsize = crypto_aead_ivsize(geniv);
284
285	aead_request_set_callback(subreq, req->base.flags, compl, data);
286	aead_request_set_crypt(subreq, req->src, req->dst,
287	req->cryptlen - ivsize, req->iv);
288	aead_request_set_ad(subreq, req->assoclen, ivsize);
289
290	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
291
292	return crypto_aead_decrypt(subreq);
293	}
294
295	static int echainiv_decrypt(struct aead_request *req)
296	{
297	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
298	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
299	struct aead_request *subreq = aead_request_ctx(req);
300	crypto_completion_t compl;
301	void *data;
302	unsigned int ivsize;
303
304	aead_request_set_tfm(subreq, ctx->child);
305
306	compl = req->base.complete;
307	data = req->base.data;
308
309	ivsize = crypto_aead_ivsize(geniv);
310
311	aead_request_set_callback(subreq, req->base.flags, compl, data);
312	aead_request_set_crypt(subreq, req->src, req->dst,
313	req->cryptlen - ivsize, req->iv);
314	aead_request_set_ad(subreq, req->assoclen + ivsize, 0);
315
316	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
317	if (req->src != req->dst)
318	scatterwalk_map_and_copy(req->iv, req->dst,
319	req->assoclen, ivsize, 1);
320
321	return crypto_aead_decrypt(subreq);
322	}
323
324	static int echainiv_encrypt_compat_first(struct aead_request *req)
325	{
326	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
327	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
328	int err = 0;
329
330	spin_lock_bh(&ctx->lock);
331	if (geniv->encrypt != echainiv_encrypt_compat_first)
332	goto unlock;
333
334	geniv->encrypt = echainiv_encrypt_compat;
335	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
336	crypto_aead_ivsize(geniv));
337
338	unlock:
339	spin_unlock_bh(&ctx->lock);
340
341	if (err)
342	return err;
343
344	return echainiv_encrypt_compat(req);
345	}
346
347	static int echainiv_encrypt_first(struct aead_request *req)
348	{
349	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
350	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
351	int err = 0;
352
353	spin_lock_bh(&ctx->lock);
354	if (geniv->encrypt != echainiv_encrypt_first)
355	goto unlock;
356
357	geniv->encrypt = echainiv_encrypt;
358	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
359	crypto_aead_ivsize(geniv));
360
361	unlock:
362	spin_unlock_bh(&ctx->lock);
363
364	if (err)
365	return err;
366
367	return echainiv_encrypt(req);
368	}
369
370	static int echainiv_compat_init(struct crypto_tfm *tfm)
371	{
372	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
373	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
374	int err;
375
376	spin_lock_init(&ctx->lock);
377
378	crypto_aead_set_reqsize(geniv, sizeof(struct echainiv_request_ctx));
379
380	err = aead_geniv_init(tfm);
381
382	ctx->child = geniv->child;
383	geniv->child = geniv;
384
385	return err;
386	}
387
388	static int echainiv_init(struct crypto_tfm *tfm)
389	{
390	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
391	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
392	int err;
393
394	spin_lock_init(&ctx->lock);
395
396	crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));
397
398	ctx->null = crypto_get_default_null_skcipher();
399	err = PTR_ERR(ctx->null);
400	if (IS_ERR(ctx->null))
401	goto out;
402
403	err = aead_geniv_init(tfm);
404	if (err)
405	goto drop_null;
406
407	ctx->child = geniv->child;
408	geniv->child = geniv;
409
410	out:
411	return err;
412
413	drop_null:
414	crypto_put_default_null_skcipher();
415	goto out;
416	}
417
418	static void echainiv_compat_exit(struct crypto_tfm *tfm)
419	{
420	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
421
422	crypto_free_aead(ctx->child);
423	}
424
425	static void echainiv_exit(struct crypto_tfm *tfm)
426	{
427	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
428
429	crypto_free_aead(ctx->child);
430	crypto_put_default_null_skcipher();
431	}
432
1e419c79 HX	433	static int echainiv_aead_create(struct crypto_template *tmpl,
1e419c79 HX	434	struct rtattr **tb)
a10f554f HX	435	{
	436	struct aead_instance *inst;
	437	struct crypto_aead_spawn *spawn;
	438	struct aead_alg *alg;
1e419c79	439	int err;
a10f554f	440
1e419c79	441	inst = aead_geniv_alloc(tmpl, tb, 0, 0);
a10f554f HX	442
a10f554f HX	443	if (IS_ERR(inst))
1e419c79	444	return PTR_ERR(inst);
a10f554f	445
1e419c79	446	err = -EINVAL;
a10f554f HX	447	if (inst->alg.ivsize < sizeof(u64) \|\|
a10f554f HX	448	inst->alg.ivsize & (sizeof(u32) - 1) \|\|
1e419c79 HX	449	inst->alg.ivsize > MAX_IV_SIZE)
1e419c79 HX	450	goto free_inst;
a10f554f HX	451
	452	spawn = aead_instance_ctx(inst);
	453	alg = crypto_spawn_aead_alg(spawn);
	454
	455	inst->alg.setkey = echainiv_setkey;
	456	inst->alg.setauthsize = echainiv_setauthsize;
	457	inst->alg.encrypt = echainiv_encrypt_first;
	458	inst->alg.decrypt = echainiv_decrypt;
	459
	460	inst->alg.base.cra_init = echainiv_init;
	461	inst->alg.base.cra_exit = echainiv_exit;
	462
	463	inst->alg.base.cra_alignmask \|= __alignof__(u32) - 1;
	464	inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx);
	465	inst->alg.base.cra_ctxsize += inst->alg.base.cra_aead.ivsize;
	466
	467	if (alg->base.cra_aead.encrypt) {
	468	inst->alg.encrypt = echainiv_encrypt_compat_first;
	469	inst->alg.decrypt = echainiv_decrypt_compat;
	470
	471	inst->alg.base.cra_init = echainiv_compat_init;
	472	inst->alg.base.cra_exit = echainiv_compat_exit;
	473	}
	474
1e419c79 HX	475	err = aead_register_instance(tmpl, inst);
	476	if (err)
	477	goto free_inst;
	478
a10f554f	479	out:
1e419c79 HX	480	return err;
	481
	482	free_inst:
	483	aead_geniv_free(inst);
	484	goto out;
a10f554f HX	485	}
a10f554f HX	486
1e419c79	487	static int echainiv_create(struct crypto_template tmpl, struct rtattr *tb)
a10f554f	488	{
a10f554f HX	489	int err;
	490
	491	err = crypto_get_default_rng();
	492	if (err)
1e419c79	493	goto out;
a10f554f	494
1e419c79 HX	495	err = echainiv_aead_create(tmpl, tb);
1e419c79 HX	496	if (err)
a10f554f HX	497	goto put_rng;
	498
	499	out:
1e419c79	500	return err;
a10f554f HX	501
	502	put_rng:
	503	crypto_put_default_rng();
	504	goto out;
	505	}
	506
	507	static void echainiv_free(struct crypto_instance *inst)
	508	{
	509	aead_geniv_free(aead_instance(inst));
	510	crypto_put_default_rng();
	511	}
	512
	513	static struct crypto_template echainiv_tmpl = {
	514	.name = "echainiv",
1e419c79	515	.create = echainiv_create,
a10f554f HX	516	.free = echainiv_free,
	517	.module = THIS_MODULE,
	518	};
	519
	520	static int __init echainiv_module_init(void)
	521	{
	522	return crypto_register_template(&echainiv_tmpl);
	523	}
	524
	525	static void __exit echainiv_module_exit(void)
	526	{
	527	crypto_unregister_template(&echainiv_tmpl);
	528	}
	529
	530	module_init(echainiv_module_init);
	531	module_exit(echainiv_module_exit);
	532
	533	MODULE_LICENSE("GPL");
	534	MODULE_DESCRIPTION("Encrypted Chain IV Generator");
	535	MODULE_ALIAS_CRYPTO("echainiv");