crypto/authencesn.c - SHIFTPHONES/mainline/linux - Gitiles

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
  *                 derived from authenc.c
  *
  * Copyright (C) 2010 secunet Security Networks AG
  * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
  */

 #include <crypto/internal/aead.h>
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/authenc.h>
 #include <crypto/null.h>
 #include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/rtnetlink.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>

 struct authenc_esn_instance_ctx {
 	struct crypto_ahash_spawn auth;
 	struct crypto_skcipher_spawn enc;
 };

 struct crypto_authenc_esn_ctx {
 	unsigned int reqoff;
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
 	struct crypto_sync_skcipher *null;
 };

 struct authenc_esn_request_ctx {
 	struct scatterlist src[2];
 	struct scatterlist dst[2];
 	char tail[];
 };

 static void authenc_esn_request_complete(struct aead_request *req, int err)
 {
 	if (err != -EINPROGRESS)
 		aead_request_complete(req, err);
 }

 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
 					  unsigned int authsize)
 {
 	if (authsize > 0 && authsize < 4)
 		return -EINVAL;

 	return 0;
 }

 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
 				     unsigned int keylen)
 {
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct crypto_ahash *auth = ctx->auth;
 	struct crypto_skcipher *enc = ctx->enc;
 	struct crypto_authenc_keys keys;
 	int err = -EINVAL;

 	if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
 		goto out;

 	crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
 	crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
 				     CRYPTO_TFM_REQ_MASK);
 	err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
 	if (err)
 		goto out;

 	crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
 	crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
 					 CRYPTO_TFM_REQ_MASK);
 	err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
 out:
 	memzero_explicit(&keys, sizeof(keys));
 	return err;
 }

 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
 					  unsigned int flags)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 	struct crypto_ahash *auth = ctx->auth;
 	u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
 			     crypto_ahash_alignmask(auth) + 1);
 	unsigned int authsize = crypto_aead_authsize(authenc_esn);
 	unsigned int assoclen = req->assoclen;
 	unsigned int cryptlen = req->cryptlen;
 	struct scatterlist *dst = req->dst;
 	u32 tmp[2];

 	/* Move high-order bits of sequence number back. */
 	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
 	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
 	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

 	scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
 	return 0;
 }

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

 	err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
 	aead_request_complete(req, err);
 }

 static int crypto_authenc_esn_genicv(struct aead_request *req,
 				     unsigned int flags)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct crypto_ahash *auth = ctx->auth;
 	u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
 			     crypto_ahash_alignmask(auth) + 1);
 	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
 	unsigned int authsize = crypto_aead_authsize(authenc_esn);
 	unsigned int assoclen = req->assoclen;
 	unsigned int cryptlen = req->cryptlen;
 	struct scatterlist *dst = req->dst;
 	u32 tmp[2];

 	if (!authsize)
 		return 0;

 	/* Move high-order bits of sequence number to the end. */
 	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
 	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
 	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

 	sg_init_table(areq_ctx->dst, 2);
 	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

 	ahash_request_set_tfm(ahreq, auth);
 	ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
 	ahash_request_set_callback(ahreq, flags,
 				   authenc_esn_geniv_ahash_done, req);

 	return crypto_ahash_digest(ahreq) ?:
 	       crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
 }


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

 	if (!err)
 		err = crypto_authenc_esn_genicv(areq, 0);

 	authenc_esn_request_complete(areq, err);
 }

 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);

 	skcipher_request_set_sync_tfm(skreq, ctx->null);
 	skcipher_request_set_callback(skreq, aead_request_flags(req),
 				      NULL, NULL);
 	skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);

 	return crypto_skcipher_encrypt(skreq);
 }

 static int crypto_authenc_esn_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct skcipher_request *skreq = (void *)(areq_ctx->tail +
 						  ctx->reqoff);
 	struct crypto_skcipher *enc = ctx->enc;
 	unsigned int assoclen = req->assoclen;
 	unsigned int cryptlen = req->cryptlen;
 	struct scatterlist *src, *dst;
 	int err;

 	sg_init_table(areq_ctx->src, 2);
 	src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
 	dst = src;

 	if (req->src != req->dst) {
 		err = crypto_authenc_esn_copy(req, assoclen);
 		if (err)
 			return err;

 		sg_init_table(areq_ctx->dst, 2);
 		dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
 	}

 	skcipher_request_set_tfm(skreq, enc);
 	skcipher_request_set_callback(skreq, aead_request_flags(req),
 				      crypto_authenc_esn_encrypt_done, req);
 	skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);

 	err = crypto_skcipher_encrypt(skreq);
 	if (err)
 		return err;

 	return crypto_authenc_esn_genicv(req, aead_request_flags(req));
 }

 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
 					   unsigned int flags)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	unsigned int authsize = crypto_aead_authsize(authenc_esn);
 	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct skcipher_request *skreq = (void *)(areq_ctx->tail +
 						  ctx->reqoff);
 	struct crypto_ahash *auth = ctx->auth;
 	u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
 			      crypto_ahash_alignmask(auth) + 1);
 	unsigned int cryptlen = req->cryptlen - authsize;
 	unsigned int assoclen = req->assoclen;
 	struct scatterlist *dst = req->dst;
 	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
 	u32 tmp[2];

 	if (!authsize)
 		goto decrypt;

 	/* Move high-order bits of sequence number back. */
 	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
 	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
 	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

 	if (crypto_memneq(ihash, ohash, authsize))
 		return -EBADMSG;

 decrypt:

 	sg_init_table(areq_ctx->dst, 2);
 	dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);

 	skcipher_request_set_tfm(skreq, ctx->enc);
 	skcipher_request_set_callback(skreq, flags,
 				      req->base.complete, req->base.data);
 	skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);

 	return crypto_skcipher_decrypt(skreq);
 }

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

 	err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
 	authenc_esn_request_complete(req, err);
 }

 static int crypto_authenc_esn_decrypt(struct aead_request *req)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
 	unsigned int authsize = crypto_aead_authsize(authenc_esn);
 	struct crypto_ahash *auth = ctx->auth;
 	u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
 			      crypto_ahash_alignmask(auth) + 1);
 	unsigned int assoclen = req->assoclen;
 	unsigned int cryptlen = req->cryptlen;
 	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
 	struct scatterlist *dst = req->dst;
 	u32 tmp[2];
 	int err;

 	cryptlen -= authsize;

 	if (req->src != dst) {
 		err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
 		if (err)
 			return err;
 	}

 	scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
 				 authsize, 0);

 	if (!authsize)
 		goto tail;

 	/* Move high-order bits of sequence number to the end. */
 	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
 	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
 	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

 	sg_init_table(areq_ctx->dst, 2);
 	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

 	ahash_request_set_tfm(ahreq, auth);
 	ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
 	ahash_request_set_callback(ahreq, aead_request_flags(req),
 				   authenc_esn_verify_ahash_done, req);

 	err = crypto_ahash_digest(ahreq);
 	if (err)
 		return err;

 tail:
 	return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
 }

 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
 {
 	struct aead_instance *inst = aead_alg_instance(tfm);
 	struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
 	struct crypto_sync_skcipher *null;
 	int err;

 	auth = crypto_spawn_ahash(&ictx->auth);
 	if (IS_ERR(auth))
 		return PTR_ERR(auth);

 	enc = crypto_spawn_skcipher(&ictx->enc);
 	err = PTR_ERR(enc);
 	if (IS_ERR(enc))
 		goto err_free_ahash;

 	null = crypto_get_default_null_skcipher();
 	err = PTR_ERR(null);
 	if (IS_ERR(null))
 		goto err_free_skcipher;

 	ctx->auth = auth;
 	ctx->enc = enc;
 	ctx->null = null;

 	ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
 			    crypto_ahash_alignmask(auth) + 1);

 	crypto_aead_set_reqsize(
 		tfm,
 		sizeof(struct authenc_esn_request_ctx) +
 		ctx->reqoff +
 		max_t(unsigned int,
 		      crypto_ahash_reqsize(auth) +
 		      sizeof(struct ahash_request),
 		      sizeof(struct skcipher_request) +
 		      crypto_skcipher_reqsize(enc)));

 	return 0;

 err_free_skcipher:
 	crypto_free_skcipher(enc);
 err_free_ahash:
 	crypto_free_ahash(auth);
 	return err;
 }

 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
 {
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);

 	crypto_free_ahash(ctx->auth);
 	crypto_free_skcipher(ctx->enc);
 	crypto_put_default_null_skcipher();
 }

 static void crypto_authenc_esn_free(struct aead_instance *inst)
 {
 	struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);

 	crypto_drop_skcipher(&ctx->enc);
 	crypto_drop_ahash(&ctx->auth);
 	kfree(inst);
 }

 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
 				     struct rtattr **tb)
 {
 	struct crypto_attr_type *algt;
 	u32 mask;
 	struct aead_instance *inst;
 	struct hash_alg_common *auth;
 	struct crypto_alg *auth_base;
 	struct skcipher_alg *enc;
 	struct authenc_esn_instance_ctx *ctx;
 	const char *enc_name;
 	int err;

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

 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 		return -EINVAL;

 	mask = crypto_requires_sync(algt->type, algt->mask);

 	auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
 			      CRYPTO_ALG_TYPE_AHASH_MASK | mask);
 	if (IS_ERR(auth))
 		return PTR_ERR(auth);

 	auth_base = &auth->base;

 	enc_name = crypto_attr_alg_name(tb[2]);
 	err = PTR_ERR(enc_name);
 	if (IS_ERR(enc_name))
 		goto out_put_auth;

 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	err = -ENOMEM;
 	if (!inst)
 		goto out_put_auth;

 	ctx = aead_instance_ctx(inst);

 	err = crypto_init_ahash_spawn(&ctx->auth, auth,
 				      aead_crypto_instance(inst));
 	if (err)
 		goto err_free_inst;

 	err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
 				   enc_name, 0, mask);
 	if (err)
 		goto err_drop_auth;

 	enc = crypto_spawn_skcipher_alg(&ctx->enc);

 	err = -ENAMETOOLONG;
 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 		     "authencesn(%s,%s)", auth_base->cra_name,
 		     enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 		goto err_drop_enc;

 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 		     "authencesn(%s,%s)", auth_base->cra_driver_name,
 		     enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 		goto err_drop_enc;

 	inst->alg.base.cra_flags = (auth_base->cra_flags |
 				    enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
 	inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
 				      auth_base->cra_priority;
 	inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
 	inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
 				       enc->base.cra_alignmask;
 	inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);

 	inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
 	inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
 	inst->alg.maxauthsize = auth->digestsize;

 	inst->alg.init = crypto_authenc_esn_init_tfm;
 	inst->alg.exit = crypto_authenc_esn_exit_tfm;

 	inst->alg.setkey = crypto_authenc_esn_setkey;
 	inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
 	inst->alg.encrypt = crypto_authenc_esn_encrypt;
 	inst->alg.decrypt = crypto_authenc_esn_decrypt;

 	inst->free = crypto_authenc_esn_free,

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

 out:
 	crypto_mod_put(auth_base);
 	return err;

 err_drop_enc:
 	crypto_drop_skcipher(&ctx->enc);
 err_drop_auth:
 	crypto_drop_ahash(&ctx->auth);
 err_free_inst:
 	kfree(inst);
 out_put_auth:
 	goto out;
 }

 static struct crypto_template crypto_authenc_esn_tmpl = {
 	.name = "authencesn",
 	.create = crypto_authenc_esn_create,
 	.module = THIS_MODULE,
 };

 static int __init crypto_authenc_esn_module_init(void)
 {
 	return crypto_register_template(&crypto_authenc_esn_tmpl);
 }

 static void __exit crypto_authenc_esn_module_exit(void)
 {
 	crypto_unregister_template(&crypto_authenc_esn_tmpl);
 }

 subsys_initcall(crypto_authenc_esn_module_init);
 module_exit(crypto_authenc_esn_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
 MODULE_ALIAS_CRYPTO("authencesn");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
	* derived from authenc.c
	*
	* Copyright (C) 2010 secunet Security Networks AG
	* Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
	* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
	*/

	#include <crypto/internal/aead.h>
	#include <crypto/internal/hash.h>
	#include <crypto/internal/skcipher.h>
	#include <crypto/authenc.h>
	#include <crypto/null.h>
	#include <crypto/scatterwalk.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/rtnetlink.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>

	struct authenc_esn_instance_ctx {
	struct crypto_ahash_spawn auth;
	struct crypto_skcipher_spawn enc;
	};

	struct crypto_authenc_esn_ctx {
	unsigned int reqoff;
	struct crypto_ahash *auth;
	struct crypto_skcipher *enc;
	struct crypto_sync_skcipher *null;
	};

	struct authenc_esn_request_ctx {
	struct scatterlist src[2];
	struct scatterlist dst[2];
	char tail[];
	};

	static void authenc_esn_request_complete(struct aead_request *req, int err)
	{
	if (err != -EINPROGRESS)
	aead_request_complete(req, err);
	}

	static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
	unsigned int authsize)
	{
	if (authsize > 0 && authsize < 4)
	return -EINVAL;

	return 0;
	}

	static int crypto_authenc_esn_setkey(struct crypto_aead authenc_esn, const u8 key,
	unsigned int keylen)
	{
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	struct crypto_skcipher *enc = ctx->enc;
	struct crypto_authenc_keys keys;
	int err = -EINVAL;

	if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
	goto out;

	crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
	crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
	CRYPTO_TFM_REQ_MASK);
	err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
	if (err)
	goto out;

	crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
	CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
	out:
	memzero_explicit(&keys, sizeof(keys));
	return err;
	}

	static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
	unsigned int flags)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_ahash *auth = ctx->auth;
	u8 hash = PTR_ALIGN((u8 )areq_ctx->tail,
	crypto_ahash_alignmask(auth) + 1);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist *dst = req->dst;
	u32 tmp[2];

	/* Move high-order bits of sequence number back. */
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

	scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
	return 0;
	}

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

	err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
	aead_request_complete(req, err);
	}

	static int crypto_authenc_esn_genicv(struct aead_request *req,
	unsigned int flags)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	u8 hash = PTR_ALIGN((u8 )areq_ctx->tail,
	crypto_ahash_alignmask(auth) + 1);
	struct ahash_request ahreq = (void )(areq_ctx->tail + ctx->reqoff);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist *dst = req->dst;
	u32 tmp[2];

	if (!authsize)
	return 0;

	/* Move high-order bits of sequence number to the end. */
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

	ahash_request_set_tfm(ahreq, auth);
	ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
	ahash_request_set_callback(ahreq, flags,
	authenc_esn_geniv_ahash_done, req);

	return crypto_ahash_digest(ahreq) ?:
	crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
	}


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

	if (!err)
	err = crypto_authenc_esn_genicv(areq, 0);

	authenc_esn_request_complete(areq, err);
	}

	static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);

	skcipher_request_set_sync_tfm(skreq, ctx->null);
	skcipher_request_set_callback(skreq, aead_request_flags(req),
	NULL, NULL);
	skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);

	return crypto_skcipher_encrypt(skreq);
	}

	static int crypto_authenc_esn_encrypt(struct aead_request *req)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct skcipher_request skreq = (void )(areq_ctx->tail +
	ctx->reqoff);
	struct crypto_skcipher *enc = ctx->enc;
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	struct scatterlist src, dst;
	int err;

	sg_init_table(areq_ctx->src, 2);
	src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
	dst = src;

	if (req->src != req->dst) {
	err = crypto_authenc_esn_copy(req, assoclen);
	if (err)
	return err;

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
	}

	skcipher_request_set_tfm(skreq, enc);
	skcipher_request_set_callback(skreq, aead_request_flags(req),
	crypto_authenc_esn_encrypt_done, req);
	skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);

	err = crypto_skcipher_encrypt(skreq);
	if (err)
	return err;

	return crypto_authenc_esn_genicv(req, aead_request_flags(req));
	}

	static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
	unsigned int flags)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct skcipher_request skreq = (void )(areq_ctx->tail +
	ctx->reqoff);
	struct crypto_ahash *auth = ctx->auth;
	u8 ohash = PTR_ALIGN((u8 )areq_ctx->tail,
	crypto_ahash_alignmask(auth) + 1);
	unsigned int cryptlen = req->cryptlen - authsize;
	unsigned int assoclen = req->assoclen;
	struct scatterlist *dst = req->dst;
	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
	u32 tmp[2];

	if (!authsize)
	goto decrypt;

	/* Move high-order bits of sequence number back. */
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);

	if (crypto_memneq(ihash, ohash, authsize))
	return -EBADMSG;

	decrypt:

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);

	skcipher_request_set_tfm(skreq, ctx->enc);
	skcipher_request_set_callback(skreq, flags,
	req->base.complete, req->base.data);
	skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);

	return crypto_skcipher_decrypt(skreq);
	}

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

	err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
	authenc_esn_request_complete(req, err);
	}

	static int crypto_authenc_esn_decrypt(struct aead_request *req)
	{
	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
	struct ahash_request ahreq = (void )(areq_ctx->tail + ctx->reqoff);
	unsigned int authsize = crypto_aead_authsize(authenc_esn);
	struct crypto_ahash *auth = ctx->auth;
	u8 ohash = PTR_ALIGN((u8 )areq_ctx->tail,
	crypto_ahash_alignmask(auth) + 1);
	unsigned int assoclen = req->assoclen;
	unsigned int cryptlen = req->cryptlen;
	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
	struct scatterlist *dst = req->dst;
	u32 tmp[2];
	int err;

	cryptlen -= authsize;

	if (req->src != dst) {
	err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
	if (err)
	return err;
	}

	scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
	authsize, 0);

	if (!authsize)
	goto tail;

	/* Move high-order bits of sequence number to the end. */
	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);

	sg_init_table(areq_ctx->dst, 2);
	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);

	ahash_request_set_tfm(ahreq, auth);
	ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
	ahash_request_set_callback(ahreq, aead_request_flags(req),
	authenc_esn_verify_ahash_done, req);

	err = crypto_ahash_digest(ahreq);
	if (err)
	return err;

	tail:
	return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
	}

	static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
	{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_ahash *auth;
	struct crypto_skcipher *enc;
	struct crypto_sync_skcipher *null;
	int err;

	auth = crypto_spawn_ahash(&ictx->auth);
	if (IS_ERR(auth))
	return PTR_ERR(auth);

	enc = crypto_spawn_skcipher(&ictx->enc);
	err = PTR_ERR(enc);
	if (IS_ERR(enc))
	goto err_free_ahash;

	null = crypto_get_default_null_skcipher();
	err = PTR_ERR(null);
	if (IS_ERR(null))
	goto err_free_skcipher;

	ctx->auth = auth;
	ctx->enc = enc;
	ctx->null = null;

	ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
	crypto_ahash_alignmask(auth) + 1);

	crypto_aead_set_reqsize(
	tfm,
	sizeof(struct authenc_esn_request_ctx) +
	ctx->reqoff +
	max_t(unsigned int,
	crypto_ahash_reqsize(auth) +
	sizeof(struct ahash_request),
	sizeof(struct skcipher_request) +
	crypto_skcipher_reqsize(enc)));

	return 0;

	err_free_skcipher:
	crypto_free_skcipher(enc);
	err_free_ahash:
	crypto_free_ahash(auth);
	return err;
	}

	static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
	{
	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_ahash(ctx->auth);
	crypto_free_skcipher(ctx->enc);
	crypto_put_default_null_skcipher();
	}

	static void crypto_authenc_esn_free(struct aead_instance *inst)
	{
	struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);

	crypto_drop_skcipher(&ctx->enc);
	crypto_drop_ahash(&ctx->auth);
	kfree(inst);
	}

	static int crypto_authenc_esn_create(struct crypto_template *tmpl,
	struct rtattr **tb)
	{
	struct crypto_attr_type *algt;
	u32 mask;
	struct aead_instance *inst;
	struct hash_alg_common *auth;
	struct crypto_alg *auth_base;
	struct skcipher_alg *enc;
	struct authenc_esn_instance_ctx *ctx;
	const char *enc_name;
	int err;

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

	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
	return -EINVAL;

	mask = crypto_requires_sync(algt->type, algt->mask);

	auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
	CRYPTO_ALG_TYPE_AHASH_MASK \| mask);
	if (IS_ERR(auth))
	return PTR_ERR(auth);

	auth_base = &auth->base;

	enc_name = crypto_attr_alg_name(tb[2]);
	err = PTR_ERR(enc_name);
	if (IS_ERR(enc_name))
	goto out_put_auth;

	inst = kzalloc(sizeof(inst) + sizeof(ctx), GFP_KERNEL);
	err = -ENOMEM;
	if (!inst)
	goto out_put_auth;

	ctx = aead_instance_ctx(inst);

	err = crypto_init_ahash_spawn(&ctx->auth, auth,
	aead_crypto_instance(inst));
	if (err)
	goto err_free_inst;

	err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
	enc_name, 0, mask);
	if (err)
	goto err_drop_auth;

	enc = crypto_spawn_skcipher_alg(&ctx->enc);

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
	"authencesn(%s,%s)", auth_base->cra_name,
	enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
	goto err_drop_enc;

	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
	"authencesn(%s,%s)", auth_base->cra_driver_name,
	enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
	goto err_drop_enc;

	inst->alg.base.cra_flags = (auth_base->cra_flags \|
	enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
	auth_base->cra_priority;
	inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
	inst->alg.base.cra_alignmask = auth_base->cra_alignmask \|
	enc->base.cra_alignmask;
	inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);

	inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
	inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
	inst->alg.maxauthsize = auth->digestsize;

	inst->alg.init = crypto_authenc_esn_init_tfm;
	inst->alg.exit = crypto_authenc_esn_exit_tfm;

	inst->alg.setkey = crypto_authenc_esn_setkey;
	inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
	inst->alg.encrypt = crypto_authenc_esn_encrypt;
	inst->alg.decrypt = crypto_authenc_esn_decrypt;

	inst->free = crypto_authenc_esn_free,

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

	out:
	crypto_mod_put(auth_base);
	return err;

	err_drop_enc:
	crypto_drop_skcipher(&ctx->enc);
	err_drop_auth:
	crypto_drop_ahash(&ctx->auth);
	err_free_inst:
	kfree(inst);
	out_put_auth:
	goto out;
	}

	static struct crypto_template crypto_authenc_esn_tmpl = {
	.name = "authencesn",
	.create = crypto_authenc_esn_create,
	.module = THIS_MODULE,
	};

	static int __init crypto_authenc_esn_module_init(void)
	{
	return crypto_register_template(&crypto_authenc_esn_tmpl);
	}

	static void __exit crypto_authenc_esn_module_exit(void)
	{
	crypto_unregister_template(&crypto_authenc_esn_tmpl);
	}

	subsys_initcall(crypto_authenc_esn_module_init);
	module_exit(crypto_authenc_esn_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
	MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
	MODULE_ALIAS_CRYPTO("authencesn");