crypto: authencesn - Add algorithm to handle IPsec extended sequence numbers

ESP with separate encryption/authentication algorithms needs a special
treatment for the associated data. This patch add a new algorithm that
handles esp with extended sequence numbers.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 835 insertions, 0 deletions

diff --git a/crypto/authencesn.c b/crypto/authencesn.c
new file mode 100644
index 0000000..136b68b
--- /dev/null
+++ b/crypto/authencesn.c
@@ -0,0 +1,835 @@
+/*
+ * 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>
+ *
+ * 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/aead.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/authenc.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_ablkcipher *enc;
+};
+
+struct authenc_esn_request_ctx {
+	unsigned int cryptlen;
+	unsigned int headlen;
+	unsigned int trailen;
+	struct scatterlist *sg;
+	struct scatterlist hsg[2];
+	struct scatterlist tsg[1];
+	struct scatterlist cipher[2];
+	crypto_completion_t complete;
+	crypto_completion_t update_complete;
+	crypto_completion_t update_complete2;
+	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_setkey(struct crypto_aead *authenc_esn, const u8 *key,
+				     unsigned int keylen)
+{
+	unsigned int authkeylen;
+	unsigned int enckeylen;
+	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
+	struct crypto_ahash *auth = ctx->auth;
+	struct crypto_ablkcipher *enc = ctx->enc;
+	struct rtattr *rta = (void *)key;
+	struct crypto_authenc_key_param *param;
+	int err = -EINVAL;
+
+	if (!RTA_OK(rta, keylen))
+		goto badkey;
+	if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
+		goto badkey;
+	if (RTA_PAYLOAD(rta) < sizeof(*param))
+		goto badkey;
+
+	param = RTA_DATA(rta);
+	enckeylen = be32_to_cpu(param->enckeylen);
+
+	key += RTA_ALIGN(rta->rta_len);
+	keylen -= RTA_ALIGN(rta->rta_len);
+
+	if (keylen < enckeylen)
+		goto badkey;
+
+	authkeylen = keylen - enckeylen;
+
+	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, key, authkeylen);
+	crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
+					   CRYPTO_TFM_RES_MASK);
+
+	if (err)
+		goto out;
+
+	crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
+	crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
+					 CRYPTO_TFM_REQ_MASK);
+	err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen);
+	crypto_aead_set_flags(authenc_esn, crypto_ablkcipher_get_flags(enc) &
+					   CRYPTO_TFM_RES_MASK);
+
+out:
+	return err;
+
+badkey:
+	crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
+	goto out;
+}
+
+static void authenc_esn_geniv_ahash_update_done(struct crypto_async_request *areq,
+						int err)
+{
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->sg, ahreq->result,
+				areq_ctx->cryptlen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) &
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->update_complete2, req);
+
+	err = crypto_ahash_update(ahreq);
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->tsg, ahreq->result,
+				areq_ctx->trailen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) &
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->complete, req);
+
+	err = crypto_ahash_finup(ahreq);
+	if (err)
+		goto out;
+
+	scatterwalk_map_and_copy(ahreq->result, areq_ctx->sg,
+				 areq_ctx->cryptlen,
+				 crypto_aead_authsize(authenc_esn), 1);
+
+out:
+	authenc_esn_request_complete(req, err);
+}
+
+static void authenc_esn_geniv_ahash_update_done2(struct crypto_async_request *areq,
+						 int err)
+{
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->tsg, ahreq->result,
+				areq_ctx->trailen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) &
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->complete, req);
+
+	err = crypto_ahash_finup(ahreq);
+	if (err)
+		goto out;
+
+	scatterwalk_map_and_copy(ahreq->result, areq_ctx->sg,
+				 areq_ctx->cryptlen,
+				 crypto_aead_authsize(authenc_esn), 1);
+
+out:
+	authenc_esn_request_complete(req, err);
+}
+
+
+static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
+					 int err)
+{
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+
+	if (err)
+		goto out;
+
+	scatterwalk_map_and_copy(ahreq->result, areq_ctx->sg,
+				 areq_ctx->cryptlen,
+				 crypto_aead_authsize(authenc_esn), 1);
+
+out:
+	aead_request_complete(req, err);
+}
+
+
+static void authenc_esn_verify_ahash_update_done(struct crypto_async_request *areq,
+						 int err)
+{
+	u8 *ihash;
+	unsigned int authsize;
+	struct ablkcipher_request *abreq;
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+	unsigned int cryptlen = req->cryptlen;
+
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->sg, ahreq->result,
+				areq_ctx->cryptlen);
+
+	ahash_request_set_callback(ahreq,
+				   aead_request_flags(req) &
+				   CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->update_complete2, req);
+
+	err = crypto_ahash_update(ahreq);
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->tsg, ahreq->result,
+				areq_ctx->trailen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) &
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->complete, req);
+
+	err = crypto_ahash_finup(ahreq);
+	if (err)
+		goto out;
+
+	authsize = crypto_aead_authsize(authenc_esn);
+	cryptlen -= authsize;
+	ihash = ahreq->result + authsize;
+	scatterwalk_map_and_copy(ihash, areq_ctx->sg, areq_ctx->cryptlen,
+				 authsize, 0);
+
+	err = memcmp(ihash, ahreq->result, authsize) ? -EBADMSG : 0;
+	if (err)
+		goto out;
+
+	abreq = aead_request_ctx(req);
+	ablkcipher_request_set_tfm(abreq, ctx->enc);
+	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
+					req->base.complete, req->base.data);
+	ablkcipher_request_set_crypt(abreq, req->src, req->dst,
+				     cryptlen, req->iv);
+
+	err = crypto_ablkcipher_decrypt(abreq);
+
+out:
+	authenc_esn_request_complete(req, err);
+}
+
+static void authenc_esn_verify_ahash_update_done2(struct crypto_async_request *areq,
+						  int err)
+{
+	u8 *ihash;
+	unsigned int authsize;
+	struct ablkcipher_request *abreq;
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+	unsigned int cryptlen = req->cryptlen;
+
+	if (err)
+		goto out;
+
+	ahash_request_set_crypt(ahreq, areq_ctx->tsg, ahreq->result,
+				areq_ctx->trailen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) &
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
+				   areq_ctx->complete, req);
+
+	err = crypto_ahash_finup(ahreq);
+	if (err)
+		goto out;
+
+	authsize = crypto_aead_authsize(authenc_esn);
+	cryptlen -= authsize;
+	ihash = ahreq->result + authsize;
+	scatterwalk_map_and_copy(ihash, areq_ctx->sg, areq_ctx->cryptlen,
+				 authsize, 0);
+
+	err = memcmp(ihash, ahreq->result, authsize) ? -EBADMSG : 0;
+	if (err)
+		goto out;
+
+	abreq = aead_request_ctx(req);
+	ablkcipher_request_set_tfm(abreq, ctx->enc);
+	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
+					req->base.complete, req->base.data);
+	ablkcipher_request_set_crypt(abreq, req->src, req->dst,
+				     cryptlen, req->iv);
+
+	err = crypto_ablkcipher_decrypt(abreq);
+
+out:
+	authenc_esn_request_complete(req, err);
+}
+
+
+static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
+					  int err)
+{
+	u8 *ihash;
+	unsigned int authsize;
+	struct ablkcipher_request *abreq;
+	struct aead_request *req = areq->data;
+	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 ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+	unsigned int cryptlen = req->cryptlen;
+
+	if (err)
+		goto out;
+
+	authsize = crypto_aead_authsize(authenc_esn);
+	cryptlen -= authsize;
+	ihash = ahreq->result + authsize;
+	scatterwalk_map_and_copy(ihash, areq_ctx->sg, areq_ctx->cryptlen,
+				 authsize, 0);
+
+	err = memcmp(ihash, ahreq->result, authsize) ? -EBADMSG : 0;
+	if (err)
+		goto out;
+
+	abreq = aead_request_ctx(req);
+	ablkcipher_request_set_tfm(abreq, ctx->enc);
+	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
+					req->base.complete, req->base.data);
+	ablkcipher_request_set_crypt(abreq, req->src, req->dst,
+				     cryptlen, req->iv);
+
+	err = crypto_ablkcipher_decrypt(abreq);
+
+out:
+	authenc_esn_request_complete(req, err);
+}
+
+static u8 *crypto_authenc_esn_ahash(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 crypto_ahash *auth = ctx->auth;
+	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
+	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
+	u8 *hash = areq_ctx->tail;
+	int err;
+
+	hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
+			    crypto_ahash_alignmask(auth) + 1);
+
+	ahash_request_set_tfm(ahreq, auth);
+
+	err = crypto_ahash_init(ahreq);
+	if (err)
+		return ERR_PTR(err);
+
+	ahash_request_set_crypt(ahreq, areq_ctx->hsg, hash, areq_ctx->headlen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) & flags,
+				   areq_ctx->update_complete, req);
+
+	err = crypto_ahash_update(ahreq);
+	if (err)
+		return ERR_PTR(err);
+
+	ahash_request_set_crypt(ahreq, areq_ctx->sg, hash, areq_ctx->cryptlen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) & flags,
+				   areq_ctx->update_complete2, req);
+
+	err = crypto_ahash_update(ahreq);
+	if (err)
+		return ERR_PTR(err);
+
+	ahash_request_set_crypt(ahreq, areq_ctx->tsg, hash,
+				areq_ctx->trailen);
+	ahash_request_set_callback(ahreq, aead_request_flags(req) & flags,
+				   areq_ctx->complete, req);
+
+	err = crypto_ahash_finup(ahreq);
+	if (err)
+		return ERR_PTR(err);
+
+	return hash;
+}
+
+static int crypto_authenc_esn_genicv(struct aead_request *req, u8 *iv,
+				     unsigned int flags)
+{
+	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
+	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
+	struct scatterlist *dst = req->dst;
+	struct scatterlist *assoc = req->assoc;
+	struct scatterlist *cipher = areq_ctx->cipher;
+	struct scatterlist *hsg = areq_ctx->hsg;
+	struct scatterlist *tsg = areq_ctx->tsg;
+	struct scatterlist *assoc1;
+	struct scatterlist *assoc2;
+	unsigned int ivsize = crypto_aead_ivsize(authenc_esn);
+	unsigned int cryptlen = req->cryptlen;
+	struct page *dstp;
+	u8 *vdst;
+	u8 *hash;
+
+	dstp = sg_page(dst);
+	vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset;
+
+	if (ivsize) {
+		sg_init_table(cipher, 2);
+		sg_set_buf(cipher, iv, ivsize);
+		scatterwalk_crypto_chain(cipher, dst, vdst == iv + ivsize, 2);
+		dst = cipher;
+		cryptlen += ivsize;
+	}
+
+	if (sg_is_last(assoc))
+		return -EINVAL;
+
+	assoc1 = assoc + 1;
+	if (sg_is_last(assoc1))
+		return -EINVAL;
+
+	assoc2 = assoc + 2;
+	if (!sg_is_last(assoc2))
+		return -EINVAL;
+
+	sg_init_table(hsg, 2);
+	sg_set_page(hsg, sg_page(assoc), assoc->length, assoc->offset);
+	sg_set_page(hsg + 1, sg_page(assoc2), assoc2->length, assoc2->offset);
+
+	sg_init_table(tsg, 1);
+	sg_set_page(tsg, sg_page(assoc1), assoc1->length, assoc1->offset);
+
+	areq_ctx->cryptlen = cryptlen;
+	areq_ctx->headlen = assoc->length + assoc2->length;
+	areq_ctx->trailen = assoc1->length;
+	areq_ctx->sg = dst;
+
+	areq_ctx->complete = authenc_esn_geniv_ahash_done;
+	areq_ctx->update_complete = authenc_esn_geniv_ahash_update_done;
+	areq_ctx->update_complete2 = authenc_esn_geniv_ahash_update_done2;
+
+	hash = crypto_authenc_esn_ahash(req, flags);
+	if (IS_ERR(hash))
+		return PTR_ERR(hash);
+
+	scatterwalk_map_and_copy(hash, dst, cryptlen,
+				 crypto_aead_authsize(authenc_esn), 1);
+	return 0;
+}
+
+
+static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
+					    int err)
+{
+	struct aead_request *areq = req->data;
+
+	if (!err) {
+		struct crypto_aead *authenc_esn = crypto_aead_reqtfm(areq);
+		struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
+		struct ablkcipher_request *abreq = aead_request_ctx(areq);
+		u8 *iv = (u8 *)(abreq + 1) +
+			 crypto_ablkcipher_reqsize(ctx->enc);
+
+		err = crypto_authenc_esn_genicv(areq, iv, 0);
+	}
+
+	authenc_esn_request_complete(areq, err);
+}
+
+static int crypto_authenc_esn_encrypt(struct aead_request *req)
+{
+	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_ablkcipher *enc = ctx->enc;
+	struct scatterlist *dst = req->dst;
+	unsigned int cryptlen = req->cryptlen;
+	struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
+						    + ctx->reqoff);
+	u8 *iv = (u8 *)abreq - crypto_ablkcipher_ivsize(enc);
+	int err;
+
+	ablkcipher_request_set_tfm(abreq, enc);
+	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
+					crypto_authenc_esn_encrypt_done, req);
+	ablkcipher_request_set_crypt(abreq, req->src, dst, cryptlen, req->iv);
+
+	memcpy(iv, req->iv, crypto_aead_ivsize(authenc_esn));
+
+	err = crypto_ablkcipher_encrypt(abreq);
+	if (err)
+		return err;
+
+	return crypto_authenc_esn_genicv(req, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
+}
+
+static void crypto_authenc_esn_givencrypt_done(struct crypto_async_request *req,
+					       int err)
+{
+	struct aead_request *areq = req->data;
+
+	if (!err) {
+		struct skcipher_givcrypt_request *greq = aead_request_ctx(areq);
+
+		err = crypto_authenc_esn_genicv(areq, greq->giv, 0);
+	}
+
+	authenc_esn_request_complete(areq, err);
+}
+
+static int crypto_authenc_esn_givencrypt(struct aead_givcrypt_request *req)
+{
+	struct crypto_aead *authenc_esn = aead_givcrypt_reqtfm(req);
+	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
+	struct aead_request *areq = &req->areq;
+	struct skcipher_givcrypt_request *greq = aead_request_ctx(areq);
+	u8 *iv = req->giv;
+	int err;
+
+	skcipher_givcrypt_set_tfm(greq, ctx->enc);
+	skcipher_givcrypt_set_callback(greq, aead_request_flags(areq),
+				       crypto_authenc_esn_givencrypt_done, areq);
+	skcipher_givcrypt_set_crypt(greq, areq->src, areq->dst, areq->cryptlen,
+				    areq->iv);
+	skcipher_givcrypt_set_giv(greq, iv, req->seq);
+
+	err = crypto_skcipher_givencrypt(greq);
+	if (err)
+		return err;
+
+	return crypto_authenc_esn_genicv(areq, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
+}
+
+static int crypto_authenc_esn_verify(struct aead_request *req)
+{
+	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
+	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
+	u8 *ohash;
+	u8 *ihash;
+	unsigned int authsize;
+
+	areq_ctx->complete = authenc_esn_verify_ahash_done;
+	areq_ctx->update_complete = authenc_esn_verify_ahash_update_done;
+
+	ohash = crypto_authenc_esn_ahash(req, CRYPTO_TFM_REQ_MAY_SLEEP);
+	if (IS_ERR(ohash))
+		return PTR_ERR(ohash);
+
+	authsize = crypto_aead_authsize(authenc_esn);
+	ihash = ohash + authsize;
+	scatterwalk_map_and_copy(ihash, areq_ctx->sg, areq_ctx->cryptlen,
+				 authsize, 0);
+	return memcmp(ihash, ohash, authsize) ? -EBADMSG : 0;
+}
+
+static int crypto_authenc_esn_iverify(struct aead_request *req, u8 *iv,
+				      unsigned int cryptlen)
+{
+	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
+	struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
+	struct scatterlist *src = req->src;
+	struct scatterlist *assoc = req->assoc;
+	struct scatterlist *cipher = areq_ctx->cipher;
+	struct scatterlist *hsg = areq_ctx->hsg;
+	struct scatterlist *tsg = areq_ctx->tsg;
+	struct scatterlist *assoc1;
+	struct scatterlist *assoc2;
+	unsigned int ivsize = crypto_aead_ivsize(authenc_esn);
+	struct page *srcp;
+	u8 *vsrc;
+
+	srcp = sg_page(src);
+	vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset;
+
+	if (ivsize) {
+		sg_init_table(cipher, 2);
+		sg_set_buf(cipher, iv, ivsize);
+		scatterwalk_crypto_chain(cipher, src, vsrc == iv + ivsize, 2);
+		src = cipher;
+		cryptlen += ivsize;
+	}
+
+	if (sg_is_last(assoc))
+		return -EINVAL;
+
+	assoc1 = assoc + 1;
+	if (sg_is_last(assoc1))
+		return -EINVAL;
+
+	assoc2 = assoc + 2;
+	if (!sg_is_last(assoc2))
+		return -EINVAL;
+
+	sg_init_table(hsg, 2);
+	sg_set_page(hsg, sg_page(assoc), assoc->length, assoc->offset);
+	sg_set_page(hsg + 1, sg_page(assoc2), assoc2->length, assoc2->offset);
+
+	sg_init_table(tsg, 1);
+	sg_set_page(tsg, sg_page(assoc1), assoc1->length, assoc1->offset);
+
+	areq_ctx->cryptlen = cryptlen;
+	areq_ctx->headlen = assoc->length + assoc2->length;
+	areq_ctx->trailen = assoc1->length;
+	areq_ctx->sg = src;
+
+	areq_ctx->complete = authenc_esn_verify_ahash_done;
+	areq_ctx->update_complete = authenc_esn_verify_ahash_update_done;
+	areq_ctx->update_complete2 = authenc_esn_verify_ahash_update_done2;
+
+	return crypto_authenc_esn_verify(req);
+}
+
+static int crypto_authenc_esn_decrypt(struct aead_request *req)
+{
+	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
+	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
+	struct ablkcipher_request *abreq = aead_request_ctx(req);
+	unsigned int cryptlen = req->cryptlen;
+	unsigned int authsize = crypto_aead_authsize(authenc_esn);
+	u8 *iv = req->iv;
+	int err;
+
+	if (cryptlen < authsize)
+		return -EINVAL;
+	cryptlen -= authsize;
+
+	err = crypto_authenc_esn_iverify(req, iv, cryptlen);
+	if (err)
+		return err;
+
+	ablkcipher_request_set_tfm(abreq, ctx->enc);
+	ablkcipher_request_set_callback(abreq, aead_request_flags(req),
+					req->base.complete, req->base.data);
+	ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, iv);
+
+	return crypto_ablkcipher_decrypt(abreq);
+}
+
+static int crypto_authenc_esn_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
+	struct authenc_esn_instance_ctx *ictx = crypto_instance_ctx(inst);
+	struct crypto_authenc_esn_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct crypto_ahash *auth;
+	struct crypto_ablkcipher *enc;
+	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;
+
+	ctx->auth = auth;
+	ctx->enc = enc;
+
+	ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth) +
+			    crypto_ahash_alignmask(auth),
+			    crypto_ahash_alignmask(auth) + 1) +
+		      crypto_ablkcipher_ivsize(enc);
+
+	tfm->crt_aead.reqsize = sizeof(struct authenc_esn_request_ctx) +
+				ctx->reqoff +
+				max_t(unsigned int,
+				crypto_ahash_reqsize(auth) +
+				sizeof(struct ahash_request),
+				sizeof(struct skcipher_givcrypt_request) +
+				crypto_ablkcipher_reqsize(enc));
+
+	return 0;
+
+err_free_ahash:
+	crypto_free_ahash(auth);
+	return err;
+}
+
+static void crypto_authenc_esn_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_authenc_esn_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	crypto_free_ahash(ctx->auth);
+	crypto_free_ablkcipher(ctx->enc);
+}
+
+static struct crypto_instance *crypto_authenc_esn_alloc(struct rtattr **tb)
+{
+	struct crypto_attr_type *algt;
+	struct crypto_instance *inst;
+	struct hash_alg_common *auth;
+	struct crypto_alg *auth_base;
+	struct crypto_alg *enc;
+	struct authenc_esn_instance_ctx *ctx;
+	const char *enc_name;
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	err = PTR_ERR(algt);
+	if (IS_ERR(algt))
+		return ERR_PTR(err);
+
+	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
+		return ERR_PTR(-EINVAL);
+
+	auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
+			       CRYPTO_ALG_TYPE_AHASH_MASK);
+	if (IS_ERR(auth))
+		return ERR_CAST(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 = crypto_instance_ctx(inst);
+
+	err = crypto_init_ahash_spawn(&ctx->auth, auth, inst);
+	if (err)
+		goto err_free_inst;
+
+	crypto_set_skcipher_spawn(&ctx->enc, inst);
+	err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
+				   crypto_requires_sync(algt->type,
+							algt->mask));
+	if (err)
+		goto err_drop_auth;
+
+	enc = crypto_skcipher_spawn_alg(&ctx->enc);
+
+	err = -ENAMETOOLONG;
+	if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
+		     "authencesn(%s,%s)", auth_base->cra_name, enc->cra_name) >=
+	    CRYPTO_MAX_ALG_NAME)
+		goto err_drop_enc;
+
+	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+		     "authencesn(%s,%s)", auth_base->cra_driver_name,
+		     enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+		goto err_drop_enc;
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
+	inst->alg.cra_flags |= enc->cra_flags & CRYPTO_ALG_ASYNC;
+	inst->alg.cra_priority = enc->cra_priority *
+				 10 + auth_base->cra_priority;
+	inst->alg.cra_blocksize = enc->cra_blocksize;
+	inst->alg.cra_alignmask = auth_base->cra_alignmask | enc->cra_alignmask;
+	inst->alg.cra_type = &crypto_aead_type;
+
+	inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize;
+	inst->alg.cra_aead.maxauthsize = auth->digestsize;
+
+	inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
+
+	inst->alg.cra_init = crypto_authenc_esn_init_tfm;
+	inst->alg.cra_exit = crypto_authenc_esn_exit_tfm;
+
+	inst->alg.cra_aead.setkey = crypto_authenc_esn_setkey;
+	inst->alg.cra_aead.encrypt = crypto_authenc_esn_encrypt;
+	inst->alg.cra_aead.decrypt = crypto_authenc_esn_decrypt;
+	inst->alg.cra_aead.givencrypt = crypto_authenc_esn_givencrypt;
+
+out:
+	crypto_mod_put(auth_base);
+	return inst;
+
+err_drop_enc:
+	crypto_drop_skcipher(&ctx->enc);
+err_drop_auth:
+	crypto_drop_ahash(&ctx->auth);
+err_free_inst:
+	kfree(inst);
+out_put_auth:
+	inst = ERR_PTR(err);
+	goto out;
+}
+
+static void crypto_authenc_esn_free(struct crypto_instance *inst)
+{
+	struct authenc_esn_instance_ctx *ctx = crypto_instance_ctx(inst);
+
+	crypto_drop_skcipher(&ctx->enc);
+	crypto_drop_ahash(&ctx->auth);
+	kfree(inst);
+}
+
+static struct crypto_template crypto_authenc_esn_tmpl = {
+	.name = "authencesn",
+	.alloc = crypto_authenc_esn_alloc,
+	.free = crypto_authenc_esn_free,
+	.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);
+}
+
+module_init(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");