text: /*
   * GCM: Galois/Counter Mode.
   *
   * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   */
  
  #include <crypto/gf128mul.h>
  #include <crypto/internal/aead.h>
  #include <crypto/internal/skcipher.h>
  #include <crypto/internal/hash.h>
  #include <crypto/null.h>
  #include <crypto/scatterwalk.h>
  #include <crypto/hash.h>
  #include "internal.h"
  #include <linux/completion.h>
  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  
  struct gcm_instance_ctx {
  	struct crypto_skcipher_spawn ctr;
  	struct crypto_ahash_spawn ghash;
  };
  
  struct crypto_gcm_ctx {
  	struct crypto_skcipher *ctr;
  	struct crypto_ahash *ghash;
  };
  
  struct crypto_rfc4106_ctx {
  	struct crypto_aead *child;
  	u8 nonce[4];
  };
  
  struct crypto_rfc4106_req_ctx {
  	struct scatterlist src[3];
  	struct scatterlist dst[3];
  	struct aead_request subreq;
  };
  
  struct crypto_rfc4543_instance_ctx {
  	struct crypto_aead_spawn aead;
  };
  
  struct crypto_rfc4543_ctx {
  	struct crypto_aead *child;
  	struct crypto_skcipher *null;
  	u8 nonce[4];
  };
  
  struct crypto_rfc4543_req_ctx {
  	struct aead_request subreq;
  };
  
  struct crypto_gcm_ghash_ctx {
  	unsigned int cryptlen;
  	struct scatterlist *src;
  	int (*complete)(struct aead_request *req, u32 flags);
  };
  
  struct crypto_gcm_req_priv_ctx {
  	u8 iv[16];
  	u8 auth_tag[16];
  	u8 iauth_tag[16];
  	struct scatterlist src[3];
  	struct scatterlist dst[3];
  	struct scatterlist sg;
  	struct crypto_gcm_ghash_ctx ghash_ctx;
  	union {
  		struct ahash_request ahreq;
  		struct skcipher_request skreq;
  	} u;
  };
  
  struct crypto_gcm_setkey_result {
  	int err;
  	struct completion completion;
  };
  
  static struct {
  	u8 buf[16];
  	struct scatterlist sg;
  } *gcm_zeroes;
  
  static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc);
  
  static inline struct crypto_gcm_req_priv_ctx *crypto_gcm_reqctx(
  	struct aead_request *req)
  {
  	unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
  
  	return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
  }
  
  static void crypto_gcm_setkey_done(struct crypto_async_request *req, int err)
  {
  	struct crypto_gcm_setkey_result *result = req->data;
  
  	if (err == -EINPROGRESS)
  		return;
  
  	result->err = err;
  	complete(&result->completion);
  }
  
  static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
  			     unsigned int keylen)
  {
  	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
  	struct crypto_ahash *ghash = ctx->ghash;
  	struct crypto_skcipher *ctr = ctx->ctr;
  	struct {
  		be128 hash;
  		u8 iv[16];
  
  		struct crypto_gcm_setkey_result result;
  
  		struct scatterlist sg[1];
  		struct skcipher_request req;
  	} *data;
  	int err;
  
  	crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
  	crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
  				       CRYPTO_TFM_REQ_MASK);
  	err = crypto_skcipher_setkey(ctr, key, keylen);
  	crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctr) &
  				    CRYPTO_TFM_RES_MASK);
  	if (err)
  		return err;
  
  	data = kzalloc(sizeof(*data) + crypto_skcipher_reqsize(ctr),
  		       GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	init_completion(&data->result.completion);
  	sg_init_one(data->sg, &data->hash, sizeof(data->hash));
  	skcipher_request_set_tfm(&data->req, ctr);
  	skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
  						  CRYPTO_TFM_REQ_MAY_BACKLOG,
  				      crypto_gcm_setkey_done,
  				      &data->result);
  	skcipher_request_set_crypt(&data->req, data->sg, data->sg,
  				   sizeof(data->hash), data->iv);
  
  	err = crypto_skcipher_encrypt(&data->req);
  	if (err == -EINPROGRESS || err == -EBUSY) {
  		err = wait_for_completion_interruptible(
  			&data->result.completion);
  		if (!err)
  			err = data->result.err;
  	}
  
  	if (err)
  		goto out;
  
  	crypto_ahash_clear_flags(ghash, CRYPTO_TFM_REQ_MASK);
  	crypto_ahash_set_flags(ghash, crypto_aead_get_flags(aead) &
  			       CRYPTO_TFM_REQ_MASK);
  	err = crypto_ahash_setkey(ghash, (u8 *)&data->hash, sizeof(be128));
  	crypto_aead_set_flags(aead, crypto_ahash_get_flags(ghash) &
  			      CRYPTO_TFM_RES_MASK);
  
  out:
  	kzfree(data);
  	return err;
  }
  
  static int crypto_gcm_setauthsize(struct crypto_aead *tfm,
  				  unsigned int authsize)
  {
  	switch (authsize) {
  	case 4:
  	case 8:
  	case 12:
  	case 13:
  	case 14:
  	case 15:
  	case 16:
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static void crypto_gcm_init_common(struct aead_request *req)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	__be32 counter = cpu_to_be32(1);
  	struct scatterlist *sg;
  
  	memset(pctx->auth_tag, 0, sizeof(pctx->auth_tag));
  	memcpy(pctx->iv, req->iv, 12);
  	memcpy(pctx->iv + 12, &counter, 4);
  
  	sg_init_table(pctx->src, 3);
  	sg_set_buf(pctx->src, pctx->auth_tag, sizeof(pctx->auth_tag));
  	sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
  	if (sg != pctx->src + 1)
  		sg_chain(pctx->src, 2, sg);
  
  	if (req->src != req->dst) {
  		sg_init_table(pctx->dst, 3);
  		sg_set_buf(pctx->dst, pctx->auth_tag, sizeof(pctx->auth_tag));
  		sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
  		if (sg != pctx->dst + 1)
  			sg_chain(pctx->dst, 2, sg);
  	}
  }
  
  static void crypto_gcm_init_crypt(struct aead_request *req,
  				  unsigned int cryptlen)
  {
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct skcipher_request *skreq = &pctx->u.skreq;
  	struct scatterlist *dst;
  
  	dst = req->src == req->dst ? pctx->src : pctx->dst;
  
  	skcipher_request_set_tfm(skreq, ctx->ctr);
  	skcipher_request_set_crypt(skreq, pctx->src, dst,
  				     cryptlen + sizeof(pctx->auth_tag),
  				     pctx->iv);
  }
  
  static inline unsigned int gcm_remain(unsigned int len)
  {
  	len &= 0xfU;
  	return len ? 16 - len : 0;
  }
  
  static void gcm_hash_len_done(struct crypto_async_request *areq, int err);
  
  static int gcm_hash_update(struct aead_request *req,
  			   crypto_completion_t compl,
  			   struct scatterlist *src,
  			   unsigned int len, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct ahash_request *ahreq = &pctx->u.ahreq;
  
  	ahash_request_set_callback(ahreq, flags, compl, req);
  	ahash_request_set_crypt(ahreq, src, NULL, len);
  
  	return crypto_ahash_update(ahreq);
  }
  
  static int gcm_hash_remain(struct aead_request *req,
  			   unsigned int remain,
  			   crypto_completion_t compl, u32 flags)
  {
  	return gcm_hash_update(req, compl, &gcm_zeroes->sg, remain, flags);
  }
  
  static int gcm_hash_len(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct ahash_request *ahreq = &pctx->u.ahreq;
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  	u128 lengths;
  
  	lengths.a = cpu_to_be64(req->assoclen * 8);
  	lengths.b = cpu_to_be64(gctx->cryptlen * 8);
  	memcpy(pctx->iauth_tag, &lengths, 16);
  	sg_init_one(&pctx->sg, pctx->iauth_tag, 16);
  	ahash_request_set_callback(ahreq, flags, gcm_hash_len_done, req);
  	ahash_request_set_crypt(ahreq, &pctx->sg,
  				pctx->iauth_tag, sizeof(lengths));
  
  	return crypto_ahash_finup(ahreq);
  }
  
  static int gcm_hash_len_continue(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  
  	return gctx->complete(req, flags);
  }
  
  static void gcm_hash_len_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_len_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash_crypt_remain_continue(struct aead_request *req, u32 flags)
  {
  	return gcm_hash_len(req, flags) ?:
  	       gcm_hash_len_continue(req, flags);
  }
  
  static void gcm_hash_crypt_remain_done(struct crypto_async_request *areq,
  				       int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_crypt_remain_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash_crypt_continue(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  	unsigned int remain;
  
  	remain = gcm_remain(gctx->cryptlen);
  	if (remain)
  		return gcm_hash_remain(req, remain,
  				       gcm_hash_crypt_remain_done, flags) ?:
  		       gcm_hash_crypt_remain_continue(req, flags);
  
  	return gcm_hash_crypt_remain_continue(req, flags);
  }
  
  static void gcm_hash_crypt_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_crypt_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash_assoc_remain_continue(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  
  	if (gctx->cryptlen)
  		return gcm_hash_update(req, gcm_hash_crypt_done,
  				       gctx->src, gctx->cryptlen, flags) ?:
  		       gcm_hash_crypt_continue(req, flags);
  
  	return gcm_hash_crypt_remain_continue(req, flags);
  }
  
  static void gcm_hash_assoc_remain_done(struct crypto_async_request *areq,
  				       int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_assoc_remain_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash_assoc_continue(struct aead_request *req, u32 flags)
  {
  	unsigned int remain;
  
  	remain = gcm_remain(req->assoclen);
  	if (remain)
  		return gcm_hash_remain(req, remain,
  				       gcm_hash_assoc_remain_done, flags) ?:
  		       gcm_hash_assoc_remain_continue(req, flags);
  
  	return gcm_hash_assoc_remain_continue(req, flags);
  }
  
  static void gcm_hash_assoc_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_assoc_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash_init_continue(struct aead_request *req, u32 flags)
  {
  	if (req->assoclen)
  		return gcm_hash_update(req, gcm_hash_assoc_done,
  				       req->src, req->assoclen, flags) ?:
  		       gcm_hash_assoc_continue(req, flags);
  
  	return gcm_hash_assoc_remain_continue(req, flags);
  }
  
  static void gcm_hash_init_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_hash_init_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int gcm_hash(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct ahash_request *ahreq = &pctx->u.ahreq;
  	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
  
  	ahash_request_set_tfm(ahreq, ctx->ghash);
  
  	ahash_request_set_callback(ahreq, flags, gcm_hash_init_done, req);
  	return crypto_ahash_init(ahreq) ?:
  	       gcm_hash_init_continue(req, flags);
  }
  
  static int gcm_enc_copy_hash(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	u8 *auth_tag = pctx->auth_tag;
  
  	crypto_xor(auth_tag, pctx->iauth_tag, 16);
  	scatterwalk_map_and_copy(auth_tag, req->dst,
  				 req->assoclen + req->cryptlen,
  				 crypto_aead_authsize(aead), 1);
  	return 0;
  }
  
  static int gcm_encrypt_continue(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  
  	gctx->src = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
  	gctx->cryptlen = req->cryptlen;
  	gctx->complete = gcm_enc_copy_hash;
  
  	return gcm_hash(req, flags);
  }
  
  static void gcm_encrypt_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (err)
  		goto out;
  
  	err = gcm_encrypt_continue(req, 0);
  	if (err == -EINPROGRESS)
  		return;
  
  out:
  	aead_request_complete(req, err);
  }
  
  static int crypto_gcm_encrypt(struct aead_request *req)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct skcipher_request *skreq = &pctx->u.skreq;
  	u32 flags = aead_request_flags(req);
  
  	crypto_gcm_init_common(req);
  	crypto_gcm_init_crypt(req, req->cryptlen);
  	skcipher_request_set_callback(skreq, flags, gcm_encrypt_done, req);
  
  	return crypto_skcipher_encrypt(skreq) ?:
  	       gcm_encrypt_continue(req, flags);
  }
  
  static int crypto_gcm_verify(struct aead_request *req)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	u8 *auth_tag = pctx->auth_tag;
  	u8 *iauth_tag = pctx->iauth_tag;
  	unsigned int authsize = crypto_aead_authsize(aead);
  	unsigned int cryptlen = req->cryptlen - authsize;
  
  	crypto_xor(auth_tag, iauth_tag, 16);
  	scatterwalk_map_and_copy(iauth_tag, req->src,
  				 req->assoclen + cryptlen, authsize, 0);
  	return crypto_memneq(iauth_tag, auth_tag, authsize) ? -EBADMSG : 0;
  }
  
  static void gcm_decrypt_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  
  	if (!err)
  		err = crypto_gcm_verify(req);
  
  	aead_request_complete(req, err);
  }
  
  static int gcm_dec_hash_continue(struct aead_request *req, u32 flags)
  {
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct skcipher_request *skreq = &pctx->u.skreq;
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  
  	crypto_gcm_init_crypt(req, gctx->cryptlen);
  	skcipher_request_set_callback(skreq, flags, gcm_decrypt_done, req);
  	return crypto_skcipher_decrypt(skreq) ?: crypto_gcm_verify(req);
  }
  
  static int crypto_gcm_decrypt(struct aead_request *req)
  {
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
  	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
  	unsigned int authsize = crypto_aead_authsize(aead);
  	unsigned int cryptlen = req->cryptlen;
  	u32 flags = aead_request_flags(req);
  
  	cryptlen -= authsize;
  
  	crypto_gcm_init_common(req);
  
  	gctx->src = sg_next(pctx->src);
  	gctx->cryptlen = cryptlen;
  	gctx->complete = gcm_dec_hash_continue;
  
  	return gcm_hash(req, flags);
  }
  
  static int crypto_gcm_init_tfm(struct crypto_aead *tfm)
  {
  	struct aead_instance *inst = aead_alg_instance(tfm);
  	struct gcm_instance_ctx *ictx = aead_instance_ctx(inst);
  	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);
  	struct crypto_skcipher *ctr;
  	struct crypto_ahash *ghash;
  	unsigned long align;
  	int err;
  
  	ghash = crypto_spawn_ahash(&ictx->ghash);
  	if (IS_ERR(ghash))
  		return PTR_ERR(ghash);
  
  	ctr = crypto_spawn_skcipher(&ictx->ctr);
  	err = PTR_ERR(ctr);
  	if (IS_ERR(ctr))
  		goto err_free_hash;
  
  	ctx->ctr = ctr;
  	ctx->ghash = ghash;
  
  	align = crypto_aead_alignmask(tfm);
  	align &= ~(crypto_tfm_ctx_alignment() - 1);
  	crypto_aead_set_reqsize(tfm,
  		align + offsetof(struct crypto_gcm_req_priv_ctx, u) +
  		max(sizeof(struct skcipher_request) +
  		    crypto_skcipher_reqsize(ctr),
  		    sizeof(struct ahash_request) +
  		    crypto_ahash_reqsize(ghash)));
  
  	return 0;
  
  err_free_hash:
  	crypto_free_ahash(ghash);
  	return err;
  }
  
  static void crypto_gcm_exit_tfm(struct crypto_aead *tfm)
  {
  	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);
  
  	crypto_free_ahash(ctx->ghash);
  	crypto_free_skcipher(ctx->ctr);
  }
  
  static void crypto_gcm_free(struct aead_instance *inst)
  {
  	struct gcm_instance_ctx *ctx = aead_instance_ctx(inst);
  
  	crypto_drop_skcipher(&ctx->ctr);
  	crypto_drop_ahash(&ctx->ghash);
  	kfree(inst);
  }
  
  static int crypto_gcm_create_common(struct crypto_template *tmpl,
  				    struct rtattr **tb,
  				    const char *full_name,
  				    const char *ctr_name,
  				    const char *ghash_name)
  {
  	struct crypto_attr_type *algt;
  	struct aead_instance *inst;
  	struct skcipher_alg *ctr;
  	struct crypto_alg *ghash_alg;
  	struct hash_alg_common *ghash;
  	struct gcm_instance_ctx *ctx;
  	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;
  
  	ghash_alg = crypto_find_alg(ghash_name, &crypto_ahash_type,
  				    CRYPTO_ALG_TYPE_HASH,
  				    CRYPTO_ALG_TYPE_AHASH_MASK |
  				    crypto_requires_sync(algt->type,
  							 algt->mask));
  	if (IS_ERR(ghash_alg))
  		return PTR_ERR(ghash_alg);
  
  	ghash = __crypto_hash_alg_common(ghash_alg);
  
  	err = -ENOMEM;
  	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
  	if (!inst)
  		goto out_put_ghash;
  
  	ctx = aead_instance_ctx(inst);
  	err = crypto_init_ahash_spawn(&ctx->ghash, ghash,
  				      aead_crypto_instance(inst));
  	if (err)
  		goto err_free_inst;
  
  	err = -EINVAL;
  	if (ghash->digestsize != 16)
  		goto err_drop_ghash;
  
  	crypto_set_skcipher_spawn(&ctx->ctr, aead_crypto_instance(inst));
  	err = crypto_grab_skcipher(&ctx->ctr, ctr_name, 0,
  				   crypto_requires_sync(algt->type,
  							algt->mask));
  	if (err)
  		goto err_drop_ghash;
  
  	ctr = crypto_spawn_skcipher_alg(&ctx->ctr);
  
  	/* We only support 16-byte blocks. */
  	err = -EINVAL;
  	if (crypto_skcipher_alg_ivsize(ctr) != 16)
  		goto out_put_ctr;
  
  	/* Not a stream cipher? */
  	if (ctr->base.cra_blocksize != 1)
  		goto out_put_ctr;
  
  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "gcm_base(%s,%s)", ctr->base.cra_driver_name,
  		     ghash_alg->cra_driver_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		goto out_put_ctr;
  
  	memcpy(inst->alg.base.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
  
  	inst->alg.base.cra_flags = (ghash->base.cra_flags |
  				    ctr->base.cra_flags) & CRYPTO_ALG_ASYNC;
  	inst->alg.base.cra_priority = (ghash->base.cra_priority +
  				       ctr->base.cra_priority) / 2;
  	inst->alg.base.cra_blocksize = 1;
  	inst->alg.base.cra_alignmask = ghash->base.cra_alignmask |
  				       ctr->base.cra_alignmask;
  	inst->alg.base.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
  	inst->alg.ivsize = 12;
  	inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
  	inst->alg.maxauthsize = 16;
  	inst->alg.init = crypto_gcm_init_tfm;
  	inst->alg.exit = crypto_gcm_exit_tfm;
  	inst->alg.setkey = crypto_gcm_setkey;
  	inst->alg.setauthsize = crypto_gcm_setauthsize;
  	inst->alg.encrypt = crypto_gcm_encrypt;
  	inst->alg.decrypt = crypto_gcm_decrypt;
  
  	inst->free = crypto_gcm_free;
  
  	err = aead_register_instance(tmpl, inst);
  	if (err)
  		goto out_put_ctr;
  
  out_put_ghash:
  	crypto_mod_put(ghash_alg);
  	return err;
  
  out_put_ctr:
  	crypto_drop_skcipher(&ctx->ctr);
  err_drop_ghash:
  	crypto_drop_ahash(&ctx->ghash);
  err_free_inst:
  	kfree(inst);
  	goto out_put_ghash;
  }
  
  static int crypto_gcm_create(struct crypto_template *tmpl, struct rtattr **tb)
  {
  	const char *cipher_name;
  	char ctr_name[CRYPTO_MAX_ALG_NAME];
  	char full_name[CRYPTO_MAX_ALG_NAME];
  
  	cipher_name = crypto_attr_alg_name(tb[1]);
  	if (IS_ERR(cipher_name))
  		return PTR_ERR(cipher_name);
  
  	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", cipher_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		return -ENAMETOOLONG;
  
  	if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm(%s)", cipher_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		return -ENAMETOOLONG;
  
  	return crypto_gcm_create_common(tmpl, tb, full_name,
  					ctr_name, "ghash");
  }
  
  static struct crypto_template crypto_gcm_tmpl = {
  	.name = "gcm",
  	.create = crypto_gcm_create,
  	.module = THIS_MODULE,
  };
  
  static int crypto_gcm_base_create(struct crypto_template *tmpl,
  				  struct rtattr **tb)
  {
  	const char *ctr_name;
  	const char *ghash_name;
  	char full_name[CRYPTO_MAX_ALG_NAME];
  
  	ctr_name = crypto_attr_alg_name(tb[1]);
  	if (IS_ERR(ctr_name))
  		return PTR_ERR(ctr_name);
  
  	ghash_name = crypto_attr_alg_name(tb[2]);
  	if (IS_ERR(ghash_name))
  		return PTR_ERR(ghash_name);
  
  	if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm_base(%s,%s)",
  		     ctr_name, ghash_name) >= CRYPTO_MAX_ALG_NAME)
  		return -ENAMETOOLONG;
  
  	return crypto_gcm_create_common(tmpl, tb, full_name,
  					ctr_name, ghash_name);
  }
  
  static struct crypto_template crypto_gcm_base_tmpl = {
  	.name = "gcm_base",
  	.create = crypto_gcm_base_create,
  	.module = THIS_MODULE,
  };
  
  static int crypto_rfc4106_setkey(struct crypto_aead *parent, const u8 *key,
  				 unsigned int keylen)
  {
  	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
  	struct crypto_aead *child = ctx->child;
  	int err;
  
  	if (keylen < 4)
  		return -EINVAL;
  
  	keylen -= 4;
  	memcpy(ctx->nonce, key + keylen, 4);
  
  	crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
  				     CRYPTO_TFM_REQ_MASK);
  	err = crypto_aead_setkey(child, key, keylen);
  	crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
  				      CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int crypto_rfc4106_setauthsize(struct crypto_aead *parent,
  				      unsigned int authsize)
  {
  	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
  
  	switch (authsize) {
  	case 8:
  	case 12:
  	case 16:
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return crypto_aead_setauthsize(ctx->child, authsize);
  }
  
  static struct aead_request *crypto_rfc4106_crypt(struct aead_request *req)
  {
  	struct crypto_rfc4106_req_ctx *rctx = aead_request_ctx(req);
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(aead);
  	struct aead_request *subreq = &rctx->subreq;
  	struct crypto_aead *child = ctx->child;
  	struct scatterlist *sg;
  	u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
  			   crypto_aead_alignmask(child) + 1);
  
  	scatterwalk_map_and_copy(iv + 12, req->src, 0, req->assoclen - 8, 0);
  
  	memcpy(iv, ctx->nonce, 4);
  	memcpy(iv + 4, req->iv, 8);
  
  	sg_init_table(rctx->src, 3);
  	sg_set_buf(rctx->src, iv + 12, req->assoclen - 8);
  	sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
  	if (sg != rctx->src + 1)
  		sg_chain(rctx->src, 2, sg);
  
  	if (req->src != req->dst) {
  		sg_init_table(rctx->dst, 3);
  		sg_set_buf(rctx->dst, iv + 12, req->assoclen - 8);
  		sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
  		if (sg != rctx->dst + 1)
  			sg_chain(rctx->dst, 2, sg);
  	}
  
  	aead_request_set_tfm(subreq, child);
  	aead_request_set_callback(subreq, req->base.flags, req->base.complete,
  				  req->base.data);
  	aead_request_set_crypt(subreq, rctx->src,
  			       req->src == req->dst ? rctx->src : rctx->dst,
  			       req->cryptlen, iv);
  	aead_request_set_ad(subreq, req->assoclen - 8);
  
  	return subreq;
  }
  
  static int crypto_rfc4106_encrypt(struct aead_request *req)
  {
  	if (req->assoclen != 16 && req->assoclen != 20)
  		return -EINVAL;
  
  	req = crypto_rfc4106_crypt(req);
  
  	return crypto_aead_encrypt(req);
  }
  
  static int crypto_rfc4106_decrypt(struct aead_request *req)
  {
  	if (req->assoclen != 16 && req->assoclen != 20)
  		return -EINVAL;
  
  	req = crypto_rfc4106_crypt(req);
  
  	return crypto_aead_decrypt(req);
  }
  
  static int crypto_rfc4106_init_tfm(struct crypto_aead *tfm)
  {
  	struct aead_instance *inst = aead_alg_instance(tfm);
  	struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
  	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);
  	struct crypto_aead *aead;
  	unsigned long align;
  
  	aead = crypto_spawn_aead(spawn);
  	if (IS_ERR(aead))
  		return PTR_ERR(aead);
  
  	ctx->child = aead;
  
  	align = crypto_aead_alignmask(aead);
  	align &= ~(crypto_tfm_ctx_alignment() - 1);
  	crypto_aead_set_reqsize(
  		tfm,
  		sizeof(struct crypto_rfc4106_req_ctx) +
  		ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
  		align + 24);
  
  	return 0;
  }
  
  static void crypto_rfc4106_exit_tfm(struct crypto_aead *tfm)
  {
  	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);
  
  	crypto_free_aead(ctx->child);
  }
  
  static void crypto_rfc4106_free(struct aead_instance *inst)
  {
  	crypto_drop_aead(aead_instance_ctx(inst));
  	kfree(inst);
  }
  
  static int crypto_rfc4106_create(struct crypto_template *tmpl,
  				 struct rtattr **tb)
  {
  	struct crypto_attr_type *algt;
  	struct aead_instance *inst;
  	struct crypto_aead_spawn *spawn;
  	struct aead_alg *alg;
  	const char *ccm_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;
  
  	ccm_name = crypto_attr_alg_name(tb[1]);
  	if (IS_ERR(ccm_name))
  		return PTR_ERR(ccm_name);
  
  	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
  	if (!inst)
  		return -ENOMEM;
  
  	spawn = aead_instance_ctx(inst);
  	crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
  	err = crypto_grab_aead(spawn, ccm_name, 0,
  			       crypto_requires_sync(algt->type, algt->mask));
  	if (err)
  		goto out_free_inst;
  
  	alg = crypto_spawn_aead_alg(spawn);
  
  	err = -EINVAL;
  
  	/* Underlying IV size must be 12. */
  	if (crypto_aead_alg_ivsize(alg) != 12)
  		goto out_drop_alg;
  
  	/* Not a stream cipher? */
  	if (alg->base.cra_blocksize != 1)
  		goto out_drop_alg;
  
  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  		     "rfc4106(%s)", alg->base.cra_name) >=
  	    CRYPTO_MAX_ALG_NAME ||
  	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "rfc4106(%s)", alg->base.cra_driver_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		goto out_drop_alg;
  
  	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
  	inst->alg.base.cra_priority = alg->base.cra_priority;
  	inst->alg.base.cra_blocksize = 1;
  	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
  
  	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4106_ctx);
  
  	inst->alg.ivsize = 8;
  	inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
  	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
  
  	inst->alg.init = crypto_rfc4106_init_tfm;
  	inst->alg.exit = crypto_rfc4106_exit_tfm;
  
  	inst->alg.setkey = crypto_rfc4106_setkey;
  	inst->alg.setauthsize = crypto_rfc4106_setauthsize;
  	inst->alg.encrypt = crypto_rfc4106_encrypt;
  	inst->alg.decrypt = crypto_rfc4106_decrypt;
  
  	inst->free = crypto_rfc4106_free;
  
  	err = aead_register_instance(tmpl, inst);
  	if (err)
  		goto out_drop_alg;
  
  out:
  	return err;
  
  out_drop_alg:
  	crypto_drop_aead(spawn);
  out_free_inst:
  	kfree(inst);
  	goto out;
  }
  
  static struct crypto_template crypto_rfc4106_tmpl = {
  	.name = "rfc4106",
  	.create = crypto_rfc4106_create,
  	.module = THIS_MODULE,
  };
  
  static int crypto_rfc4543_setkey(struct crypto_aead *parent, const u8 *key,
  				 unsigned int keylen)
  {
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);
  	struct crypto_aead *child = ctx->child;
  	int err;
  
  	if (keylen < 4)
  		return -EINVAL;
  
  	keylen -= 4;
  	memcpy(ctx->nonce, key + keylen, 4);
  
  	crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
  				     CRYPTO_TFM_REQ_MASK);
  	err = crypto_aead_setkey(child, key, keylen);
  	crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
  				      CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int crypto_rfc4543_setauthsize(struct crypto_aead *parent,
  				      unsigned int authsize)
  {
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);
  
  	if (authsize != 16)
  		return -EINVAL;
  
  	return crypto_aead_setauthsize(ctx->child, authsize);
  }
  
  static int crypto_rfc4543_crypt(struct aead_request *req, bool enc)
  {
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead);
  	struct crypto_rfc4543_req_ctx *rctx = aead_request_ctx(req);
  	struct aead_request *subreq = &rctx->subreq;
  	unsigned int authsize = crypto_aead_authsize(aead);
  	u8 *iv = PTR_ALIGN((u8 *)(rctx + 1) + crypto_aead_reqsize(ctx->child),
  			   crypto_aead_alignmask(ctx->child) + 1);
  	int err;
  
  	if (req->src != req->dst) {
  		err = crypto_rfc4543_copy_src_to_dst(req, enc);
  		if (err)
  			return err;
  	}
  
  	memcpy(iv, ctx->nonce, 4);
  	memcpy(iv + 4, req->iv, 8);
  
  	aead_request_set_tfm(subreq, ctx->child);
  	aead_request_set_callback(subreq, req->base.flags,
  				  req->base.complete, req->base.data);
  	aead_request_set_crypt(subreq, req->src, req->dst,
  			       enc ? 0 : authsize, iv);
  	aead_request_set_ad(subreq, req->assoclen + req->cryptlen -
  				    subreq->cryptlen);
  
  	return enc ? crypto_aead_encrypt(subreq) : crypto_aead_decrypt(subreq);
  }
  
  static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)
  {
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead);
  	unsigned int authsize = crypto_aead_authsize(aead);
  	unsigned int nbytes = req->assoclen + req->cryptlen -
  			      (enc ? 0 : authsize);
  	SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);
  
  	skcipher_request_set_tfm(nreq, ctx->null);
  	skcipher_request_set_callback(nreq, req->base.flags, NULL, NULL);
  	skcipher_request_set_crypt(nreq, req->src, req->dst, nbytes, NULL);
  
  	return crypto_skcipher_encrypt(nreq);
  }
  
  static int crypto_rfc4543_encrypt(struct aead_request *req)
  {
  	return crypto_rfc4543_crypt(req, true);
  }
  
  static int crypto_rfc4543_decrypt(struct aead_request *req)
  {
  	return crypto_rfc4543_crypt(req, false);
  }
  
  static int crypto_rfc4543_init_tfm(struct crypto_aead *tfm)
  {
  	struct aead_instance *inst = aead_alg_instance(tfm);
  	struct crypto_rfc4543_instance_ctx *ictx = aead_instance_ctx(inst);
  	struct crypto_aead_spawn *spawn = &ictx->aead;
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);
  	struct crypto_aead *aead;
  	struct crypto_skcipher *null;
  	unsigned long align;
  	int err = 0;
  
  	aead = crypto_spawn_aead(spawn);
  	if (IS_ERR(aead))
  		return PTR_ERR(aead);
  
  	null = crypto_get_default_null_skcipher2();
  	err = PTR_ERR(null);
  	if (IS_ERR(null))
  		goto err_free_aead;
  
  	ctx->child = aead;
  	ctx->null = null;
  
  	align = crypto_aead_alignmask(aead);
  	align &= ~(crypto_tfm_ctx_alignment() - 1);
  	crypto_aead_set_reqsize(
  		tfm,
  		sizeof(struct crypto_rfc4543_req_ctx) +
  		ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
  		align + 12);
  
  	return 0;
  
  err_free_aead:
  	crypto_free_aead(aead);
  	return err;
  }
  
  static void crypto_rfc4543_exit_tfm(struct crypto_aead *tfm)
  {
  	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);
  
  	crypto_free_aead(ctx->child);
  	crypto_put_default_null_skcipher2();
  }
  
  static void crypto_rfc4543_free(struct aead_instance *inst)
  {
  	struct crypto_rfc4543_instance_ctx *ctx = aead_instance_ctx(inst);
  
  	crypto_drop_aead(&ctx->aead);
  
  	kfree(inst);
  }
  
  static int crypto_rfc4543_create(struct crypto_template *tmpl,
  				struct rtattr **tb)
  {
  	struct crypto_attr_type *algt;
  	struct aead_instance *inst;
  	struct crypto_aead_spawn *spawn;
  	struct aead_alg *alg;
  	struct crypto_rfc4543_instance_ctx *ctx;
  	const char *ccm_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;
  
  	ccm_name = crypto_attr_alg_name(tb[1]);
  	if (IS_ERR(ccm_name))
  		return PTR_ERR(ccm_name);
  
  	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
  	if (!inst)
  		return -ENOMEM;
  
  	ctx = aead_instance_ctx(inst);
  	spawn = &ctx->aead;
  	crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
  	err = crypto_grab_aead(spawn, ccm_name, 0,
  			       crypto_requires_sync(algt->type, algt->mask));
  	if (err)
  		goto out_free_inst;
  
  	alg = crypto_spawn_aead_alg(spawn);
  
  	err = -EINVAL;
  
  	/* Underlying IV size must be 12. */
  	if (crypto_aead_alg_ivsize(alg) != 12)
  		goto out_drop_alg;
  
  	/* Not a stream cipher? */
  	if (alg->base.cra_blocksize != 1)
  		goto out_drop_alg;
  
  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  		     "rfc4543(%s)", alg->base.cra_name) >=
  	    CRYPTO_MAX_ALG_NAME ||
  	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "rfc4543(%s)", alg->base.cra_driver_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		goto out_drop_alg;
  
  	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
  	inst->alg.base.cra_priority = alg->base.cra_priority;
  	inst->alg.base.cra_blocksize = 1;
  	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
  
  	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4543_ctx);
  
  	inst->alg.ivsize = 8;
  	inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
  	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
  
  	inst->alg.init = crypto_rfc4543_init_tfm;
  	inst->alg.exit = crypto_rfc4543_exit_tfm;
  
  	inst->alg.setkey = crypto_rfc4543_setkey;
  	inst->alg.setauthsize = crypto_rfc4543_setauthsize;
  	inst->alg.encrypt = crypto_rfc4543_encrypt;
  	inst->alg.decrypt = crypto_rfc4543_decrypt;
  
  	inst->free = crypto_rfc4543_free,
  
  	err = aead_register_instance(tmpl, inst);
  	if (err)
  		goto out_drop_alg;
  
  out:
  	return err;
  
  out_drop_alg:
  	crypto_drop_aead(spawn);
  out_free_inst:
  	kfree(inst);
  	goto out;
  }
  
  static struct crypto_template crypto_rfc4543_tmpl = {
  	.name = "rfc4543",
  	.create = crypto_rfc4543_create,
  	.module = THIS_MODULE,
  };
  
  static int __init crypto_gcm_module_init(void)
  {
  	int err;
  
  	gcm_zeroes = kzalloc(sizeof(*gcm_zeroes), GFP_KERNEL);
  	if (!gcm_zeroes)
  		return -ENOMEM;
  
  	sg_init_one(&gcm_zeroes->sg, gcm_zeroes->buf, sizeof(gcm_zeroes->buf));
  
  	err = crypto_register_template(&crypto_gcm_base_tmpl);
  	if (err)
  		goto out;
  
  	err = crypto_register_template(&crypto_gcm_tmpl);
  	if (err)
  		goto out_undo_base;
  
  	err = crypto_register_template(&crypto_rfc4106_tmpl);
  	if (err)
  		goto out_undo_gcm;
  
  	err = crypto_register_template(&crypto_rfc4543_tmpl);
  	if (err)
  		goto out_undo_rfc4106;
  
  	return 0;
  
  out_undo_rfc4106:
  	crypto_unregister_template(&crypto_rfc4106_tmpl);
  out_undo_gcm:
  	crypto_unregister_template(&crypto_gcm_tmpl);
  out_undo_base:
  	crypto_unregister_template(&crypto_gcm_base_tmpl);
  out:
  	kfree(gcm_zeroes);
  	return err;
  }
  
  static void __exit crypto_gcm_module_exit(void)
  {
  	kfree(gcm_zeroes);
  	crypto_unregister_template(&crypto_rfc4543_tmpl);
  	crypto_unregister_template(&crypto_rfc4106_tmpl);
  	crypto_unregister_template(&crypto_gcm_tmpl);
  	crypto_unregister_template(&crypto_gcm_base_tmpl);
  }
  
  module_init(crypto_gcm_module_init);
  module_exit(crypto_gcm_module_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Galois/Counter Mode");
  MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");
  MODULE_ALIAS_CRYPTO("gcm_base");
  MODULE_ALIAS_CRYPTO("rfc4106");
  MODULE_ALIAS_CRYPTO("rfc4543");
  MODULE_ALIAS_CRYPTO("gcm");
  