397 lines
10 KiB
C
397 lines
10 KiB
C
/*
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* Authenc: Simple AEAD wrapper for IPsec
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/algapi.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include "scatterwalk.h"
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struct authenc_instance_ctx {
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struct crypto_spawn auth;
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struct crypto_spawn enc;
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unsigned int authsize;
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unsigned int enckeylen;
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};
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struct crypto_authenc_ctx {
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spinlock_t auth_lock;
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struct crypto_hash *auth;
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struct crypto_ablkcipher *enc;
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};
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static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
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unsigned int keylen)
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{
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struct authenc_instance_ctx *ictx =
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crypto_instance_ctx(crypto_aead_alg_instance(authenc));
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unsigned int enckeylen = ictx->enckeylen;
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unsigned int authkeylen;
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struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
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struct crypto_hash *auth = ctx->auth;
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struct crypto_ablkcipher *enc = ctx->enc;
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int err = -EINVAL;
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if (keylen < enckeylen) {
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crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN);
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goto out;
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}
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authkeylen = keylen - enckeylen;
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crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
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crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_hash_setkey(auth, key, authkeylen);
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crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) &
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CRYPTO_TFM_RES_MASK);
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if (err)
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goto out;
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crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
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crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen);
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crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) &
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CRYPTO_TFM_RES_MASK);
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out:
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return err;
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}
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static int crypto_authenc_hash(struct aead_request *req)
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{
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struct crypto_aead *authenc = crypto_aead_reqtfm(req);
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struct authenc_instance_ctx *ictx =
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crypto_instance_ctx(crypto_aead_alg_instance(authenc));
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struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
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struct crypto_hash *auth = ctx->auth;
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struct hash_desc desc = {
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.tfm = auth,
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};
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u8 *hash = aead_request_ctx(req);
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struct scatterlist *dst = req->dst;
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unsigned int cryptlen = req->cryptlen;
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int err;
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hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth),
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crypto_hash_alignmask(auth) + 1);
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spin_lock_bh(&ctx->auth_lock);
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err = crypto_hash_init(&desc);
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if (err)
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goto auth_unlock;
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err = crypto_hash_update(&desc, req->assoc, req->assoclen);
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if (err)
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goto auth_unlock;
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err = crypto_hash_update(&desc, dst, cryptlen);
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if (err)
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goto auth_unlock;
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err = crypto_hash_final(&desc, hash);
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auth_unlock:
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spin_unlock_bh(&ctx->auth_lock);
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if (err)
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return err;
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scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1);
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return 0;
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}
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static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
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int err)
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{
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if (!err)
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err = crypto_authenc_hash(req->data);
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aead_request_complete(req->data, err);
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}
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static int crypto_authenc_encrypt(struct aead_request *req)
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{
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struct crypto_aead *authenc = crypto_aead_reqtfm(req);
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struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
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struct ablkcipher_request *abreq = aead_request_ctx(req);
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int err;
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ablkcipher_request_set_tfm(abreq, ctx->enc);
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ablkcipher_request_set_callback(abreq, aead_request_flags(req),
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crypto_authenc_encrypt_done, req);
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ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
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req->iv);
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err = crypto_ablkcipher_encrypt(abreq);
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if (err)
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return err;
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return crypto_authenc_hash(req);
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}
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static int crypto_authenc_verify(struct aead_request *req)
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{
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struct crypto_aead *authenc = crypto_aead_reqtfm(req);
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struct authenc_instance_ctx *ictx =
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crypto_instance_ctx(crypto_aead_alg_instance(authenc));
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struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
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struct crypto_hash *auth = ctx->auth;
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struct hash_desc desc = {
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.tfm = auth,
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.flags = aead_request_flags(req),
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};
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u8 *ohash = aead_request_ctx(req);
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u8 *ihash;
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struct scatterlist *src = req->src;
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unsigned int cryptlen = req->cryptlen;
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unsigned int authsize;
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int err;
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ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth),
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crypto_hash_alignmask(auth) + 1);
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ihash = ohash + crypto_hash_digestsize(auth);
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spin_lock_bh(&ctx->auth_lock);
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err = crypto_hash_init(&desc);
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if (err)
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goto auth_unlock;
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err = crypto_hash_update(&desc, req->assoc, req->assoclen);
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if (err)
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goto auth_unlock;
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err = crypto_hash_update(&desc, src, cryptlen);
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if (err)
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goto auth_unlock;
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err = crypto_hash_final(&desc, ohash);
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auth_unlock:
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spin_unlock_bh(&ctx->auth_lock);
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if (err)
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return err;
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authsize = ictx->authsize;
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scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0);
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return memcmp(ihash, ohash, authsize) ? -EINVAL : 0;
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}
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static void crypto_authenc_decrypt_done(struct crypto_async_request *req,
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int err)
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{
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aead_request_complete(req->data, err);
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}
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static int crypto_authenc_decrypt(struct aead_request *req)
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{
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struct crypto_aead *authenc = crypto_aead_reqtfm(req);
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struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
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struct ablkcipher_request *abreq = aead_request_ctx(req);
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int err;
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err = crypto_authenc_verify(req);
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if (err)
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return err;
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ablkcipher_request_set_tfm(abreq, ctx->enc);
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ablkcipher_request_set_callback(abreq, aead_request_flags(req),
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crypto_authenc_decrypt_done, req);
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ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
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req->iv);
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return crypto_ablkcipher_decrypt(abreq);
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}
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static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_instance *inst = (void *)tfm->__crt_alg;
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struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst);
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struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
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struct crypto_hash *auth;
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struct crypto_ablkcipher *enc;
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unsigned int digestsize;
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int err;
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auth = crypto_spawn_hash(&ictx->auth);
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if (IS_ERR(auth))
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return PTR_ERR(auth);
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err = -EINVAL;
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digestsize = crypto_hash_digestsize(auth);
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if (ictx->authsize > digestsize)
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goto err_free_hash;
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enc = crypto_spawn_ablkcipher(&ictx->enc);
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err = PTR_ERR(enc);
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if (IS_ERR(enc))
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goto err_free_hash;
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ctx->auth = auth;
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ctx->enc = enc;
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tfm->crt_aead.reqsize = max_t(unsigned int,
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(crypto_hash_alignmask(auth) &
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~(crypto_tfm_ctx_alignment() - 1)) +
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digestsize * 2,
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sizeof(struct ablkcipher_request) +
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crypto_ablkcipher_reqsize(enc));
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spin_lock_init(&ctx->auth_lock);
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return 0;
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err_free_hash:
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crypto_free_hash(auth);
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return err;
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}
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static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
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crypto_free_hash(ctx->auth);
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crypto_free_ablkcipher(ctx->enc);
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}
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static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
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{
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struct crypto_instance *inst;
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struct crypto_alg *auth;
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struct crypto_alg *enc;
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struct authenc_instance_ctx *ctx;
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unsigned int authsize;
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unsigned int enckeylen;
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int err;
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);
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if (err)
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return ERR_PTR(err);
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auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
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CRYPTO_ALG_TYPE_HASH_MASK);
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if (IS_ERR(auth))
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return ERR_PTR(PTR_ERR(auth));
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err = crypto_attr_u32(tb[2], &authsize);
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inst = ERR_PTR(err);
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if (err)
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goto out_put_auth;
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enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER,
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CRYPTO_ALG_TYPE_MASK);
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inst = ERR_PTR(PTR_ERR(enc));
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if (IS_ERR(enc))
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goto out_put_auth;
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err = crypto_attr_u32(tb[4], &enckeylen);
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if (err)
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goto out_put_enc;
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inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
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err = -ENOMEM;
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if (!inst)
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goto out_put_enc;
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err = -ENAMETOOLONG;
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if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
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"authenc(%s,%u,%s,%u)", auth->cra_name, authsize,
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enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME)
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goto err_free_inst;
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if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
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"authenc(%s,%u,%s,%u)", auth->cra_driver_name,
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authsize, enc->cra_driver_name, enckeylen) >=
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CRYPTO_MAX_ALG_NAME)
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goto err_free_inst;
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ctx = crypto_instance_ctx(inst);
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ctx->authsize = authsize;
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ctx->enckeylen = enckeylen;
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err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK);
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if (err)
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goto err_free_inst;
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err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK);
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if (err)
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goto err_drop_auth;
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inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
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inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority;
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inst->alg.cra_blocksize = enc->cra_blocksize;
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inst->alg.cra_alignmask = max(auth->cra_alignmask, enc->cra_alignmask);
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inst->alg.cra_type = &crypto_aead_type;
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inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize;
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inst->alg.cra_aead.authsize = authsize;
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inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
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inst->alg.cra_init = crypto_authenc_init_tfm;
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inst->alg.cra_exit = crypto_authenc_exit_tfm;
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inst->alg.cra_aead.setkey = crypto_authenc_setkey;
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inst->alg.cra_aead.encrypt = crypto_authenc_encrypt;
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inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
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out:
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crypto_mod_put(enc);
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out_put_auth:
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crypto_mod_put(auth);
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return inst;
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err_drop_auth:
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crypto_drop_spawn(&ctx->auth);
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err_free_inst:
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kfree(inst);
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out_put_enc:
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inst = ERR_PTR(err);
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goto out;
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}
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static void crypto_authenc_free(struct crypto_instance *inst)
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{
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struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst);
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crypto_drop_spawn(&ctx->enc);
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crypto_drop_spawn(&ctx->auth);
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kfree(inst);
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}
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static struct crypto_template crypto_authenc_tmpl = {
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.name = "authenc",
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.alloc = crypto_authenc_alloc,
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.free = crypto_authenc_free,
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.module = THIS_MODULE,
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};
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static int __init crypto_authenc_module_init(void)
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{
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return crypto_register_template(&crypto_authenc_tmpl);
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}
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static void __exit crypto_authenc_module_exit(void)
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{
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crypto_unregister_template(&crypto_authenc_tmpl);
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}
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module_init(crypto_authenc_module_init);
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module_exit(crypto_authenc_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
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