linux/crypto/authenc.c

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