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linux/crypto/authenc.c
Herbert Xu 332f8840f7 [CRYPTO] ablkcipher: Add distinct ABLKCIPHER type 
Up until now we have ablkcipher algorithms have been identified as
type BLKCIPHER with the ASYNC bit set.  This is suboptimal because
ablkcipher refers to two things.  On the one hand it refers to the
top-level ablkcipher interface with requests.  On the other hand it
refers to and algorithm type underneath.

As it is you cannot request a synchronous block cipher algorithm
with the ablkcipher interface on top.  This is a problem because
we want to be able to eventually phase out the blkcipher top-level
interface.

This patch fixes this by making ABLKCIPHER its own type, just as
we have distinct types for HASH and DIGEST.  The type it associated
with the algorithm implementation only.

Which top-level interface is used for synchronous block ciphers is
then determined by the mask that's used.  If it's a specific mask
then the old blkcipher interface is given, otherwise we go with the
new ablkcipher interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2008-01-11 08:16:15 +11:00

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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 authsize;
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 authenc_instance_ctx *ictx =
crypto_instance_ctx(crypto_aead_alg_instance(authenc));
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, ictx->authsize, 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 authenc_instance_ctx *ictx =
crypto_instance_ctx(crypto_aead_alg_instance(authenc));
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 = ictx->authsize;
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;
unsigned int digestsize;
int err;
auth = crypto_spawn_hash(&ictx->auth);
if (IS_ERR(auth))
return PTR_ERR(auth);
err = -EINVAL;
digestsize = crypto_hash_digestsize(auth);
if (ictx->authsize > digestsize)
goto err_free_hash;
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)) +
digestsize * 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 authsize;
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));
err = crypto_attr_u32(tb[2], &authsize);
inst = ERR_PTR(err);
if (err)
goto out_put_auth;
enc = crypto_attr_alg(tb[3], 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[4], &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,%u,%s,%u)", auth->cra_name, authsize,
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,%u,%s,%u)", auth->cra_driver_name,
authsize, enc->cra_driver_name, enckeylen) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
ctx = crypto_instance_ctx(inst);
ctx->authsize = authsize;
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 = max(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.authsize = authsize;
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");
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