root/crypto/cipher.c

DEFINITIONS

1. setkey_unaligned
2. setkey
3. cipher_crypt_unaligned
4. cipher_encrypt_unaligned
5. cipher_decrypt_unaligned
6. crypto_init_cipher_ops
7. crypto_exit_cipher_ops

/*
 * Cryptographic API.
 *
 * Cipher operations.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2005 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 <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "internal.h"

static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
                            unsigned int keylen)
{
        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
        int ret;
        u8 *buffer, *alignbuffer;
        unsigned long absize;

        absize = keylen + alignmask;
        buffer = kmalloc(absize, GFP_ATOMIC);
        if (!buffer)
                return -ENOMEM;

        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
        memcpy(alignbuffer, key, keylen);
        ret = cia->cia_setkey(tfm, alignbuffer, keylen);
        memset(alignbuffer, 0, keylen);
        kfree(buffer);
        return ret;

}

static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);

        tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
        if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
                tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
                return -EINVAL;
        }

        if ((unsigned long)key & alignmask)
                return setkey_unaligned(tfm, key, keylen);

        return cia->cia_setkey(tfm, key, keylen);
}

static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
                                              const u8 *),
                                   struct crypto_tfm *tfm,
                                   u8 *dst, const u8 *src)
{
        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
        unsigned int size = crypto_tfm_alg_blocksize(tfm);
        u8 buffer[size + alignmask];
        u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);

        memcpy(tmp, src, size);
        fn(tfm, tmp, tmp);
        memcpy(dst, tmp, size);
}

static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
                                     u8 *dst, const u8 *src)
{
        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
                cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
                return;
        }

        cipher->cia_encrypt(tfm, dst, src);
}

static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
                                     u8 *dst, const u8 *src)
{
        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
                cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
                return;
        }

        cipher->cia_decrypt(tfm, dst, src);
}

int crypto_init_cipher_ops(struct crypto_tfm *tfm)
{
        struct cipher_tfm *ops = &tfm->crt_cipher;
        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

        ops->cit_setkey = setkey;
        ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
                cipher_encrypt_unaligned : cipher->cia_encrypt;
        ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
                cipher_decrypt_unaligned : cipher->cia_decrypt;

        return 0;
}

void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
{
}