LXR linux/crypto/cipher.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Cryptographic API.
   4 *
   5 * Cipher operations.
   6 *
   7 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   8 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   9 */
  10
  11#include <crypto/algapi.h>
  12#include <linux/kernel.h>
  13#include <linux/crypto.h>
  14#include <linux/errno.h>
  15#include <linux/slab.h>
  16#include <linux/string.h>
  17#include "internal.h"
  18
  19static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
  20                            unsigned int keylen)
  21{
  22        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  23        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  24        int ret;
  25        u8 *buffer, *alignbuffer;
  26        unsigned long absize;
  27
  28        absize = keylen + alignmask;
  29        buffer = kmalloc(absize, GFP_ATOMIC);
  30        if (!buffer)
  31                return -ENOMEM;
  32
  33        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  34        memcpy(alignbuffer, key, keylen);
  35        ret = cia->cia_setkey(tfm, alignbuffer, keylen);
  36        memset(alignbuffer, 0, keylen);
  37        kfree(buffer);
  38        return ret;
  39
  40}
  41
  42static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  43{
  44        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  45        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  46
  47        tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  48        if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
  49                tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  50                return -EINVAL;
  51        }
  52
  53        if ((unsigned long)key & alignmask)
  54                return setkey_unaligned(tfm, key, keylen);
  55
  56        return cia->cia_setkey(tfm, key, keylen);
  57}
  58
  59static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
  60                                              const u8 *),
  61                                   struct crypto_tfm *tfm,
  62                                   u8 *dst, const u8 *src)
  63{
  64        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  65        unsigned int size = crypto_tfm_alg_blocksize(tfm);
  66        u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
  67        u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  68
  69        memcpy(tmp, src, size);
  70        fn(tfm, tmp, tmp);
  71        memcpy(dst, tmp, size);
  72}
  73
  74static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
  75                                     u8 *dst, const u8 *src)
  76{
  77        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  78        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  79
  80        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  81                cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
  82                return;
  83        }
  84
  85        cipher->cia_encrypt(tfm, dst, src);
  86}
  87
  88static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
  89                                     u8 *dst, const u8 *src)
  90{
  91        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  92        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  93
  94        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  95                cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
  96                return;
  97        }
  98
  99        cipher->cia_decrypt(tfm, dst, src);
 100}
 101
 102int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 103{
 104        struct cipher_tfm *ops = &tfm->crt_cipher;
 105        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
 106
 107        ops->cit_setkey = setkey;
 108        ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 109                cipher_encrypt_unaligned : cipher->cia_encrypt;
 110        ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 111                cipher_decrypt_unaligned : cipher->cia_decrypt;
 112
 113        return 0;
 114}
 115