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
  19 static 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
  42 static 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
  59 static 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
  74 static 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
  88 static 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
 102 int 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 }