crypto/cipher.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cryptographic API.
   4  *
   5  * Single-block 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 <crypto/internal/cipher.h>
  13 #include <linux/kernel.h>
  14 #include <linux/crypto.h>
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17 #include <linux/string.h>
  18 #include "internal.h"
  19
  20 static int setkey_unaligned(struct crypto_cipher *tfm, const u8 *key,
  21                             unsigned int keylen)
  22 {
  23         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  24         unsigned long alignmask = crypto_cipher_alignmask(tfm);
  25         int ret;
  26         u8 *buffer, *alignbuffer;
  27         unsigned long absize;
  28
  29         absize = keylen + alignmask;
  30         buffer = kmalloc(absize, GFP_ATOMIC);
  31         if (!buffer)
  32                 return -ENOMEM;
  33
  34         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  35         memcpy(alignbuffer, key, keylen);
  36         ret = cia->cia_setkey(crypto_cipher_tfm(tfm), alignbuffer, keylen);
  37         memset(alignbuffer, 0, keylen);
  38         kfree(buffer);
  39         return ret;
  40
  41 }
  42
  43 int crypto_cipher_setkey(struct crypto_cipher *tfm,
  44                          const u8 *key, unsigned int keylen)
  45 {
  46         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  47         unsigned long alignmask = crypto_cipher_alignmask(tfm);
  48
  49         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize)
  50                 return -EINVAL;
  51
  52         if ((unsigned long)key & alignmask)
  53                 return setkey_unaligned(tfm, key, keylen);
  54
  55         return cia->cia_setkey(crypto_cipher_tfm(tfm), key, keylen);
  56 }
  57 EXPORT_SYMBOL_NS_GPL(crypto_cipher_setkey, CRYPTO_INTERNAL);
  58
  59 static inline void cipher_crypt_one(struct crypto_cipher *tfm,
  60                                     u8 *dst, const u8 *src, bool enc)
  61 {
  62         unsigned long alignmask = crypto_cipher_alignmask(tfm);
  63         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  64         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
  65                 enc ? cia->cia_encrypt : cia->cia_decrypt;
  66
  67         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  68                 unsigned int bs = crypto_cipher_blocksize(tfm);
  69                 u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
  70                 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  71
  72                 memcpy(tmp, src, bs);
  73                 fn(crypto_cipher_tfm(tfm), tmp, tmp);
  74                 memcpy(dst, tmp, bs);
  75         } else {
  76                 fn(crypto_cipher_tfm(tfm), dst, src);
  77         }
  78 }
  79
  80 void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
  81                                u8 *dst, const u8 *src)
  82 {
  83         cipher_crypt_one(tfm, dst, src, true);
  84 }
  85 EXPORT_SYMBOL_NS_GPL(crypto_cipher_encrypt_one, CRYPTO_INTERNAL);
  86
  87 void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
  88                                u8 *dst, const u8 *src)
  89 {
  90         cipher_crypt_one(tfm, dst, src, false);
  91 }
  92 EXPORT_SYMBOL_NS_GPL(crypto_cipher_decrypt_one, CRYPTO_INTERNAL);