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 <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_cipher *tfm, const u8 *key,
  20                             unsigned int keylen)
  21 {
  22         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  23         unsigned long alignmask = crypto_cipher_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(crypto_cipher_tfm(tfm), alignbuffer, keylen);
  36         memset(alignbuffer, 0, keylen);
  37         kfree(buffer);
  38         return ret;
  39
  40 }
  41
  42 int crypto_cipher_setkey(struct crypto_cipher *tfm,
  43                          const u8 *key, unsigned int keylen)
  44 {
  45         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  46         unsigned long alignmask = crypto_cipher_alignmask(tfm);
  47
  48         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize)
  49                 return -EINVAL;
  50
  51         if ((unsigned long)key & alignmask)
  52                 return setkey_unaligned(tfm, key, keylen);
  53
  54         return cia->cia_setkey(crypto_cipher_tfm(tfm), key, keylen);
  55 }
  56 EXPORT_SYMBOL_GPL(crypto_cipher_setkey);
  57
  58 static inline void cipher_crypt_one(struct crypto_cipher *tfm,
  59                                     u8 *dst, const u8 *src, bool enc)
  60 {
  61         unsigned long alignmask = crypto_cipher_alignmask(tfm);
  62         struct cipher_alg *cia = crypto_cipher_alg(tfm);
  63         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
  64                 enc ? cia->cia_encrypt : cia->cia_decrypt;
  65
  66         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  67                 unsigned int bs = crypto_cipher_blocksize(tfm);
  68                 u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
  69                 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  70
  71                 memcpy(tmp, src, bs);
  72                 fn(crypto_cipher_tfm(tfm), tmp, tmp);
  73                 memcpy(dst, tmp, bs);
  74         } else {
  75                 fn(crypto_cipher_tfm(tfm), dst, src);
  76         }
  77 }
  78
  79 void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
  80                                u8 *dst, const u8 *src)
  81 {
  82         cipher_crypt_one(tfm, dst, src, true);
  83 }
  84 EXPORT_SYMBOL_GPL(crypto_cipher_encrypt_one);
  85
  86 void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
  87                                u8 *dst, const u8 *src)
  88 {
  89         cipher_crypt_one(tfm, dst, src, false);
  90 }
  91 EXPORT_SYMBOL_GPL(crypto_cipher_decrypt_one);