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 <[email protected]>
   8  * Copyright (c) 2005 Herbert Xu <[email protected]>
   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         kfree_sensitive(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_NS_GPL(crypto_cipher_setkey, CRYPTO_INTERNAL);
  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_NS_GPL(crypto_cipher_encrypt_one, CRYPTO_INTERNAL);
  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_NS_GPL(crypto_cipher_decrypt_one, CRYPTO_INTERNAL);
  92
  93 struct crypto_cipher *crypto_clone_cipher(struct crypto_cipher *cipher)
  94 {
  95         struct crypto_tfm *tfm = crypto_cipher_tfm(cipher);
  96         struct crypto_alg *alg = tfm->__crt_alg;
  97         struct crypto_cipher *ncipher;
  98         struct crypto_tfm *ntfm;
  99
 100         if (alg->cra_init)
 101                 return ERR_PTR(-ENOSYS);
 102
 103         if (unlikely(!crypto_mod_get(alg)))
 104                 return ERR_PTR(-ESTALE);
 105
 106         ntfm = __crypto_alloc_tfmgfp(alg, CRYPTO_ALG_TYPE_CIPHER,
 107                                      CRYPTO_ALG_TYPE_MASK, GFP_ATOMIC);
 108         if (IS_ERR(ntfm)) {
 109                 crypto_mod_put(alg);
 110                 return ERR_CAST(ntfm);
 111         }
 112
 113         ntfm->crt_flags = tfm->crt_flags;
 114
 115         ncipher = __crypto_cipher_cast(ntfm);
 116
 117         return ncipher;
 118 }
 119 EXPORT_SYMBOL_GPL(crypto_clone_cipher);