Root/crypto/cipher.c

1/*
2 * Cryptographic API.
3 *
4 * Cipher operations.
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16#include <linux/kernel.h>
17#include <linux/crypto.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include "internal.h"
22
23static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
24                unsigned int keylen)
25{
26    struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
27    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
28    int ret;
29    u8 *buffer, *alignbuffer;
30    unsigned long absize;
31
32    absize = keylen + alignmask;
33    buffer = kmalloc(absize, GFP_ATOMIC);
34    if (!buffer)
35        return -ENOMEM;
36
37    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
38    memcpy(alignbuffer, key, keylen);
39    ret = cia->cia_setkey(tfm, alignbuffer, keylen);
40    memset(alignbuffer, 0, keylen);
41    kfree(buffer);
42    return ret;
43
44}
45
46static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
47{
48    struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
49    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
50
51    tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
52    if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
53        tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
54        return -EINVAL;
55    }
56
57    if ((unsigned long)key & alignmask)
58        return setkey_unaligned(tfm, key, keylen);
59
60    return cia->cia_setkey(tfm, key, keylen);
61}
62
63static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
64                          const u8 *),
65                   struct crypto_tfm *tfm,
66                   u8 *dst, const u8 *src)
67{
68    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
69    unsigned int size = crypto_tfm_alg_blocksize(tfm);
70    u8 buffer[size + alignmask];
71    u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
72
73    memcpy(tmp, src, size);
74    fn(tfm, tmp, tmp);
75    memcpy(dst, tmp, size);
76}
77
78static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
79                     u8 *dst, const u8 *src)
80{
81    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
82    struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
83
84    if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
85        cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
86        return;
87    }
88
89    cipher->cia_encrypt(tfm, dst, src);
90}
91
92static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
93                     u8 *dst, const u8 *src)
94{
95    unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
96    struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
97
98    if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
99        cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
100        return;
101    }
102
103    cipher->cia_decrypt(tfm, dst, src);
104}
105
106int crypto_init_cipher_ops(struct crypto_tfm *tfm)
107{
108    struct cipher_tfm *ops = &tfm->crt_cipher;
109    struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
110
111    ops->cit_setkey = setkey;
112    ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
113        cipher_encrypt_unaligned : cipher->cia_encrypt;
114    ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
115        cipher_decrypt_unaligned : cipher->cia_decrypt;
116
117    return 0;
118}
119
120void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
121{
122}
123

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