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