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 <crypto/algapi.h>
17 #include <linux/kernel.h>
18 #include <linux/crypto.h>
19 #include <linux/errno.h>
20 #include <linux/slab.h>
21 #include <linux/string.h>
22 #include "internal.h"
23 
setkey_unaligned(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)24 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
25 			    unsigned int keylen)
26 {
27 	struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
28 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
29 	int ret;
30 	u8 *buffer, *alignbuffer;
31 	unsigned long absize;
32 
33 	absize = keylen + alignmask;
34 	buffer = kmalloc(absize, GFP_ATOMIC);
35 	if (!buffer)
36 		return -ENOMEM;
37 
38 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
39 	memcpy(alignbuffer, key, keylen);
40 	ret = cia->cia_setkey(tfm, alignbuffer, keylen);
41 	memset(alignbuffer, 0, keylen);
42 	kfree(buffer);
43 	return ret;
44 
45 }
46 
setkey(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)47 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
48 {
49 	struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
50 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
51 
52 	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
53 	if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
54 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
55 		return -EINVAL;
56 	}
57 
58 	if ((unsigned long)key & alignmask)
59 		return setkey_unaligned(tfm, key, keylen);
60 
61 	return cia->cia_setkey(tfm, key, keylen);
62 }
63 
cipher_crypt_unaligned(void (* fn)(struct crypto_tfm *,u8 *,const u8 *),struct crypto_tfm * tfm,u8 * dst,const u8 * src)64 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
65 					      const u8 *),
66 				   struct crypto_tfm *tfm,
67 				   u8 *dst, const u8 *src)
68 {
69 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
70 	unsigned int size = crypto_tfm_alg_blocksize(tfm);
71 	u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
72 	u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
73 
74 	memcpy(tmp, src, size);
75 	fn(tfm, tmp, tmp);
76 	memcpy(dst, tmp, size);
77 }
78 
cipher_encrypt_unaligned(struct crypto_tfm * tfm,u8 * dst,const u8 * src)79 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
80 				     u8 *dst, const u8 *src)
81 {
82 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
83 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
84 
85 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
86 		cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
87 		return;
88 	}
89 
90 	cipher->cia_encrypt(tfm, dst, src);
91 }
92 
cipher_decrypt_unaligned(struct crypto_tfm * tfm,u8 * dst,const u8 * src)93 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
94 				     u8 *dst, const u8 *src)
95 {
96 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
97 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
98 
99 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
100 		cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
101 		return;
102 	}
103 
104 	cipher->cia_decrypt(tfm, dst, src);
105 }
106 
crypto_init_cipher_ops(struct crypto_tfm * tfm)107 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
108 {
109 	struct cipher_tfm *ops = &tfm->crt_cipher;
110 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
111 
112 	ops->cit_setkey = setkey;
113 	ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
114 		cipher_encrypt_unaligned : cipher->cia_encrypt;
115 	ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
116 		cipher_decrypt_unaligned : cipher->cia_decrypt;
117 
118 	return 0;
119 }
120