xref: /openbmc/linux/crypto/cipher.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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/scatterlist.h>
20 #include <linux/string.h>
21 #include "internal.h"
22 
23 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
24 {
25 	struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
26 
27 	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
28 	if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
29 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
30 		return -EINVAL;
31 	} else
32 		return cia->cia_setkey(tfm, key, keylen);
33 }
34 
35 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
36 					      const u8 *),
37 				   struct crypto_tfm *tfm,
38 				   u8 *dst, const u8 *src)
39 {
40 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
41 	unsigned int size = crypto_tfm_alg_blocksize(tfm);
42 	u8 buffer[size + alignmask];
43 	u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
44 
45 	memcpy(tmp, src, size);
46 	fn(tfm, tmp, tmp);
47 	memcpy(dst, tmp, size);
48 }
49 
50 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
51 				     u8 *dst, const u8 *src)
52 {
53 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
54 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
55 
56 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
57 		cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
58 		return;
59 	}
60 
61 	cipher->cia_encrypt(tfm, dst, src);
62 }
63 
64 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
65 				     u8 *dst, const u8 *src)
66 {
67 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
68 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
69 
70 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
71 		cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
72 		return;
73 	}
74 
75 	cipher->cia_decrypt(tfm, dst, src);
76 }
77 
78 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
79 {
80 	struct cipher_tfm *ops = &tfm->crt_cipher;
81 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
82 
83 	ops->cit_setkey = setkey;
84 	ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
85 		cipher_encrypt_unaligned : cipher->cia_encrypt;
86 	ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
87 		cipher_decrypt_unaligned : cipher->cia_decrypt;
88 
89 	return 0;
90 }
91 
92 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
93 {
94 }
95