1 /*
2 * Cryptographic API.
3 *
4 * Cipher operations.
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14 #include <linux/kernel.h>
15 //#include <linux/crypto.h>
16 #include "rtl_crypto.h"
17 #include <linux/errno.h>
18 #include <linux/mm.h>
19 #include <linux/slab.h>
20 #include <asm/scatterlist.h>
21 #include "internal.h"
22 #include "scatterwalk.h"
23
24 typedef void (cryptfn_t)(void *, u8 *, const u8 *);
25 typedef void (procfn_t)(struct crypto_tfm *, u8 *,
26 u8*, cryptfn_t, int enc, void *, int);
27
28 static inline void xor_64(u8 *a, const u8 *b)
29 {
30 ((u32 *)a)[0] ^= ((u32 *)b)[0];
31 ((u32 *)a)[1] ^= ((u32 *)b)[1];
32 }
33
34 static inline void xor_128(u8 *a, const u8 *b)
35 {
36 ((u32 *)a)[0] ^= ((u32 *)b)[0];
37 ((u32 *)a)[1] ^= ((u32 *)b)[1];
38 ((u32 *)a)[2] ^= ((u32 *)b)[2];
39 ((u32 *)a)[3] ^= ((u32 *)b)[3];
40 }
41
42
43 /*
44 * Generic encrypt/decrypt wrapper for ciphers, handles operations across
45 * multiple page boundaries by using temporary blocks. In user context,
46 * the kernel is given a chance to schedule us once per block.
47 */
48 static int crypt(struct crypto_tfm *tfm,
49 struct scatterlist *dst,
50 struct scatterlist *src,
51 unsigned int nbytes, cryptfn_t crfn,
52 procfn_t prfn, int enc, void *info)
53 {
54 struct scatter_walk walk_in, walk_out;
55 const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
56 u8 tmp_src[bsize];
57 u8 tmp_dst[bsize];
58
59 if (!nbytes)
60 return 0;
61
62 if (nbytes % bsize) {
63 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
64 return -EINVAL;
65 }
66
67 scatterwalk_start(&walk_in, src);
68 scatterwalk_start(&walk_out, dst);
69
70 for(;;) {
71 u8 *src_p, *dst_p;
72 int in_place;
73
74 scatterwalk_map(&walk_in, 0);
75 scatterwalk_map(&walk_out, 1);
76 src_p = scatterwalk_whichbuf(&walk_in, bsize, tmp_src);
77 dst_p = scatterwalk_whichbuf(&walk_out, bsize, tmp_dst);
78 in_place = scatterwalk_samebuf(&walk_in, &walk_out,
79 src_p, dst_p);
80
81 nbytes -= bsize;
82
83 scatterwalk_copychunks(src_p, &walk_in, bsize, 0);
84
85 prfn(tfm, dst_p, src_p, crfn, enc, info, in_place);
86
87 scatterwalk_done(&walk_in, 0, nbytes);
88
89 scatterwalk_copychunks(dst_p, &walk_out, bsize, 1);
90 scatterwalk_done(&walk_out, 1, nbytes);
91
92 if (!nbytes)
93 return 0;
94
95 crypto_yield(tfm);
96 }
97 }
98
99 static void cbc_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
100 cryptfn_t fn, int enc, void *info, int in_place)
101 {
102 u8 *iv = info;
103
104 /* Null encryption */
105 if (!iv)
106 return;
107
108 if (enc) {
109 tfm->crt_u.cipher.cit_xor_block(iv, src);
110 fn(crypto_tfm_ctx(tfm), dst, iv);
111 memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
112 } else {
113 u8 stack[in_place ? crypto_tfm_alg_blocksize(tfm) : 0];
114 u8 *buf = in_place ? stack : dst;
115
116 fn(crypto_tfm_ctx(tfm), buf, src);
117 tfm->crt_u.cipher.cit_xor_block(buf, iv);
118 memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
119 if (buf != dst)
120 memcpy(dst, buf, crypto_tfm_alg_blocksize(tfm));
121 }
122 }
123
124 static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
125 cryptfn_t fn, int enc, void *info, int in_place)
126 {
127 fn(crypto_tfm_ctx(tfm), dst, src);
128 }
129
130 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
131 {
132 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
133
134 if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
135 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
136 return -EINVAL;
137 } else
138 return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
139 &tfm->crt_flags);
140 }
141
142 static int ecb_encrypt(struct crypto_tfm *tfm,
143 struct scatterlist *dst,
144 struct scatterlist *src, unsigned int nbytes)
145 {
146 return crypt(tfm, dst, src, nbytes,
147 tfm->__crt_alg->cra_cipher.cia_encrypt,
148 ecb_process, 1, NULL);
149 }
150
151 static int ecb_decrypt(struct crypto_tfm *tfm,
152 struct scatterlist *dst,
153 struct scatterlist *src,
154 unsigned int nbytes)
155 {
156 return crypt(tfm, dst, src, nbytes,
157 tfm->__crt_alg->cra_cipher.cia_decrypt,
158 ecb_process, 1, NULL);
159 }
160
161 static int cbc_encrypt(struct crypto_tfm *tfm,
162 struct scatterlist *dst,
163 struct scatterlist *src,
164 unsigned int nbytes)
165 {
166 return crypt(tfm, dst, src, nbytes,
167 tfm->__crt_alg->cra_cipher.cia_encrypt,
168 cbc_process, 1, tfm->crt_cipher.cit_iv);
169 }
170
171 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
172 struct scatterlist *dst,
173 struct scatterlist *src,
174 unsigned int nbytes, u8 *iv)
175 {
176 return crypt(tfm, dst, src, nbytes,
177 tfm->__crt_alg->cra_cipher.cia_encrypt,
178 cbc_process, 1, iv);
179 }
180
181 static int cbc_decrypt(struct crypto_tfm *tfm,
182 struct scatterlist *dst,
183 struct scatterlist *src,
184 unsigned int nbytes)
185 {
186 return crypt(tfm, dst, src, nbytes,
187 tfm->__crt_alg->cra_cipher.cia_decrypt,
188 cbc_process, 0, tfm->crt_cipher.cit_iv);
189 }
190
191 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
192 struct scatterlist *dst,
193 struct scatterlist *src,
194 unsigned int nbytes, u8 *iv)
195 {
196 return crypt(tfm, dst, src, nbytes,
197 tfm->__crt_alg->cra_cipher.cia_decrypt,
198 cbc_process, 0, iv);
199 }
200
201 static int nocrypt(struct crypto_tfm *tfm,
202 struct scatterlist *dst,
203 struct scatterlist *src,
204 unsigned int nbytes)
205 {
206 return -ENOSYS;
207 }
208
209 static int nocrypt_iv(struct crypto_tfm *tfm,
210 struct scatterlist *dst,
211 struct scatterlist *src,
212 unsigned int nbytes, u8 *iv)
213 {
214 return -ENOSYS;
215 }
216
217 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
218 {
219 u32 mode = flags & CRYPTO_TFM_MODE_MASK;
220
221 tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
222 if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
223 tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;
224
225 return 0;
226 }
227
228 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
229 {
230 int ret = 0;
231 struct cipher_tfm *ops = &tfm->crt_cipher;
232
233 ops->cit_setkey = setkey;
234
235 switch (tfm->crt_cipher.cit_mode) {
236 case CRYPTO_TFM_MODE_ECB:
237 ops->cit_encrypt = ecb_encrypt;
238 ops->cit_decrypt = ecb_decrypt;
239 break;
240
241 case CRYPTO_TFM_MODE_CBC:
242 ops->cit_encrypt = cbc_encrypt;
243 ops->cit_decrypt = cbc_decrypt;
244 ops->cit_encrypt_iv = cbc_encrypt_iv;
245 ops->cit_decrypt_iv = cbc_decrypt_iv;
246 break;
247
248 case CRYPTO_TFM_MODE_CFB:
249 ops->cit_encrypt = nocrypt;
250 ops->cit_decrypt = nocrypt;
251 ops->cit_encrypt_iv = nocrypt_iv;
252 ops->cit_decrypt_iv = nocrypt_iv;
253 break;
254
255 case CRYPTO_TFM_MODE_CTR:
256 ops->cit_encrypt = nocrypt;
257 ops->cit_decrypt = nocrypt;
258 ops->cit_encrypt_iv = nocrypt_iv;
259 ops->cit_decrypt_iv = nocrypt_iv;
260 break;
261
262 default:
263 BUG();
264 }
265
266 if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
267
268 switch (crypto_tfm_alg_blocksize(tfm)) {
269 case 8:
270 ops->cit_xor_block = xor_64;
271 break;
272
273 case 16:
274 ops->cit_xor_block = xor_128;
275 break;
276
277 default:
278 printk(KERN_WARNING "%s: block size %u not supported\n",
279 crypto_tfm_alg_name(tfm),
280 crypto_tfm_alg_blocksize(tfm));
281 ret = -EINVAL;
282 goto out;
283 }
284
285 ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
286 ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
287 if (ops->cit_iv == NULL)
288 ret = -ENOMEM;
289 }
290
291 out:
292 return ret;
293 }
294
295 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
296 {
297 if (tfm->crt_cipher.cit_iv)
298 kfree(tfm->crt_cipher.cit_iv);
299 }
300
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