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