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