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[net-next-2.6.git] / crypto / cipher.c
CommitLineData
1da177e4
LT
1/*
2 * Cryptographic API.
3 *
4 * Cipher operations.
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
c774e93e 7 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
1da177e4
LT
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#include <linux/compiler.h>
16#include <linux/kernel.h>
17#include <linux/crypto.h>
18#include <linux/errno.h>
19#include <linux/mm.h>
20#include <linux/slab.h>
21#include <linux/string.h>
22#include <asm/scatterlist.h>
23#include "internal.h"
24#include "scatterwalk.h"
25
1da177e4
LT
26static inline void xor_64(u8 *a, const u8 *b)
27{
28 ((u32 *)a)[0] ^= ((u32 *)b)[0];
29 ((u32 *)a)[1] ^= ((u32 *)b)[1];
30}
31
32static inline void xor_128(u8 *a, const u8 *b)
33{
34 ((u32 *)a)[0] ^= ((u32 *)b)[0];
35 ((u32 *)a)[1] ^= ((u32 *)b)[1];
36 ((u32 *)a)[2] ^= ((u32 *)b)[2];
37 ((u32 *)a)[3] ^= ((u32 *)b)[3];
38}
c774e93e
HX
39
40static unsigned int crypt_slow(const struct cipher_desc *desc,
41 struct scatter_walk *in,
42 struct scatter_walk *out, unsigned int bsize)
1da177e4 43{
9d853c37 44 unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
95477377
HX
45 u8 buffer[bsize * 2 + alignmask];
46 u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
47 u8 *dst = src + bsize;
c774e93e 48 unsigned int n;
1da177e4 49
c774e93e
HX
50 n = scatterwalk_copychunks(src, in, bsize, 0);
51 scatterwalk_advance(in, n);
1da177e4 52
c774e93e 53 desc->prfn(desc, dst, src, bsize);
1da177e4 54
c774e93e
HX
55 n = scatterwalk_copychunks(dst, out, bsize, 1);
56 scatterwalk_advance(out, n);
1da177e4 57
c774e93e 58 return bsize;
1da177e4
LT
59}
60
c774e93e
HX
61static inline unsigned int crypt_fast(const struct cipher_desc *desc,
62 struct scatter_walk *in,
63 struct scatter_walk *out,
95477377 64 unsigned int nbytes, u8 *tmp)
1da177e4 65{
c774e93e
HX
66 u8 *src, *dst;
67
68 src = in->data;
69 dst = scatterwalk_samebuf(in, out) ? src : out->data;
70
95477377
HX
71 if (tmp) {
72 memcpy(tmp, in->data, nbytes);
73 src = tmp;
74 dst = tmp;
75 }
76
c774e93e
HX
77 nbytes = desc->prfn(desc, dst, src, nbytes);
78
95477377
HX
79 if (tmp)
80 memcpy(out->data, tmp, nbytes);
81
c774e93e
HX
82 scatterwalk_advance(in, nbytes);
83 scatterwalk_advance(out, nbytes);
1da177e4 84
c774e93e 85 return nbytes;
1da177e4
LT
86}
87
88/*
89 * Generic encrypt/decrypt wrapper for ciphers, handles operations across
90 * multiple page boundaries by using temporary blocks. In user context,
c774e93e 91 * the kernel is given a chance to schedule us once per page.
1da177e4 92 */
c774e93e 93static int crypt(const struct cipher_desc *desc,
1da177e4
LT
94 struct scatterlist *dst,
95 struct scatterlist *src,
c774e93e 96 unsigned int nbytes)
1da177e4
LT
97{
98 struct scatter_walk walk_in, walk_out;
c774e93e 99 struct crypto_tfm *tfm = desc->tfm;
1da177e4 100 const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
fbdae9f3 101 unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
95477377 102 unsigned long buffer = 0;
1da177e4
LT
103
104 if (!nbytes)
105 return 0;
106
107 if (nbytes % bsize) {
108 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
109 return -EINVAL;
110 }
111
112 scatterwalk_start(&walk_in, src);
113 scatterwalk_start(&walk_out, dst);
114
115 for(;;) {
95477377
HX
116 unsigned int n = nbytes;
117 u8 *tmp = NULL;
118
119 if (!scatterwalk_aligned(&walk_in, alignmask) ||
120 !scatterwalk_aligned(&walk_out, alignmask)) {
121 if (!buffer) {
122 buffer = __get_free_page(GFP_ATOMIC);
123 if (!buffer)
124 n = 0;
125 }
126 tmp = (u8 *)buffer;
127 }
1da177e4
LT
128
129 scatterwalk_map(&walk_in, 0);
130 scatterwalk_map(&walk_out, 1);
131
95477377 132 n = scatterwalk_clamp(&walk_in, n);
c774e93e 133 n = scatterwalk_clamp(&walk_out, n);
1da177e4 134
c774e93e 135 if (likely(n >= bsize))
95477377 136 n = crypt_fast(desc, &walk_in, &walk_out, n, tmp);
c774e93e
HX
137 else
138 n = crypt_slow(desc, &walk_in, &walk_out, bsize);
1da177e4 139
c774e93e 140 nbytes -= n;
1da177e4
LT
141
142 scatterwalk_done(&walk_in, 0, nbytes);
143 scatterwalk_done(&walk_out, 1, nbytes);
144
145 if (!nbytes)
95477377 146 break;
1da177e4
LT
147
148 crypto_yield(tfm);
149 }
95477377
HX
150
151 if (buffer)
152 free_page(buffer);
153
154 return 0;
1da177e4
LT
155}
156
915e8561
HX
157static int crypt_iv_unaligned(struct cipher_desc *desc,
158 struct scatterlist *dst,
159 struct scatterlist *src,
160 unsigned int nbytes)
161{
162 struct crypto_tfm *tfm = desc->tfm;
9d853c37 163 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
915e8561
HX
164 u8 *iv = desc->info;
165
166 if (unlikely(((unsigned long)iv & alignmask))) {
167 unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
168 u8 buffer[ivsize + alignmask];
169 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
170 int err;
171
172 desc->info = memcpy(tmp, iv, ivsize);
173 err = crypt(desc, dst, src, nbytes);
174 memcpy(iv, tmp, ivsize);
175
176 return err;
177 }
178
179 return crypt(desc, dst, src, nbytes);
180}
181
c774e93e
HX
182static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
183 u8 *dst, const u8 *src,
184 unsigned int nbytes)
1da177e4 185{
c774e93e
HX
186 struct crypto_tfm *tfm = desc->tfm;
187 void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
188 int bsize = crypto_tfm_alg_blocksize(tfm);
189
190 void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
191 u8 *iv = desc->info;
192 unsigned int done = 0;
193
fe2d5295
HX
194 nbytes -= bsize;
195
c774e93e
HX
196 do {
197 xor(iv, src);
198 fn(crypto_tfm_ctx(tfm), dst, iv);
199 memcpy(iv, dst, bsize);
1da177e4 200
c774e93e
HX
201 src += bsize;
202 dst += bsize;
fe2d5295 203 } while ((done += bsize) <= nbytes);
c774e93e
HX
204
205 return done;
1da177e4
LT
206}
207
c774e93e
HX
208static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
209 u8 *dst, const u8 *src,
210 unsigned int nbytes)
1da177e4 211{
c774e93e
HX
212 struct crypto_tfm *tfm = desc->tfm;
213 void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
214 int bsize = crypto_tfm_alg_blocksize(tfm);
215
216 u8 stack[src == dst ? bsize : 0];
217 u8 *buf = stack;
218 u8 **dst_p = src == dst ? &buf : &dst;
219
220 void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
221 u8 *iv = desc->info;
222 unsigned int done = 0;
223
fe2d5295
HX
224 nbytes -= bsize;
225
c774e93e
HX
226 do {
227 u8 *tmp_dst = *dst_p;
1da177e4 228
c774e93e
HX
229 fn(crypto_tfm_ctx(tfm), tmp_dst, src);
230 xor(tmp_dst, iv);
231 memcpy(iv, src, bsize);
232 if (tmp_dst != dst)
233 memcpy(dst, tmp_dst, bsize);
234
235 src += bsize;
236 dst += bsize;
fe2d5295 237 } while ((done += bsize) <= nbytes);
c774e93e
HX
238
239 return done;
1da177e4
LT
240}
241
c774e93e
HX
242static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
243 const u8 *src, unsigned int nbytes)
1da177e4 244{
c774e93e
HX
245 struct crypto_tfm *tfm = desc->tfm;
246 int bsize = crypto_tfm_alg_blocksize(tfm);
247 void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
248 unsigned int done = 0;
249
fe2d5295
HX
250 nbytes -= bsize;
251
c774e93e
HX
252 do {
253 fn(crypto_tfm_ctx(tfm), dst, src);
254
255 src += bsize;
256 dst += bsize;
fe2d5295 257 } while ((done += bsize) <= nbytes);
c774e93e
HX
258
259 return done;
1da177e4
LT
260}
261
262static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
263{
264 struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
265
266 if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
267 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
268 return -EINVAL;
269 } else
270 return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
271 &tfm->crt_flags);
272}
273
274static int ecb_encrypt(struct crypto_tfm *tfm,
275 struct scatterlist *dst,
276 struct scatterlist *src, unsigned int nbytes)
277{
c774e93e 278 struct cipher_desc desc;
40725181 279 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
280
281 desc.tfm = tfm;
40725181
HX
282 desc.crfn = cipher->cia_encrypt;
283 desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;
c774e93e
HX
284
285 return crypt(&desc, dst, src, nbytes);
1da177e4
LT
286}
287
288static int ecb_decrypt(struct crypto_tfm *tfm,
289 struct scatterlist *dst,
290 struct scatterlist *src,
291 unsigned int nbytes)
292{
c774e93e 293 struct cipher_desc desc;
40725181 294 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
295
296 desc.tfm = tfm;
40725181
HX
297 desc.crfn = cipher->cia_decrypt;
298 desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;
c774e93e
HX
299
300 return crypt(&desc, dst, src, nbytes);
1da177e4
LT
301}
302
303static int cbc_encrypt(struct crypto_tfm *tfm,
304 struct scatterlist *dst,
305 struct scatterlist *src,
306 unsigned int nbytes)
307{
c774e93e 308 struct cipher_desc desc;
40725181 309 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
310
311 desc.tfm = tfm;
40725181
HX
312 desc.crfn = cipher->cia_encrypt;
313 desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
c774e93e
HX
314 desc.info = tfm->crt_cipher.cit_iv;
315
316 return crypt(&desc, dst, src, nbytes);
1da177e4
LT
317}
318
319static int cbc_encrypt_iv(struct crypto_tfm *tfm,
320 struct scatterlist *dst,
321 struct scatterlist *src,
322 unsigned int nbytes, u8 *iv)
323{
c774e93e 324 struct cipher_desc desc;
40725181 325 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
326
327 desc.tfm = tfm;
40725181
HX
328 desc.crfn = cipher->cia_encrypt;
329 desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
c774e93e
HX
330 desc.info = iv;
331
915e8561 332 return crypt_iv_unaligned(&desc, dst, src, nbytes);
1da177e4
LT
333}
334
335static int cbc_decrypt(struct crypto_tfm *tfm,
336 struct scatterlist *dst,
337 struct scatterlist *src,
338 unsigned int nbytes)
339{
c774e93e 340 struct cipher_desc desc;
40725181 341 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
342
343 desc.tfm = tfm;
40725181
HX
344 desc.crfn = cipher->cia_decrypt;
345 desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
c774e93e
HX
346 desc.info = tfm->crt_cipher.cit_iv;
347
348 return crypt(&desc, dst, src, nbytes);
1da177e4
LT
349}
350
351static int cbc_decrypt_iv(struct crypto_tfm *tfm,
352 struct scatterlist *dst,
353 struct scatterlist *src,
354 unsigned int nbytes, u8 *iv)
355{
c774e93e 356 struct cipher_desc desc;
40725181 357 struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
c774e93e
HX
358
359 desc.tfm = tfm;
40725181
HX
360 desc.crfn = cipher->cia_decrypt;
361 desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
c774e93e
HX
362 desc.info = iv;
363
915e8561 364 return crypt_iv_unaligned(&desc, dst, src, nbytes);
1da177e4
LT
365}
366
367static int nocrypt(struct crypto_tfm *tfm,
368 struct scatterlist *dst,
369 struct scatterlist *src,
370 unsigned int nbytes)
371{
372 return -ENOSYS;
373}
374
375static int nocrypt_iv(struct crypto_tfm *tfm,
376 struct scatterlist *dst,
377 struct scatterlist *src,
378 unsigned int nbytes, u8 *iv)
379{
380 return -ENOSYS;
381}
382
383int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
384{
385 u32 mode = flags & CRYPTO_TFM_MODE_MASK;
1da177e4 386 tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
1da177e4
LT
387 return 0;
388}
389
390int crypto_init_cipher_ops(struct crypto_tfm *tfm)
391{
392 int ret = 0;
393 struct cipher_tfm *ops = &tfm->crt_cipher;
394
395 ops->cit_setkey = setkey;
396
397 switch (tfm->crt_cipher.cit_mode) {
398 case CRYPTO_TFM_MODE_ECB:
399 ops->cit_encrypt = ecb_encrypt;
400 ops->cit_decrypt = ecb_decrypt;
401 break;
402
403 case CRYPTO_TFM_MODE_CBC:
404 ops->cit_encrypt = cbc_encrypt;
405 ops->cit_decrypt = cbc_decrypt;
406 ops->cit_encrypt_iv = cbc_encrypt_iv;
407 ops->cit_decrypt_iv = cbc_decrypt_iv;
408 break;
409
410 case CRYPTO_TFM_MODE_CFB:
411 ops->cit_encrypt = nocrypt;
412 ops->cit_decrypt = nocrypt;
413 ops->cit_encrypt_iv = nocrypt_iv;
414 ops->cit_decrypt_iv = nocrypt_iv;
415 break;
416
417 case CRYPTO_TFM_MODE_CTR:
418 ops->cit_encrypt = nocrypt;
419 ops->cit_decrypt = nocrypt;
420 ops->cit_encrypt_iv = nocrypt_iv;
421 ops->cit_decrypt_iv = nocrypt_iv;
422 break;
423
424 default:
425 BUG();
426 }
427
428 if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
9d853c37 429 unsigned long align;
fbdae9f3 430 unsigned long addr;
1da177e4
LT
431
432 switch (crypto_tfm_alg_blocksize(tfm)) {
433 case 8:
434 ops->cit_xor_block = xor_64;
435 break;
436
437 case 16:
438 ops->cit_xor_block = xor_128;
439 break;
440
441 default:
442 printk(KERN_WARNING "%s: block size %u not supported\n",
443 crypto_tfm_alg_name(tfm),
444 crypto_tfm_alg_blocksize(tfm));
445 ret = -EINVAL;
446 goto out;
447 }
448
449 ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
fbdae9f3
HX
450 align = crypto_tfm_alg_alignmask(tfm) + 1;
451 addr = (unsigned long)crypto_tfm_ctx(tfm);
452 addr = ALIGN(addr, align);
453 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
454 ops->cit_iv = (void *)addr;
1da177e4
LT
455 }
456
457out:
458 return ret;
459}
460
461void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
462{
1da177e4 463}