[CRYPTO] api: Mark parts of cipher interface as deprecated
[linux-2.6.git] / crypto / cipher.c
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 #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
26 struct cipher_alg_compat {
27         unsigned int cia_min_keysize;
28         unsigned int cia_max_keysize;
29         int (*cia_setkey)(struct crypto_tfm *tfm, const u8 *key,
30                           unsigned int keylen);
31         void (*cia_encrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
32         void (*cia_decrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
33
34         unsigned int (*cia_encrypt_ecb)(const struct cipher_desc *desc,
35                                         u8 *dst, const u8 *src,
36                                         unsigned int nbytes);
37         unsigned int (*cia_decrypt_ecb)(const struct cipher_desc *desc,
38                                         u8 *dst, const u8 *src,
39                                         unsigned int nbytes);
40         unsigned int (*cia_encrypt_cbc)(const struct cipher_desc *desc,
41                                         u8 *dst, const u8 *src,
42                                         unsigned int nbytes);
43         unsigned int (*cia_decrypt_cbc)(const struct cipher_desc *desc,
44                                         u8 *dst, const u8 *src,
45                                         unsigned int nbytes);
46 };
47
48 static inline void xor_64(u8 *a, const u8 *b)
49 {
50         ((u32 *)a)[0] ^= ((u32 *)b)[0];
51         ((u32 *)a)[1] ^= ((u32 *)b)[1];
52 }
53
54 static inline void xor_128(u8 *a, const u8 *b)
55 {
56         ((u32 *)a)[0] ^= ((u32 *)b)[0];
57         ((u32 *)a)[1] ^= ((u32 *)b)[1];
58         ((u32 *)a)[2] ^= ((u32 *)b)[2];
59         ((u32 *)a)[3] ^= ((u32 *)b)[3];
60 }
61
62 static unsigned int crypt_slow(const struct cipher_desc *desc,
63                                struct scatter_walk *in,
64                                struct scatter_walk *out, unsigned int bsize)
65 {
66         unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
67         u8 buffer[bsize * 2 + alignmask];
68         u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
69         u8 *dst = src + bsize;
70
71         scatterwalk_copychunks(src, in, bsize, 0);
72         desc->prfn(desc, dst, src, bsize);
73         scatterwalk_copychunks(dst, out, bsize, 1);
74
75         return bsize;
76 }
77
78 static inline unsigned int crypt_fast(const struct cipher_desc *desc,
79                                       struct scatter_walk *in,
80                                       struct scatter_walk *out,
81                                       unsigned int nbytes, u8 *tmp)
82 {
83         u8 *src, *dst;
84         u8 *real_src, *real_dst;
85
86         real_src = scatterwalk_map(in, 0);
87         real_dst = scatterwalk_map(out, 1);
88
89         src = real_src;
90         dst = scatterwalk_samebuf(in, out) ? src : real_dst;
91
92         if (tmp) {
93                 memcpy(tmp, src, nbytes);
94                 src = tmp;
95                 dst = tmp;
96         }
97
98         nbytes = desc->prfn(desc, dst, src, nbytes);
99
100         if (tmp)
101                 memcpy(real_dst, tmp, nbytes);
102
103         scatterwalk_unmap(real_src, 0);
104         scatterwalk_unmap(real_dst, 1);
105
106         scatterwalk_advance(in, nbytes);
107         scatterwalk_advance(out, nbytes);
108
109         return nbytes;
110 }
111
112 /* 
113  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
114  * multiple page boundaries by using temporary blocks.  In user context,
115  * the kernel is given a chance to schedule us once per page.
116  */
117 static int crypt(const struct cipher_desc *desc,
118                  struct scatterlist *dst,
119                  struct scatterlist *src,
120                  unsigned int nbytes)
121 {
122         struct scatter_walk walk_in, walk_out;
123         struct crypto_tfm *tfm = desc->tfm;
124         const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
125         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
126         unsigned long buffer = 0;
127
128         if (!nbytes)
129                 return 0;
130
131         if (nbytes % bsize) {
132                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
133                 return -EINVAL;
134         }
135
136         scatterwalk_start(&walk_in, src);
137         scatterwalk_start(&walk_out, dst);
138
139         for(;;) {
140                 unsigned int n = nbytes;
141                 u8 *tmp = NULL;
142
143                 if (!scatterwalk_aligned(&walk_in, alignmask) ||
144                     !scatterwalk_aligned(&walk_out, alignmask)) {
145                         if (!buffer) {
146                                 buffer = __get_free_page(GFP_ATOMIC);
147                                 if (!buffer)
148                                         n = 0;
149                         }
150                         tmp = (u8 *)buffer;
151                 }
152
153                 n = scatterwalk_clamp(&walk_in, n);
154                 n = scatterwalk_clamp(&walk_out, n);
155
156                 if (likely(n >= bsize))
157                         n = crypt_fast(desc, &walk_in, &walk_out, n, tmp);
158                 else
159                         n = crypt_slow(desc, &walk_in, &walk_out, bsize);
160
161                 nbytes -= n;
162
163                 scatterwalk_done(&walk_in, 0, nbytes);
164                 scatterwalk_done(&walk_out, 1, nbytes);
165
166                 if (!nbytes)
167                         break;
168
169                 crypto_yield(tfm->crt_flags);
170         }
171
172         if (buffer)
173                 free_page(buffer);
174
175         return 0;
176 }
177
178 static int crypt_iv_unaligned(struct cipher_desc *desc,
179                               struct scatterlist *dst,
180                               struct scatterlist *src,
181                               unsigned int nbytes)
182 {
183         struct crypto_tfm *tfm = desc->tfm;
184         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
185         u8 *iv = desc->info;
186
187         if (unlikely(((unsigned long)iv & alignmask))) {
188                 unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
189                 u8 buffer[ivsize + alignmask];
190                 u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
191                 int err;
192
193                 desc->info = memcpy(tmp, iv, ivsize);
194                 err = crypt(desc, dst, src, nbytes);
195                 memcpy(iv, tmp, ivsize);
196
197                 return err;
198         }
199
200         return crypt(desc, dst, src, nbytes);
201 }
202
203 static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
204                                         u8 *dst, const u8 *src,
205                                         unsigned int nbytes)
206 {
207         struct crypto_tfm *tfm = desc->tfm;
208         void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
209         int bsize = crypto_tfm_alg_blocksize(tfm);
210
211         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
212         u8 *iv = desc->info;
213         unsigned int done = 0;
214
215         nbytes -= bsize;
216
217         do {
218                 xor(iv, src);
219                 fn(tfm, dst, iv);
220                 memcpy(iv, dst, bsize);
221
222                 src += bsize;
223                 dst += bsize;
224         } while ((done += bsize) <= nbytes);
225
226         return done;
227 }
228
229 static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
230                                         u8 *dst, const u8 *src,
231                                         unsigned int nbytes)
232 {
233         struct crypto_tfm *tfm = desc->tfm;
234         void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
235         int bsize = crypto_tfm_alg_blocksize(tfm);
236         unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
237
238         u8 stack[src == dst ? bsize + alignmask : 0];
239         u8 *buf = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);
240         u8 **dst_p = src == dst ? &buf : &dst;
241
242         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
243         u8 *iv = desc->info;
244         unsigned int done = 0;
245
246         nbytes -= bsize;
247
248         do {
249                 u8 *tmp_dst = *dst_p;
250
251                 fn(tfm, tmp_dst, src);
252                 xor(tmp_dst, iv);
253                 memcpy(iv, src, bsize);
254                 if (tmp_dst != dst)
255                         memcpy(dst, tmp_dst, bsize);
256
257                 src += bsize;
258                 dst += bsize;
259         } while ((done += bsize) <= nbytes);
260
261         return done;
262 }
263
264 static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
265                                 const u8 *src, unsigned int nbytes)
266 {
267         struct crypto_tfm *tfm = desc->tfm;
268         int bsize = crypto_tfm_alg_blocksize(tfm);
269         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
270         unsigned int done = 0;
271
272         nbytes -= bsize;
273
274         do {
275                 fn(tfm, dst, src);
276
277                 src += bsize;
278                 dst += bsize;
279         } while ((done += bsize) <= nbytes);
280
281         return done;
282 }
283
284 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
285 {
286         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
287         
288         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
289         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
290                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
291                 return -EINVAL;
292         } else
293                 return cia->cia_setkey(tfm, key, keylen);
294 }
295
296 static int ecb_encrypt(struct crypto_tfm *tfm,
297                        struct scatterlist *dst,
298                        struct scatterlist *src, unsigned int nbytes)
299 {
300         struct cipher_desc desc;
301         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
302
303         desc.tfm = tfm;
304         desc.crfn = cipher->cia_encrypt;
305         desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;
306
307         return crypt(&desc, dst, src, nbytes);
308 }
309
310 static int ecb_decrypt(struct crypto_tfm *tfm,
311                        struct scatterlist *dst,
312                        struct scatterlist *src,
313                        unsigned int nbytes)
314 {
315         struct cipher_desc desc;
316         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
317
318         desc.tfm = tfm;
319         desc.crfn = cipher->cia_decrypt;
320         desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;
321
322         return crypt(&desc, dst, src, nbytes);
323 }
324
325 static int cbc_encrypt(struct crypto_tfm *tfm,
326                        struct scatterlist *dst,
327                        struct scatterlist *src,
328                        unsigned int nbytes)
329 {
330         struct cipher_desc desc;
331         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
332
333         desc.tfm = tfm;
334         desc.crfn = cipher->cia_encrypt;
335         desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
336         desc.info = tfm->crt_cipher.cit_iv;
337
338         return crypt(&desc, dst, src, nbytes);
339 }
340
341 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
342                           struct scatterlist *dst,
343                           struct scatterlist *src,
344                           unsigned int nbytes, u8 *iv)
345 {
346         struct cipher_desc desc;
347         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
348
349         desc.tfm = tfm;
350         desc.crfn = cipher->cia_encrypt;
351         desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
352         desc.info = iv;
353
354         return crypt_iv_unaligned(&desc, dst, src, nbytes);
355 }
356
357 static int cbc_decrypt(struct crypto_tfm *tfm,
358                        struct scatterlist *dst,
359                        struct scatterlist *src,
360                        unsigned int nbytes)
361 {
362         struct cipher_desc desc;
363         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
364
365         desc.tfm = tfm;
366         desc.crfn = cipher->cia_decrypt;
367         desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
368         desc.info = tfm->crt_cipher.cit_iv;
369
370         return crypt(&desc, dst, src, nbytes);
371 }
372
373 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
374                           struct scatterlist *dst,
375                           struct scatterlist *src,
376                           unsigned int nbytes, u8 *iv)
377 {
378         struct cipher_desc desc;
379         struct cipher_alg_compat *cipher = (void *)&tfm->__crt_alg->cra_cipher;
380
381         desc.tfm = tfm;
382         desc.crfn = cipher->cia_decrypt;
383         desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
384         desc.info = iv;
385
386         return crypt_iv_unaligned(&desc, dst, src, nbytes);
387 }
388
389 static int nocrypt(struct crypto_tfm *tfm,
390                    struct scatterlist *dst,
391                    struct scatterlist *src,
392                    unsigned int nbytes)
393 {
394         return -ENOSYS;
395 }
396
397 static int nocrypt_iv(struct crypto_tfm *tfm,
398                       struct scatterlist *dst,
399                       struct scatterlist *src,
400                       unsigned int nbytes, u8 *iv)
401 {
402         return -ENOSYS;
403 }
404
405 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
406 {
407         u32 mode = flags & CRYPTO_TFM_MODE_MASK;
408         tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
409         return 0;
410 }
411
412 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
413                                               const u8 *),
414                                    struct crypto_tfm *tfm,
415                                    u8 *dst, const u8 *src)
416 {
417         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
418         unsigned int size = crypto_tfm_alg_blocksize(tfm);
419         u8 buffer[size + alignmask];
420         u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
421
422         memcpy(tmp, src, size);
423         fn(tfm, tmp, tmp);
424         memcpy(dst, tmp, size);
425 }
426
427 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
428                                      u8 *dst, const u8 *src)
429 {
430         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
431         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
432
433         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
434                 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
435                 return;
436         }
437
438         cipher->cia_encrypt(tfm, dst, src);
439 }
440
441 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
442                                      u8 *dst, const u8 *src)
443 {
444         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
445         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
446
447         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
448                 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
449                 return;
450         }
451
452         cipher->cia_decrypt(tfm, dst, src);
453 }
454
455 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
456 {
457         int ret = 0;
458         struct cipher_tfm *ops = &tfm->crt_cipher;
459         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
460
461         ops->cit_setkey = setkey;
462         ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
463                 cipher_encrypt_unaligned : cipher->cia_encrypt;
464         ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
465                 cipher_decrypt_unaligned : cipher->cia_decrypt;
466
467         switch (tfm->crt_cipher.cit_mode) {
468         case CRYPTO_TFM_MODE_ECB:
469                 ops->cit_encrypt = ecb_encrypt;
470                 ops->cit_decrypt = ecb_decrypt;
471                 ops->cit_encrypt_iv = nocrypt_iv;
472                 ops->cit_decrypt_iv = nocrypt_iv;
473                 break;
474                 
475         case CRYPTO_TFM_MODE_CBC:
476                 ops->cit_encrypt = cbc_encrypt;
477                 ops->cit_decrypt = cbc_decrypt;
478                 ops->cit_encrypt_iv = cbc_encrypt_iv;
479                 ops->cit_decrypt_iv = cbc_decrypt_iv;
480                 break;
481                 
482         case CRYPTO_TFM_MODE_CFB:
483                 ops->cit_encrypt = nocrypt;
484                 ops->cit_decrypt = nocrypt;
485                 ops->cit_encrypt_iv = nocrypt_iv;
486                 ops->cit_decrypt_iv = nocrypt_iv;
487                 break;
488         
489         case CRYPTO_TFM_MODE_CTR:
490                 ops->cit_encrypt = nocrypt;
491                 ops->cit_decrypt = nocrypt;
492                 ops->cit_encrypt_iv = nocrypt_iv;
493                 ops->cit_decrypt_iv = nocrypt_iv;
494                 break;
495
496         default:
497                 BUG();
498         }
499         
500         if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
501                 unsigned long align;
502                 unsigned long addr;
503                 
504                 switch (crypto_tfm_alg_blocksize(tfm)) {
505                 case 8:
506                         ops->cit_xor_block = xor_64;
507                         break;
508                         
509                 case 16:
510                         ops->cit_xor_block = xor_128;
511                         break;
512                         
513                 default:
514                         printk(KERN_WARNING "%s: block size %u not supported\n",
515                                crypto_tfm_alg_name(tfm),
516                                crypto_tfm_alg_blocksize(tfm));
517                         ret = -EINVAL;
518                         goto out;
519                 }
520                 
521                 ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
522                 align = crypto_tfm_alg_alignmask(tfm) + 1;
523                 addr = (unsigned long)crypto_tfm_ctx(tfm);
524                 addr = ALIGN(addr, align);
525                 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
526                 ops->cit_iv = (void *)addr;
527         }
528
529 out:    
530         return ret;
531 }
532
533 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
534 {
535 }