blob: f6c67f9d4e5c2f9085558991a6fc87893e269670 [file] [log] [blame]
Herbert Xu5cde0af2006-08-22 00:07:53 +10001/*
2 * Block chaining cipher operations.
3 *
4 * Generic encrypt/decrypt wrapper for ciphers, handles operations across
5 * multiple page boundaries by using temporary blocks. In user context,
6 * the kernel is given a chance to schedule us once per page.
7 *
8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 */
16
17#include <linux/crypto.h>
18#include <linux/errno.h>
Herbert Xufb469842006-12-10 10:45:28 +110019#include <linux/hardirq.h>
Herbert Xu5cde0af2006-08-22 00:07:53 +100020#include <linux/kernel.h>
Herbert Xu5cde0af2006-08-22 00:07:53 +100021#include <linux/module.h>
22#include <linux/scatterlist.h>
23#include <linux/seq_file.h>
24#include <linux/slab.h>
25#include <linux/string.h>
26
27#include "internal.h"
28#include "scatterwalk.h"
29
30enum {
31 BLKCIPHER_WALK_PHYS = 1 << 0,
32 BLKCIPHER_WALK_SLOW = 1 << 1,
33 BLKCIPHER_WALK_COPY = 1 << 2,
34 BLKCIPHER_WALK_DIFF = 1 << 3,
35};
36
37static int blkcipher_walk_next(struct blkcipher_desc *desc,
38 struct blkcipher_walk *walk);
39static int blkcipher_walk_first(struct blkcipher_desc *desc,
40 struct blkcipher_walk *walk);
41
42static inline void blkcipher_map_src(struct blkcipher_walk *walk)
43{
44 walk->src.virt.addr = scatterwalk_map(&walk->in, 0);
45}
46
47static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
48{
49 walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
50}
51
52static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
53{
54 scatterwalk_unmap(walk->src.virt.addr, 0);
55}
56
57static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
58{
59 scatterwalk_unmap(walk->dst.virt.addr, 1);
60}
61
Herbert Xue4630f92007-09-09 08:45:21 +010062/* Get a spot of the specified length that does not straddle a page.
63 * The caller needs to ensure that there is enough space for this operation.
64 */
Herbert Xu5cde0af2006-08-22 00:07:53 +100065static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
66{
Herbert Xue4630f92007-09-09 08:45:21 +010067 u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
Ingo Oeser5aaff0c2007-09-19 19:11:41 +080068 return max(start, end_page);
Herbert Xu5cde0af2006-08-22 00:07:53 +100069}
70
71static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
72 struct blkcipher_walk *walk,
73 unsigned int bsize)
74{
75 u8 *addr;
76 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
77
78 addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
79 addr = blkcipher_get_spot(addr, bsize);
80 scatterwalk_copychunks(addr, &walk->out, bsize, 1);
81 return bsize;
82}
83
84static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
85 unsigned int n)
86{
Herbert Xu5cde0af2006-08-22 00:07:53 +100087 if (walk->flags & BLKCIPHER_WALK_COPY) {
88 blkcipher_map_dst(walk);
89 memcpy(walk->dst.virt.addr, walk->page, n);
90 blkcipher_unmap_dst(walk);
91 } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
92 blkcipher_unmap_src(walk);
93 if (walk->flags & BLKCIPHER_WALK_DIFF)
94 blkcipher_unmap_dst(walk);
95 }
96
97 scatterwalk_advance(&walk->in, n);
98 scatterwalk_advance(&walk->out, n);
99
100 return n;
101}
102
103int blkcipher_walk_done(struct blkcipher_desc *desc,
104 struct blkcipher_walk *walk, int err)
105{
106 struct crypto_blkcipher *tfm = desc->tfm;
107 unsigned int nbytes = 0;
108
109 if (likely(err >= 0)) {
Herbert Xu7607bd82007-10-04 15:24:05 +0800110 unsigned int n = walk->nbytes - err;
Herbert Xu5cde0af2006-08-22 00:07:53 +1000111
112 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
Herbert Xu7607bd82007-10-04 15:24:05 +0800113 n = blkcipher_done_fast(walk, n);
114 else if (WARN_ON(err)) {
115 err = -EINVAL;
116 goto err;
117 } else
118 n = blkcipher_done_slow(tfm, walk, n);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000119
120 nbytes = walk->total - n;
121 err = 0;
122 }
123
124 scatterwalk_done(&walk->in, 0, nbytes);
125 scatterwalk_done(&walk->out, 1, nbytes);
126
127 walk->total = nbytes;
128 walk->nbytes = nbytes;
129
130 if (nbytes) {
131 crypto_yield(desc->flags);
132 return blkcipher_walk_next(desc, walk);
133 }
134
Herbert Xu7607bd82007-10-04 15:24:05 +0800135err:
Herbert Xu5cde0af2006-08-22 00:07:53 +1000136 if (walk->iv != desc->info)
137 memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
138 if (walk->buffer != walk->page)
139 kfree(walk->buffer);
140 if (walk->page)
141 free_page((unsigned long)walk->page);
142
143 return err;
144}
145EXPORT_SYMBOL_GPL(blkcipher_walk_done);
146
147static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
148 struct blkcipher_walk *walk,
149 unsigned int bsize,
150 unsigned int alignmask)
151{
152 unsigned int n;
Herbert Xu70613782007-09-29 21:24:23 +0800153 unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000154
155 if (walk->buffer)
156 goto ok;
157
158 walk->buffer = walk->page;
159 if (walk->buffer)
160 goto ok;
161
Herbert Xu2614de12007-10-04 14:49:00 +0800162 n = aligned_bsize * 3 - (alignmask + 1) +
Herbert Xue4630f92007-09-09 08:45:21 +0100163 (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
Herbert Xu5cde0af2006-08-22 00:07:53 +1000164 walk->buffer = kmalloc(n, GFP_ATOMIC);
165 if (!walk->buffer)
166 return blkcipher_walk_done(desc, walk, -ENOMEM);
167
168ok:
169 walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
170 alignmask + 1);
171 walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
Herbert Xu70613782007-09-29 21:24:23 +0800172 walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
173 aligned_bsize, bsize);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000174
175 scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
176
177 walk->nbytes = bsize;
178 walk->flags |= BLKCIPHER_WALK_SLOW;
179
180 return 0;
181}
182
183static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
184{
185 u8 *tmp = walk->page;
186
187 blkcipher_map_src(walk);
188 memcpy(tmp, walk->src.virt.addr, walk->nbytes);
189 blkcipher_unmap_src(walk);
190
191 walk->src.virt.addr = tmp;
192 walk->dst.virt.addr = tmp;
193
194 return 0;
195}
196
197static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
198 struct blkcipher_walk *walk)
199{
200 unsigned long diff;
201
202 walk->src.phys.page = scatterwalk_page(&walk->in);
203 walk->src.phys.offset = offset_in_page(walk->in.offset);
204 walk->dst.phys.page = scatterwalk_page(&walk->out);
205 walk->dst.phys.offset = offset_in_page(walk->out.offset);
206
207 if (walk->flags & BLKCIPHER_WALK_PHYS)
208 return 0;
209
210 diff = walk->src.phys.offset - walk->dst.phys.offset;
211 diff |= walk->src.virt.page - walk->dst.virt.page;
212
213 blkcipher_map_src(walk);
214 walk->dst.virt.addr = walk->src.virt.addr;
215
216 if (diff) {
217 walk->flags |= BLKCIPHER_WALK_DIFF;
218 blkcipher_map_dst(walk);
219 }
220
221 return 0;
222}
223
224static int blkcipher_walk_next(struct blkcipher_desc *desc,
225 struct blkcipher_walk *walk)
226{
227 struct crypto_blkcipher *tfm = desc->tfm;
228 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
Herbert Xu7607bd82007-10-04 15:24:05 +0800229 unsigned int bsize;
Herbert Xu5cde0af2006-08-22 00:07:53 +1000230 unsigned int n;
231 int err;
232
233 n = walk->total;
Herbert Xu7607bd82007-10-04 15:24:05 +0800234 if (unlikely(n < crypto_blkcipher_blocksize(tfm))) {
Herbert Xu5cde0af2006-08-22 00:07:53 +1000235 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
236 return blkcipher_walk_done(desc, walk, -EINVAL);
237 }
238
239 walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
240 BLKCIPHER_WALK_DIFF);
241 if (!scatterwalk_aligned(&walk->in, alignmask) ||
242 !scatterwalk_aligned(&walk->out, alignmask)) {
243 walk->flags |= BLKCIPHER_WALK_COPY;
244 if (!walk->page) {
245 walk->page = (void *)__get_free_page(GFP_ATOMIC);
246 if (!walk->page)
247 n = 0;
248 }
249 }
250
Herbert Xu7607bd82007-10-04 15:24:05 +0800251 bsize = min(walk->blocksize, n);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000252 n = scatterwalk_clamp(&walk->in, n);
253 n = scatterwalk_clamp(&walk->out, n);
254
255 if (unlikely(n < bsize)) {
256 err = blkcipher_next_slow(desc, walk, bsize, alignmask);
257 goto set_phys_lowmem;
258 }
259
260 walk->nbytes = n;
261 if (walk->flags & BLKCIPHER_WALK_COPY) {
262 err = blkcipher_next_copy(walk);
263 goto set_phys_lowmem;
264 }
265
266 return blkcipher_next_fast(desc, walk);
267
268set_phys_lowmem:
269 if (walk->flags & BLKCIPHER_WALK_PHYS) {
270 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
271 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
272 walk->src.phys.offset &= PAGE_SIZE - 1;
273 walk->dst.phys.offset &= PAGE_SIZE - 1;
274 }
275 return err;
276}
277
278static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
279 struct crypto_blkcipher *tfm,
280 unsigned int alignmask)
281{
Herbert Xu7607bd82007-10-04 15:24:05 +0800282 unsigned bs = walk->blocksize;
Herbert Xu5cde0af2006-08-22 00:07:53 +1000283 unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
Herbert Xu70613782007-09-29 21:24:23 +0800284 unsigned aligned_bs = ALIGN(bs, alignmask + 1);
285 unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
286 (alignmask + 1);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000287 u8 *iv;
288
289 size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
290 walk->buffer = kmalloc(size, GFP_ATOMIC);
291 if (!walk->buffer)
292 return -ENOMEM;
293
294 iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
Herbert Xu70613782007-09-29 21:24:23 +0800295 iv = blkcipher_get_spot(iv, bs) + aligned_bs;
296 iv = blkcipher_get_spot(iv, bs) + aligned_bs;
Herbert Xu5cde0af2006-08-22 00:07:53 +1000297 iv = blkcipher_get_spot(iv, ivsize);
298
299 walk->iv = memcpy(iv, walk->iv, ivsize);
300 return 0;
301}
302
303int blkcipher_walk_virt(struct blkcipher_desc *desc,
304 struct blkcipher_walk *walk)
305{
306 walk->flags &= ~BLKCIPHER_WALK_PHYS;
Herbert Xu7607bd82007-10-04 15:24:05 +0800307 walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000308 return blkcipher_walk_first(desc, walk);
309}
310EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
311
312int blkcipher_walk_phys(struct blkcipher_desc *desc,
313 struct blkcipher_walk *walk)
314{
315 walk->flags |= BLKCIPHER_WALK_PHYS;
Herbert Xu7607bd82007-10-04 15:24:05 +0800316 walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000317 return blkcipher_walk_first(desc, walk);
318}
319EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
320
321static int blkcipher_walk_first(struct blkcipher_desc *desc,
322 struct blkcipher_walk *walk)
323{
324 struct crypto_blkcipher *tfm = desc->tfm;
325 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
326
Herbert Xufb469842006-12-10 10:45:28 +1100327 if (WARN_ON_ONCE(in_irq()))
328 return -EDEADLK;
329
Herbert Xu5cde0af2006-08-22 00:07:53 +1000330 walk->nbytes = walk->total;
331 if (unlikely(!walk->total))
332 return 0;
333
334 walk->buffer = NULL;
335 walk->iv = desc->info;
336 if (unlikely(((unsigned long)walk->iv & alignmask))) {
337 int err = blkcipher_copy_iv(walk, tfm, alignmask);
338 if (err)
339 return err;
340 }
341
342 scatterwalk_start(&walk->in, walk->in.sg);
343 scatterwalk_start(&walk->out, walk->out.sg);
344 walk->page = NULL;
345
346 return blkcipher_walk_next(desc, walk);
347}
348
Herbert Xu7607bd82007-10-04 15:24:05 +0800349int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
350 struct blkcipher_walk *walk,
351 unsigned int blocksize)
352{
353 walk->flags &= ~BLKCIPHER_WALK_PHYS;
354 walk->blocksize = blocksize;
355 return blkcipher_walk_first(desc, walk);
356}
357EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
358
Herbert Xu791b4d52007-08-23 16:23:01 +0800359static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
360 unsigned int keylen)
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000361{
362 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
363 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
364 int ret;
365 u8 *buffer, *alignbuffer;
366 unsigned long absize;
367
368 absize = keylen + alignmask;
369 buffer = kmalloc(absize, GFP_ATOMIC);
370 if (!buffer)
371 return -ENOMEM;
372
373 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
374 memcpy(alignbuffer, key, keylen);
375 ret = cipher->setkey(tfm, alignbuffer, keylen);
Sebastian Siewior06817172007-08-03 20:33:47 +0800376 memset(alignbuffer, 0, keylen);
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000377 kfree(buffer);
378 return ret;
379}
380
Herbert Xu791b4d52007-08-23 16:23:01 +0800381static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
Herbert Xu5cde0af2006-08-22 00:07:53 +1000382{
383 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000384 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000385
386 if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
387 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
388 return -EINVAL;
389 }
390
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000391 if ((unsigned long)key & alignmask)
392 return setkey_unaligned(tfm, key, keylen);
393
Herbert Xu5cde0af2006-08-22 00:07:53 +1000394 return cipher->setkey(tfm, key, keylen);
395}
396
Herbert Xu32e39832007-03-24 14:35:34 +1100397static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
398 unsigned int keylen)
399{
400 return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
401}
402
403static int async_encrypt(struct ablkcipher_request *req)
404{
405 struct crypto_tfm *tfm = req->base.tfm;
406 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
407 struct blkcipher_desc desc = {
408 .tfm = __crypto_blkcipher_cast(tfm),
409 .info = req->info,
410 .flags = req->base.flags,
411 };
412
413
414 return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
415}
416
417static int async_decrypt(struct ablkcipher_request *req)
418{
419 struct crypto_tfm *tfm = req->base.tfm;
420 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
421 struct blkcipher_desc desc = {
422 .tfm = __crypto_blkcipher_cast(tfm),
423 .info = req->info,
424 .flags = req->base.flags,
425 };
426
427 return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
428}
429
Herbert Xu27d2a332007-01-24 20:50:26 +1100430static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
431 u32 mask)
Herbert Xu5cde0af2006-08-22 00:07:53 +1000432{
433 struct blkcipher_alg *cipher = &alg->cra_blkcipher;
434 unsigned int len = alg->cra_ctxsize;
435
Herbert Xu32e39832007-03-24 14:35:34 +1100436 type ^= CRYPTO_ALG_ASYNC;
437 mask &= CRYPTO_ALG_ASYNC;
438 if ((type & mask) && cipher->ivsize) {
Herbert Xu5cde0af2006-08-22 00:07:53 +1000439 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
440 len += cipher->ivsize;
441 }
442
443 return len;
444}
445
Herbert Xu32e39832007-03-24 14:35:34 +1100446static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
447{
448 struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
449 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
450
451 crt->setkey = async_setkey;
452 crt->encrypt = async_encrypt;
453 crt->decrypt = async_decrypt;
454 crt->ivsize = alg->ivsize;
455
456 return 0;
457}
458
459static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
Herbert Xu5cde0af2006-08-22 00:07:53 +1000460{
461 struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
462 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
463 unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
464 unsigned long addr;
465
Herbert Xu5cde0af2006-08-22 00:07:53 +1000466 crt->setkey = setkey;
467 crt->encrypt = alg->encrypt;
468 crt->decrypt = alg->decrypt;
469
470 addr = (unsigned long)crypto_tfm_ctx(tfm);
471 addr = ALIGN(addr, align);
472 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
473 crt->iv = (void *)addr;
474
475 return 0;
476}
477
Herbert Xu32e39832007-03-24 14:35:34 +1100478static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
479{
480 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
481
482 if (alg->ivsize > PAGE_SIZE / 8)
483 return -EINVAL;
484
485 type ^= CRYPTO_ALG_ASYNC;
486 mask &= CRYPTO_ALG_ASYNC;
487 if (type & mask)
488 return crypto_init_blkcipher_ops_sync(tfm);
489 else
490 return crypto_init_blkcipher_ops_async(tfm);
491}
492
Herbert Xu5cde0af2006-08-22 00:07:53 +1000493static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
Herbert Xu03f5d8c2006-12-31 10:42:06 +1100494 __attribute__ ((unused));
Herbert Xu5cde0af2006-08-22 00:07:53 +1000495static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
496{
497 seq_printf(m, "type : blkcipher\n");
498 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
499 seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
500 seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
501 seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
502}
503
504const struct crypto_type crypto_blkcipher_type = {
505 .ctxsize = crypto_blkcipher_ctxsize,
506 .init = crypto_init_blkcipher_ops,
507#ifdef CONFIG_PROC_FS
508 .show = crypto_blkcipher_show,
509#endif
510};
511EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
512
513MODULE_LICENSE("GPL");
514MODULE_DESCRIPTION("Generic block chaining cipher type");