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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);
Herbert Xu32528d02007-09-10 15:51:11 +080068 return start > end_page ? 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{
87 n = walk->nbytes - n;
88
89 if (walk->flags & BLKCIPHER_WALK_COPY) {
90 blkcipher_map_dst(walk);
91 memcpy(walk->dst.virt.addr, walk->page, n);
92 blkcipher_unmap_dst(walk);
93 } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
94 blkcipher_unmap_src(walk);
95 if (walk->flags & BLKCIPHER_WALK_DIFF)
96 blkcipher_unmap_dst(walk);
97 }
98
99 scatterwalk_advance(&walk->in, n);
100 scatterwalk_advance(&walk->out, n);
101
102 return n;
103}
104
105int blkcipher_walk_done(struct blkcipher_desc *desc,
106 struct blkcipher_walk *walk, int err)
107{
108 struct crypto_blkcipher *tfm = desc->tfm;
109 unsigned int nbytes = 0;
110
111 if (likely(err >= 0)) {
112 unsigned int bsize = crypto_blkcipher_blocksize(tfm);
113 unsigned int n;
114
115 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
116 n = blkcipher_done_fast(walk, err);
117 else
118 n = blkcipher_done_slow(tfm, walk, bsize);
119
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
135 if (walk->iv != desc->info)
136 memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
137 if (walk->buffer != walk->page)
138 kfree(walk->buffer);
139 if (walk->page)
140 free_page((unsigned long)walk->page);
141
142 return err;
143}
144EXPORT_SYMBOL_GPL(blkcipher_walk_done);
145
146static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
147 struct blkcipher_walk *walk,
148 unsigned int bsize,
149 unsigned int alignmask)
150{
151 unsigned int n;
152
153 if (walk->buffer)
154 goto ok;
155
156 walk->buffer = walk->page;
157 if (walk->buffer)
158 goto ok;
159
Herbert Xue4630f92007-09-09 08:45:21 +0100160 n = bsize * 3 - (alignmask + 1) +
161 (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
Herbert Xu5cde0af2006-08-22 00:07:53 +1000162 walk->buffer = kmalloc(n, GFP_ATOMIC);
163 if (!walk->buffer)
164 return blkcipher_walk_done(desc, walk, -ENOMEM);
165
166ok:
167 walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
168 alignmask + 1);
169 walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
170 walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize,
171 bsize);
172
173 scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
174
175 walk->nbytes = bsize;
176 walk->flags |= BLKCIPHER_WALK_SLOW;
177
178 return 0;
179}
180
181static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
182{
183 u8 *tmp = walk->page;
184
185 blkcipher_map_src(walk);
186 memcpy(tmp, walk->src.virt.addr, walk->nbytes);
187 blkcipher_unmap_src(walk);
188
189 walk->src.virt.addr = tmp;
190 walk->dst.virt.addr = tmp;
191
192 return 0;
193}
194
195static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
196 struct blkcipher_walk *walk)
197{
198 unsigned long diff;
199
200 walk->src.phys.page = scatterwalk_page(&walk->in);
201 walk->src.phys.offset = offset_in_page(walk->in.offset);
202 walk->dst.phys.page = scatterwalk_page(&walk->out);
203 walk->dst.phys.offset = offset_in_page(walk->out.offset);
204
205 if (walk->flags & BLKCIPHER_WALK_PHYS)
206 return 0;
207
208 diff = walk->src.phys.offset - walk->dst.phys.offset;
209 diff |= walk->src.virt.page - walk->dst.virt.page;
210
211 blkcipher_map_src(walk);
212 walk->dst.virt.addr = walk->src.virt.addr;
213
214 if (diff) {
215 walk->flags |= BLKCIPHER_WALK_DIFF;
216 blkcipher_map_dst(walk);
217 }
218
219 return 0;
220}
221
222static int blkcipher_walk_next(struct blkcipher_desc *desc,
223 struct blkcipher_walk *walk)
224{
225 struct crypto_blkcipher *tfm = desc->tfm;
226 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
227 unsigned int bsize = crypto_blkcipher_blocksize(tfm);
228 unsigned int n;
229 int err;
230
231 n = walk->total;
232 if (unlikely(n < bsize)) {
233 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
234 return blkcipher_walk_done(desc, walk, -EINVAL);
235 }
236
237 walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
238 BLKCIPHER_WALK_DIFF);
239 if (!scatterwalk_aligned(&walk->in, alignmask) ||
240 !scatterwalk_aligned(&walk->out, alignmask)) {
241 walk->flags |= BLKCIPHER_WALK_COPY;
242 if (!walk->page) {
243 walk->page = (void *)__get_free_page(GFP_ATOMIC);
244 if (!walk->page)
245 n = 0;
246 }
247 }
248
249 n = scatterwalk_clamp(&walk->in, n);
250 n = scatterwalk_clamp(&walk->out, n);
251
252 if (unlikely(n < bsize)) {
253 err = blkcipher_next_slow(desc, walk, bsize, alignmask);
254 goto set_phys_lowmem;
255 }
256
257 walk->nbytes = n;
258 if (walk->flags & BLKCIPHER_WALK_COPY) {
259 err = blkcipher_next_copy(walk);
260 goto set_phys_lowmem;
261 }
262
263 return blkcipher_next_fast(desc, walk);
264
265set_phys_lowmem:
266 if (walk->flags & BLKCIPHER_WALK_PHYS) {
267 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
268 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
269 walk->src.phys.offset &= PAGE_SIZE - 1;
270 walk->dst.phys.offset &= PAGE_SIZE - 1;
271 }
272 return err;
273}
274
275static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
276 struct crypto_blkcipher *tfm,
277 unsigned int alignmask)
278{
279 unsigned bs = crypto_blkcipher_blocksize(tfm);
280 unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
281 unsigned int size = bs * 2 + ivsize + max(bs, ivsize) - (alignmask + 1);
282 u8 *iv;
283
284 size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
285 walk->buffer = kmalloc(size, GFP_ATOMIC);
286 if (!walk->buffer)
287 return -ENOMEM;
288
289 iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
290 iv = blkcipher_get_spot(iv, bs) + bs;
291 iv = blkcipher_get_spot(iv, bs) + bs;
292 iv = blkcipher_get_spot(iv, ivsize);
293
294 walk->iv = memcpy(iv, walk->iv, ivsize);
295 return 0;
296}
297
298int blkcipher_walk_virt(struct blkcipher_desc *desc,
299 struct blkcipher_walk *walk)
300{
301 walk->flags &= ~BLKCIPHER_WALK_PHYS;
302 return blkcipher_walk_first(desc, walk);
303}
304EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
305
306int blkcipher_walk_phys(struct blkcipher_desc *desc,
307 struct blkcipher_walk *walk)
308{
309 walk->flags |= BLKCIPHER_WALK_PHYS;
310 return blkcipher_walk_first(desc, walk);
311}
312EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
313
314static int blkcipher_walk_first(struct blkcipher_desc *desc,
315 struct blkcipher_walk *walk)
316{
317 struct crypto_blkcipher *tfm = desc->tfm;
318 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
319
Herbert Xufb469842006-12-10 10:45:28 +1100320 if (WARN_ON_ONCE(in_irq()))
321 return -EDEADLK;
322
Herbert Xu5cde0af2006-08-22 00:07:53 +1000323 walk->nbytes = walk->total;
324 if (unlikely(!walk->total))
325 return 0;
326
327 walk->buffer = NULL;
328 walk->iv = desc->info;
329 if (unlikely(((unsigned long)walk->iv & alignmask))) {
330 int err = blkcipher_copy_iv(walk, tfm, alignmask);
331 if (err)
332 return err;
333 }
334
335 scatterwalk_start(&walk->in, walk->in.sg);
336 scatterwalk_start(&walk->out, walk->out.sg);
337 walk->page = NULL;
338
339 return blkcipher_walk_next(desc, walk);
340}
341
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000342static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
343{
344 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
345 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
346 int ret;
347 u8 *buffer, *alignbuffer;
348 unsigned long absize;
349
350 absize = keylen + alignmask;
351 buffer = kmalloc(absize, GFP_ATOMIC);
352 if (!buffer)
353 return -ENOMEM;
354
355 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
356 memcpy(alignbuffer, key, keylen);
357 ret = cipher->setkey(tfm, alignbuffer, keylen);
Sebastian Siewior06817172007-08-03 20:33:47 +0800358 memset(alignbuffer, 0, keylen);
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000359 kfree(buffer);
360 return ret;
361}
362
Herbert Xu5cde0af2006-08-22 00:07:53 +1000363static int setkey(struct crypto_tfm *tfm, const u8 *key,
364 unsigned int keylen)
365{
366 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000367 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
Herbert Xu5cde0af2006-08-22 00:07:53 +1000368
369 if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
370 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
371 return -EINVAL;
372 }
373
Sebastian Siewiorca7c3932007-05-19 19:51:21 +1000374 if ((unsigned long)key & alignmask)
375 return setkey_unaligned(tfm, key, keylen);
376
Herbert Xu5cde0af2006-08-22 00:07:53 +1000377 return cipher->setkey(tfm, key, keylen);
378}
379
Herbert Xu32e39832007-03-24 14:35:34 +1100380static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
381 unsigned int keylen)
382{
383 return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
384}
385
386static int async_encrypt(struct ablkcipher_request *req)
387{
388 struct crypto_tfm *tfm = req->base.tfm;
389 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
390 struct blkcipher_desc desc = {
391 .tfm = __crypto_blkcipher_cast(tfm),
392 .info = req->info,
393 .flags = req->base.flags,
394 };
395
396
397 return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
398}
399
400static int async_decrypt(struct ablkcipher_request *req)
401{
402 struct crypto_tfm *tfm = req->base.tfm;
403 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
404 struct blkcipher_desc desc = {
405 .tfm = __crypto_blkcipher_cast(tfm),
406 .info = req->info,
407 .flags = req->base.flags,
408 };
409
410 return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
411}
412
Herbert Xu27d2a332007-01-24 20:50:26 +1100413static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
414 u32 mask)
Herbert Xu5cde0af2006-08-22 00:07:53 +1000415{
416 struct blkcipher_alg *cipher = &alg->cra_blkcipher;
417 unsigned int len = alg->cra_ctxsize;
418
Herbert Xu32e39832007-03-24 14:35:34 +1100419 type ^= CRYPTO_ALG_ASYNC;
420 mask &= CRYPTO_ALG_ASYNC;
421 if ((type & mask) && cipher->ivsize) {
Herbert Xu5cde0af2006-08-22 00:07:53 +1000422 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
423 len += cipher->ivsize;
424 }
425
426 return len;
427}
428
Herbert Xu32e39832007-03-24 14:35:34 +1100429static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
430{
431 struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
432 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
433
434 crt->setkey = async_setkey;
435 crt->encrypt = async_encrypt;
436 crt->decrypt = async_decrypt;
437 crt->ivsize = alg->ivsize;
438
439 return 0;
440}
441
442static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
Herbert Xu5cde0af2006-08-22 00:07:53 +1000443{
444 struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
445 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
446 unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
447 unsigned long addr;
448
Herbert Xu5cde0af2006-08-22 00:07:53 +1000449 crt->setkey = setkey;
450 crt->encrypt = alg->encrypt;
451 crt->decrypt = alg->decrypt;
452
453 addr = (unsigned long)crypto_tfm_ctx(tfm);
454 addr = ALIGN(addr, align);
455 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
456 crt->iv = (void *)addr;
457
458 return 0;
459}
460
Herbert Xu32e39832007-03-24 14:35:34 +1100461static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
462{
463 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
464
465 if (alg->ivsize > PAGE_SIZE / 8)
466 return -EINVAL;
467
468 type ^= CRYPTO_ALG_ASYNC;
469 mask &= CRYPTO_ALG_ASYNC;
470 if (type & mask)
471 return crypto_init_blkcipher_ops_sync(tfm);
472 else
473 return crypto_init_blkcipher_ops_async(tfm);
474}
475
Herbert Xu5cde0af2006-08-22 00:07:53 +1000476static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
Herbert Xu03f5d8c2006-12-31 10:42:06 +1100477 __attribute__ ((unused));
Herbert Xu5cde0af2006-08-22 00:07:53 +1000478static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
479{
480 seq_printf(m, "type : blkcipher\n");
481 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
482 seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
483 seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
484 seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
485}
486
487const struct crypto_type crypto_blkcipher_type = {
488 .ctxsize = crypto_blkcipher_ctxsize,
489 .init = crypto_init_blkcipher_ops,
490#ifdef CONFIG_PROC_FS
491 .show = crypto_blkcipher_show,
492#endif
493};
494EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
495
496MODULE_LICENSE("GPL");
497MODULE_DESCRIPTION("Generic block chaining cipher type");