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1 | /* | |
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> | |
19 | #include <linux/hardirq.h> | |
20 | #include <linux/kernel.h> | |
21 | #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 | ||
30 | enum { | |
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 | ||
37 | static int blkcipher_walk_next(struct blkcipher_desc *desc, | |
38 | struct blkcipher_walk *walk); | |
39 | static int blkcipher_walk_first(struct blkcipher_desc *desc, | |
40 | struct blkcipher_walk *walk); | |
41 | ||
42 | static inline void blkcipher_map_src(struct blkcipher_walk *walk) | |
43 | { | |
44 | walk->src.virt.addr = scatterwalk_map(&walk->in, 0); | |
45 | } | |
46 | ||
47 | static inline void blkcipher_map_dst(struct blkcipher_walk *walk) | |
48 | { | |
49 | walk->dst.virt.addr = scatterwalk_map(&walk->out, 1); | |
50 | } | |
51 | ||
52 | static inline void blkcipher_unmap_src(struct blkcipher_walk *walk) | |
53 | { | |
54 | scatterwalk_unmap(walk->src.virt.addr, 0); | |
55 | } | |
56 | ||
57 | static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) | |
58 | { | |
59 | scatterwalk_unmap(walk->dst.virt.addr, 1); | |
60 | } | |
61 | ||
62 | /* 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 | */ | |
65 | static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) | |
66 | { | |
67 | u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK); | |
68 | return max(start, end_page); | |
69 | } | |
70 | ||
71 | static 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 | ||
84 | static 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 | ||
105 | int 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 | } | |
144 | EXPORT_SYMBOL_GPL(blkcipher_walk_done); | |
145 | ||
146 | static 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 | unsigned aligned_bsize = ALIGN(bsize, alignmask + 1); | |
153 | ||
154 | if (walk->buffer) | |
155 | goto ok; | |
156 | ||
157 | walk->buffer = walk->page; | |
158 | if (walk->buffer) | |
159 | goto ok; | |
160 | ||
161 | n = bsize * 3 - (alignmask + 1) + | |
162 | (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); | |
163 | walk->buffer = kmalloc(n, GFP_ATOMIC); | |
164 | if (!walk->buffer) | |
165 | return blkcipher_walk_done(desc, walk, -ENOMEM); | |
166 | ||
167 | ok: | |
168 | walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer, | |
169 | alignmask + 1); | |
170 | walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize); | |
171 | walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + | |
172 | aligned_bsize, bsize); | |
173 | ||
174 | scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); | |
175 | ||
176 | walk->nbytes = bsize; | |
177 | walk->flags |= BLKCIPHER_WALK_SLOW; | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
182 | static inline int blkcipher_next_copy(struct blkcipher_walk *walk) | |
183 | { | |
184 | u8 *tmp = walk->page; | |
185 | ||
186 | blkcipher_map_src(walk); | |
187 | memcpy(tmp, walk->src.virt.addr, walk->nbytes); | |
188 | blkcipher_unmap_src(walk); | |
189 | ||
190 | walk->src.virt.addr = tmp; | |
191 | walk->dst.virt.addr = tmp; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | static inline int blkcipher_next_fast(struct blkcipher_desc *desc, | |
197 | struct blkcipher_walk *walk) | |
198 | { | |
199 | unsigned long diff; | |
200 | ||
201 | walk->src.phys.page = scatterwalk_page(&walk->in); | |
202 | walk->src.phys.offset = offset_in_page(walk->in.offset); | |
203 | walk->dst.phys.page = scatterwalk_page(&walk->out); | |
204 | walk->dst.phys.offset = offset_in_page(walk->out.offset); | |
205 | ||
206 | if (walk->flags & BLKCIPHER_WALK_PHYS) | |
207 | return 0; | |
208 | ||
209 | diff = walk->src.phys.offset - walk->dst.phys.offset; | |
210 | diff |= walk->src.virt.page - walk->dst.virt.page; | |
211 | ||
212 | blkcipher_map_src(walk); | |
213 | walk->dst.virt.addr = walk->src.virt.addr; | |
214 | ||
215 | if (diff) { | |
216 | walk->flags |= BLKCIPHER_WALK_DIFF; | |
217 | blkcipher_map_dst(walk); | |
218 | } | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | static int blkcipher_walk_next(struct blkcipher_desc *desc, | |
224 | struct blkcipher_walk *walk) | |
225 | { | |
226 | struct crypto_blkcipher *tfm = desc->tfm; | |
227 | unsigned int alignmask = crypto_blkcipher_alignmask(tfm); | |
228 | unsigned int bsize = crypto_blkcipher_blocksize(tfm); | |
229 | unsigned int n; | |
230 | int err; | |
231 | ||
232 | n = walk->total; | |
233 | if (unlikely(n < bsize)) { | |
234 | desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; | |
235 | return blkcipher_walk_done(desc, walk, -EINVAL); | |
236 | } | |
237 | ||
238 | walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY | | |
239 | BLKCIPHER_WALK_DIFF); | |
240 | if (!scatterwalk_aligned(&walk->in, alignmask) || | |
241 | !scatterwalk_aligned(&walk->out, alignmask)) { | |
242 | walk->flags |= BLKCIPHER_WALK_COPY; | |
243 | if (!walk->page) { | |
244 | walk->page = (void *)__get_free_page(GFP_ATOMIC); | |
245 | if (!walk->page) | |
246 | n = 0; | |
247 | } | |
248 | } | |
249 | ||
250 | n = scatterwalk_clamp(&walk->in, n); | |
251 | n = scatterwalk_clamp(&walk->out, n); | |
252 | ||
253 | if (unlikely(n < bsize)) { | |
254 | err = blkcipher_next_slow(desc, walk, bsize, alignmask); | |
255 | goto set_phys_lowmem; | |
256 | } | |
257 | ||
258 | walk->nbytes = n; | |
259 | if (walk->flags & BLKCIPHER_WALK_COPY) { | |
260 | err = blkcipher_next_copy(walk); | |
261 | goto set_phys_lowmem; | |
262 | } | |
263 | ||
264 | return blkcipher_next_fast(desc, walk); | |
265 | ||
266 | set_phys_lowmem: | |
267 | if (walk->flags & BLKCIPHER_WALK_PHYS) { | |
268 | walk->src.phys.page = virt_to_page(walk->src.virt.addr); | |
269 | walk->dst.phys.page = virt_to_page(walk->dst.virt.addr); | |
270 | walk->src.phys.offset &= PAGE_SIZE - 1; | |
271 | walk->dst.phys.offset &= PAGE_SIZE - 1; | |
272 | } | |
273 | return err; | |
274 | } | |
275 | ||
276 | static inline int blkcipher_copy_iv(struct blkcipher_walk *walk, | |
277 | struct crypto_blkcipher *tfm, | |
278 | unsigned int alignmask) | |
279 | { | |
280 | unsigned bs = crypto_blkcipher_blocksize(tfm); | |
281 | unsigned int ivsize = crypto_blkcipher_ivsize(tfm); | |
282 | unsigned aligned_bs = ALIGN(bs, alignmask + 1); | |
283 | unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) - | |
284 | (alignmask + 1); | |
285 | u8 *iv; | |
286 | ||
287 | size += alignmask & ~(crypto_tfm_ctx_alignment() - 1); | |
288 | walk->buffer = kmalloc(size, GFP_ATOMIC); | |
289 | if (!walk->buffer) | |
290 | return -ENOMEM; | |
291 | ||
292 | iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); | |
293 | iv = blkcipher_get_spot(iv, bs) + aligned_bs; | |
294 | iv = blkcipher_get_spot(iv, bs) + aligned_bs; | |
295 | iv = blkcipher_get_spot(iv, ivsize); | |
296 | ||
297 | walk->iv = memcpy(iv, walk->iv, ivsize); | |
298 | return 0; | |
299 | } | |
300 | ||
301 | int blkcipher_walk_virt(struct blkcipher_desc *desc, | |
302 | struct blkcipher_walk *walk) | |
303 | { | |
304 | walk->flags &= ~BLKCIPHER_WALK_PHYS; | |
305 | return blkcipher_walk_first(desc, walk); | |
306 | } | |
307 | EXPORT_SYMBOL_GPL(blkcipher_walk_virt); | |
308 | ||
309 | int blkcipher_walk_phys(struct blkcipher_desc *desc, | |
310 | struct blkcipher_walk *walk) | |
311 | { | |
312 | walk->flags |= BLKCIPHER_WALK_PHYS; | |
313 | return blkcipher_walk_first(desc, walk); | |
314 | } | |
315 | EXPORT_SYMBOL_GPL(blkcipher_walk_phys); | |
316 | ||
317 | static int blkcipher_walk_first(struct blkcipher_desc *desc, | |
318 | struct blkcipher_walk *walk) | |
319 | { | |
320 | struct crypto_blkcipher *tfm = desc->tfm; | |
321 | unsigned int alignmask = crypto_blkcipher_alignmask(tfm); | |
322 | ||
323 | if (WARN_ON_ONCE(in_irq())) | |
324 | return -EDEADLK; | |
325 | ||
326 | walk->nbytes = walk->total; | |
327 | if (unlikely(!walk->total)) | |
328 | return 0; | |
329 | ||
330 | walk->buffer = NULL; | |
331 | walk->iv = desc->info; | |
332 | if (unlikely(((unsigned long)walk->iv & alignmask))) { | |
333 | int err = blkcipher_copy_iv(walk, tfm, alignmask); | |
334 | if (err) | |
335 | return err; | |
336 | } | |
337 | ||
338 | scatterwalk_start(&walk->in, walk->in.sg); | |
339 | scatterwalk_start(&walk->out, walk->out.sg); | |
340 | walk->page = NULL; | |
341 | ||
342 | return blkcipher_walk_next(desc, walk); | |
343 | } | |
344 | ||
345 | static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key, | |
346 | unsigned int keylen) | |
347 | { | |
348 | struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; | |
349 | unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); | |
350 | int ret; | |
351 | u8 *buffer, *alignbuffer; | |
352 | unsigned long absize; | |
353 | ||
354 | absize = keylen + alignmask; | |
355 | buffer = kmalloc(absize, GFP_ATOMIC); | |
356 | if (!buffer) | |
357 | return -ENOMEM; | |
358 | ||
359 | alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); | |
360 | memcpy(alignbuffer, key, keylen); | |
361 | ret = cipher->setkey(tfm, alignbuffer, keylen); | |
362 | memset(alignbuffer, 0, keylen); | |
363 | kfree(buffer); | |
364 | return ret; | |
365 | } | |
366 | ||
367 | static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) | |
368 | { | |
369 | struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; | |
370 | unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); | |
371 | ||
372 | if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { | |
373 | tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; | |
374 | return -EINVAL; | |
375 | } | |
376 | ||
377 | if ((unsigned long)key & alignmask) | |
378 | return setkey_unaligned(tfm, key, keylen); | |
379 | ||
380 | return cipher->setkey(tfm, key, keylen); | |
381 | } | |
382 | ||
383 | static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key, | |
384 | unsigned int keylen) | |
385 | { | |
386 | return setkey(crypto_ablkcipher_tfm(tfm), key, keylen); | |
387 | } | |
388 | ||
389 | static int async_encrypt(struct ablkcipher_request *req) | |
390 | { | |
391 | struct crypto_tfm *tfm = req->base.tfm; | |
392 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
393 | struct blkcipher_desc desc = { | |
394 | .tfm = __crypto_blkcipher_cast(tfm), | |
395 | .info = req->info, | |
396 | .flags = req->base.flags, | |
397 | }; | |
398 | ||
399 | ||
400 | return alg->encrypt(&desc, req->dst, req->src, req->nbytes); | |
401 | } | |
402 | ||
403 | static int async_decrypt(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 | return alg->decrypt(&desc, req->dst, req->src, req->nbytes); | |
414 | } | |
415 | ||
416 | static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type, | |
417 | u32 mask) | |
418 | { | |
419 | struct blkcipher_alg *cipher = &alg->cra_blkcipher; | |
420 | unsigned int len = alg->cra_ctxsize; | |
421 | ||
422 | type ^= CRYPTO_ALG_ASYNC; | |
423 | mask &= CRYPTO_ALG_ASYNC; | |
424 | if ((type & mask) && cipher->ivsize) { | |
425 | len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1); | |
426 | len += cipher->ivsize; | |
427 | } | |
428 | ||
429 | return len; | |
430 | } | |
431 | ||
432 | static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm) | |
433 | { | |
434 | struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher; | |
435 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
436 | ||
437 | crt->setkey = async_setkey; | |
438 | crt->encrypt = async_encrypt; | |
439 | crt->decrypt = async_decrypt; | |
440 | crt->ivsize = alg->ivsize; | |
441 | ||
442 | return 0; | |
443 | } | |
444 | ||
445 | static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm) | |
446 | { | |
447 | struct blkcipher_tfm *crt = &tfm->crt_blkcipher; | |
448 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
449 | unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1; | |
450 | unsigned long addr; | |
451 | ||
452 | crt->setkey = setkey; | |
453 | crt->encrypt = alg->encrypt; | |
454 | crt->decrypt = alg->decrypt; | |
455 | ||
456 | addr = (unsigned long)crypto_tfm_ctx(tfm); | |
457 | addr = ALIGN(addr, align); | |
458 | addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align); | |
459 | crt->iv = (void *)addr; | |
460 | ||
461 | return 0; | |
462 | } | |
463 | ||
464 | static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask) | |
465 | { | |
466 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
467 | ||
468 | if (alg->ivsize > PAGE_SIZE / 8) | |
469 | return -EINVAL; | |
470 | ||
471 | type ^= CRYPTO_ALG_ASYNC; | |
472 | mask &= CRYPTO_ALG_ASYNC; | |
473 | if (type & mask) | |
474 | return crypto_init_blkcipher_ops_sync(tfm); | |
475 | else | |
476 | return crypto_init_blkcipher_ops_async(tfm); | |
477 | } | |
478 | ||
479 | static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) | |
480 | __attribute__ ((unused)); | |
481 | static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) | |
482 | { | |
483 | seq_printf(m, "type : blkcipher\n"); | |
484 | seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); | |
485 | seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize); | |
486 | seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize); | |
487 | seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize); | |
488 | } | |
489 | ||
490 | const struct crypto_type crypto_blkcipher_type = { | |
491 | .ctxsize = crypto_blkcipher_ctxsize, | |
492 | .init = crypto_init_blkcipher_ops, | |
493 | #ifdef CONFIG_PROC_FS | |
494 | .show = crypto_blkcipher_show, | |
495 | #endif | |
496 | }; | |
497 | EXPORT_SYMBOL_GPL(crypto_blkcipher_type); | |
498 | ||
499 | MODULE_LICENSE("GPL"); | |
500 | MODULE_DESCRIPTION("Generic block chaining cipher type"); |