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5cde0af2 HX |
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/kernel.h> | |
5cde0af2 HX |
20 | #include <linux/module.h> |
21 | #include <linux/scatterlist.h> | |
22 | #include <linux/seq_file.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/string.h> | |
25 | ||
26 | #include "internal.h" | |
27 | #include "scatterwalk.h" | |
28 | ||
29 | enum { | |
30 | BLKCIPHER_WALK_PHYS = 1 << 0, | |
31 | BLKCIPHER_WALK_SLOW = 1 << 1, | |
32 | BLKCIPHER_WALK_COPY = 1 << 2, | |
33 | BLKCIPHER_WALK_DIFF = 1 << 3, | |
34 | }; | |
35 | ||
36 | static int blkcipher_walk_next(struct blkcipher_desc *desc, | |
37 | struct blkcipher_walk *walk); | |
38 | static int blkcipher_walk_first(struct blkcipher_desc *desc, | |
39 | struct blkcipher_walk *walk); | |
40 | ||
41 | static inline void blkcipher_map_src(struct blkcipher_walk *walk) | |
42 | { | |
43 | walk->src.virt.addr = scatterwalk_map(&walk->in, 0); | |
44 | } | |
45 | ||
46 | static inline void blkcipher_map_dst(struct blkcipher_walk *walk) | |
47 | { | |
48 | walk->dst.virt.addr = scatterwalk_map(&walk->out, 1); | |
49 | } | |
50 | ||
51 | static inline void blkcipher_unmap_src(struct blkcipher_walk *walk) | |
52 | { | |
53 | scatterwalk_unmap(walk->src.virt.addr, 0); | |
54 | } | |
55 | ||
56 | static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) | |
57 | { | |
58 | scatterwalk_unmap(walk->dst.virt.addr, 1); | |
59 | } | |
60 | ||
61 | static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) | |
62 | { | |
63 | if (offset_in_page(start + len) < len) | |
64 | return (u8 *)((unsigned long)(start + len) & PAGE_MASK); | |
65 | return start; | |
66 | } | |
67 | ||
68 | static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm, | |
69 | struct blkcipher_walk *walk, | |
70 | unsigned int bsize) | |
71 | { | |
72 | u8 *addr; | |
73 | unsigned int alignmask = crypto_blkcipher_alignmask(tfm); | |
74 | ||
75 | addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); | |
76 | addr = blkcipher_get_spot(addr, bsize); | |
77 | scatterwalk_copychunks(addr, &walk->out, bsize, 1); | |
78 | return bsize; | |
79 | } | |
80 | ||
81 | static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk, | |
82 | unsigned int n) | |
83 | { | |
84 | n = walk->nbytes - n; | |
85 | ||
86 | if (walk->flags & BLKCIPHER_WALK_COPY) { | |
87 | blkcipher_map_dst(walk); | |
88 | memcpy(walk->dst.virt.addr, walk->page, n); | |
89 | blkcipher_unmap_dst(walk); | |
90 | } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) { | |
91 | blkcipher_unmap_src(walk); | |
92 | if (walk->flags & BLKCIPHER_WALK_DIFF) | |
93 | blkcipher_unmap_dst(walk); | |
94 | } | |
95 | ||
96 | scatterwalk_advance(&walk->in, n); | |
97 | scatterwalk_advance(&walk->out, n); | |
98 | ||
99 | return n; | |
100 | } | |
101 | ||
102 | int blkcipher_walk_done(struct blkcipher_desc *desc, | |
103 | struct blkcipher_walk *walk, int err) | |
104 | { | |
105 | struct crypto_blkcipher *tfm = desc->tfm; | |
106 | unsigned int nbytes = 0; | |
107 | ||
108 | if (likely(err >= 0)) { | |
109 | unsigned int bsize = crypto_blkcipher_blocksize(tfm); | |
110 | unsigned int n; | |
111 | ||
112 | if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) | |
113 | n = blkcipher_done_fast(walk, err); | |
114 | else | |
115 | n = blkcipher_done_slow(tfm, walk, bsize); | |
116 | ||
117 | nbytes = walk->total - n; | |
118 | err = 0; | |
119 | } | |
120 | ||
121 | scatterwalk_done(&walk->in, 0, nbytes); | |
122 | scatterwalk_done(&walk->out, 1, nbytes); | |
123 | ||
124 | walk->total = nbytes; | |
125 | walk->nbytes = nbytes; | |
126 | ||
127 | if (nbytes) { | |
128 | crypto_yield(desc->flags); | |
129 | return blkcipher_walk_next(desc, walk); | |
130 | } | |
131 | ||
132 | if (walk->iv != desc->info) | |
133 | memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm)); | |
134 | if (walk->buffer != walk->page) | |
135 | kfree(walk->buffer); | |
136 | if (walk->page) | |
137 | free_page((unsigned long)walk->page); | |
138 | ||
139 | return err; | |
140 | } | |
141 | EXPORT_SYMBOL_GPL(blkcipher_walk_done); | |
142 | ||
143 | static inline int blkcipher_next_slow(struct blkcipher_desc *desc, | |
144 | struct blkcipher_walk *walk, | |
145 | unsigned int bsize, | |
146 | unsigned int alignmask) | |
147 | { | |
148 | unsigned int n; | |
149 | ||
150 | if (walk->buffer) | |
151 | goto ok; | |
152 | ||
153 | walk->buffer = walk->page; | |
154 | if (walk->buffer) | |
155 | goto ok; | |
156 | ||
157 | n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); | |
158 | walk->buffer = kmalloc(n, GFP_ATOMIC); | |
159 | if (!walk->buffer) | |
160 | return blkcipher_walk_done(desc, walk, -ENOMEM); | |
161 | ||
162 | ok: | |
163 | walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer, | |
164 | alignmask + 1); | |
165 | walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize); | |
166 | walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize, | |
167 | bsize); | |
168 | ||
169 | scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); | |
170 | ||
171 | walk->nbytes = bsize; | |
172 | walk->flags |= BLKCIPHER_WALK_SLOW; | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | static inline int blkcipher_next_copy(struct blkcipher_walk *walk) | |
178 | { | |
179 | u8 *tmp = walk->page; | |
180 | ||
181 | blkcipher_map_src(walk); | |
182 | memcpy(tmp, walk->src.virt.addr, walk->nbytes); | |
183 | blkcipher_unmap_src(walk); | |
184 | ||
185 | walk->src.virt.addr = tmp; | |
186 | walk->dst.virt.addr = tmp; | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | static inline int blkcipher_next_fast(struct blkcipher_desc *desc, | |
192 | struct blkcipher_walk *walk) | |
193 | { | |
194 | unsigned long diff; | |
195 | ||
196 | walk->src.phys.page = scatterwalk_page(&walk->in); | |
197 | walk->src.phys.offset = offset_in_page(walk->in.offset); | |
198 | walk->dst.phys.page = scatterwalk_page(&walk->out); | |
199 | walk->dst.phys.offset = offset_in_page(walk->out.offset); | |
200 | ||
201 | if (walk->flags & BLKCIPHER_WALK_PHYS) | |
202 | return 0; | |
203 | ||
204 | diff = walk->src.phys.offset - walk->dst.phys.offset; | |
205 | diff |= walk->src.virt.page - walk->dst.virt.page; | |
206 | ||
207 | blkcipher_map_src(walk); | |
208 | walk->dst.virt.addr = walk->src.virt.addr; | |
209 | ||
210 | if (diff) { | |
211 | walk->flags |= BLKCIPHER_WALK_DIFF; | |
212 | blkcipher_map_dst(walk); | |
213 | } | |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
218 | static int blkcipher_walk_next(struct blkcipher_desc *desc, | |
219 | struct blkcipher_walk *walk) | |
220 | { | |
221 | struct crypto_blkcipher *tfm = desc->tfm; | |
222 | unsigned int alignmask = crypto_blkcipher_alignmask(tfm); | |
223 | unsigned int bsize = crypto_blkcipher_blocksize(tfm); | |
224 | unsigned int n; | |
225 | int err; | |
226 | ||
227 | n = walk->total; | |
228 | if (unlikely(n < bsize)) { | |
229 | desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; | |
230 | return blkcipher_walk_done(desc, walk, -EINVAL); | |
231 | } | |
232 | ||
233 | walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY | | |
234 | BLKCIPHER_WALK_DIFF); | |
235 | if (!scatterwalk_aligned(&walk->in, alignmask) || | |
236 | !scatterwalk_aligned(&walk->out, alignmask)) { | |
237 | walk->flags |= BLKCIPHER_WALK_COPY; | |
238 | if (!walk->page) { | |
239 | walk->page = (void *)__get_free_page(GFP_ATOMIC); | |
240 | if (!walk->page) | |
241 | n = 0; | |
242 | } | |
243 | } | |
244 | ||
245 | n = scatterwalk_clamp(&walk->in, n); | |
246 | n = scatterwalk_clamp(&walk->out, n); | |
247 | ||
248 | if (unlikely(n < bsize)) { | |
249 | err = blkcipher_next_slow(desc, walk, bsize, alignmask); | |
250 | goto set_phys_lowmem; | |
251 | } | |
252 | ||
253 | walk->nbytes = n; | |
254 | if (walk->flags & BLKCIPHER_WALK_COPY) { | |
255 | err = blkcipher_next_copy(walk); | |
256 | goto set_phys_lowmem; | |
257 | } | |
258 | ||
259 | return blkcipher_next_fast(desc, walk); | |
260 | ||
261 | set_phys_lowmem: | |
262 | if (walk->flags & BLKCIPHER_WALK_PHYS) { | |
263 | walk->src.phys.page = virt_to_page(walk->src.virt.addr); | |
264 | walk->dst.phys.page = virt_to_page(walk->dst.virt.addr); | |
265 | walk->src.phys.offset &= PAGE_SIZE - 1; | |
266 | walk->dst.phys.offset &= PAGE_SIZE - 1; | |
267 | } | |
268 | return err; | |
269 | } | |
270 | ||
271 | static inline int blkcipher_copy_iv(struct blkcipher_walk *walk, | |
272 | struct crypto_blkcipher *tfm, | |
273 | unsigned int alignmask) | |
274 | { | |
275 | unsigned bs = crypto_blkcipher_blocksize(tfm); | |
276 | unsigned int ivsize = crypto_blkcipher_ivsize(tfm); | |
277 | unsigned int size = bs * 2 + ivsize + max(bs, ivsize) - (alignmask + 1); | |
278 | u8 *iv; | |
279 | ||
280 | size += alignmask & ~(crypto_tfm_ctx_alignment() - 1); | |
281 | walk->buffer = kmalloc(size, GFP_ATOMIC); | |
282 | if (!walk->buffer) | |
283 | return -ENOMEM; | |
284 | ||
285 | iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); | |
286 | iv = blkcipher_get_spot(iv, bs) + bs; | |
287 | iv = blkcipher_get_spot(iv, bs) + bs; | |
288 | iv = blkcipher_get_spot(iv, ivsize); | |
289 | ||
290 | walk->iv = memcpy(iv, walk->iv, ivsize); | |
291 | return 0; | |
292 | } | |
293 | ||
294 | int blkcipher_walk_virt(struct blkcipher_desc *desc, | |
295 | struct blkcipher_walk *walk) | |
296 | { | |
297 | walk->flags &= ~BLKCIPHER_WALK_PHYS; | |
298 | return blkcipher_walk_first(desc, walk); | |
299 | } | |
300 | EXPORT_SYMBOL_GPL(blkcipher_walk_virt); | |
301 | ||
302 | int blkcipher_walk_phys(struct blkcipher_desc *desc, | |
303 | struct blkcipher_walk *walk) | |
304 | { | |
305 | walk->flags |= BLKCIPHER_WALK_PHYS; | |
306 | return blkcipher_walk_first(desc, walk); | |
307 | } | |
308 | EXPORT_SYMBOL_GPL(blkcipher_walk_phys); | |
309 | ||
310 | static int blkcipher_walk_first(struct blkcipher_desc *desc, | |
311 | struct blkcipher_walk *walk) | |
312 | { | |
313 | struct crypto_blkcipher *tfm = desc->tfm; | |
314 | unsigned int alignmask = crypto_blkcipher_alignmask(tfm); | |
315 | ||
316 | walk->nbytes = walk->total; | |
317 | if (unlikely(!walk->total)) | |
318 | return 0; | |
319 | ||
320 | walk->buffer = NULL; | |
321 | walk->iv = desc->info; | |
322 | if (unlikely(((unsigned long)walk->iv & alignmask))) { | |
323 | int err = blkcipher_copy_iv(walk, tfm, alignmask); | |
324 | if (err) | |
325 | return err; | |
326 | } | |
327 | ||
328 | scatterwalk_start(&walk->in, walk->in.sg); | |
329 | scatterwalk_start(&walk->out, walk->out.sg); | |
330 | walk->page = NULL; | |
331 | ||
332 | return blkcipher_walk_next(desc, walk); | |
333 | } | |
334 | ||
335 | static int setkey(struct crypto_tfm *tfm, const u8 *key, | |
336 | unsigned int keylen) | |
337 | { | |
338 | struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; | |
339 | ||
340 | if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { | |
341 | tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; | |
342 | return -EINVAL; | |
343 | } | |
344 | ||
345 | return cipher->setkey(tfm, key, keylen); | |
346 | } | |
347 | ||
348 | static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg) | |
349 | { | |
350 | struct blkcipher_alg *cipher = &alg->cra_blkcipher; | |
351 | unsigned int len = alg->cra_ctxsize; | |
352 | ||
353 | if (cipher->ivsize) { | |
354 | len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1); | |
355 | len += cipher->ivsize; | |
356 | } | |
357 | ||
358 | return len; | |
359 | } | |
360 | ||
361 | static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm) | |
362 | { | |
363 | struct blkcipher_tfm *crt = &tfm->crt_blkcipher; | |
364 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
365 | unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1; | |
366 | unsigned long addr; | |
367 | ||
368 | if (alg->ivsize > PAGE_SIZE / 8) | |
369 | return -EINVAL; | |
370 | ||
371 | crt->setkey = setkey; | |
372 | crt->encrypt = alg->encrypt; | |
373 | crt->decrypt = alg->decrypt; | |
374 | ||
375 | addr = (unsigned long)crypto_tfm_ctx(tfm); | |
376 | addr = ALIGN(addr, align); | |
377 | addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align); | |
378 | crt->iv = (void *)addr; | |
379 | ||
380 | return 0; | |
381 | } | |
382 | ||
383 | static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) | |
384 | __attribute_used__; | |
385 | static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) | |
386 | { | |
387 | seq_printf(m, "type : blkcipher\n"); | |
388 | seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); | |
389 | seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize); | |
390 | seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize); | |
391 | seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize); | |
392 | } | |
393 | ||
394 | const struct crypto_type crypto_blkcipher_type = { | |
395 | .ctxsize = crypto_blkcipher_ctxsize, | |
396 | .init = crypto_init_blkcipher_ops, | |
397 | #ifdef CONFIG_PROC_FS | |
398 | .show = crypto_blkcipher_show, | |
399 | #endif | |
400 | }; | |
401 | EXPORT_SYMBOL_GPL(crypto_blkcipher_type); | |
402 | ||
403 | MODULE_LICENSE("GPL"); | |
404 | MODULE_DESCRIPTION("Generic block chaining cipher type"); |