1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Block chaining cipher operations.
4 *
5 * Generic encrypt/decrypt wrapper for ciphers, handles operations across
6 * multiple page boundaries by using temporary blocks. In user context,
7 * the kernel is given a chance to schedule us once per page.
8 *
9 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
10 */
11
12 #include <crypto/aead.h>
13 #include <crypto/internal/skcipher.h>
14 #include <crypto/scatterwalk.h>
15 #include <linux/errno.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/seq_file.h>
19 #include <linux/slab.h>
20 #include <linux/string.h>
21 #include <linux/cryptouser.h>
22 #include <linux/compiler.h>
23 #include <net/netlink.h>
24
25 #include "internal.h"
26
27 enum {
28 BLKCIPHER_WALK_PHYS = 1 << 0,
29 BLKCIPHER_WALK_SLOW = 1 << 1,
30 BLKCIPHER_WALK_COPY = 1 << 2,
31 BLKCIPHER_WALK_DIFF = 1 << 3,
32 };
33
34 static int blkcipher_walk_next(struct blkcipher_desc *desc,
35 struct blkcipher_walk *walk);
36 static int blkcipher_walk_first(struct blkcipher_desc *desc,
37 struct blkcipher_walk *walk);
38
blkcipher_map_src(struct blkcipher_walk * walk)39 static inline void blkcipher_map_src(struct blkcipher_walk *walk)
40 {
41 walk->src.virt.addr = scatterwalk_map(&walk->in);
42 }
43
blkcipher_map_dst(struct blkcipher_walk * walk)44 static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
45 {
46 walk->dst.virt.addr = scatterwalk_map(&walk->out);
47 }
48
blkcipher_unmap_src(struct blkcipher_walk * walk)49 static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
50 {
51 scatterwalk_unmap(walk->src.virt.addr);
52 }
53
blkcipher_unmap_dst(struct blkcipher_walk * walk)54 static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
55 {
56 scatterwalk_unmap(walk->dst.virt.addr);
57 }
58
59 /* Get a spot of the specified length that does not straddle a page.
60 * The caller needs to ensure that there is enough space for this operation.
61 */
blkcipher_get_spot(u8 * start,unsigned int len)62 static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
63 {
64 u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
65 return max(start, end_page);
66 }
67
blkcipher_done_slow(struct blkcipher_walk * walk,unsigned int bsize)68 static inline void blkcipher_done_slow(struct blkcipher_walk *walk,
69 unsigned int bsize)
70 {
71 u8 *addr;
72
73 addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
74 addr = blkcipher_get_spot(addr, bsize);
75 scatterwalk_copychunks(addr, &walk->out, bsize, 1);
76 }
77
blkcipher_done_fast(struct blkcipher_walk * walk,unsigned int n)78 static inline void blkcipher_done_fast(struct blkcipher_walk *walk,
79 unsigned int n)
80 {
81 if (walk->flags & BLKCIPHER_WALK_COPY) {
82 blkcipher_map_dst(walk);
83 memcpy(walk->dst.virt.addr, walk->page, n);
84 blkcipher_unmap_dst(walk);
85 } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
86 if (walk->flags & BLKCIPHER_WALK_DIFF)
87 blkcipher_unmap_dst(walk);
88 blkcipher_unmap_src(walk);
89 }
90
91 scatterwalk_advance(&walk->in, n);
92 scatterwalk_advance(&walk->out, n);
93 }
94
blkcipher_walk_done(struct blkcipher_desc * desc,struct blkcipher_walk * walk,int err)95 int blkcipher_walk_done(struct blkcipher_desc *desc,
96 struct blkcipher_walk *walk, int err)
97 {
98 unsigned int n; /* bytes processed */
99 bool more;
100
101 if (unlikely(err < 0))
102 goto finish;
103
104 n = walk->nbytes - err;
105 walk->total -= n;
106 more = (walk->total != 0);
107
108 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) {
109 blkcipher_done_fast(walk, n);
110 } else {
111 if (WARN_ON(err)) {
112 /* unexpected case; didn't process all bytes */
113 err = -EINVAL;
114 goto finish;
115 }
116 blkcipher_done_slow(walk, n);
117 }
118
119 scatterwalk_done(&walk->in, 0, more);
120 scatterwalk_done(&walk->out, 1, more);
121
122 if (more) {
123 crypto_yield(desc->flags);
124 return blkcipher_walk_next(desc, walk);
125 }
126 err = 0;
127 finish:
128 walk->nbytes = 0;
129 if (walk->iv != desc->info)
130 memcpy(desc->info, walk->iv, walk->ivsize);
131 if (walk->buffer != walk->page)
132 kfree(walk->buffer);
133 if (walk->page)
134 free_page((unsigned long)walk->page);
135 return err;
136 }
137 EXPORT_SYMBOL_GPL(blkcipher_walk_done);
138
blkcipher_next_slow(struct blkcipher_desc * desc,struct blkcipher_walk * walk,unsigned int bsize,unsigned int alignmask)139 static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
140 struct blkcipher_walk *walk,
141 unsigned int bsize,
142 unsigned int alignmask)
143 {
144 unsigned int n;
145 unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
146
147 if (walk->buffer)
148 goto ok;
149
150 walk->buffer = walk->page;
151 if (walk->buffer)
152 goto ok;
153
154 n = aligned_bsize * 3 - (alignmask + 1) +
155 (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
156 walk->buffer = kmalloc(n, GFP_ATOMIC);
157 if (!walk->buffer)
158 return blkcipher_walk_done(desc, walk, -ENOMEM);
159
160 ok:
161 walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
162 alignmask + 1);
163 walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
164 walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
165 aligned_bsize, bsize);
166
167 scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
168
169 walk->nbytes = bsize;
170 walk->flags |= BLKCIPHER_WALK_SLOW;
171
172 return 0;
173 }
174
blkcipher_next_copy(struct blkcipher_walk * walk)175 static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
176 {
177 u8 *tmp = walk->page;
178
179 blkcipher_map_src(walk);
180 memcpy(tmp, walk->src.virt.addr, walk->nbytes);
181 blkcipher_unmap_src(walk);
182
183 walk->src.virt.addr = tmp;
184 walk->dst.virt.addr = tmp;
185
186 return 0;
187 }
188
blkcipher_next_fast(struct blkcipher_desc * desc,struct blkcipher_walk * walk)189 static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
190 struct blkcipher_walk *walk)
191 {
192 unsigned long diff;
193
194 walk->src.phys.page = scatterwalk_page(&walk->in);
195 walk->src.phys.offset = offset_in_page(walk->in.offset);
196 walk->dst.phys.page = scatterwalk_page(&walk->out);
197 walk->dst.phys.offset = offset_in_page(walk->out.offset);
198
199 if (walk->flags & BLKCIPHER_WALK_PHYS)
200 return 0;
201
202 diff = walk->src.phys.offset - walk->dst.phys.offset;
203 diff |= walk->src.virt.page - walk->dst.virt.page;
204
205 blkcipher_map_src(walk);
206 walk->dst.virt.addr = walk->src.virt.addr;
207
208 if (diff) {
209 walk->flags |= BLKCIPHER_WALK_DIFF;
210 blkcipher_map_dst(walk);
211 }
212
213 return 0;
214 }
215
blkcipher_walk_next(struct blkcipher_desc * desc,struct blkcipher_walk * walk)216 static int blkcipher_walk_next(struct blkcipher_desc *desc,
217 struct blkcipher_walk *walk)
218 {
219 unsigned int bsize;
220 unsigned int n;
221 int err;
222
223 n = walk->total;
224 if (unlikely(n < walk->cipher_blocksize)) {
225 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
226 return blkcipher_walk_done(desc, walk, -EINVAL);
227 }
228
229 bsize = min(walk->walk_blocksize, n);
230
231 walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
232 BLKCIPHER_WALK_DIFF);
233 if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
234 !scatterwalk_aligned(&walk->out, walk->alignmask)) {
235 walk->flags |= BLKCIPHER_WALK_COPY;
236 if (!walk->page) {
237 walk->page = (void *)__get_free_page(GFP_ATOMIC);
238 if (!walk->page)
239 n = 0;
240 }
241 }
242
243 n = scatterwalk_clamp(&walk->in, n);
244 n = scatterwalk_clamp(&walk->out, n);
245
246 if (unlikely(n < bsize)) {
247 err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
248 goto set_phys_lowmem;
249 }
250
251 walk->nbytes = n;
252 if (walk->flags & BLKCIPHER_WALK_COPY) {
253 err = blkcipher_next_copy(walk);
254 goto set_phys_lowmem;
255 }
256
257 return blkcipher_next_fast(desc, walk);
258
259 set_phys_lowmem:
260 if (walk->flags & BLKCIPHER_WALK_PHYS) {
261 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
262 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
263 walk->src.phys.offset &= PAGE_SIZE - 1;
264 walk->dst.phys.offset &= PAGE_SIZE - 1;
265 }
266 return err;
267 }
268
blkcipher_copy_iv(struct blkcipher_walk * walk)269 static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
270 {
271 unsigned bs = walk->walk_blocksize;
272 unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
273 unsigned int size = aligned_bs * 2 +
274 walk->ivsize + max(aligned_bs, walk->ivsize) -
275 (walk->alignmask + 1);
276 u8 *iv;
277
278 size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
279 walk->buffer = kmalloc(size, GFP_ATOMIC);
280 if (!walk->buffer)
281 return -ENOMEM;
282
283 iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
284 iv = blkcipher_get_spot(iv, bs) + aligned_bs;
285 iv = blkcipher_get_spot(iv, bs) + aligned_bs;
286 iv = blkcipher_get_spot(iv, walk->ivsize);
287
288 walk->iv = memcpy(iv, walk->iv, walk->ivsize);
289 return 0;
290 }
291
blkcipher_walk_virt(struct blkcipher_desc * desc,struct blkcipher_walk * walk)292 int blkcipher_walk_virt(struct blkcipher_desc *desc,
293 struct blkcipher_walk *walk)
294 {
295 walk->flags &= ~BLKCIPHER_WALK_PHYS;
296 walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
297 walk->cipher_blocksize = walk->walk_blocksize;
298 walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
299 walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
300 return blkcipher_walk_first(desc, walk);
301 }
302 EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
303
blkcipher_walk_phys(struct blkcipher_desc * desc,struct blkcipher_walk * walk)304 int blkcipher_walk_phys(struct blkcipher_desc *desc,
305 struct blkcipher_walk *walk)
306 {
307 walk->flags |= BLKCIPHER_WALK_PHYS;
308 walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
309 walk->cipher_blocksize = walk->walk_blocksize;
310 walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
311 walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
312 return blkcipher_walk_first(desc, walk);
313 }
314 EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
315
blkcipher_walk_first(struct blkcipher_desc * desc,struct blkcipher_walk * walk)316 static int blkcipher_walk_first(struct blkcipher_desc *desc,
317 struct blkcipher_walk *walk)
318 {
319 if (WARN_ON_ONCE(in_irq()))
320 return -EDEADLK;
321
322 walk->iv = desc->info;
323 walk->nbytes = walk->total;
324 if (unlikely(!walk->total))
325 return 0;
326
327 walk->buffer = NULL;
328 if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
329 int err = blkcipher_copy_iv(walk);
330 if (err)
331 return err;
332 }
333
334 scatterwalk_start(&walk->in, walk->in.sg);
335 scatterwalk_start(&walk->out, walk->out.sg);
336 walk->page = NULL;
337
338 return blkcipher_walk_next(desc, walk);
339 }
340
blkcipher_walk_virt_block(struct blkcipher_desc * desc,struct blkcipher_walk * walk,unsigned int blocksize)341 int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
342 struct blkcipher_walk *walk,
343 unsigned int blocksize)
344 {
345 walk->flags &= ~BLKCIPHER_WALK_PHYS;
346 walk->walk_blocksize = blocksize;
347 walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
348 walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
349 walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
350 return blkcipher_walk_first(desc, walk);
351 }
352 EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
353
blkcipher_aead_walk_virt_block(struct blkcipher_desc * desc,struct blkcipher_walk * walk,struct crypto_aead * tfm,unsigned int blocksize)354 int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
355 struct blkcipher_walk *walk,
356 struct crypto_aead *tfm,
357 unsigned int blocksize)
358 {
359 walk->flags &= ~BLKCIPHER_WALK_PHYS;
360 walk->walk_blocksize = blocksize;
361 walk->cipher_blocksize = crypto_aead_blocksize(tfm);
362 walk->ivsize = crypto_aead_ivsize(tfm);
363 walk->alignmask = crypto_aead_alignmask(tfm);
364 return blkcipher_walk_first(desc, walk);
365 }
366 EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
367
setkey_unaligned(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)368 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
369 unsigned int keylen)
370 {
371 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
372 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
373 int ret;
374 u8 *buffer, *alignbuffer;
375 unsigned long absize;
376
377 absize = keylen + alignmask;
378 buffer = kmalloc(absize, GFP_ATOMIC);
379 if (!buffer)
380 return -ENOMEM;
381
382 alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
383 memcpy(alignbuffer, key, keylen);
384 ret = cipher->setkey(tfm, alignbuffer, keylen);
385 memset(alignbuffer, 0, keylen);
386 kfree(buffer);
387 return ret;
388 }
389
setkey(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)390 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
391 {
392 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
393 unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
394
395 if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
396 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
397 return -EINVAL;
398 }
399
400 if ((unsigned long)key & alignmask)
401 return setkey_unaligned(tfm, key, keylen);
402
403 return cipher->setkey(tfm, key, keylen);
404 }
405
async_setkey(struct crypto_ablkcipher * tfm,const u8 * key,unsigned int keylen)406 static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
407 unsigned int keylen)
408 {
409 return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
410 }
411
async_encrypt(struct ablkcipher_request * req)412 static int async_encrypt(struct ablkcipher_request *req)
413 {
414 struct crypto_tfm *tfm = req->base.tfm;
415 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
416 struct blkcipher_desc desc = {
417 .tfm = __crypto_blkcipher_cast(tfm),
418 .info = req->info,
419 .flags = req->base.flags,
420 };
421
422
423 return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
424 }
425
async_decrypt(struct ablkcipher_request * req)426 static int async_decrypt(struct ablkcipher_request *req)
427 {
428 struct crypto_tfm *tfm = req->base.tfm;
429 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
430 struct blkcipher_desc desc = {
431 .tfm = __crypto_blkcipher_cast(tfm),
432 .info = req->info,
433 .flags = req->base.flags,
434 };
435
436 return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
437 }
438
crypto_blkcipher_ctxsize(struct crypto_alg * alg,u32 type,u32 mask)439 static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
440 u32 mask)
441 {
442 struct blkcipher_alg *cipher = &alg->cra_blkcipher;
443 unsigned int len = alg->cra_ctxsize;
444
445 if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
446 cipher->ivsize) {
447 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
448 len += cipher->ivsize;
449 }
450
451 return len;
452 }
453
crypto_init_blkcipher_ops_async(struct crypto_tfm * tfm)454 static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
455 {
456 struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
457 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
458
459 crt->setkey = async_setkey;
460 crt->encrypt = async_encrypt;
461 crt->decrypt = async_decrypt;
462 crt->base = __crypto_ablkcipher_cast(tfm);
463 crt->ivsize = alg->ivsize;
464
465 return 0;
466 }
467
crypto_init_blkcipher_ops_sync(struct crypto_tfm * tfm)468 static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
469 {
470 struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
471 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
472 unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
473 unsigned long addr;
474
475 crt->setkey = setkey;
476 crt->encrypt = alg->encrypt;
477 crt->decrypt = alg->decrypt;
478
479 addr = (unsigned long)crypto_tfm_ctx(tfm);
480 addr = ALIGN(addr, align);
481 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
482 crt->iv = (void *)addr;
483
484 return 0;
485 }
486
crypto_init_blkcipher_ops(struct crypto_tfm * tfm,u32 type,u32 mask)487 static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
488 {
489 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
490
491 if (alg->ivsize > PAGE_SIZE / 8)
492 return -EINVAL;
493
494 if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
495 return crypto_init_blkcipher_ops_sync(tfm);
496 else
497 return crypto_init_blkcipher_ops_async(tfm);
498 }
499
500 #ifdef CONFIG_NET
crypto_blkcipher_report(struct sk_buff * skb,struct crypto_alg * alg)501 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
502 {
503 struct crypto_report_blkcipher rblkcipher;
504
505 memset(&rblkcipher, 0, sizeof(rblkcipher));
506
507 strscpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
508 strscpy(rblkcipher.geniv, "<default>", sizeof(rblkcipher.geniv));
509
510 rblkcipher.blocksize = alg->cra_blocksize;
511 rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
512 rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
513 rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
514
515 return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
516 sizeof(rblkcipher), &rblkcipher);
517 }
518 #else
crypto_blkcipher_report(struct sk_buff * skb,struct crypto_alg * alg)519 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
520 {
521 return -ENOSYS;
522 }
523 #endif
524
525 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
526 __maybe_unused;
crypto_blkcipher_show(struct seq_file * m,struct crypto_alg * alg)527 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
528 {
529 seq_printf(m, "type : blkcipher\n");
530 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
531 seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
532 seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
533 seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
534 seq_printf(m, "geniv : <default>\n");
535 }
536
537 const struct crypto_type crypto_blkcipher_type = {
538 .ctxsize = crypto_blkcipher_ctxsize,
539 .init = crypto_init_blkcipher_ops,
540 #ifdef CONFIG_PROC_FS
541 .show = crypto_blkcipher_show,
542 #endif
543 .report = crypto_blkcipher_report,
544 };
545 EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
546
547 MODULE_LICENSE("GPL");
548 MODULE_DESCRIPTION("Generic block chaining cipher type");
549