1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Bit sliced AES using NEON instructions
4 *
5 * Copyright (C) 2016 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
6 */
7
8 #include <asm/neon.h>
9 #include <asm/simd.h>
10 #include <crypto/aes.h>
11 #include <crypto/ctr.h>
12 #include <crypto/internal/simd.h>
13 #include <crypto/internal/skcipher.h>
14 #include <crypto/scatterwalk.h>
15 #include <crypto/xts.h>
16 #include <linux/module.h>
17
18 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
19 MODULE_LICENSE("GPL v2");
20
21 MODULE_ALIAS_CRYPTO("ecb(aes)");
22 MODULE_ALIAS_CRYPTO("cbc(aes)");
23 MODULE_ALIAS_CRYPTO("ctr(aes)");
24 MODULE_ALIAS_CRYPTO("xts(aes)");
25
26 asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
27
28 asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
29 int rounds, int blocks);
30 asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
31 int rounds, int blocks);
32
33 asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
34 int rounds, int blocks, u8 iv[]);
35
36 asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
37 int rounds, int blocks, u8 iv[]);
38
39 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
40 int rounds, int blocks, u8 iv[]);
41 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
42 int rounds, int blocks, u8 iv[]);
43
44 /* borrowed from aes-neon-blk.ko */
45 asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
46 int rounds, int blocks);
47 asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
48 int rounds, int blocks, u8 iv[]);
49 asmlinkage void neon_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[],
50 int rounds, int bytes, u8 ctr[]);
51 asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[],
52 u32 const rk1[], int rounds, int bytes,
53 u32 const rk2[], u8 iv[], int first);
54 asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[],
55 u32 const rk1[], int rounds, int bytes,
56 u32 const rk2[], u8 iv[], int first);
57
58 struct aesbs_ctx {
59 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32];
60 int rounds;
61 } __aligned(AES_BLOCK_SIZE);
62
63 struct aesbs_cbc_ctr_ctx {
64 struct aesbs_ctx key;
65 u32 enc[AES_MAX_KEYLENGTH_U32];
66 };
67
68 struct aesbs_xts_ctx {
69 struct aesbs_ctx key;
70 u32 twkey[AES_MAX_KEYLENGTH_U32];
71 struct crypto_aes_ctx cts;
72 };
73
aesbs_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)74 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
75 unsigned int key_len)
76 {
77 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
78 struct crypto_aes_ctx rk;
79 int err;
80
81 err = aes_expandkey(&rk, in_key, key_len);
82 if (err)
83 return err;
84
85 ctx->rounds = 6 + key_len / 4;
86
87 kernel_neon_begin();
88 aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
89 kernel_neon_end();
90
91 return 0;
92 }
93
__ecb_crypt(struct skcipher_request * req,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks))94 static int __ecb_crypt(struct skcipher_request *req,
95 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
96 int rounds, int blocks))
97 {
98 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
99 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
100 struct skcipher_walk walk;
101 int err;
102
103 err = skcipher_walk_virt(&walk, req, false);
104
105 while (walk.nbytes >= AES_BLOCK_SIZE) {
106 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
107
108 if (walk.nbytes < walk.total)
109 blocks = round_down(blocks,
110 walk.stride / AES_BLOCK_SIZE);
111
112 kernel_neon_begin();
113 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
114 ctx->rounds, blocks);
115 kernel_neon_end();
116 err = skcipher_walk_done(&walk,
117 walk.nbytes - blocks * AES_BLOCK_SIZE);
118 }
119
120 return err;
121 }
122
ecb_encrypt(struct skcipher_request * req)123 static int ecb_encrypt(struct skcipher_request *req)
124 {
125 return __ecb_crypt(req, aesbs_ecb_encrypt);
126 }
127
ecb_decrypt(struct skcipher_request * req)128 static int ecb_decrypt(struct skcipher_request *req)
129 {
130 return __ecb_crypt(req, aesbs_ecb_decrypt);
131 }
132
aesbs_cbc_ctr_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)133 static int aesbs_cbc_ctr_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
134 unsigned int key_len)
135 {
136 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
137 struct crypto_aes_ctx rk;
138 int err;
139
140 err = aes_expandkey(&rk, in_key, key_len);
141 if (err)
142 return err;
143
144 ctx->key.rounds = 6 + key_len / 4;
145
146 memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));
147
148 kernel_neon_begin();
149 aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
150 kernel_neon_end();
151 memzero_explicit(&rk, sizeof(rk));
152
153 return 0;
154 }
155
cbc_encrypt(struct skcipher_request * req)156 static int cbc_encrypt(struct skcipher_request *req)
157 {
158 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
159 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
160 struct skcipher_walk walk;
161 int err;
162
163 err = skcipher_walk_virt(&walk, req, false);
164
165 while (walk.nbytes >= AES_BLOCK_SIZE) {
166 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
167
168 /* fall back to the non-bitsliced NEON implementation */
169 kernel_neon_begin();
170 neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
171 ctx->enc, ctx->key.rounds, blocks,
172 walk.iv);
173 kernel_neon_end();
174 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
175 }
176 return err;
177 }
178
cbc_decrypt(struct skcipher_request * req)179 static int cbc_decrypt(struct skcipher_request *req)
180 {
181 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
182 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
183 struct skcipher_walk walk;
184 int err;
185
186 err = skcipher_walk_virt(&walk, req, false);
187
188 while (walk.nbytes >= AES_BLOCK_SIZE) {
189 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
190
191 if (walk.nbytes < walk.total)
192 blocks = round_down(blocks,
193 walk.stride / AES_BLOCK_SIZE);
194
195 kernel_neon_begin();
196 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
197 ctx->key.rk, ctx->key.rounds, blocks,
198 walk.iv);
199 kernel_neon_end();
200 err = skcipher_walk_done(&walk,
201 walk.nbytes - blocks * AES_BLOCK_SIZE);
202 }
203
204 return err;
205 }
206
ctr_encrypt(struct skcipher_request * req)207 static int ctr_encrypt(struct skcipher_request *req)
208 {
209 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
210 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
211 struct skcipher_walk walk;
212 int err;
213
214 err = skcipher_walk_virt(&walk, req, false);
215
216 while (walk.nbytes > 0) {
217 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
218 int nbytes = walk.nbytes % (8 * AES_BLOCK_SIZE);
219 const u8 *src = walk.src.virt.addr;
220 u8 *dst = walk.dst.virt.addr;
221
222 kernel_neon_begin();
223 if (blocks >= 8) {
224 aesbs_ctr_encrypt(dst, src, ctx->key.rk, ctx->key.rounds,
225 blocks, walk.iv);
226 dst += blocks * AES_BLOCK_SIZE;
227 src += blocks * AES_BLOCK_SIZE;
228 }
229 if (nbytes && walk.nbytes == walk.total) {
230 u8 buf[AES_BLOCK_SIZE];
231 u8 *d = dst;
232
233 if (unlikely(nbytes < AES_BLOCK_SIZE))
234 src = dst = memcpy(buf + sizeof(buf) - nbytes,
235 src, nbytes);
236
237 neon_aes_ctr_encrypt(dst, src, ctx->enc, ctx->key.rounds,
238 nbytes, walk.iv);
239
240 if (unlikely(nbytes < AES_BLOCK_SIZE))
241 memcpy(d, dst, nbytes);
242
243 nbytes = 0;
244 }
245 kernel_neon_end();
246 err = skcipher_walk_done(&walk, nbytes);
247 }
248 return err;
249 }
250
aesbs_xts_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)251 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
252 unsigned int key_len)
253 {
254 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
255 struct crypto_aes_ctx rk;
256 int err;
257
258 err = xts_verify_key(tfm, in_key, key_len);
259 if (err)
260 return err;
261
262 key_len /= 2;
263 err = aes_expandkey(&ctx->cts, in_key, key_len);
264 if (err)
265 return err;
266
267 err = aes_expandkey(&rk, in_key + key_len, key_len);
268 if (err)
269 return err;
270
271 memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
272
273 return aesbs_setkey(tfm, in_key, key_len);
274 }
275
__xts_crypt(struct skcipher_request * req,bool encrypt,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks,u8 iv[]))276 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
277 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
278 int rounds, int blocks, u8 iv[]))
279 {
280 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
281 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
282 int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
283 struct scatterlist sg_src[2], sg_dst[2];
284 struct skcipher_request subreq;
285 struct scatterlist *src, *dst;
286 struct skcipher_walk walk;
287 int nbytes, err;
288 int first = 1;
289 u8 *out, *in;
290
291 if (req->cryptlen < AES_BLOCK_SIZE)
292 return -EINVAL;
293
294 /* ensure that the cts tail is covered by a single step */
295 if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
296 int xts_blocks = DIV_ROUND_UP(req->cryptlen,
297 AES_BLOCK_SIZE) - 2;
298
299 skcipher_request_set_tfm(&subreq, tfm);
300 skcipher_request_set_callback(&subreq,
301 skcipher_request_flags(req),
302 NULL, NULL);
303 skcipher_request_set_crypt(&subreq, req->src, req->dst,
304 xts_blocks * AES_BLOCK_SIZE,
305 req->iv);
306 req = &subreq;
307 } else {
308 tail = 0;
309 }
310
311 err = skcipher_walk_virt(&walk, req, false);
312 if (err)
313 return err;
314
315 while (walk.nbytes >= AES_BLOCK_SIZE) {
316 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
317 out = walk.dst.virt.addr;
318 in = walk.src.virt.addr;
319 nbytes = walk.nbytes;
320
321 kernel_neon_begin();
322 if (blocks >= 8) {
323 if (first == 1)
324 neon_aes_ecb_encrypt(walk.iv, walk.iv,
325 ctx->twkey,
326 ctx->key.rounds, 1);
327 first = 2;
328
329 fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
330 walk.iv);
331
332 out += blocks * AES_BLOCK_SIZE;
333 in += blocks * AES_BLOCK_SIZE;
334 nbytes -= blocks * AES_BLOCK_SIZE;
335 }
336 if (walk.nbytes == walk.total && nbytes > 0) {
337 if (encrypt)
338 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc,
339 ctx->key.rounds, nbytes,
340 ctx->twkey, walk.iv, first);
341 else
342 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec,
343 ctx->key.rounds, nbytes,
344 ctx->twkey, walk.iv, first);
345 nbytes = first = 0;
346 }
347 kernel_neon_end();
348 err = skcipher_walk_done(&walk, nbytes);
349 }
350
351 if (err || likely(!tail))
352 return err;
353
354 /* handle ciphertext stealing */
355 dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
356 if (req->dst != req->src)
357 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
358
359 skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
360 req->iv);
361
362 err = skcipher_walk_virt(&walk, req, false);
363 if (err)
364 return err;
365
366 out = walk.dst.virt.addr;
367 in = walk.src.virt.addr;
368 nbytes = walk.nbytes;
369
370 kernel_neon_begin();
371 if (encrypt)
372 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds,
373 nbytes, ctx->twkey, walk.iv, first);
374 else
375 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds,
376 nbytes, ctx->twkey, walk.iv, first);
377 kernel_neon_end();
378
379 return skcipher_walk_done(&walk, 0);
380 }
381
xts_encrypt(struct skcipher_request * req)382 static int xts_encrypt(struct skcipher_request *req)
383 {
384 return __xts_crypt(req, true, aesbs_xts_encrypt);
385 }
386
xts_decrypt(struct skcipher_request * req)387 static int xts_decrypt(struct skcipher_request *req)
388 {
389 return __xts_crypt(req, false, aesbs_xts_decrypt);
390 }
391
392 static struct skcipher_alg aes_algs[] = { {
393 .base.cra_name = "ecb(aes)",
394 .base.cra_driver_name = "ecb-aes-neonbs",
395 .base.cra_priority = 250,
396 .base.cra_blocksize = AES_BLOCK_SIZE,
397 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
398 .base.cra_module = THIS_MODULE,
399
400 .min_keysize = AES_MIN_KEY_SIZE,
401 .max_keysize = AES_MAX_KEY_SIZE,
402 .walksize = 8 * AES_BLOCK_SIZE,
403 .setkey = aesbs_setkey,
404 .encrypt = ecb_encrypt,
405 .decrypt = ecb_decrypt,
406 }, {
407 .base.cra_name = "cbc(aes)",
408 .base.cra_driver_name = "cbc-aes-neonbs",
409 .base.cra_priority = 250,
410 .base.cra_blocksize = AES_BLOCK_SIZE,
411 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
412 .base.cra_module = THIS_MODULE,
413
414 .min_keysize = AES_MIN_KEY_SIZE,
415 .max_keysize = AES_MAX_KEY_SIZE,
416 .walksize = 8 * AES_BLOCK_SIZE,
417 .ivsize = AES_BLOCK_SIZE,
418 .setkey = aesbs_cbc_ctr_setkey,
419 .encrypt = cbc_encrypt,
420 .decrypt = cbc_decrypt,
421 }, {
422 .base.cra_name = "ctr(aes)",
423 .base.cra_driver_name = "ctr-aes-neonbs",
424 .base.cra_priority = 250,
425 .base.cra_blocksize = 1,
426 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
427 .base.cra_module = THIS_MODULE,
428
429 .min_keysize = AES_MIN_KEY_SIZE,
430 .max_keysize = AES_MAX_KEY_SIZE,
431 .chunksize = AES_BLOCK_SIZE,
432 .walksize = 8 * AES_BLOCK_SIZE,
433 .ivsize = AES_BLOCK_SIZE,
434 .setkey = aesbs_cbc_ctr_setkey,
435 .encrypt = ctr_encrypt,
436 .decrypt = ctr_encrypt,
437 }, {
438 .base.cra_name = "xts(aes)",
439 .base.cra_driver_name = "xts-aes-neonbs",
440 .base.cra_priority = 250,
441 .base.cra_blocksize = AES_BLOCK_SIZE,
442 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
443 .base.cra_module = THIS_MODULE,
444
445 .min_keysize = 2 * AES_MIN_KEY_SIZE,
446 .max_keysize = 2 * AES_MAX_KEY_SIZE,
447 .walksize = 8 * AES_BLOCK_SIZE,
448 .ivsize = AES_BLOCK_SIZE,
449 .setkey = aesbs_xts_setkey,
450 .encrypt = xts_encrypt,
451 .decrypt = xts_decrypt,
452 } };
453
aes_exit(void)454 static void aes_exit(void)
455 {
456 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
457 }
458
aes_init(void)459 static int __init aes_init(void)
460 {
461 if (!cpu_have_named_feature(ASIMD))
462 return -ENODEV;
463
464 return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
465 }
466
467 module_init(aes_init);
468 module_exit(aes_exit);
469