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_DESCRIPTION("Bit sliced AES using NEON instructions");
20 MODULE_LICENSE("GPL v2");
21
22 MODULE_ALIAS_CRYPTO("ecb(aes)");
23 MODULE_ALIAS_CRYPTO("cbc(aes)");
24 MODULE_ALIAS_CRYPTO("ctr(aes)");
25 MODULE_ALIAS_CRYPTO("xts(aes)");
26
27 asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
28
29 asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
30 int rounds, int blocks);
31 asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
32 int rounds, int blocks);
33
34 asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
35 int rounds, int blocks, u8 iv[]);
36
37 asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
38 int rounds, int blocks, u8 iv[]);
39
40 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
41 int rounds, int blocks, u8 iv[]);
42 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
43 int rounds, int blocks, u8 iv[]);
44
45 /* borrowed from aes-neon-blk.ko */
46 asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
47 int rounds, int blocks);
48 asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
49 int rounds, int blocks, u8 iv[]);
50 asmlinkage void neon_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[],
51 int rounds, int bytes, u8 ctr[]);
52 asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[],
53 u32 const rk1[], int rounds, int bytes,
54 u32 const rk2[], u8 iv[], int first);
55 asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[],
56 u32 const rk1[], int rounds, int bytes,
57 u32 const rk2[], u8 iv[], int first);
58
59 struct aesbs_ctx {
60 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32];
61 int rounds;
62 } __aligned(AES_BLOCK_SIZE);
63
64 struct aesbs_cbc_ctr_ctx {
65 struct aesbs_ctx key;
66 u32 enc[AES_MAX_KEYLENGTH_U32];
67 };
68
69 struct aesbs_xts_ctx {
70 struct aesbs_ctx key;
71 u32 twkey[AES_MAX_KEYLENGTH_U32];
72 struct crypto_aes_ctx cts;
73 };
74
aesbs_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)75 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
76 unsigned int key_len)
77 {
78 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
79 struct crypto_aes_ctx *rk;
80 int err;
81
82 rk = kmalloc(sizeof(*rk), GFP_KERNEL);
83 if (!rk)
84 return -ENOMEM;
85
86 err = aes_expandkey(rk, in_key, key_len);
87 if (err)
88 goto out;
89
90 ctx->rounds = 6 + key_len / 4;
91
92 scoped_ksimd()
93 aesbs_convert_key(ctx->rk, rk->key_enc, ctx->rounds);
94 out:
95 kfree_sensitive(rk);
96 return err;
97 }
98
__ecb_crypt(struct skcipher_request * req,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks))99 static int __ecb_crypt(struct skcipher_request *req,
100 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
101 int rounds, int blocks))
102 {
103 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
104 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
105 struct skcipher_walk walk;
106 int err;
107
108 err = skcipher_walk_virt(&walk, req, false);
109
110 while (walk.nbytes >= AES_BLOCK_SIZE) {
111 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
112
113 if (walk.nbytes < walk.total)
114 blocks = round_down(blocks,
115 walk.stride / AES_BLOCK_SIZE);
116
117 scoped_ksimd()
118 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
119 ctx->rounds, blocks);
120 err = skcipher_walk_done(&walk,
121 walk.nbytes - blocks * AES_BLOCK_SIZE);
122 }
123
124 return err;
125 }
126
ecb_encrypt(struct skcipher_request * req)127 static int ecb_encrypt(struct skcipher_request *req)
128 {
129 return __ecb_crypt(req, aesbs_ecb_encrypt);
130 }
131
ecb_decrypt(struct skcipher_request * req)132 static int ecb_decrypt(struct skcipher_request *req)
133 {
134 return __ecb_crypt(req, aesbs_ecb_decrypt);
135 }
136
aesbs_cbc_ctr_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)137 static int aesbs_cbc_ctr_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
138 unsigned int key_len)
139 {
140 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
141 struct crypto_aes_ctx *rk;
142 int err;
143
144 rk = kmalloc(sizeof(*rk), GFP_KERNEL);
145 if (!rk)
146 return -ENOMEM;
147
148 err = aes_expandkey(rk, in_key, key_len);
149 if (err)
150 goto out;
151
152 ctx->key.rounds = 6 + key_len / 4;
153
154 memcpy(ctx->enc, rk->key_enc, sizeof(ctx->enc));
155
156 scoped_ksimd()
157 aesbs_convert_key(ctx->key.rk, rk->key_enc, ctx->key.rounds);
158 out:
159 kfree_sensitive(rk);
160 return err;
161 }
162
cbc_encrypt(struct skcipher_request * req)163 static int cbc_encrypt(struct skcipher_request *req)
164 {
165 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
166 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
167 struct skcipher_walk walk;
168 int err;
169
170 err = skcipher_walk_virt(&walk, req, false);
171
172 while (walk.nbytes >= AES_BLOCK_SIZE) {
173 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
174
175 /* fall back to the non-bitsliced NEON implementation */
176 scoped_ksimd()
177 neon_aes_cbc_encrypt(walk.dst.virt.addr,
178 walk.src.virt.addr,
179 ctx->enc, ctx->key.rounds, blocks,
180 walk.iv);
181 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
182 }
183 return err;
184 }
185
cbc_decrypt(struct skcipher_request * req)186 static int cbc_decrypt(struct skcipher_request *req)
187 {
188 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
189 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
190 struct skcipher_walk walk;
191 int err;
192
193 err = skcipher_walk_virt(&walk, req, false);
194
195 while (walk.nbytes >= AES_BLOCK_SIZE) {
196 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
197
198 if (walk.nbytes < walk.total)
199 blocks = round_down(blocks,
200 walk.stride / AES_BLOCK_SIZE);
201
202 scoped_ksimd()
203 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
204 ctx->key.rk, ctx->key.rounds, blocks,
205 walk.iv);
206 err = skcipher_walk_done(&walk,
207 walk.nbytes - blocks * AES_BLOCK_SIZE);
208 }
209
210 return err;
211 }
212
ctr_encrypt(struct skcipher_request * req)213 static int ctr_encrypt(struct skcipher_request *req)
214 {
215 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
216 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
217 struct skcipher_walk walk;
218 int err;
219
220 err = skcipher_walk_virt(&walk, req, false);
221
222 while (walk.nbytes > 0) {
223 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
224 int nbytes = walk.nbytes % (8 * AES_BLOCK_SIZE);
225 const u8 *src = walk.src.virt.addr;
226 u8 *dst = walk.dst.virt.addr;
227
228 scoped_ksimd() {
229 if (blocks >= 8) {
230 aesbs_ctr_encrypt(dst, src, ctx->key.rk,
231 ctx->key.rounds, blocks,
232 walk.iv);
233 dst += blocks * AES_BLOCK_SIZE;
234 src += blocks * AES_BLOCK_SIZE;
235 }
236 if (nbytes && walk.nbytes == walk.total) {
237 u8 buf[AES_BLOCK_SIZE];
238 u8 *d = dst;
239
240 if (unlikely(nbytes < AES_BLOCK_SIZE))
241 src = dst = memcpy(buf + sizeof(buf) -
242 nbytes, src, nbytes);
243
244 neon_aes_ctr_encrypt(dst, src, ctx->enc,
245 ctx->key.rounds, nbytes,
246 walk.iv);
247
248 if (unlikely(nbytes < AES_BLOCK_SIZE))
249 memcpy(d, dst, nbytes);
250
251 nbytes = 0;
252 }
253 }
254 err = skcipher_walk_done(&walk, nbytes);
255 }
256 return err;
257 }
258
aesbs_xts_setkey(struct crypto_skcipher * tfm,const u8 * in_key,unsigned int key_len)259 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
260 unsigned int key_len)
261 {
262 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
263 struct crypto_aes_ctx rk;
264 int err;
265
266 err = xts_verify_key(tfm, in_key, key_len);
267 if (err)
268 return err;
269
270 key_len /= 2;
271 err = aes_expandkey(&ctx->cts, in_key, key_len);
272 if (err)
273 return err;
274
275 err = aes_expandkey(&rk, in_key + key_len, key_len);
276 if (err)
277 return err;
278
279 memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
280
281 return aesbs_setkey(tfm, in_key, key_len);
282 }
283
__xts_crypt(struct skcipher_request * req,bool encrypt,void (* fn)(u8 out[],u8 const in[],u8 const rk[],int rounds,int blocks,u8 iv[]))284 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
285 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
286 int rounds, int blocks, u8 iv[]))
287 {
288 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
289 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
290 int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
291 struct scatterlist sg_src[2], sg_dst[2];
292 struct skcipher_request subreq;
293 struct scatterlist *src, *dst;
294 struct skcipher_walk walk;
295 int nbytes, err;
296 int first = 1;
297 const u8 *in;
298 u8 *out;
299
300 if (req->cryptlen < AES_BLOCK_SIZE)
301 return -EINVAL;
302
303 /* ensure that the cts tail is covered by a single step */
304 if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
305 int xts_blocks = DIV_ROUND_UP(req->cryptlen,
306 AES_BLOCK_SIZE) - 2;
307
308 skcipher_request_set_tfm(&subreq, tfm);
309 skcipher_request_set_callback(&subreq,
310 skcipher_request_flags(req),
311 NULL, NULL);
312 skcipher_request_set_crypt(&subreq, req->src, req->dst,
313 xts_blocks * AES_BLOCK_SIZE,
314 req->iv);
315 req = &subreq;
316 } else {
317 tail = 0;
318 }
319
320 err = skcipher_walk_virt(&walk, req, false);
321 if (err)
322 return err;
323
324 scoped_ksimd() {
325 while (walk.nbytes >= AES_BLOCK_SIZE) {
326 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
327 out = walk.dst.virt.addr;
328 in = walk.src.virt.addr;
329 nbytes = walk.nbytes;
330
331 if (blocks >= 8) {
332 if (first == 1)
333 neon_aes_ecb_encrypt(walk.iv, walk.iv,
334 ctx->twkey,
335 ctx->key.rounds, 1);
336 first = 2;
337
338 fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
339 walk.iv);
340
341 out += blocks * AES_BLOCK_SIZE;
342 in += blocks * AES_BLOCK_SIZE;
343 nbytes -= blocks * AES_BLOCK_SIZE;
344 }
345 if (walk.nbytes == walk.total && nbytes > 0) {
346 if (encrypt)
347 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc,
348 ctx->key.rounds, nbytes,
349 ctx->twkey, walk.iv, first);
350 else
351 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec,
352 ctx->key.rounds, nbytes,
353 ctx->twkey, walk.iv, first);
354 nbytes = first = 0;
355 }
356 err = skcipher_walk_done(&walk, nbytes);
357 }
358
359 if (err || likely(!tail))
360 return err;
361
362 /* handle ciphertext stealing */
363 dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
364 if (req->dst != req->src)
365 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
366
367 skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
368 req->iv);
369
370 err = skcipher_walk_virt(&walk, req, false);
371 if (err)
372 return err;
373
374 out = walk.dst.virt.addr;
375 in = walk.src.virt.addr;
376 nbytes = walk.nbytes;
377
378 if (encrypt)
379 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc,
380 ctx->key.rounds, nbytes, ctx->twkey,
381 walk.iv, first);
382 else
383 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec,
384 ctx->key.rounds, nbytes, ctx->twkey,
385 walk.iv, first);
386 }
387
388 return skcipher_walk_done(&walk, 0);
389 }
390
xts_encrypt(struct skcipher_request * req)391 static int xts_encrypt(struct skcipher_request *req)
392 {
393 return __xts_crypt(req, true, aesbs_xts_encrypt);
394 }
395
xts_decrypt(struct skcipher_request * req)396 static int xts_decrypt(struct skcipher_request *req)
397 {
398 return __xts_crypt(req, false, aesbs_xts_decrypt);
399 }
400
401 static struct skcipher_alg aes_algs[] = { {
402 .base.cra_name = "ecb(aes)",
403 .base.cra_driver_name = "ecb-aes-neonbs",
404 .base.cra_priority = 250,
405 .base.cra_blocksize = AES_BLOCK_SIZE,
406 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
407 .base.cra_module = THIS_MODULE,
408
409 .min_keysize = AES_MIN_KEY_SIZE,
410 .max_keysize = AES_MAX_KEY_SIZE,
411 .walksize = 8 * AES_BLOCK_SIZE,
412 .setkey = aesbs_setkey,
413 .encrypt = ecb_encrypt,
414 .decrypt = ecb_decrypt,
415 }, {
416 .base.cra_name = "cbc(aes)",
417 .base.cra_driver_name = "cbc-aes-neonbs",
418 .base.cra_priority = 250,
419 .base.cra_blocksize = AES_BLOCK_SIZE,
420 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
421 .base.cra_module = THIS_MODULE,
422
423 .min_keysize = AES_MIN_KEY_SIZE,
424 .max_keysize = AES_MAX_KEY_SIZE,
425 .walksize = 8 * AES_BLOCK_SIZE,
426 .ivsize = AES_BLOCK_SIZE,
427 .setkey = aesbs_cbc_ctr_setkey,
428 .encrypt = cbc_encrypt,
429 .decrypt = cbc_decrypt,
430 }, {
431 .base.cra_name = "ctr(aes)",
432 .base.cra_driver_name = "ctr-aes-neonbs",
433 .base.cra_priority = 250,
434 .base.cra_blocksize = 1,
435 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
436 .base.cra_module = THIS_MODULE,
437
438 .min_keysize = AES_MIN_KEY_SIZE,
439 .max_keysize = AES_MAX_KEY_SIZE,
440 .chunksize = AES_BLOCK_SIZE,
441 .walksize = 8 * AES_BLOCK_SIZE,
442 .ivsize = AES_BLOCK_SIZE,
443 .setkey = aesbs_cbc_ctr_setkey,
444 .encrypt = ctr_encrypt,
445 .decrypt = ctr_encrypt,
446 }, {
447 .base.cra_name = "xts(aes)",
448 .base.cra_driver_name = "xts-aes-neonbs",
449 .base.cra_priority = 250,
450 .base.cra_blocksize = AES_BLOCK_SIZE,
451 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
452 .base.cra_module = THIS_MODULE,
453
454 .min_keysize = 2 * AES_MIN_KEY_SIZE,
455 .max_keysize = 2 * AES_MAX_KEY_SIZE,
456 .walksize = 8 * AES_BLOCK_SIZE,
457 .ivsize = AES_BLOCK_SIZE,
458 .setkey = aesbs_xts_setkey,
459 .encrypt = xts_encrypt,
460 .decrypt = xts_decrypt,
461 } };
462
aes_exit(void)463 static void aes_exit(void)
464 {
465 crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
466 }
467
aes_init(void)468 static int __init aes_init(void)
469 {
470 if (!cpu_have_named_feature(ASIMD))
471 return -ENODEV;
472
473 return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
474 }
475
476 module_init(aes_init);
477 module_exit(aes_exit);
478