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
18MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
19MODULE_DESCRIPTION("Bit sliced AES using NEON instructions");
20MODULE_LICENSE("GPL v2");
21
22MODULE_ALIAS_CRYPTO("ecb(aes)");
23MODULE_ALIAS_CRYPTO("cbc(aes)");
24MODULE_ALIAS_CRYPTO("ctr(aes)");
25MODULE_ALIAS_CRYPTO("xts(aes)");
26
27asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
28
29asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
30 int rounds, int blocks);
31asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
32 int rounds, int blocks);
33
34asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
35 int rounds, int blocks, u8 iv[]);
36
37asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
38 int rounds, int blocks, u8 iv[]);
39
40asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
41 int rounds, int blocks, u8 iv[]);
42asmlinkage 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 */
46asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
47 int rounds, int blocks);
48asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
49 int rounds, int blocks, u8 iv[]);
50asmlinkage void neon_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[],
51 int rounds, int bytes, u8 ctr[]);
52asmlinkage 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);
55asmlinkage 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
59struct aesbs_ctx {
60 u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32];
61 int rounds;
62} __aligned(AES_BLOCK_SIZE);
63
64struct aesbs_cbc_ctr_ctx {
65 struct aesbs_ctx key;
66 u32 enc[AES_MAX_KEYLENGTH_U32];
67};
68
69struct aesbs_xts_ctx {
70 struct aesbs_ctx key;
71 u32 twkey[AES_MAX_KEYLENGTH_U32];
72 struct crypto_aes_ctx cts;
73};
74
75static 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 err = aes_expandkey(ctx: &rk, in_key, key_len);
83 if (err)
84 return err;
85
86 ctx->rounds = 6 + key_len / 4;
87
88 kernel_neon_begin();
89 aesbs_convert_key(out: ctx->rk, rk: rk.key_enc, rounds: ctx->rounds);
90 kernel_neon_end();
91
92 return 0;
93}
94
95static int __ecb_crypt(struct skcipher_request *req,
96 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
97 int rounds, int blocks))
98{
99 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
100 struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
101 struct skcipher_walk walk;
102 int err;
103
104 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
105
106 while (walk.nbytes >= AES_BLOCK_SIZE) {
107 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
108
109 if (walk.nbytes < walk.total)
110 blocks = round_down(blocks,
111 walk.stride / AES_BLOCK_SIZE);
112
113 kernel_neon_begin();
114 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
115 ctx->rounds, blocks);
116 kernel_neon_end();
117 err = skcipher_walk_done(walk: &walk,
118 res: walk.nbytes - blocks * AES_BLOCK_SIZE);
119 }
120
121 return err;
122}
123
124static int ecb_encrypt(struct skcipher_request *req)
125{
126 return __ecb_crypt(req, fn: aesbs_ecb_encrypt);
127}
128
129static int ecb_decrypt(struct skcipher_request *req)
130{
131 return __ecb_crypt(req, fn: aesbs_ecb_decrypt);
132}
133
134static int aesbs_cbc_ctr_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
135 unsigned int key_len)
136{
137 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
138 struct crypto_aes_ctx rk;
139 int err;
140
141 err = aes_expandkey(ctx: &rk, in_key, key_len);
142 if (err)
143 return err;
144
145 ctx->key.rounds = 6 + key_len / 4;
146
147 memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));
148
149 kernel_neon_begin();
150 aesbs_convert_key(out: ctx->key.rk, rk: rk.key_enc, rounds: ctx->key.rounds);
151 kernel_neon_end();
152 memzero_explicit(s: &rk, count: sizeof(rk));
153
154 return 0;
155}
156
157static int cbc_encrypt(struct skcipher_request *req)
158{
159 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
160 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
161 struct skcipher_walk walk;
162 int err;
163
164 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
165
166 while (walk.nbytes >= AES_BLOCK_SIZE) {
167 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
168
169 /* fall back to the non-bitsliced NEON implementation */
170 kernel_neon_begin();
171 neon_aes_cbc_encrypt(out: walk.dst.virt.addr, in: walk.src.virt.addr,
172 rk: ctx->enc, rounds: ctx->key.rounds, blocks,
173 iv: walk.iv);
174 kernel_neon_end();
175 err = skcipher_walk_done(walk: &walk, res: walk.nbytes % AES_BLOCK_SIZE);
176 }
177 return err;
178}
179
180static int cbc_decrypt(struct skcipher_request *req)
181{
182 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
183 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
184 struct skcipher_walk walk;
185 int err;
186
187 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
188
189 while (walk.nbytes >= AES_BLOCK_SIZE) {
190 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
191
192 if (walk.nbytes < walk.total)
193 blocks = round_down(blocks,
194 walk.stride / AES_BLOCK_SIZE);
195
196 kernel_neon_begin();
197 aesbs_cbc_decrypt(out: walk.dst.virt.addr, in: walk.src.virt.addr,
198 rk: ctx->key.rk, rounds: ctx->key.rounds, blocks,
199 iv: walk.iv);
200 kernel_neon_end();
201 err = skcipher_walk_done(walk: &walk,
202 res: walk.nbytes - blocks * AES_BLOCK_SIZE);
203 }
204
205 return err;
206}
207
208static int ctr_encrypt(struct skcipher_request *req)
209{
210 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
211 struct aesbs_cbc_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
212 struct skcipher_walk walk;
213 int err;
214
215 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
216
217 while (walk.nbytes > 0) {
218 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
219 int nbytes = walk.nbytes % (8 * AES_BLOCK_SIZE);
220 const u8 *src = walk.src.virt.addr;
221 u8 *dst = walk.dst.virt.addr;
222
223 kernel_neon_begin();
224 if (blocks >= 8) {
225 aesbs_ctr_encrypt(out: dst, in: src, rk: ctx->key.rk, rounds: ctx->key.rounds,
226 blocks, iv: walk.iv);
227 dst += blocks * AES_BLOCK_SIZE;
228 src += blocks * AES_BLOCK_SIZE;
229 }
230 if (nbytes && walk.nbytes == walk.total) {
231 u8 buf[AES_BLOCK_SIZE];
232 u8 *d = dst;
233
234 if (unlikely(nbytes < AES_BLOCK_SIZE))
235 src = dst = memcpy(buf + sizeof(buf) - nbytes,
236 src, nbytes);
237
238 neon_aes_ctr_encrypt(out: dst, in: src, rk: ctx->enc, rounds: ctx->key.rounds,
239 bytes: nbytes, ctr: walk.iv);
240
241 if (unlikely(nbytes < AES_BLOCK_SIZE))
242 memcpy(d, dst, nbytes);
243
244 nbytes = 0;
245 }
246 kernel_neon_end();
247 err = skcipher_walk_done(walk: &walk, res: nbytes);
248 }
249 return err;
250}
251
252static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
253 unsigned int key_len)
254{
255 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
256 struct crypto_aes_ctx rk;
257 int err;
258
259 err = xts_verify_key(tfm, key: in_key, keylen: key_len);
260 if (err)
261 return err;
262
263 key_len /= 2;
264 err = aes_expandkey(ctx: &ctx->cts, in_key, key_len);
265 if (err)
266 return err;
267
268 err = aes_expandkey(ctx: &rk, in_key: in_key + key_len, key_len);
269 if (err)
270 return err;
271
272 memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
273
274 return aesbs_setkey(tfm, in_key, key_len);
275}
276
277static int __xts_crypt(struct skcipher_request *req, bool encrypt,
278 void (*fn)(u8 out[], u8 const in[], u8 const rk[],
279 int rounds, int blocks, u8 iv[]))
280{
281 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
282 struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
283 int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
284 struct scatterlist sg_src[2], sg_dst[2];
285 struct skcipher_request subreq;
286 struct scatterlist *src, *dst;
287 struct skcipher_walk walk;
288 int nbytes, err;
289 int first = 1;
290 const u8 *in;
291 u8 *out;
292
293 if (req->cryptlen < AES_BLOCK_SIZE)
294 return -EINVAL;
295
296 /* ensure that the cts tail is covered by a single step */
297 if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
298 int xts_blocks = DIV_ROUND_UP(req->cryptlen,
299 AES_BLOCK_SIZE) - 2;
300
301 skcipher_request_set_tfm(req: &subreq, tfm);
302 skcipher_request_set_callback(req: &subreq,
303 flags: skcipher_request_flags(req),
304 NULL, NULL);
305 skcipher_request_set_crypt(req: &subreq, src: req->src, dst: req->dst,
306 cryptlen: xts_blocks * AES_BLOCK_SIZE,
307 iv: req->iv);
308 req = &subreq;
309 } else {
310 tail = 0;
311 }
312
313 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
314 if (err)
315 return err;
316
317 while (walk.nbytes >= AES_BLOCK_SIZE) {
318 int blocks = (walk.nbytes / AES_BLOCK_SIZE) & ~7;
319 out = walk.dst.virt.addr;
320 in = walk.src.virt.addr;
321 nbytes = walk.nbytes;
322
323 kernel_neon_begin();
324 if (blocks >= 8) {
325 if (first == 1)
326 neon_aes_ecb_encrypt(out: walk.iv, in: walk.iv,
327 rk: ctx->twkey,
328 rounds: ctx->key.rounds, blocks: 1);
329 first = 2;
330
331 fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
332 walk.iv);
333
334 out += blocks * AES_BLOCK_SIZE;
335 in += blocks * AES_BLOCK_SIZE;
336 nbytes -= blocks * AES_BLOCK_SIZE;
337 }
338 if (walk.nbytes == walk.total && nbytes > 0) {
339 if (encrypt)
340 neon_aes_xts_encrypt(out, in, rk1: ctx->cts.key_enc,
341 rounds: ctx->key.rounds, bytes: nbytes,
342 rk2: ctx->twkey, iv: walk.iv, first);
343 else
344 neon_aes_xts_decrypt(out, in, rk1: ctx->cts.key_dec,
345 rounds: ctx->key.rounds, bytes: nbytes,
346 rk2: ctx->twkey, iv: walk.iv, first);
347 nbytes = first = 0;
348 }
349 kernel_neon_end();
350 err = skcipher_walk_done(walk: &walk, res: nbytes);
351 }
352
353 if (err || likely(!tail))
354 return err;
355
356 /* handle ciphertext stealing */
357 dst = src = scatterwalk_ffwd(dst: sg_src, src: req->src, len: req->cryptlen);
358 if (req->dst != req->src)
359 dst = scatterwalk_ffwd(dst: sg_dst, src: req->dst, len: req->cryptlen);
360
361 skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
362 iv: req->iv);
363
364 err = skcipher_walk_virt(walk: &walk, req, atomic: false);
365 if (err)
366 return err;
367
368 out = walk.dst.virt.addr;
369 in = walk.src.virt.addr;
370 nbytes = walk.nbytes;
371
372 kernel_neon_begin();
373 if (encrypt)
374 neon_aes_xts_encrypt(out, in, rk1: ctx->cts.key_enc, rounds: ctx->key.rounds,
375 bytes: nbytes, rk2: ctx->twkey, iv: walk.iv, first);
376 else
377 neon_aes_xts_decrypt(out, in, rk1: ctx->cts.key_dec, rounds: ctx->key.rounds,
378 bytes: nbytes, rk2: ctx->twkey, iv: walk.iv, first);
379 kernel_neon_end();
380
381 return skcipher_walk_done(walk: &walk, res: 0);
382}
383
384static int xts_encrypt(struct skcipher_request *req)
385{
386 return __xts_crypt(req, encrypt: true, fn: aesbs_xts_encrypt);
387}
388
389static int xts_decrypt(struct skcipher_request *req)
390{
391 return __xts_crypt(req, encrypt: false, fn: aesbs_xts_decrypt);
392}
393
394static struct skcipher_alg aes_algs[] = { {
395 .base.cra_name = "ecb(aes)",
396 .base.cra_driver_name = "ecb-aes-neonbs",
397 .base.cra_priority = 250,
398 .base.cra_blocksize = AES_BLOCK_SIZE,
399 .base.cra_ctxsize = sizeof(struct aesbs_ctx),
400 .base.cra_module = THIS_MODULE,
401
402 .min_keysize = AES_MIN_KEY_SIZE,
403 .max_keysize = AES_MAX_KEY_SIZE,
404 .walksize = 8 * AES_BLOCK_SIZE,
405 .setkey = aesbs_setkey,
406 .encrypt = ecb_encrypt,
407 .decrypt = ecb_decrypt,
408}, {
409 .base.cra_name = "cbc(aes)",
410 .base.cra_driver_name = "cbc-aes-neonbs",
411 .base.cra_priority = 250,
412 .base.cra_blocksize = AES_BLOCK_SIZE,
413 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
414 .base.cra_module = THIS_MODULE,
415
416 .min_keysize = AES_MIN_KEY_SIZE,
417 .max_keysize = AES_MAX_KEY_SIZE,
418 .walksize = 8 * AES_BLOCK_SIZE,
419 .ivsize = AES_BLOCK_SIZE,
420 .setkey = aesbs_cbc_ctr_setkey,
421 .encrypt = cbc_encrypt,
422 .decrypt = cbc_decrypt,
423}, {
424 .base.cra_name = "ctr(aes)",
425 .base.cra_driver_name = "ctr-aes-neonbs",
426 .base.cra_priority = 250,
427 .base.cra_blocksize = 1,
428 .base.cra_ctxsize = sizeof(struct aesbs_cbc_ctr_ctx),
429 .base.cra_module = THIS_MODULE,
430
431 .min_keysize = AES_MIN_KEY_SIZE,
432 .max_keysize = AES_MAX_KEY_SIZE,
433 .chunksize = AES_BLOCK_SIZE,
434 .walksize = 8 * AES_BLOCK_SIZE,
435 .ivsize = AES_BLOCK_SIZE,
436 .setkey = aesbs_cbc_ctr_setkey,
437 .encrypt = ctr_encrypt,
438 .decrypt = ctr_encrypt,
439}, {
440 .base.cra_name = "xts(aes)",
441 .base.cra_driver_name = "xts-aes-neonbs",
442 .base.cra_priority = 250,
443 .base.cra_blocksize = AES_BLOCK_SIZE,
444 .base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
445 .base.cra_module = THIS_MODULE,
446
447 .min_keysize = 2 * AES_MIN_KEY_SIZE,
448 .max_keysize = 2 * AES_MAX_KEY_SIZE,
449 .walksize = 8 * AES_BLOCK_SIZE,
450 .ivsize = AES_BLOCK_SIZE,
451 .setkey = aesbs_xts_setkey,
452 .encrypt = xts_encrypt,
453 .decrypt = xts_decrypt,
454} };
455
456static void aes_exit(void)
457{
458 crypto_unregister_skciphers(algs: aes_algs, ARRAY_SIZE(aes_algs));
459}
460
461static int __init aes_init(void)
462{
463 if (!cpu_have_named_feature(ASIMD))
464 return -ENODEV;
465
466 return crypto_register_skciphers(algs: aes_algs, ARRAY_SIZE(aes_algs));
467}
468
469module_init(aes_init);
470module_exit(aes_exit);
471

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source code of linux/arch/arm64/crypto/aes-neonbs-glue.c