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11#include <asm/neon.h>
12#include <asm/simd.h>
13#include <asm/unaligned.h>
14#include <crypto/aes.h>
15#include <crypto/algapi.h>
16#include <crypto/b128ops.h>
17#include <crypto/gf128mul.h>
18#include <crypto/internal/aead.h>
19#include <crypto/internal/hash.h>
20#include <crypto/internal/skcipher.h>
21#include <crypto/scatterwalk.h>
22#include <linux/cpufeature.h>
23#include <linux/crypto.h>
24#include <linux/module.h>
25
26MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
27MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
28MODULE_LICENSE("GPL v2");
29MODULE_ALIAS_CRYPTO("ghash");
30
31#define GHASH_BLOCK_SIZE 16
32#define GHASH_DIGEST_SIZE 16
33#define GCM_IV_SIZE 12
34
35struct ghash_key {
36 u64 a;
37 u64 b;
38 be128 k;
39};
40
41struct ghash_desc_ctx {
42 u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
43 u8 buf[GHASH_BLOCK_SIZE];
44 u32 count;
45};
46
47struct gcm_aes_ctx {
48 struct crypto_aes_ctx aes_key;
49 struct ghash_key ghash_key;
50};
51
52asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
53 struct ghash_key const *k,
54 const char *head);
55
56asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
57 struct ghash_key const *k,
58 const char *head);
59
60static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
61 struct ghash_key const *k,
62 const char *head);
63
64asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[],
65 const u8 src[], struct ghash_key const *k,
66 u8 ctr[], int rounds, u8 ks[]);
67
68asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
69 const u8 src[], struct ghash_key const *k,
70 u8 ctr[], int rounds);
71
72asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
73 u32 const rk[], int rounds);
74
75asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
76
77static int ghash_init(struct shash_desc *desc)
78{
79 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
80
81 *ctx = (struct ghash_desc_ctx){};
82 return 0;
83}
84
85static void ghash_do_update(int blocks, u64 dg[], const char *src,
86 struct ghash_key *key, const char *head)
87{
88 if (likely(may_use_simd())) {
89 kernel_neon_begin();
90 pmull_ghash_update(blocks, dg, src, key, head);
91 kernel_neon_end();
92 } else {
93 be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
94
95 do {
96 const u8 *in = src;
97
98 if (head) {
99 in = head;
100 blocks++;
101 head = NULL;
102 } else {
103 src += GHASH_BLOCK_SIZE;
104 }
105
106 crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
107 gf128mul_lle(&dst, &key->k);
108 } while (--blocks);
109
110 dg[0] = be64_to_cpu(dst.b);
111 dg[1] = be64_to_cpu(dst.a);
112 }
113}
114
115static int ghash_update(struct shash_desc *desc, const u8 *src,
116 unsigned int len)
117{
118 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
119 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
120
121 ctx->count += len;
122
123 if ((partial + len) >= GHASH_BLOCK_SIZE) {
124 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
125 int blocks;
126
127 if (partial) {
128 int p = GHASH_BLOCK_SIZE - partial;
129
130 memcpy(ctx->buf + partial, src, p);
131 src += p;
132 len -= p;
133 }
134
135 blocks = len / GHASH_BLOCK_SIZE;
136 len %= GHASH_BLOCK_SIZE;
137
138 ghash_do_update(blocks, ctx->digest, src, key,
139 partial ? ctx->buf : NULL);
140
141 src += blocks * GHASH_BLOCK_SIZE;
142 partial = 0;
143 }
144 if (len)
145 memcpy(ctx->buf + partial, src, len);
146 return 0;
147}
148
149static int ghash_final(struct shash_desc *desc, u8 *dst)
150{
151 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
152 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
153
154 if (partial) {
155 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
156
157 memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
158
159 ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
160 }
161 put_unaligned_be64(ctx->digest[1], dst);
162 put_unaligned_be64(ctx->digest[0], dst + 8);
163
164 *ctx = (struct ghash_desc_ctx){};
165 return 0;
166}
167
168static int __ghash_setkey(struct ghash_key *key,
169 const u8 *inkey, unsigned int keylen)
170{
171 u64 a, b;
172
173
174 memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
175
176
177 b = get_unaligned_be64(inkey);
178 a = get_unaligned_be64(inkey + 8);
179
180 key->a = (a << 1) | (b >> 63);
181 key->b = (b << 1) | (a >> 63);
182
183 if (b >> 63)
184 key->b ^= 0xc200000000000000UL;
185
186 return 0;
187}
188
189static int ghash_setkey(struct crypto_shash *tfm,
190 const u8 *inkey, unsigned int keylen)
191{
192 struct ghash_key *key = crypto_shash_ctx(tfm);
193
194 if (keylen != GHASH_BLOCK_SIZE) {
195 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
196 return -EINVAL;
197 }
198
199 return __ghash_setkey(key, inkey, keylen);
200}
201
202static struct shash_alg ghash_alg = {
203 .base.cra_name = "ghash",
204 .base.cra_driver_name = "ghash-ce",
205 .base.cra_priority = 200,
206 .base.cra_flags = CRYPTO_ALG_TYPE_SHASH,
207 .base.cra_blocksize = GHASH_BLOCK_SIZE,
208 .base.cra_ctxsize = sizeof(struct ghash_key),
209 .base.cra_module = THIS_MODULE,
210
211 .digestsize = GHASH_DIGEST_SIZE,
212 .init = ghash_init,
213 .update = ghash_update,
214 .final = ghash_final,
215 .setkey = ghash_setkey,
216 .descsize = sizeof(struct ghash_desc_ctx),
217};
218
219static int num_rounds(struct crypto_aes_ctx *ctx)
220{
221
222
223
224
225
226
227
228 return 6 + ctx->key_length / 4;
229}
230
231static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
232 unsigned int keylen)
233{
234 struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
235 u8 key[GHASH_BLOCK_SIZE];
236 int ret;
237
238 ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
239 if (ret) {
240 tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
241 return -EINVAL;
242 }
243
244 __aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
245 num_rounds(&ctx->aes_key));
246
247 return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
248}
249
250static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
251{
252 switch (authsize) {
253 case 4:
254 case 8:
255 case 12 ... 16:
256 break;
257 default:
258 return -EINVAL;
259 }
260 return 0;
261}
262
263static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
264 int *buf_count, struct gcm_aes_ctx *ctx)
265{
266 if (*buf_count > 0) {
267 int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);
268
269 memcpy(&buf[*buf_count], src, buf_added);
270
271 *buf_count += buf_added;
272 src += buf_added;
273 count -= buf_added;
274 }
275
276 if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
277 int blocks = count / GHASH_BLOCK_SIZE;
278
279 ghash_do_update(blocks, dg, src, &ctx->ghash_key,
280 *buf_count ? buf : NULL);
281
282 src += blocks * GHASH_BLOCK_SIZE;
283 count %= GHASH_BLOCK_SIZE;
284 *buf_count = 0;
285 }
286
287 if (count > 0) {
288 memcpy(buf, src, count);
289 *buf_count = count;
290 }
291}
292
293static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
294{
295 struct crypto_aead *aead = crypto_aead_reqtfm(req);
296 struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
297 u8 buf[GHASH_BLOCK_SIZE];
298 struct scatter_walk walk;
299 u32 len = req->assoclen;
300 int buf_count = 0;
301
302 scatterwalk_start(&walk, req->src);
303
304 do {
305 u32 n = scatterwalk_clamp(&walk, len);
306 u8 *p;
307
308 if (!n) {
309 scatterwalk_start(&walk, sg_next(walk.sg));
310 n = scatterwalk_clamp(&walk, len);
311 }
312 p = scatterwalk_map(&walk);
313
314 gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
315 len -= n;
316
317 scatterwalk_unmap(p);
318 scatterwalk_advance(&walk, n);
319 scatterwalk_done(&walk, 0, len);
320 } while (len);
321
322 if (buf_count) {
323 memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
324 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
325 }
326}
327
328static void gcm_final(struct aead_request *req, struct gcm_aes_ctx *ctx,
329 u64 dg[], u8 tag[], int cryptlen)
330{
331 u8 mac[AES_BLOCK_SIZE];
332 u128 lengths;
333
334 lengths.a = cpu_to_be64(req->assoclen * 8);
335 lengths.b = cpu_to_be64(cryptlen * 8);
336
337 ghash_do_update(1, dg, (void *)&lengths, &ctx->ghash_key, NULL);
338
339 put_unaligned_be64(dg[1], mac);
340 put_unaligned_be64(dg[0], mac + 8);
341
342 crypto_xor(tag, mac, AES_BLOCK_SIZE);
343}
344
345static int gcm_encrypt(struct aead_request *req)
346{
347 struct crypto_aead *aead = crypto_aead_reqtfm(req);
348 struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
349 struct skcipher_walk walk;
350 u8 iv[AES_BLOCK_SIZE];
351 u8 ks[AES_BLOCK_SIZE];
352 u8 tag[AES_BLOCK_SIZE];
353 u64 dg[2] = {};
354 int err;
355
356 if (req->assoclen)
357 gcm_calculate_auth_mac(req, dg);
358
359 memcpy(iv, req->iv, GCM_IV_SIZE);
360 put_unaligned_be32(1, iv + GCM_IV_SIZE);
361
362 if (likely(may_use_simd())) {
363 kernel_neon_begin();
364
365 pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
366 num_rounds(&ctx->aes_key));
367 put_unaligned_be32(2, iv + GCM_IV_SIZE);
368 pmull_gcm_encrypt_block(ks, iv, NULL,
369 num_rounds(&ctx->aes_key));
370 put_unaligned_be32(3, iv + GCM_IV_SIZE);
371
372 err = skcipher_walk_aead_encrypt(&walk, req, true);
373
374 while (walk.nbytes >= AES_BLOCK_SIZE) {
375 int blocks = walk.nbytes / AES_BLOCK_SIZE;
376
377 pmull_gcm_encrypt(blocks, dg, walk.dst.virt.addr,
378 walk.src.virt.addr, &ctx->ghash_key,
379 iv, num_rounds(&ctx->aes_key), ks);
380
381 err = skcipher_walk_done(&walk,
382 walk.nbytes % AES_BLOCK_SIZE);
383 }
384 kernel_neon_end();
385 } else {
386 __aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
387 num_rounds(&ctx->aes_key));
388 put_unaligned_be32(2, iv + GCM_IV_SIZE);
389
390 err = skcipher_walk_aead_encrypt(&walk, req, true);
391
392 while (walk.nbytes >= AES_BLOCK_SIZE) {
393 int blocks = walk.nbytes / AES_BLOCK_SIZE;
394 u8 *dst = walk.dst.virt.addr;
395 u8 *src = walk.src.virt.addr;
396
397 do {
398 __aes_arm64_encrypt(ctx->aes_key.key_enc,
399 ks, iv,
400 num_rounds(&ctx->aes_key));
401 crypto_xor_cpy(dst, src, ks, AES_BLOCK_SIZE);
402 crypto_inc(iv, AES_BLOCK_SIZE);
403
404 dst += AES_BLOCK_SIZE;
405 src += AES_BLOCK_SIZE;
406 } while (--blocks > 0);
407
408 ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg,
409 walk.dst.virt.addr, &ctx->ghash_key,
410 NULL);
411
412 err = skcipher_walk_done(&walk,
413 walk.nbytes % AES_BLOCK_SIZE);
414 }
415 if (walk.nbytes)
416 __aes_arm64_encrypt(ctx->aes_key.key_enc, ks, iv,
417 num_rounds(&ctx->aes_key));
418 }
419
420
421 if (walk.nbytes) {
422 u8 buf[GHASH_BLOCK_SIZE];
423
424 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, ks,
425 walk.nbytes);
426
427 memcpy(buf, walk.dst.virt.addr, walk.nbytes);
428 memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
429 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
430
431 err = skcipher_walk_done(&walk, 0);
432 }
433
434 if (err)
435 return err;
436
437 gcm_final(req, ctx, dg, tag, req->cryptlen);
438
439
440 scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
441 crypto_aead_authsize(aead), 1);
442
443 return 0;
444}
445
446static int gcm_decrypt(struct aead_request *req)
447{
448 struct crypto_aead *aead = crypto_aead_reqtfm(req);
449 struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
450 unsigned int authsize = crypto_aead_authsize(aead);
451 struct skcipher_walk walk;
452 u8 iv[AES_BLOCK_SIZE];
453 u8 tag[AES_BLOCK_SIZE];
454 u8 buf[GHASH_BLOCK_SIZE];
455 u64 dg[2] = {};
456 int err;
457
458 if (req->assoclen)
459 gcm_calculate_auth_mac(req, dg);
460
461 memcpy(iv, req->iv, GCM_IV_SIZE);
462 put_unaligned_be32(1, iv + GCM_IV_SIZE);
463
464 if (likely(may_use_simd())) {
465 kernel_neon_begin();
466
467 pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
468 num_rounds(&ctx->aes_key));
469 put_unaligned_be32(2, iv + GCM_IV_SIZE);
470
471 err = skcipher_walk_aead_decrypt(&walk, req, true);
472
473 while (walk.nbytes >= AES_BLOCK_SIZE) {
474 int blocks = walk.nbytes / AES_BLOCK_SIZE;
475
476 pmull_gcm_decrypt(blocks, dg, walk.dst.virt.addr,
477 walk.src.virt.addr, &ctx->ghash_key,
478 iv, num_rounds(&ctx->aes_key));
479
480 err = skcipher_walk_done(&walk,
481 walk.nbytes % AES_BLOCK_SIZE);
482 }
483 if (walk.nbytes)
484 pmull_gcm_encrypt_block(iv, iv, NULL,
485 num_rounds(&ctx->aes_key));
486
487 kernel_neon_end();
488 } else {
489 __aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
490 num_rounds(&ctx->aes_key));
491 put_unaligned_be32(2, iv + GCM_IV_SIZE);
492
493 err = skcipher_walk_aead_decrypt(&walk, req, true);
494
495 while (walk.nbytes >= AES_BLOCK_SIZE) {
496 int blocks = walk.nbytes / AES_BLOCK_SIZE;
497 u8 *dst = walk.dst.virt.addr;
498 u8 *src = walk.src.virt.addr;
499
500 ghash_do_update(blocks, dg, walk.src.virt.addr,
501 &ctx->ghash_key, NULL);
502
503 do {
504 __aes_arm64_encrypt(ctx->aes_key.key_enc,
505 buf, iv,
506 num_rounds(&ctx->aes_key));
507 crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
508 crypto_inc(iv, AES_BLOCK_SIZE);
509
510 dst += AES_BLOCK_SIZE;
511 src += AES_BLOCK_SIZE;
512 } while (--blocks > 0);
513
514 err = skcipher_walk_done(&walk,
515 walk.nbytes % AES_BLOCK_SIZE);
516 }
517 if (walk.nbytes)
518 __aes_arm64_encrypt(ctx->aes_key.key_enc, iv, iv,
519 num_rounds(&ctx->aes_key));
520 }
521
522
523 if (walk.nbytes) {
524 memcpy(buf, walk.src.virt.addr, walk.nbytes);
525 memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
526 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
527
528 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, iv,
529 walk.nbytes);
530
531 err = skcipher_walk_done(&walk, 0);
532 }
533
534 if (err)
535 return err;
536
537 gcm_final(req, ctx, dg, tag, req->cryptlen - authsize);
538
539
540 scatterwalk_map_and_copy(buf, req->src,
541 req->assoclen + req->cryptlen - authsize,
542 authsize, 0);
543
544 if (crypto_memneq(tag, buf, authsize))
545 return -EBADMSG;
546 return 0;
547}
548
549static struct aead_alg gcm_aes_alg = {
550 .ivsize = GCM_IV_SIZE,
551 .chunksize = AES_BLOCK_SIZE,
552 .maxauthsize = AES_BLOCK_SIZE,
553 .setkey = gcm_setkey,
554 .setauthsize = gcm_setauthsize,
555 .encrypt = gcm_encrypt,
556 .decrypt = gcm_decrypt,
557
558 .base.cra_name = "gcm(aes)",
559 .base.cra_driver_name = "gcm-aes-ce",
560 .base.cra_priority = 300,
561 .base.cra_blocksize = 1,
562 .base.cra_ctxsize = sizeof(struct gcm_aes_ctx),
563 .base.cra_module = THIS_MODULE,
564};
565
566static int __init ghash_ce_mod_init(void)
567{
568 int ret;
569
570 if (!(elf_hwcap & HWCAP_ASIMD))
571 return -ENODEV;
572
573 if (elf_hwcap & HWCAP_PMULL)
574 pmull_ghash_update = pmull_ghash_update_p64;
575
576 else
577 pmull_ghash_update = pmull_ghash_update_p8;
578
579 ret = crypto_register_shash(&ghash_alg);
580 if (ret)
581 return ret;
582
583 if (elf_hwcap & HWCAP_PMULL) {
584 ret = crypto_register_aead(&gcm_aes_alg);
585 if (ret)
586 crypto_unregister_shash(&ghash_alg);
587 }
588 return ret;
589}
590
591static void __exit ghash_ce_mod_exit(void)
592{
593 crypto_unregister_shash(&ghash_alg);
594 crypto_unregister_aead(&gcm_aes_alg);
595}
596
597static const struct cpu_feature ghash_cpu_feature[] = {
598 { cpu_feature(PMULL) }, { }
599};
600MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);
601
602module_init(ghash_ce_mod_init);
603module_exit(ghash_ce_mod_exit);
604
