2 * Accelerated GHASH implementation with ARMv8 PMULL instructions.
4 * Copyright (C) 2014 - 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
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>
26 MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
27 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
28 MODULE_LICENSE("GPL v2");
29 MODULE_ALIAS_CRYPTO("ghash");
31 #define GHASH_BLOCK_SIZE 16
32 #define GHASH_DIGEST_SIZE 16
33 #define GCM_IV_SIZE 12
41 struct ghash_desc_ctx {
42 u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
43 u8 buf[GHASH_BLOCK_SIZE];
48 struct crypto_aes_ctx aes_key;
49 struct ghash_key ghash_key;
52 asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
53 struct ghash_key const *k,
56 asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
57 struct ghash_key const *k,
60 static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
61 struct ghash_key const *k,
64 asmlinkage 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[]);
68 asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
69 const u8 src[], struct ghash_key const *k,
70 u8 ctr[], int rounds);
72 asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
73 u32 const rk[], int rounds);
75 asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
77 static int ghash_init(struct shash_desc *desc)
79 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
81 *ctx = (struct ghash_desc_ctx){};
85 static void ghash_do_update(int blocks, u64 dg[], const char *src,
86 struct ghash_key *key, const char *head)
88 if (likely(may_use_simd())) {
90 pmull_ghash_update(blocks, dg, src, key, head);
93 be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
103 src += GHASH_BLOCK_SIZE;
106 crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
107 gf128mul_lle(&dst, &key->k);
110 dg[0] = be64_to_cpu(dst.b);
111 dg[1] = be64_to_cpu(dst.a);
115 static int ghash_update(struct shash_desc *desc, const u8 *src,
118 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
119 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
123 if ((partial + len) >= GHASH_BLOCK_SIZE) {
124 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
128 int p = GHASH_BLOCK_SIZE - partial;
130 memcpy(ctx->buf + partial, src, p);
135 blocks = len / GHASH_BLOCK_SIZE;
136 len %= GHASH_BLOCK_SIZE;
138 ghash_do_update(blocks, ctx->digest, src, key,
139 partial ? ctx->buf : NULL);
141 src += blocks * GHASH_BLOCK_SIZE;
145 memcpy(ctx->buf + partial, src, len);
149 static int ghash_final(struct shash_desc *desc, u8 *dst)
151 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
152 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
155 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
157 memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
159 ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
161 put_unaligned_be64(ctx->digest[1], dst);
162 put_unaligned_be64(ctx->digest[0], dst + 8);
164 *ctx = (struct ghash_desc_ctx){};
168 static int __ghash_setkey(struct ghash_key *key,
169 const u8 *inkey, unsigned int keylen)
173 /* needed for the fallback */
174 memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
176 /* perform multiplication by 'x' in GF(2^128) */
177 b = get_unaligned_be64(inkey);
178 a = get_unaligned_be64(inkey + 8);
180 key->a = (a << 1) | (b >> 63);
181 key->b = (b << 1) | (a >> 63);
184 key->b ^= 0xc200000000000000UL;
189 static int ghash_setkey(struct crypto_shash *tfm,
190 const u8 *inkey, unsigned int keylen)
192 struct ghash_key *key = crypto_shash_ctx(tfm);
194 if (keylen != GHASH_BLOCK_SIZE) {
195 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
199 return __ghash_setkey(key, inkey, keylen);
202 static 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,
211 .digestsize = GHASH_DIGEST_SIZE,
213 .update = ghash_update,
214 .final = ghash_final,
215 .setkey = ghash_setkey,
216 .descsize = sizeof(struct ghash_desc_ctx),
219 static int num_rounds(struct crypto_aes_ctx *ctx)
222 * # of rounds specified by AES:
223 * 128 bit key 10 rounds
224 * 192 bit key 12 rounds
225 * 256 bit key 14 rounds
226 * => n byte key => 6 + (n/4) rounds
228 return 6 + ctx->key_length / 4;
231 static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
234 struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
235 u8 key[GHASH_BLOCK_SIZE];
238 ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
240 tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
244 __aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
245 num_rounds(&ctx->aes_key));
247 return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
250 static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
263 static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
264 int *buf_count, struct gcm_aes_ctx *ctx)
266 if (*buf_count > 0) {
267 int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);
269 memcpy(&buf[*buf_count], src, buf_added);
271 *buf_count += buf_added;
276 if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
277 int blocks = count / GHASH_BLOCK_SIZE;
279 ghash_do_update(blocks, dg, src, &ctx->ghash_key,
280 *buf_count ? buf : NULL);
282 src += blocks * GHASH_BLOCK_SIZE;
283 count %= GHASH_BLOCK_SIZE;
288 memcpy(buf, src, count);
293 static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
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;
302 scatterwalk_start(&walk, req->src);
305 u32 n = scatterwalk_clamp(&walk, len);
309 scatterwalk_start(&walk, sg_next(walk.sg));
310 n = scatterwalk_clamp(&walk, len);
312 p = scatterwalk_map(&walk);
314 gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
317 scatterwalk_unmap(p);
318 scatterwalk_advance(&walk, n);
319 scatterwalk_done(&walk, 0, len);
323 memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
324 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
328 static void gcm_final(struct aead_request *req, struct gcm_aes_ctx *ctx,
329 u64 dg[], u8 tag[], int cryptlen)
331 u8 mac[AES_BLOCK_SIZE];
334 lengths.a = cpu_to_be64(req->assoclen * 8);
335 lengths.b = cpu_to_be64(cryptlen * 8);
337 ghash_do_update(1, dg, (void *)&lengths, &ctx->ghash_key, NULL);
339 put_unaligned_be64(dg[1], mac);
340 put_unaligned_be64(dg[0], mac + 8);
342 crypto_xor(tag, mac, AES_BLOCK_SIZE);
345 static int gcm_encrypt(struct aead_request *req)
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];
357 gcm_calculate_auth_mac(req, dg);
359 memcpy(iv, req->iv, GCM_IV_SIZE);
360 put_unaligned_be32(1, iv + GCM_IV_SIZE);
362 if (likely(may_use_simd())) {
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);
372 err = skcipher_walk_aead_encrypt(&walk, req, true);
374 while (walk.nbytes >= AES_BLOCK_SIZE) {
375 int blocks = walk.nbytes / AES_BLOCK_SIZE;
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);
381 err = skcipher_walk_done(&walk,
382 walk.nbytes % AES_BLOCK_SIZE);
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);
390 err = skcipher_walk_aead_encrypt(&walk, req, true);
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;
398 __aes_arm64_encrypt(ctx->aes_key.key_enc,
400 num_rounds(&ctx->aes_key));
401 crypto_xor_cpy(dst, src, ks, AES_BLOCK_SIZE);
402 crypto_inc(iv, AES_BLOCK_SIZE);
404 dst += AES_BLOCK_SIZE;
405 src += AES_BLOCK_SIZE;
406 } while (--blocks > 0);
408 ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg,
409 walk.dst.virt.addr, &ctx->ghash_key,
412 err = skcipher_walk_done(&walk,
413 walk.nbytes % AES_BLOCK_SIZE);
416 __aes_arm64_encrypt(ctx->aes_key.key_enc, ks, iv,
417 num_rounds(&ctx->aes_key));
420 /* handle the tail */
422 u8 buf[GHASH_BLOCK_SIZE];
424 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, ks,
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);
431 err = skcipher_walk_done(&walk, 0);
437 gcm_final(req, ctx, dg, tag, req->cryptlen);
439 /* copy authtag to end of dst */
440 scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
441 crypto_aead_authsize(aead), 1);
446 static int gcm_decrypt(struct aead_request *req)
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];
459 gcm_calculate_auth_mac(req, dg);
461 memcpy(iv, req->iv, GCM_IV_SIZE);
462 put_unaligned_be32(1, iv + GCM_IV_SIZE);
464 if (likely(may_use_simd())) {
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);
471 err = skcipher_walk_aead_decrypt(&walk, req, true);
473 while (walk.nbytes >= AES_BLOCK_SIZE) {
474 int blocks = walk.nbytes / AES_BLOCK_SIZE;
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));
480 err = skcipher_walk_done(&walk,
481 walk.nbytes % AES_BLOCK_SIZE);
484 pmull_gcm_encrypt_block(iv, iv, NULL,
485 num_rounds(&ctx->aes_key));
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);
493 err = skcipher_walk_aead_decrypt(&walk, req, true);
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;
500 ghash_do_update(blocks, dg, walk.src.virt.addr,
501 &ctx->ghash_key, NULL);
504 __aes_arm64_encrypt(ctx->aes_key.key_enc,
506 num_rounds(&ctx->aes_key));
507 crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
508 crypto_inc(iv, AES_BLOCK_SIZE);
510 dst += AES_BLOCK_SIZE;
511 src += AES_BLOCK_SIZE;
512 } while (--blocks > 0);
514 err = skcipher_walk_done(&walk,
515 walk.nbytes % AES_BLOCK_SIZE);
518 __aes_arm64_encrypt(ctx->aes_key.key_enc, iv, iv,
519 num_rounds(&ctx->aes_key));
522 /* handle the tail */
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);
528 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, iv,
531 err = skcipher_walk_done(&walk, 0);
537 gcm_final(req, ctx, dg, tag, req->cryptlen - authsize);
539 /* compare calculated auth tag with the stored one */
540 scatterwalk_map_and_copy(buf, req->src,
541 req->assoclen + req->cryptlen - authsize,
544 if (crypto_memneq(tag, buf, authsize))
549 static 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,
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,
566 static int __init ghash_ce_mod_init(void)
570 if (!(elf_hwcap & HWCAP_ASIMD))
573 if (elf_hwcap & HWCAP_PMULL)
574 pmull_ghash_update = pmull_ghash_update_p64;
577 pmull_ghash_update = pmull_ghash_update_p8;
579 ret = crypto_register_shash(&ghash_alg);
583 if (elf_hwcap & HWCAP_PMULL) {
584 ret = crypto_register_aead(&gcm_aes_alg);
586 crypto_unregister_shash(&ghash_alg);
591 static void __exit ghash_ce_mod_exit(void)
593 crypto_unregister_shash(&ghash_alg);
594 crypto_unregister_aead(&gcm_aes_alg);
597 static const struct cpu_feature ghash_cpu_feature[] = {
598 { cpu_feature(PMULL) }, { }
600 MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);
602 module_init(ghash_ce_mod_init);
603 module_exit(ghash_ce_mod_exit);