1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Scalar fixed time AES core transform |
4 | * |
5 | * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org> |
6 | */ |
7 | |
8 | #include <crypto/aes.h> |
9 | #include <crypto/algapi.h> |
10 | #include <linux/module.h> |
11 | |
12 | static int aesti_set_key(struct crypto_tfm *tfm, const u8 *in_key, |
13 | unsigned int key_len) |
14 | { |
15 | struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); |
16 | |
17 | return aes_expandkey(ctx, in_key, key_len); |
18 | } |
19 | |
20 | static void aesti_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
21 | { |
22 | const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); |
23 | unsigned long flags; |
24 | |
25 | /* |
26 | * Temporarily disable interrupts to avoid races where cachelines are |
27 | * evicted when the CPU is interrupted to do something else. |
28 | */ |
29 | local_irq_save(flags); |
30 | |
31 | aes_encrypt(ctx, out, in); |
32 | |
33 | local_irq_restore(flags); |
34 | } |
35 | |
36 | static void aesti_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
37 | { |
38 | const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); |
39 | unsigned long flags; |
40 | |
41 | /* |
42 | * Temporarily disable interrupts to avoid races where cachelines are |
43 | * evicted when the CPU is interrupted to do something else. |
44 | */ |
45 | local_irq_save(flags); |
46 | |
47 | aes_decrypt(ctx, out, in); |
48 | |
49 | local_irq_restore(flags); |
50 | } |
51 | |
52 | static struct crypto_alg aes_alg = { |
53 | .cra_name = "aes" , |
54 | .cra_driver_name = "aes-fixed-time" , |
55 | .cra_priority = 100 + 1, |
56 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
57 | .cra_blocksize = AES_BLOCK_SIZE, |
58 | .cra_ctxsize = sizeof(struct crypto_aes_ctx), |
59 | .cra_module = THIS_MODULE, |
60 | |
61 | .cra_cipher.cia_min_keysize = AES_MIN_KEY_SIZE, |
62 | .cra_cipher.cia_max_keysize = AES_MAX_KEY_SIZE, |
63 | .cra_cipher.cia_setkey = aesti_set_key, |
64 | .cra_cipher.cia_encrypt = aesti_encrypt, |
65 | .cra_cipher.cia_decrypt = aesti_decrypt |
66 | }; |
67 | |
68 | static int __init aes_init(void) |
69 | { |
70 | return crypto_register_alg(alg: &aes_alg); |
71 | } |
72 | |
73 | static void __exit aes_fini(void) |
74 | { |
75 | crypto_unregister_alg(alg: &aes_alg); |
76 | } |
77 | |
78 | module_init(aes_init); |
79 | module_exit(aes_fini); |
80 | |
81 | MODULE_DESCRIPTION("Generic fixed time AES" ); |
82 | MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>" ); |
83 | MODULE_LICENSE("GPL v2" ); |
84 | |