diff options
Diffstat (limited to 'arch/arm64/crypto/aes-ce-glue.c')
| -rw-r--r-- | arch/arm64/crypto/aes-ce-glue.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/arm64/crypto/aes-ce-glue.c b/arch/arm64/crypto/aes-ce-glue.c new file mode 100644 index 000000000..56a5f6f0b --- /dev/null +++ b/arch/arm64/crypto/aes-ce-glue.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions + * + * Copyright (C) 2013 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org> + */ + +#include <asm/neon.h> +#include <asm/simd.h> +#include <asm/unaligned.h> +#include <crypto/aes.h> +#include <crypto/internal/simd.h> +#include <linux/cpufeature.h> +#include <linux/crypto.h> +#include <linux/module.h> + +#include "aes-ce-setkey.h" + +MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions"); +MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); +MODULE_LICENSE("GPL v2"); + +struct aes_block { + u8 b[AES_BLOCK_SIZE]; +}; + +asmlinkage void __aes_ce_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds); +asmlinkage void __aes_ce_decrypt(u32 *rk, u8 *out, const u8 *in, int rounds); + +asmlinkage u32 __aes_ce_sub(u32 l); +asmlinkage void __aes_ce_invert(struct aes_block *out, + const struct aes_block *in); + +static int num_rounds(struct crypto_aes_ctx *ctx) +{ + /* + * # of rounds specified by AES: + * 128 bit key 10 rounds + * 192 bit key 12 rounds + * 256 bit key 14 rounds + * => n byte key => 6 + (n/4) rounds + */ + return 6 + ctx->key_length / 4; +} + +static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[]) +{ + struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + + if (!crypto_simd_usable()) { + aes_encrypt(ctx, dst, src); + return; + } + + kernel_neon_begin(); + __aes_ce_encrypt(ctx->key_enc, dst, src, num_rounds(ctx)); + kernel_neon_end(); +} + +static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[]) +{ + struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + + if (!crypto_simd_usable()) { + aes_decrypt(ctx, dst, src); + return; + } + + kernel_neon_begin(); + __aes_ce_decrypt(ctx->key_dec, dst, src, num_rounds(ctx)); + kernel_neon_end(); +} + +int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key, + unsigned int key_len) +{ + /* + * The AES key schedule round constants + */ + static u8 const rcon[] = { + 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, + }; + + u32 kwords = key_len / sizeof(u32); + struct aes_block *key_enc, *key_dec; + int i, j; + + if (key_len != AES_KEYSIZE_128 && + key_len != AES_KEYSIZE_192 && + key_len != AES_KEYSIZE_256) + return -EINVAL; + + ctx->key_length = key_len; + for (i = 0; i < kwords; i++) + ctx->key_enc[i] = get_unaligned_le32(in_key + i * sizeof(u32)); + + kernel_neon_begin(); + for (i = 0; i < sizeof(rcon); i++) { + u32 *rki = ctx->key_enc + (i * kwords); + u32 *rko = rki + kwords; + + rko[0] = ror32(__aes_ce_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0]; + rko[1] = rko[0] ^ rki[1]; + rko[2] = rko[1] ^ rki[2]; + rko[3] = rko[2] ^ rki[3]; + + if (key_len == AES_KEYSIZE_192) { + if (i >= 7) + break; + rko[4] = rko[3] ^ rki[4]; + rko[5] = rko[4] ^ rki[5]; + } else if (key_len == AES_KEYSIZE_256) { + if (i >= 6) + break; + rko[4] = __aes_ce_sub(rko[3]) ^ rki[4]; + rko[5] = rko[4] ^ rki[5]; + rko[6] = rko[5] ^ rki[6]; + rko[7] = rko[6] ^ rki[7]; + } + } + + /* + * Generate the decryption keys for the Equivalent Inverse Cipher. + * This involves reversing the order of the round keys, and applying + * the Inverse Mix Columns transformation on all but the first and + * the last one. + */ + key_enc = (struct aes_block *)ctx->key_enc; + key_dec = (struct aes_block *)ctx->key_dec; + j = num_rounds(ctx); + + key_dec[0] = key_enc[j]; + for (i = 1, j--; j > 0; i++, j--) + __aes_ce_invert(key_dec + i, key_enc + j); + key_dec[i] = key_enc[0]; + + kernel_neon_end(); + return 0; +} +EXPORT_SYMBOL(ce_aes_expandkey); + +int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + + return ce_aes_expandkey(ctx, in_key, key_len); +} +EXPORT_SYMBOL(ce_aes_setkey); + +static struct crypto_alg aes_alg = { + .cra_name = "aes", + .cra_driver_name = "aes-ce", + .cra_priority = 250, + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = AES_BLOCK_SIZE, + .cra_ctxsize = sizeof(struct crypto_aes_ctx), + .cra_module = THIS_MODULE, + .cra_cipher = { + .cia_min_keysize = AES_MIN_KEY_SIZE, + .cia_max_keysize = AES_MAX_KEY_SIZE, + .cia_setkey = ce_aes_setkey, + .cia_encrypt = aes_cipher_encrypt, + .cia_decrypt = aes_cipher_decrypt + } +}; + +static int __init aes_mod_init(void) +{ + return crypto_register_alg(&aes_alg); +} + +static void __exit aes_mod_exit(void) +{ + crypto_unregister_alg(&aes_alg); +} + +module_cpu_feature_match(AES, aes_mod_init); +module_exit(aes_mod_exit); |