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