diff options
| -rw-r--r-- | crypto/Kconfig | 17 | ||||
| -rw-r--r-- | crypto/Makefile | 1 | ||||
| -rw-r--r-- | crypto/aes_ti.c | 375 |
3 files changed, 393 insertions, 0 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig index 160f08e721cc..419ff5fe6939 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -895,6 +895,23 @@ config CRYPTO_AES See <http://csrc.nist.gov/CryptoToolkit/aes/> for more information. +config CRYPTO_AES_TI + tristate "Fixed time AES cipher" + select CRYPTO_ALGAPI + help + This is a generic implementation of AES that attempts to eliminate + data dependent latencies as much as possible without affecting + performance too much. It is intended for use by the generic CCM + and GCM drivers, and other CTR or CMAC/XCBC based modes that rely + solely on encryption (although decryption is supported as well, but + with a more dramatic performance hit) + + Instead of using 16 lookup tables of 1 KB each, (8 for encryption and + 8 for decryption), this implementation only uses just two S-boxes of + 256 bytes each, and attempts to eliminate data dependent latencies by + prefetching the entire table into the cache at the start of each + block. + config CRYPTO_AES_586 tristate "AES cipher algorithms (i586)" depends on (X86 || UML_X86) && !64BIT diff --git a/crypto/Makefile b/crypto/Makefile index b8f0e3eb0791..bcd834536163 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -99,6 +99,7 @@ obj-$(CONFIG_CRYPTO_TWOFISH) += twofish_generic.o obj-$(CONFIG_CRYPTO_TWOFISH_COMMON) += twofish_common.o obj-$(CONFIG_CRYPTO_SERPENT) += serpent_generic.o obj-$(CONFIG_CRYPTO_AES) += aes_generic.o +obj-$(CONFIG_CRYPTO_AES_TI) += aes_ti.o obj-$(CONFIG_CRYPTO_CAMELLIA) += camellia_generic.o obj-$(CONFIG_CRYPTO_CAST_COMMON) += cast_common.o obj-$(CONFIG_CRYPTO_CAST5) += cast5_generic.o diff --git a/crypto/aes_ti.c b/crypto/aes_ti.c new file mode 100644 index 000000000000..92644fd1ac19 --- /dev/null +++ b/crypto/aes_ti.c @@ -0,0 +1,375 @@ +/* + * Scalar fixed time AES core transform + * + * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <crypto/aes.h> +#include <linux/crypto.h> +#include <linux/module.h> +#include <asm/unaligned.h> + +/* + * Emit the sbox as volatile const to prevent the compiler from doing + * constant folding on sbox references involving fixed indexes. + */ +static volatile const u8 __cacheline_aligned __aesti_sbox[] = { + 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, + 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, + 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, + 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, + 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, + 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, + 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, + 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, + 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, + 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, + 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, + 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, + 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, + 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, + 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, + 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, + 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, + 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, + 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, + 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, + 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, + 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, + 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, + 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, + 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, + 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, + 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, + 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, + 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, + 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, + 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, + 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16, +}; + +static volatile const u8 __cacheline_aligned __aesti_inv_sbox[] = { + 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, + 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, + 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, + 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, + 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, + 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, + 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, + 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, + 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, + 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, + 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, + 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, + 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, + 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, + 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, + 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, + 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, + 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, + 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, + 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, + 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, + 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, + 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, + 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, + 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, + 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, + 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, + 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, + 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, + 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, + 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, + 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d, +}; + +static u32 mul_by_x(u32 w) +{ + u32 x = w & 0x7f7f7f7f; + u32 y = w & 0x80808080; + + /* multiply by polynomial 'x' (0b10) in GF(2^8) */ + return (x << 1) ^ (y >> 7) * 0x1b; +} + +static u32 mul_by_x2(u32 w) +{ + u32 x = w & 0x3f3f3f3f; + u32 y = w & 0x80808080; + u32 z = w & 0x40404040; + + /* multiply by polynomial 'x^2' (0b100) in GF(2^8) */ + return (x << 2) ^ (y >> 7) * 0x36 ^ (z >> 6) * 0x1b; +} + +static u32 mix_columns(u32 x) +{ + /* + * Perform the following matrix multiplication in GF(2^8) + * + * | 0x2 0x3 0x1 0x1 | | x[0] | + * | 0x1 0x2 0x3 0x1 | | x[1] | + * | 0x1 0x1 0x2 0x3 | x | x[2] | + * | 0x3 0x1 0x1 0x3 | | x[3] | + */ + u32 y = mul_by_x(x) ^ ror32(x, 16); + + return y ^ ror32(x ^ y, 8); +} + +static u32 inv_mix_columns(u32 x) +{ + /* + * Perform the following matrix multiplication in GF(2^8) + * + * | 0xe 0xb 0xd 0x9 | | x[0] | + * | 0x9 0xe 0xb 0xd | | x[1] | + * | 0xd 0x9 0xe 0xb | x | x[2] | + * | 0xb 0xd 0x9 0xe | | x[3] | + * + * which can conveniently be reduced to + * + * | 0x2 0x3 0x1 0x1 | | 0x5 0x0 0x4 0x0 | | x[0] | + * | 0x1 0x2 0x3 0x1 | | 0x0 0x5 0x0 0x4 | | x[1] | + * | 0x1 0x1 0x2 0x3 | x | 0x4 0x0 0x5 0x0 | x | x[2] | + * | 0x3 0x1 0x1 0x2 | | 0x0 0x4 0x0 0x5 | | x[3] | + */ + u32 y = mul_by_x2(x); + + return mix_columns(x ^ y ^ ror32(y, 16)); +} + +static __always_inline u32 subshift(u32 in[], int pos) +{ + return (__aesti_sbox[in[pos] & 0xff]) ^ + (__aesti_sbox[(in[(pos + 1) % 4] >> 8) & 0xff] << 8) ^ + (__aesti_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^ + (__aesti_sbox[(in[(pos + 3) % 4] >> 24) & 0xff] << 24); +} + +static __always_inline u32 inv_subshift(u32 in[], int pos) +{ + return (__aesti_inv_sbox[in[pos] & 0xff]) ^ + (__aesti_inv_sbox[(in[(pos + 3) % 4] >> 8) & 0xff] << 8) ^ + (__aesti_inv_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^ + (__aesti_inv_sbox[(in[(pos + 1) % 4] >> 24) & 0xff] << 24); +} + +static u32 subw(u32 in) +{ + return (__aesti_sbox[in & 0xff]) ^ + (__aesti_sbox[(in >> 8) & 0xff] << 8) ^ + (__aesti_sbox[(in >> 16) & 0xff] << 16) ^ + (__aesti_sbox[(in >> 24) & 0xff] << 24); +} + +static int aesti_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key, + unsigned int key_len) +{ + u32 kwords = key_len / sizeof(u32); + u32 rc, 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)); + + for (i = 0, rc = 1; i < 10; i++, rc = mul_by_x(rc)) { + u32 *rki = ctx->key_enc + (i * kwords); + u32 *rko = rki + kwords; + + rko[0] = ror32(subw(rki[kwords - 1]), 8) ^ rc ^ rki[0]; + rko[1] = rko[0] ^ rki[1]; + rko[2] = rko[1] ^ rki[2]; + rko[3] = rko[2] ^ rki[3]; + + if (key_len == 24) { + if (i >= 7) + break; + rko[4] = rko[3] ^ rki[4]; + rko[5] = rko[4] ^ rki[5]; + } else if (key_len == 32) { + if (i >= 6) + break; + rko[4] = subw(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 to all but the first and + * the last one. + */ + ctx->key_dec[0] = ctx->key_enc[key_len + 24]; + ctx->key_dec[1] = ctx->key_enc[key_len + 25]; + ctx->key_dec[2] = ctx->key_enc[key_len + 26]; + ctx->key_dec[3] = ctx->key_enc[key_len + 27]; + + for (i = 4, j = key_len + 20; j > 0; i += 4, j -= 4) { + ctx->key_dec[i] = inv_mix_columns(ctx->key_enc[j]); + ctx->key_dec[i + 1] = inv_mix_columns(ctx->key_enc[j + 1]); + ctx->key_dec[i + 2] = inv_mix_columns(ctx->key_enc[j + 2]); + ctx->key_dec[i + 3] = inv_mix_columns(ctx->key_enc[j + 3]); + } + + ctx->key_dec[i] = ctx->key_enc[0]; + ctx->key_dec[i + 1] = ctx->key_enc[1]; + ctx->key_dec[i + 2] = ctx->key_enc[2]; + ctx->key_dec[i + 3] = ctx->key_enc[3]; + + return 0; +} + +static int aesti_set_key(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + int err; + + err = aesti_expand_key(ctx, in_key, key_len); + if (err) + return err; + + /* + * In order to force the compiler to emit data independent Sbox lookups + * at the start of each block, xor the first round key with values at + * fixed indexes in the Sbox. This will need to be repeated each time + * the key is used, which will pull the entire Sbox into the D-cache + * before any data dependent Sbox lookups are performed. + */ + ctx->key_enc[0] ^= __aesti_sbox[ 0] ^ __aesti_sbox[128]; + ctx->key_enc[1] ^= __aesti_sbox[32] ^ __aesti_sbox[160]; + ctx->key_enc[2] ^= __aesti_sbox[64] ^ __aesti_sbox[192]; + ctx->key_enc[3] ^= __aesti_sbox[96] ^ __aesti_sbox[224]; + + ctx->key_dec[0] ^= __aesti_inv_sbox[ 0] ^ __aesti_inv_sbox[128]; + ctx->key_dec[1] ^= __aesti_inv_sbox[32] ^ __aesti_inv_sbox[160]; + ctx->key_dec[2] ^= __aesti_inv_sbox[64] ^ __aesti_inv_sbox[192]; + ctx->key_dec[3] ^= __aesti_inv_sbox[96] ^ __aesti_inv_sbox[224]; + + return 0; +} + +static void aesti_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + const u32 *rkp = ctx->key_enc + 4; + int rounds = 6 + ctx->key_length / 4; + u32 st0[4], st1[4]; + int round; + + st0[0] = ctx->key_enc[0] ^ get_unaligned_le32(in); + st0[1] = ctx->key_enc[1] ^ get_unaligned_le32(in + 4); + st0[2] = ctx->key_enc[2] ^ get_unaligned_le32(in + 8); + st0[3] = ctx->key_enc[3] ^ get_unaligned_le32(in + 12); + + st0[0] ^= __aesti_sbox[ 0] ^ __aesti_sbox[128]; + st0[1] ^= __aesti_sbox[32] ^ __aesti_sbox[160]; + st0[2] ^= __aesti_sbox[64] ^ __aesti_sbox[192]; + st0[3] ^= __aesti_sbox[96] ^ __aesti_sbox[224]; + + for (round = 0;; round += 2, rkp += 8) { + st1[0] = mix_columns(subshift(st0, 0)) ^ rkp[0]; + st1[1] = mix_columns(subshift(st0, 1)) ^ rkp[1]; + st1[2] = mix_columns(subshift(st0, 2)) ^ rkp[2]; + st1[3] = mix_columns(subshift(st0, 3)) ^ rkp[3]; + + if (round == rounds - 2) + break; + + st0[0] = mix_columns(subshift(st1, 0)) ^ rkp[4]; + st0[1] = mix_columns(subshift(st1, 1)) ^ rkp[5]; + st0[2] = mix_columns(subshift(st1, 2)) ^ rkp[6]; + st0[3] = mix_columns(subshift(st1, 3)) ^ rkp[7]; + } + + put_unaligned_le32(subshift(st1, 0) ^ rkp[4], out); + put_unaligned_le32(subshift(st1, 1) ^ rkp[5], out + 4); + put_unaligned_le32(subshift(st1, 2) ^ rkp[6], out + 8); + put_unaligned_le32(subshift(st1, 3) ^ rkp[7], out + 12); +} + +static void aesti_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm); + const u32 *rkp = ctx->key_dec + 4; + int rounds = 6 + ctx->key_length / 4; + u32 st0[4], st1[4]; + int round; + + st0[0] = ctx->key_dec[0] ^ get_unaligned_le32(in); + st0[1] = ctx->key_dec[1] ^ get_unaligned_le32(in + 4); + st0[2] = ctx->key_dec[2] ^ get_unaligned_le32(in + 8); + st0[3] = ctx->key_dec[3] ^ get_unaligned_le32(in + 12); + + st0[0] ^= __aesti_inv_sbox[ 0] ^ __aesti_inv_sbox[128]; + st0[1] ^= __aesti_inv_sbox[32] ^ __aesti_inv_sbox[160]; + st0[2] ^= __aesti_inv_sbox[64] ^ __aesti_inv_sbox[192]; + st0[3] ^= __aesti_inv_sbox[96] ^ __aesti_inv_sbox[224]; + + for (round = 0;; round += 2, rkp += 8) { + st1[0] = inv_mix_columns(inv_subshift(st0, 0)) ^ rkp[0]; + st1[1] = inv_mix_columns(inv_subshift(st0, 1)) ^ rkp[1]; + st1[2] = inv_mix_columns(inv_subshift(st0, 2)) ^ rkp[2]; + st1[3] = inv_mix_columns(inv_subshift(st0, 3)) ^ rkp[3]; + + if (round == rounds - 2) + break; + + st0[0] = inv_mix_columns(inv_subshift(st1, 0)) ^ rkp[4]; + st0[1] = inv_mix_columns(inv_subshift(st1, 1)) ^ rkp[5]; + st0[2] = inv_mix_columns(inv_subshift(st1, 2)) ^ rkp[6]; + st0[3] = inv_mix_columns(inv_subshift(st1, 3)) ^ rkp[7]; + } + + put_unaligned_le32(inv_subshift(st1, 0) ^ rkp[4], out); + put_unaligned_le32(inv_subshift(st1, 1) ^ rkp[5], out + 4); + put_unaligned_le32(inv_subshift(st1, 2) ^ rkp[6], out + 8); + put_unaligned_le32(inv_subshift(st1, 3) ^ rkp[7], out + 12); +} + +static struct crypto_alg aes_alg = { + .cra_name = "aes", + .cra_driver_name = "aes-fixed-time", + .cra_priority = 100 + 1, + .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, + .cra_cipher.cia_max_keysize = AES_MAX_KEY_SIZE, + .cra_cipher.cia_setkey = aesti_set_key, + .cra_cipher.cia_encrypt = aesti_encrypt, + .cra_cipher.cia_decrypt = aesti_decrypt +}; + +static int __init aes_init(void) +{ + return crypto_register_alg(&aes_alg); +} + +static void __exit aes_fini(void) +{ + crypto_unregister_alg(&aes_alg); +} + +module_init(aes_init); +module_exit(aes_fini); + +MODULE_DESCRIPTION("Generic fixed time AES"); +MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); +MODULE_LICENSE("GPL v2"); |