Take the existing small footprint and mostly time invariant C code
and turn it into a AES library that can be used for non-performance
critical, casual use of AES, and as a fallback for, e.g., SIMD code
that needs a secondary path that can be taken in contexts where the
SIMD unit is off limits (e.g., in hard interrupts taken from kernel
context)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
crypto/Kconfig | 4 +
crypto/aes_ti.c | 307 +----------------
include/crypto/aes.h | 34 ++
lib/crypto/Makefile | 3 +
lib/crypto/aes.c | 350 ++++++++++++++++++++
5 files changed, 395 insertions(+), 303 deletions(-)
diff --git a/crypto/Kconfig b/crypto/Kconfig
index e801450bcb1c..091ebbbc9655 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1066,6 +1066,9 @@ config CRYPTO_GHASH_CLMUL_NI_INTEL
comment "Ciphers"
+config CRYPTO_LIB_AES
+ tristate
+
config CRYPTO_AES
tristate "AES cipher algorithms"
select CRYPTO_ALGAPI
@@ -1089,6 +1092,7 @@ config CRYPTO_AES
config CRYPTO_AES_TI
tristate "Fixed time AES cipher"
select CRYPTO_ALGAPI
+ select CRYPTO_LIB_AES
help
This is a generic implementation of AES that attempts to eliminate
data dependent latencies as much as possible without affecting
diff --git a/crypto/aes_ti.c b/crypto/aes_ti.c
index fd70dc322634..339915db9aeb 100644
--- a/crypto/aes_ti.c
+++ b/crypto/aes_ti.c
@@ -1,259 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Scalar fixed time AES core transform
*
* Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@xxxxxxxxxx>
- *
- * 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 0x2 | | 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);
- return aesti_expand_key(ctx, in_key, key_len);
+ return aes_expandkey(ctx, in_key, key_len);
}
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];
unsigned long flags;
- 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);
/*
* Temporarily disable interrupts to avoid races where cachelines are
@@ -261,36 +29,7 @@ static void aesti_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
*/
local_irq_save(flags);
- /*
- * Force the compiler to emit data independent Sbox references,
- * by xoring the input with Sbox values that are known to add up
- * to zero. This pulls the entire Sbox into the D-cache before any
- * data dependent lookups are done.
- */
- st0[0] ^= __aesti_sbox[ 0] ^ __aesti_sbox[ 64] ^ __aesti_sbox[134] ^ __aesti_sbox[195];
- st0[1] ^= __aesti_sbox[16] ^ __aesti_sbox[ 82] ^ __aesti_sbox[158] ^ __aesti_sbox[221];
- st0[2] ^= __aesti_sbox[32] ^ __aesti_sbox[ 96] ^ __aesti_sbox[160] ^ __aesti_sbox[234];
- st0[3] ^= __aesti_sbox[48] ^ __aesti_sbox[112] ^ __aesti_sbox[186] ^ __aesti_sbox[241];
-
- 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);
+ aes_encrypt(ctx, out, in);
local_irq_restore(flags);
}
@@ -298,16 +37,7 @@ static void aesti_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
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];
unsigned long flags;
- 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);
/*
* Temporarily disable interrupts to avoid races where cachelines are
@@ -315,36 +45,7 @@ static void aesti_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
*/
local_irq_save(flags);
- /*
- * Force the compiler to emit data independent Sbox references,
- * by xoring the input with Sbox values that are known to add up
- * to zero. This pulls the entire Sbox into the D-cache before any
- * data dependent lookups are done.
- */
- st0[0] ^= __aesti_inv_sbox[ 0] ^ __aesti_inv_sbox[ 64] ^ __aesti_inv_sbox[129] ^ __aesti_inv_sbox[200];
- st0[1] ^= __aesti_inv_sbox[16] ^ __aesti_inv_sbox[ 83] ^ __aesti_inv_sbox[150] ^ __aesti_inv_sbox[212];
- st0[2] ^= __aesti_inv_sbox[32] ^ __aesti_inv_sbox[ 96] ^ __aesti_inv_sbox[160] ^ __aesti_inv_sbox[236];
- st0[3] ^= __aesti_inv_sbox[48] ^ __aesti_inv_sbox[112] ^ __aesti_inv_sbox[187] ^ __aesti_inv_sbox[247];
-
- 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);
+ aes_decrypt(ctx, out, in);
local_irq_restore(flags);
}
diff --git a/include/crypto/aes.h b/include/crypto/aes.h
index 0fdb542c70cd..d0067fca0cd0 100644
--- a/include/crypto/aes.h
+++ b/include/crypto/aes.h
@@ -37,4 +37,38 @@ int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len);
int crypto_aes_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len);
+
+/**
+ * aes_expandkey - Expands the AES key as described in FIPS-197
+ * @ctx: The location where the computed key will be stored.
+ * @in_key: The supplied key.
+ * @key_len: The length of the supplied key.
+ *
+ * Returns 0 on success. The function fails only if an invalid key size (or
+ * pointer) is supplied.
+ * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
+ * key schedule plus a 16 bytes key which is used before the first round).
+ * The decryption key is prepared for the "Equivalent Inverse Cipher" as
+ * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
+ * for the initial combination, the second slot for the first round and so on.
+ */
+int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
+ unsigned int key_len);
+
+/**
+ * aes_encrypt - Encrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the ciphertext
+ * @in: Buffer containing the plaintext
+ */
+void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
+
+/**
+ * aes_decrypt - Decrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the plaintext
+ * @in: Buffer containing the ciphertext
+ */
+void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
+
#endif
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 88195c34932d..42a91c62d96d 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -1,4 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CRYPTO_LIB_AES) += libaes.o
+libaes-y := aes.o
+
obj-$(CONFIG_CRYPTO_LIB_ARC4) += libarc4.o
libarc4-y := arc4.o
diff --git a/lib/crypto/aes.c b/lib/crypto/aes.c
new file mode 100644
index 000000000000..9928b23e0a8a
--- /dev/null
+++ b/lib/crypto/aes.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017-2019 Linaro Ltd <ard.biesheuvel@xxxxxxxxxx>
+ */
+
+#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 aes_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 aes_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 0x2 | | 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 (aes_sbox[in[pos] & 0xff]) ^
+ (aes_sbox[(in[(pos + 1) % 4] >> 8) & 0xff] << 8) ^
+ (aes_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^
+ (aes_sbox[(in[(pos + 3) % 4] >> 24) & 0xff] << 24);
+}
+
+static __always_inline u32 inv_subshift(u32 in[], int pos)
+{
+ return (aes_inv_sbox[in[pos] & 0xff]) ^
+ (aes_inv_sbox[(in[(pos + 3) % 4] >> 8) & 0xff] << 8) ^
+ (aes_inv_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^
+ (aes_inv_sbox[(in[(pos + 1) % 4] >> 24) & 0xff] << 24);
+}
+
+static u32 subw(u32 in)
+{
+ return (aes_sbox[in & 0xff]) ^
+ (aes_sbox[(in >> 8) & 0xff] << 8) ^
+ (aes_sbox[(in >> 16) & 0xff] << 16) ^
+ (aes_sbox[(in >> 24) & 0xff] << 24);
+}
+
+/**
+ * aes_expandkey - Expands the AES key as described in FIPS-197
+ * @ctx: The location where the computed key will be stored.
+ * @in_key: The supplied key.
+ * @key_len: The length of the supplied key.
+ *
+ * Returns 0 on success. The function fails only if an invalid key size (or
+ * pointer) is supplied.
+ * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
+ * key schedule plus a 16 bytes key which is used before the first round).
+ * The decryption key is prepared for the "Equivalent Inverse Cipher" as
+ * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
+ * for the initial combination, the second slot for the first round and so on.
+ */
+int aes_expandkey(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 == 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] = 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;
+}
+EXPORT_SYMBOL(aes_expandkey);
+
+/**
+ * aes_encrypt - Encrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the ciphertext
+ * @in: Buffer containing the plaintext
+ */
+void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
+{
+ 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);
+
+ /*
+ * Force the compiler to emit data independent Sbox references,
+ * by xoring the input with Sbox values that are known to add up
+ * to zero. This pulls the entire Sbox into the D-cache before any
+ * data dependent lookups are done.
+ */
+ st0[0] ^= aes_sbox[ 0] ^ aes_sbox[ 64] ^ aes_sbox[134] ^ aes_sbox[195];
+ st0[1] ^= aes_sbox[16] ^ aes_sbox[ 82] ^ aes_sbox[158] ^ aes_sbox[221];
+ st0[2] ^= aes_sbox[32] ^ aes_sbox[ 96] ^ aes_sbox[160] ^ aes_sbox[234];
+ st0[3] ^= aes_sbox[48] ^ aes_sbox[112] ^ aes_sbox[186] ^ aes_sbox[241];
+
+ 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);
+}
+EXPORT_SYMBOL(aes_encrypt);
+
+/**
+ * aes_decrypt - Decrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the plaintext
+ * @in: Buffer containing the ciphertext
+ */
+void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
+{
+ 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);
+
+ /*
+ * Force the compiler to emit data independent Sbox references,
+ * by xoring the input with Sbox values that are known to add up
+ * to zero. This pulls the entire Sbox into the D-cache before any
+ * data dependent lookups are done.
+ */
+ st0[0] ^= aes_inv_sbox[ 0] ^ aes_inv_sbox[ 64] ^ aes_inv_sbox[129] ^ aes_inv_sbox[200];
+ st0[1] ^= aes_inv_sbox[16] ^ aes_inv_sbox[ 83] ^ aes_inv_sbox[150] ^ aes_inv_sbox[212];
+ st0[2] ^= aes_inv_sbox[32] ^ aes_inv_sbox[ 96] ^ aes_inv_sbox[160] ^ aes_inv_sbox[236];
+ st0[3] ^= aes_inv_sbox[48] ^ aes_inv_sbox[112] ^ aes_inv_sbox[187] ^ aes_inv_sbox[247];
+
+ 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);
+}
+EXPORT_SYMBOL(aes_decrypt);
+
+MODULE_DESCRIPTION("Generic AES library");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
2.20.1
