mirror of
https://github.com/brain-hackers/linux-brain.git
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bc67d04e75
Add inline helper function to check key length for AES algorithms. The key can be 128, 192 or 256 bits size. This function is used in the generic aes implementation. Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
357 lines
12 KiB
C
357 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017-2019 Linaro Ltd <ard.biesheuvel@linaro.org>
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*/
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#include <crypto/aes.h>
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#include <linux/crypto.h>
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#include <linux/module.h>
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#include <asm/unaligned.h>
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/*
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* Emit the sbox as volatile const to prevent the compiler from doing
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* constant folding on sbox references involving fixed indexes.
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*/
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static volatile const u8 __cacheline_aligned aes_sbox[] = {
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0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
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0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
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0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
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0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
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0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
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0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
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0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
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0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
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0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
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0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
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0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
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0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
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0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
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0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
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0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
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0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
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0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
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0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
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0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
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0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
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0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
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0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
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0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
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0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
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0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
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0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
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0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
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0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
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0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
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0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
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0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
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0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
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};
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static volatile const u8 __cacheline_aligned aes_inv_sbox[] = {
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0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
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0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
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0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
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0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
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0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
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0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
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0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
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0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
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0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
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0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
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0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
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0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
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0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
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0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
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0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
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0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
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0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
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0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
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0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
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0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
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0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
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0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
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0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
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0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
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0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
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0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
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0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
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0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
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0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
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0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
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0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
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0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
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};
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extern const u8 crypto_aes_sbox[256] __alias(aes_sbox);
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extern const u8 crypto_aes_inv_sbox[256] __alias(aes_inv_sbox);
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EXPORT_SYMBOL(crypto_aes_sbox);
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EXPORT_SYMBOL(crypto_aes_inv_sbox);
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static u32 mul_by_x(u32 w)
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{
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u32 x = w & 0x7f7f7f7f;
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u32 y = w & 0x80808080;
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/* multiply by polynomial 'x' (0b10) in GF(2^8) */
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return (x << 1) ^ (y >> 7) * 0x1b;
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}
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static u32 mul_by_x2(u32 w)
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{
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u32 x = w & 0x3f3f3f3f;
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u32 y = w & 0x80808080;
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u32 z = w & 0x40404040;
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/* multiply by polynomial 'x^2' (0b100) in GF(2^8) */
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return (x << 2) ^ (y >> 7) * 0x36 ^ (z >> 6) * 0x1b;
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}
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static u32 mix_columns(u32 x)
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{
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/*
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* Perform the following matrix multiplication in GF(2^8)
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*
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* | 0x2 0x3 0x1 0x1 | | x[0] |
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* | 0x1 0x2 0x3 0x1 | | x[1] |
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* | 0x1 0x1 0x2 0x3 | x | x[2] |
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* | 0x3 0x1 0x1 0x2 | | x[3] |
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*/
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u32 y = mul_by_x(x) ^ ror32(x, 16);
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return y ^ ror32(x ^ y, 8);
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}
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static u32 inv_mix_columns(u32 x)
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{
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/*
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* Perform the following matrix multiplication in GF(2^8)
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*
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* | 0xe 0xb 0xd 0x9 | | x[0] |
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* | 0x9 0xe 0xb 0xd | | x[1] |
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* | 0xd 0x9 0xe 0xb | x | x[2] |
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* | 0xb 0xd 0x9 0xe | | x[3] |
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*
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* which can conveniently be reduced to
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*
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* | 0x2 0x3 0x1 0x1 | | 0x5 0x0 0x4 0x0 | | x[0] |
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* | 0x1 0x2 0x3 0x1 | | 0x0 0x5 0x0 0x4 | | x[1] |
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* | 0x1 0x1 0x2 0x3 | x | 0x4 0x0 0x5 0x0 | x | x[2] |
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* | 0x3 0x1 0x1 0x2 | | 0x0 0x4 0x0 0x5 | | x[3] |
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*/
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u32 y = mul_by_x2(x);
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return mix_columns(x ^ y ^ ror32(y, 16));
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}
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static __always_inline u32 subshift(u32 in[], int pos)
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{
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return (aes_sbox[in[pos] & 0xff]) ^
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(aes_sbox[(in[(pos + 1) % 4] >> 8) & 0xff] << 8) ^
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(aes_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^
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(aes_sbox[(in[(pos + 3) % 4] >> 24) & 0xff] << 24);
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}
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static __always_inline u32 inv_subshift(u32 in[], int pos)
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{
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return (aes_inv_sbox[in[pos] & 0xff]) ^
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(aes_inv_sbox[(in[(pos + 3) % 4] >> 8) & 0xff] << 8) ^
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(aes_inv_sbox[(in[(pos + 2) % 4] >> 16) & 0xff] << 16) ^
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(aes_inv_sbox[(in[(pos + 1) % 4] >> 24) & 0xff] << 24);
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}
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static u32 subw(u32 in)
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{
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return (aes_sbox[in & 0xff]) ^
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(aes_sbox[(in >> 8) & 0xff] << 8) ^
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(aes_sbox[(in >> 16) & 0xff] << 16) ^
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(aes_sbox[(in >> 24) & 0xff] << 24);
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}
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/**
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* aes_expandkey - Expands the AES key as described in FIPS-197
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* @ctx: The location where the computed key will be stored.
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* @in_key: The supplied key.
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* @key_len: The length of the supplied key.
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*
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* Returns 0 on success. The function fails only if an invalid key size (or
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* pointer) is supplied.
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* The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
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* key schedule plus a 16 bytes key which is used before the first round).
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* The decryption key is prepared for the "Equivalent Inverse Cipher" as
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* described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
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* for the initial combination, the second slot for the first round and so on.
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*/
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int 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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u32 kwords = key_len / sizeof(u32);
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u32 rc, i, j;
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int err;
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err = aes_check_keylen(key_len);
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if (err)
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return err;
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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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for (i = 0, rc = 1; i < 10; i++, rc = mul_by_x(rc)) {
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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(subw(rki[kwords - 1]), 8) ^ rc ^ 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] = subw(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 to all but the first and
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* the last one.
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*/
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ctx->key_dec[0] = ctx->key_enc[key_len + 24];
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ctx->key_dec[1] = ctx->key_enc[key_len + 25];
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ctx->key_dec[2] = ctx->key_enc[key_len + 26];
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ctx->key_dec[3] = ctx->key_enc[key_len + 27];
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for (i = 4, j = key_len + 20; j > 0; i += 4, j -= 4) {
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ctx->key_dec[i] = inv_mix_columns(ctx->key_enc[j]);
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ctx->key_dec[i + 1] = inv_mix_columns(ctx->key_enc[j + 1]);
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ctx->key_dec[i + 2] = inv_mix_columns(ctx->key_enc[j + 2]);
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ctx->key_dec[i + 3] = inv_mix_columns(ctx->key_enc[j + 3]);
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}
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ctx->key_dec[i] = ctx->key_enc[0];
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ctx->key_dec[i + 1] = ctx->key_enc[1];
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ctx->key_dec[i + 2] = ctx->key_enc[2];
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ctx->key_dec[i + 3] = ctx->key_enc[3];
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return 0;
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}
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EXPORT_SYMBOL(aes_expandkey);
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/**
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* aes_encrypt - Encrypt a single AES block
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* @ctx: Context struct containing the key schedule
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* @out: Buffer to store the ciphertext
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* @in: Buffer containing the plaintext
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*/
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void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
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{
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const u32 *rkp = ctx->key_enc + 4;
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int rounds = 6 + ctx->key_length / 4;
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u32 st0[4], st1[4];
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int round;
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st0[0] = ctx->key_enc[0] ^ get_unaligned_le32(in);
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st0[1] = ctx->key_enc[1] ^ get_unaligned_le32(in + 4);
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st0[2] = ctx->key_enc[2] ^ get_unaligned_le32(in + 8);
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st0[3] = ctx->key_enc[3] ^ get_unaligned_le32(in + 12);
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/*
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* Force the compiler to emit data independent Sbox references,
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* by xoring the input with Sbox values that are known to add up
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* to zero. This pulls the entire Sbox into the D-cache before any
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* data dependent lookups are done.
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*/
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st0[0] ^= aes_sbox[ 0] ^ aes_sbox[ 64] ^ aes_sbox[134] ^ aes_sbox[195];
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st0[1] ^= aes_sbox[16] ^ aes_sbox[ 82] ^ aes_sbox[158] ^ aes_sbox[221];
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st0[2] ^= aes_sbox[32] ^ aes_sbox[ 96] ^ aes_sbox[160] ^ aes_sbox[234];
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st0[3] ^= aes_sbox[48] ^ aes_sbox[112] ^ aes_sbox[186] ^ aes_sbox[241];
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for (round = 0;; round += 2, rkp += 8) {
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st1[0] = mix_columns(subshift(st0, 0)) ^ rkp[0];
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st1[1] = mix_columns(subshift(st0, 1)) ^ rkp[1];
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st1[2] = mix_columns(subshift(st0, 2)) ^ rkp[2];
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st1[3] = mix_columns(subshift(st0, 3)) ^ rkp[3];
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if (round == rounds - 2)
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break;
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st0[0] = mix_columns(subshift(st1, 0)) ^ rkp[4];
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st0[1] = mix_columns(subshift(st1, 1)) ^ rkp[5];
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st0[2] = mix_columns(subshift(st1, 2)) ^ rkp[6];
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st0[3] = mix_columns(subshift(st1, 3)) ^ rkp[7];
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}
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put_unaligned_le32(subshift(st1, 0) ^ rkp[4], out);
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put_unaligned_le32(subshift(st1, 1) ^ rkp[5], out + 4);
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put_unaligned_le32(subshift(st1, 2) ^ rkp[6], out + 8);
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put_unaligned_le32(subshift(st1, 3) ^ rkp[7], out + 12);
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}
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EXPORT_SYMBOL(aes_encrypt);
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/**
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* aes_decrypt - Decrypt a single AES block
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* @ctx: Context struct containing the key schedule
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* @out: Buffer to store the plaintext
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* @in: Buffer containing the ciphertext
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*/
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void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
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{
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const u32 *rkp = ctx->key_dec + 4;
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int rounds = 6 + ctx->key_length / 4;
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u32 st0[4], st1[4];
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int round;
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st0[0] = ctx->key_dec[0] ^ get_unaligned_le32(in);
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st0[1] = ctx->key_dec[1] ^ get_unaligned_le32(in + 4);
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st0[2] = ctx->key_dec[2] ^ get_unaligned_le32(in + 8);
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st0[3] = ctx->key_dec[3] ^ get_unaligned_le32(in + 12);
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/*
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* Force the compiler to emit data independent Sbox references,
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* by xoring the input with Sbox values that are known to add up
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* to zero. This pulls the entire Sbox into the D-cache before any
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* data dependent lookups are done.
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*/
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st0[0] ^= aes_inv_sbox[ 0] ^ aes_inv_sbox[ 64] ^ aes_inv_sbox[129] ^ aes_inv_sbox[200];
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st0[1] ^= aes_inv_sbox[16] ^ aes_inv_sbox[ 83] ^ aes_inv_sbox[150] ^ aes_inv_sbox[212];
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st0[2] ^= aes_inv_sbox[32] ^ aes_inv_sbox[ 96] ^ aes_inv_sbox[160] ^ aes_inv_sbox[236];
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st0[3] ^= aes_inv_sbox[48] ^ aes_inv_sbox[112] ^ aes_inv_sbox[187] ^ aes_inv_sbox[247];
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for (round = 0;; round += 2, rkp += 8) {
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st1[0] = inv_mix_columns(inv_subshift(st0, 0)) ^ rkp[0];
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st1[1] = inv_mix_columns(inv_subshift(st0, 1)) ^ rkp[1];
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st1[2] = inv_mix_columns(inv_subshift(st0, 2)) ^ rkp[2];
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st1[3] = inv_mix_columns(inv_subshift(st0, 3)) ^ rkp[3];
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|
|
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if (round == rounds - 2)
|
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break;
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|
|
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st0[0] = inv_mix_columns(inv_subshift(st1, 0)) ^ rkp[4];
|
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st0[1] = inv_mix_columns(inv_subshift(st1, 1)) ^ rkp[5];
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st0[2] = inv_mix_columns(inv_subshift(st1, 2)) ^ rkp[6];
|
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st0[3] = inv_mix_columns(inv_subshift(st1, 3)) ^ rkp[7];
|
|
}
|
|
|
|
put_unaligned_le32(inv_subshift(st1, 0) ^ rkp[4], out);
|
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put_unaligned_le32(inv_subshift(st1, 1) ^ rkp[5], out + 4);
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put_unaligned_le32(inv_subshift(st1, 2) ^ rkp[6], out + 8);
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put_unaligned_le32(inv_subshift(st1, 3) ^ rkp[7], out + 12);
|
|
}
|
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EXPORT_SYMBOL(aes_decrypt);
|
|
|
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MODULE_DESCRIPTION("Generic AES library");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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