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f135440447
Implement AES in CFB mode using the existing, mostly constant-time generic AES library implementation. This will be used by the TPM code to encrypt communications with TPM hardware, which is often a discrete component connected using sniffable wires or traces. While a CFB template does exist, using a skcipher is a major pain for non-performance critical synchronous crypto where the algorithm is known at compile time and the data is in contiguous buffers with valid kernel virtual addresses. Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/20230216201410.15010-1-James.Bottomley@HansenPartnership.com/ Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Tested-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Common values for AES algorithms
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*/
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#ifndef _CRYPTO_AES_H
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#define _CRYPTO_AES_H
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#include <linux/types.h>
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#include <linux/crypto.h>
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#define AES_MIN_KEY_SIZE 16
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#define AES_MAX_KEY_SIZE 32
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#define AES_KEYSIZE_128 16
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#define AES_KEYSIZE_192 24
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#define AES_KEYSIZE_256 32
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#define AES_BLOCK_SIZE 16
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#define AES_MAX_KEYLENGTH (15 * 16)
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#define AES_MAX_KEYLENGTH_U32 (AES_MAX_KEYLENGTH / sizeof(u32))
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/*
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* Please ensure that the first two fields are 16-byte aligned
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* relative to the start of the structure, i.e., don't move them!
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*/
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struct crypto_aes_ctx {
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u32 key_enc[AES_MAX_KEYLENGTH_U32];
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u32 key_dec[AES_MAX_KEYLENGTH_U32];
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u32 key_length;
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};
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extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
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extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
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/*
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* validate key length for AES algorithms
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*/
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static inline int aes_check_keylen(unsigned int keylen)
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{
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switch (keylen) {
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case AES_KEYSIZE_128:
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case AES_KEYSIZE_192:
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case AES_KEYSIZE_256:
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
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unsigned int key_len);
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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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* 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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* 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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extern const u8 crypto_aes_sbox[];
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extern const u8 crypto_aes_inv_sbox[];
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void aescfb_encrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
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int len, const u8 iv[AES_BLOCK_SIZE]);
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void aescfb_decrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
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int len, const u8 iv[AES_BLOCK_SIZE]);
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#endif
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