linux/include/crypto/aes.h
Ard Biesheuvel f135440447 crypto: lib - implement library version of AES in CFB mode
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>
2024-05-09 22:30:51 +03:00

96 lines
2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common values for AES algorithms
*/
#ifndef _CRYPTO_AES_H
#define _CRYPTO_AES_H
#include <linux/types.h>
#include <linux/crypto.h>
#define AES_MIN_KEY_SIZE 16
#define AES_MAX_KEY_SIZE 32
#define AES_KEYSIZE_128 16
#define AES_KEYSIZE_192 24
#define AES_KEYSIZE_256 32
#define AES_BLOCK_SIZE 16
#define AES_MAX_KEYLENGTH (15 * 16)
#define AES_MAX_KEYLENGTH_U32 (AES_MAX_KEYLENGTH / sizeof(u32))
/*
* Please ensure that the first two fields are 16-byte aligned
* relative to the start of the structure, i.e., don't move them!
*/
struct crypto_aes_ctx {
u32 key_enc[AES_MAX_KEYLENGTH_U32];
u32 key_dec[AES_MAX_KEYLENGTH_U32];
u32 key_length;
};
extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
/*
* validate key length for AES algorithms
*/
static inline int aes_check_keylen(unsigned int keylen)
{
switch (keylen) {
case AES_KEYSIZE_128:
case AES_KEYSIZE_192:
case AES_KEYSIZE_256:
break;
default:
return -EINVAL;
}
return 0;
}
int crypto_aes_set_key(struct crypto_tfm *tfm, 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);
extern const u8 crypto_aes_sbox[];
extern const u8 crypto_aes_inv_sbox[];
void aescfb_encrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
int len, const u8 iv[AES_BLOCK_SIZE]);
void aescfb_decrypt(const struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src,
int len, const u8 iv[AES_BLOCK_SIZE]);
#endif