1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 /* 4 * Copyright (C) 2021, Stephan Mueller <smueller@chronox.de> 5 */ 6 7 #ifndef _CRYPTO_KDF108_H 8 #define _CRYPTO_KDF108_H 9 10 #include <crypto/hash.h> 11 #include <linux/uio.h> 12 13 /** 14 * Counter KDF generate operation according to SP800-108 section 5.1 15 * as well as SP800-56A section 5.8.1 (Single-step KDF). 16 * 17 * @kmd Keyed message digest whose key was set with crypto_kdf108_setkey or 18 * unkeyed message digest 19 * @info optional context and application specific information - this may be 20 * NULL 21 * @info_vec number of optional context/application specific information entries 22 * @dst destination buffer that the caller already allocated 23 * @dlen length of the destination buffer - the KDF derives that amount of 24 * bytes. 25 * 26 * To comply with SP800-108, the caller must provide Label || 0x00 || Context 27 * in the info parameter. 28 * 29 * @return 0 on success, < 0 on error 30 */ 31 int crypto_kdf108_ctr_generate(struct crypto_shash *kmd, 32 const struct kvec *info, unsigned int info_nvec, 33 u8 *dst, unsigned int dlen); 34 35 /** 36 * Counter KDF setkey operation 37 * 38 * @kmd Keyed message digest allocated by the caller. The key should not have 39 * been set. 40 * @key Seed key to be used to initialize the keyed message digest context. 41 * @keylen This length of the key buffer. 42 * @ikm The SP800-108 KDF does not support IKM - this parameter must be NULL 43 * @ikmlen This parameter must be 0. 44 * 45 * According to SP800-108 section 7.2, the seed key must be at least as large as 46 * the message digest size of the used keyed message digest. This limitation 47 * is enforced by the implementation. 48 * 49 * SP800-108 allows the use of either a HMAC or a hash primitive. When 50 * the caller intends to use a hash primitive, the call to 51 * crypto_kdf108_setkey is not required and the key derivation operation can 52 * immediately performed using crypto_kdf108_ctr_generate after allocating 53 * a handle. 54 * 55 * @return 0 on success, < 0 on error 56 */ 57 int crypto_kdf108_setkey(struct crypto_shash *kmd, 58 const u8 *key, size_t keylen, 59 const u8 *ikm, size_t ikmlen); 60 61 #endif /* _CRYPTO_KDF108_H */ 62