diff options
Diffstat (limited to 'src/libstrongswan/plugins/hmac/hmac.c')
| -rw-r--r-- | src/libstrongswan/plugins/hmac/hmac.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/hmac/hmac.c b/src/libstrongswan/plugins/hmac/hmac.c new file mode 100644 index 000000000..ecfb01913 --- /dev/null +++ b/src/libstrongswan/plugins/hmac/hmac.c @@ -0,0 +1,220 @@ +/* + * Copyright (C) 2012 Tobias Brunner + * Copyright (C) 2005-2006 Martin Willi + * Copyright (C) 2005 Jan Hutter + * Hochschule fuer Technik Rapperswil + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +#include "hmac.h" + +#include <crypto/mac.h> +#include <crypto/prfs/mac_prf.h> +#include <crypto/signers/mac_signer.h> + +typedef struct private_mac_t private_mac_t; + +/** + * Private data of a mac_t object. + * + * The variable names are the same as in the RFC. + */ +struct private_mac_t { + + /** + * Implements mac_t interface + */ + mac_t public; + + /** + * Block size, as in RFC. + */ + u_int8_t b; + + /** + * Hash function. + */ + hasher_t *h; + + /** + * Previously xor'ed key using opad. + */ + chunk_t opaded_key; + + /** + * Previously xor'ed key using ipad. + */ + chunk_t ipaded_key; +}; + +METHOD(mac_t, get_mac, void, + private_mac_t *this, chunk_t data, u_int8_t *out) +{ + /* H(K XOR opad, H(K XOR ipad, text)) + * + * if out is NULL, we append text to the inner hash. + * else, we complete the inner and do the outer. + * + */ + + u_int8_t buffer[this->h->get_hash_size(this->h)]; + chunk_t inner; + + if (out == NULL) + { + /* append data to inner */ + this->h->get_hash(this->h, data, NULL); + } + else + { + /* append and do outer hash */ + inner.ptr = buffer; + inner.len = this->h->get_hash_size(this->h); + + /* complete inner */ + this->h->get_hash(this->h, data, buffer); + + /* do outer */ + this->h->get_hash(this->h, this->opaded_key, NULL); + this->h->get_hash(this->h, inner, out); + + /* reinit for next call */ + this->h->get_hash(this->h, this->ipaded_key, NULL); + } +} + +METHOD(mac_t, get_mac_size, size_t, + private_mac_t *this) +{ + return this->h->get_hash_size(this->h); +} + +METHOD(mac_t, set_key, void, + private_mac_t *this, chunk_t key) +{ + int i; + u_int8_t buffer[this->b]; + + memset(buffer, 0, this->b); + + if (key.len > this->b) + { + /* if key is too long, it will be hashed */ + this->h->get_hash(this->h, key, buffer); + } + else + { + /* if not, just copy it in our pre-padded k */ + memcpy(buffer, key.ptr, key.len); + } + + /* apply ipad and opad to key */ + for (i = 0; i < this->b; i++) + { + this->ipaded_key.ptr[i] = buffer[i] ^ 0x36; + this->opaded_key.ptr[i] = buffer[i] ^ 0x5C; + } + + /* begin hashing of inner pad */ + this->h->reset(this->h); + this->h->get_hash(this->h, this->ipaded_key, NULL); +} + +METHOD(mac_t, destroy, void, + private_mac_t *this) +{ + this->h->destroy(this->h); + chunk_clear(&this->opaded_key); + chunk_clear(&this->ipaded_key); + free(this); +} + +/* + * Creates an mac_t object + */ +static mac_t *hmac_create(hash_algorithm_t hash_algorithm) +{ + private_mac_t *this; + + INIT(this, + .public = { + .get_mac = _get_mac, + .get_mac_size = _get_mac_size, + .set_key = _set_key, + .destroy = _destroy, + }, + ); + + /* set b, according to hasher */ + switch (hash_algorithm) + { + case HASH_SHA1: + case HASH_MD5: + case HASH_SHA256: + this->b = 64; + break; + case HASH_SHA384: + case HASH_SHA512: + this->b = 128; + break; + default: + free(this); + return NULL; + } + + this->h = lib->crypto->create_hasher(lib->crypto, hash_algorithm); + if (this->h == NULL) + { + free(this); + return NULL; + } + + /* build ipad and opad */ + this->opaded_key.ptr = malloc(this->b); + this->opaded_key.len = this->b; + + this->ipaded_key.ptr = malloc(this->b); + this->ipaded_key.len = this->b; + + return &this->public; +} + +/* + * Described in header + */ +prf_t *hmac_prf_create(pseudo_random_function_t algo) +{ + mac_t *hmac; + + hmac = hmac_create(hasher_algorithm_from_prf(algo)); + if (hmac) + { + return mac_prf_create(hmac); + } + return NULL; +} + +/* + * Described in header + */ +signer_t *hmac_signer_create(integrity_algorithm_t algo) +{ + mac_t *hmac; + size_t trunc; + + hmac = hmac_create(hasher_algorithm_from_integrity(algo, &trunc)); + if (hmac) + { + return mac_signer_create(hmac, trunc); + } + return NULL; +} |