diff --git a/src/libstrongswan/Makefile.am b/src/libstrongswan/Makefile.am index 233bfcf95..ba1e46f2f 100644 --- a/src/libstrongswan/Makefile.am +++ b/src/libstrongswan/Makefile.am @@ -11,7 +11,8 @@ crypto/prfs/prf.c crypto/prfs/mac_prf.c crypto/pkcs5.c \ crypto/rngs/rng.c crypto/prf_plus.c crypto/signers/signer.c \ crypto/signers/mac_signer.c crypto/crypto_factory.c crypto/crypto_tester.c \ crypto/diffie_hellman.c crypto/aead.c crypto/transform.c \ -crypto/iv/iv_gen_rand.c crypto/iv/iv_gen_seq.c crypto/mgf1/mgf1.c \ +crypto/iv/iv_gen_rand.c crypto/iv/iv_gen_seq.c \ +crypto/mgf1/mgf1.c crypto/mgf1/mgf1_bitspender.c \ credentials/credential_factory.c credentials/builder.c \ credentials/cred_encoding.c credentials/keys/private_key.c \ credentials/keys/public_key.c credentials/keys/shared_key.c \ @@ -66,7 +67,8 @@ crypto/prfs/prf.h crypto/prfs/mac_prf.h crypto/rngs/rng.h crypto/nonce_gen.h \ crypto/prf_plus.h crypto/signers/signer.h crypto/signers/mac_signer.h \ crypto/crypto_factory.h crypto/crypto_tester.h crypto/diffie_hellman.h \ crypto/aead.h crypto/transform.h crypto/pkcs5.h crypto/iv/iv_gen.h \ -crypto/iv/iv_gen_rand.h crypto/iv/iv_gen_seq.h crypto/mgf1/mgf1.h \ +crypto/iv/iv_gen_rand.h crypto/iv/iv_gen_seq.h \ +crypto/mgf1/mgf1.h crypto/mgf1/mgf1_bitspender.h \ credentials/credential_factory.h credentials/builder.h \ credentials/cred_encoding.h credentials/keys/private_key.h \ credentials/keys/public_key.h credentials/keys/shared_key.h \ diff --git a/src/libstrongswan/crypto/mgf1/mgf1.h b/src/libstrongswan/crypto/mgf1/mgf1.h index 5b43d72af..9ebf60ae4 100644 --- a/src/libstrongswan/crypto/mgf1/mgf1.h +++ b/src/libstrongswan/crypto/mgf1/mgf1.h @@ -68,7 +68,7 @@ struct mgf1_t { * * @param alg hash algorithm to be used by MGF1 * @param seed seed used by MGF1 to generate mask from - * @param hash_seed hash seed before using it as a seed from MGF1 + * @param hash_seed hash seed before using it as a seed for MGF1 */ mgf1_t *mgf1_create(hash_algorithm_t alg, chunk_t seed, bool hash_seed); diff --git a/src/libstrongswan/crypto/mgf1/mgf1_bitspender.c b/src/libstrongswan/crypto/mgf1/mgf1_bitspender.c new file mode 100644 index 000000000..1b3533f13 --- /dev/null +++ b/src/libstrongswan/crypto/mgf1/mgf1_bitspender.c @@ -0,0 +1,158 @@ +/* + * Copyright (C) 2014 Andreas Steffen + * HSR 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 . + * + * 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 "mgf1_bitspender.h" + +#include + +typedef struct private_mgf1_bitspender_t private_mgf1_bitspender_t; + +/** + * Private data structure for mgf1_bitspender_t object + */ +struct private_mgf1_bitspender_t { + /** + * Public interface. + */ + mgf1_bitspender_t public; + + /** + * MGF1 bit mask generator + */ + mgf1_t *mgf1; + + /** + * Octet storage (accommodates up to 64 octets) + */ + uint8_t octets[HASH_SIZE_SHA512]; + + /** + * Length of the returned hash value in octets + */ + int hash_len; + + /** + * Number of generated octets + */ + int octets_count; + + /** + * Number of available octets + */ + int octets_left; + + /** + * Bit storage (accomodates up to 32 bits) + */ + uint32_t bits; + + /** + * Number of available bits + */ + int bits_left; +}; + +METHOD(mgf1_bitspender_t, get_bits, uint32_t, + private_mgf1_bitspender_t *this, int bits_needed) +{ + uint32_t bits = 0x00000000; + int bits_now; + + if (bits_needed > 31) + { + /* too many bits requested */ + return MGF1_BITSPENDER_ERROR; + } + + while (bits_needed) + { + if (this->bits_left == 0) + { + if (this->octets_left == 0) + { + /* get another block from MGF1 */ + if (!this->mgf1->get_mask(this->mgf1, this->hash_len, + this->octets)) + { + /* no block available */ + return MGF1_BITSPENDER_ERROR; + } + this->octets_left = this->hash_len; + this->octets_count += this->hash_len; + } + this->bits = untoh32(this->octets + this->hash_len - + this->octets_left); + this->bits_left = 32; + this->octets_left -= 4; + } + if (bits_needed > this->bits_left) + { + bits_now = this->bits_left; + this->bits_left = 0; + bits_needed -= bits_now; + bits <<= bits_now; + bits |= this->bits; + } + else + { + bits_now = bits_needed; + this->bits_left -= bits_needed; + bits_needed = 0; + bits <<= bits_now; + bits |= this->bits >> this->bits_left; + this->bits &= 0xffffffff >> (32 - this->bits_left); + } + } + return bits; +} + + +METHOD(mgf1_bitspender_t, destroy, void, + private_mgf1_bitspender_t *this) +{ + DBG2(DBG_LIB, "mgf1 generated %u octets", this->octets_count); + memwipe(this->octets, sizeof(this->octets)); + this->mgf1->destroy(this->mgf1); + free(this); +} + +/** + * See header. + */ +mgf1_bitspender_t *mgf1_bitspender_create(hash_algorithm_t alg, chunk_t seed, + bool hash_seed) +{ + private_mgf1_bitspender_t *this; + mgf1_t *mgf1; + + mgf1 = mgf1_create(alg, seed, hash_seed); + if (!mgf1) + { + return NULL; + } + DBG2(DBG_LIB, "mgf1 based on %N is seeded with %u octets", + hash_algorithm_short_names, alg, seed.len); + + INIT(this, + .public = { + .get_bits = _get_bits, + .destroy = _destroy, + }, + .mgf1 = mgf1, + .hash_len = mgf1->get_hash_size(mgf1), + ); + + return &this->public; +} diff --git a/src/libstrongswan/crypto/mgf1/mgf1_bitspender.h b/src/libstrongswan/crypto/mgf1/mgf1_bitspender.h new file mode 100644 index 000000000..a748695e5 --- /dev/null +++ b/src/libstrongswan/crypto/mgf1/mgf1_bitspender.h @@ -0,0 +1,60 @@ +/* + * Copyright (C) 2014 Andreas Steffen + * HSR 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 . + * + * 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. + */ + +/** + * @defgroup mgf1_bitspender mgf1_bitspender + * @{ @ingroup bliss_p + */ + +#ifndef MGF1_BITSPENDER_H_ +#define MGF1_BITSPENDER_H_ + +#include +#include + +typedef struct mgf1_bitspender_t mgf1_bitspender_t; + +#define MGF1_BITSPENDER_ERROR 0xffffffff + +/** + * Generates a given number of pseudo-random bits at a time using MFG1 + */ +struct mgf1_bitspender_t { + + /** + * Get pseudo-random bits + * + * @param bits_needed Number of needed bits (1..31) + * @result Return between 1 and 31 pseudo-random bits + */ + uint32_t (*get_bits)(mgf1_bitspender_t *this, int bits_needed); + + /** + * Destroy mgf1_bitspender_t object + */ + void (*destroy)(mgf1_bitspender_t *this); +}; + +/** + * Create a mgf1_bitspender_t object + * + * @param alg Hash algorithm to be used with MGF1 + * @param seed Seed used to initialize MGF1 + * @param hash_seed Hash seed before using it as a seed for MFG1 + */ +mgf1_bitspender_t *mgf1_bitspender_create(hash_algorithm_t alg, chunk_t seed, + bool hash_seed); + +#endif /** MGF1_BITSPENDER_H_ @}*/