From 6862128151fb78f63685a8da5575783c426d64a7 Mon Sep 17 00:00:00 2001 From: Martin Willi Date: Wed, 5 Apr 2006 12:10:50 +0000 Subject: ../svn-commit.tmp --- Source/lib/crypto/rsa/rsa_public_key.c | 468 +++++++++++++++++++++++++++++++++ 1 file changed, 468 insertions(+) create mode 100644 Source/lib/crypto/rsa/rsa_public_key.c (limited to 'Source/lib/crypto/rsa/rsa_public_key.c') diff --git a/Source/lib/crypto/rsa/rsa_public_key.c b/Source/lib/crypto/rsa/rsa_public_key.c new file mode 100644 index 000000000..57ad10128 --- /dev/null +++ b/Source/lib/crypto/rsa/rsa_public_key.c @@ -0,0 +1,468 @@ +/** + * @file rsa_public_key.c + * + * @brief Implementation of rsa_public_key_t. + * + */ + +/* + * Copyright (C) 2005 Jan Hutter, Martin Willi + * 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 +#include +#include + +#include "rsa_public_key.h" + +#include +#include +#include +#include + +/* + * For simplicity, + * we use these predefined values for + * hash algorithm OIDs. These also contain + * the length of the following hash. + * These values are also used in rsa_private_key.c. + */ + +u_int8_t md2_oid[] = { + 0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86, + 0x48,0x86,0xf7,0x0d,0x02,0x02,0x05,0x00, + 0x04,0x10 +}; + +u_int8_t md5_oid[] = { + 0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86, + 0x48,0x86,0xf7,0x0d,0x02,0x05,0x05,0x00, + 0x04,0x10 +}; + +u_int8_t sha1_oid[] = { + 0x30,0x21,0x30,0x09,0x06,0x05,0x2b,0x0e, + 0x03,0x02,0x1a,0x05,0x00,0x04,0x14 +}; + +u_int8_t sha256_oid[] = { + 0x30,0x31,0x30,0x0d,0x06,0x09,0x60,0x86, + 0x48,0x01,0x65,0x03,0x04,0x02,0x01,0x05, + 0x00,0x04,0x20 +}; + +u_int8_t sha384_oid[] = { + 0x30,0x41,0x30,0x0d,0x06,0x09,0x60,0x86, + 0x48,0x01,0x65,0x03,0x04,0x02,0x02,0x05, + 0x00,0x04,0x30 +}; + +u_int8_t sha512_oid[] = { + 0x30,0x51,0x30,0x0d,0x06,0x09,0x60,0x86, + 0x48,0x01,0x65,0x03,0x04,0x02,0x03,0x05, + 0x00,0x04,0x40 +}; + + +typedef struct private_rsa_public_key_t private_rsa_public_key_t; + +/** + * Private data structure with signing context. + */ +struct private_rsa_public_key_t { + /** + * Public interface for this signer. + */ + rsa_public_key_t public; + + /** + * Public modulus. + */ + mpz_t n; + + /** + * Public exponent. + */ + mpz_t e; + + /** + * Keysize in bytes. + */ + size_t k; + + /** + * @brief Implements the RSAEP algorithm specified in PKCS#1. + * + * @param this calling object + * @param data data to process + * @return processed data + */ + chunk_t (*rsaep) (private_rsa_public_key_t *this, chunk_t data); + + /** + * @brief Implements the RSASVP1 algorithm specified in PKCS#1. + * + * @param this calling object + * @param data data to process + * @return processed data + */ + chunk_t (*rsavp1) (private_rsa_public_key_t *this, chunk_t data); +}; + + +typedef struct rsa_public_key_info_t rsa_public_key_info_t; + +/** + * KeyInfo, as it appears in a public key file + */ +struct rsa_public_key_info_t { + /** + * Algorithm for this key + */ + chunk_t algorithm_oid; + + /** + * Public key, parseable with rsa_public_key_rules + */ + chunk_t public_key; +}; + +/** + * Rules for de-/encoding of a public key from/in ASN1 + */ +static asn1_rule_t rsa_public_key_rules[] = { + {ASN1_SEQUENCE, 0, 0, 0}, + { ASN1_INTEGER, ASN1_MPZ, offsetof(private_rsa_public_key_t, n), 0}, + { ASN1_INTEGER, ASN1_MPZ, offsetof(private_rsa_public_key_t, e), 0}, + {ASN1_END, 0, 0, 0}, +}; + +/** + * Rules for de-/encoding of a PublicKeyInfo from/in ASN1 + */ +static asn1_rule_t rsa_public_key_info_rules[] = { + {ASN1_SEQUENCE, 0, 0, 0}, + { ASN1_SEQUENCE, 0, 0, 0}, + { ASN1_OID, 0, offsetof(rsa_public_key_info_t, algorithm_oid), 0}, + { ASN1_NULL, 0, 0, 0}, + { ASN1_END, 0, 0, 0}, + { ASN1_BITSTRING, 0, offsetof(rsa_public_key_info_t, public_key), 0}, + {ASN1_END, 0, 0, 0}, +}; + +private_rsa_public_key_t *rsa_public_key_create_empty(); + +/** + * Implementation of private_rsa_public_key_t.rsaep and private_rsa_public_key_t.rsavp1 + */ +static chunk_t rsaep(private_rsa_public_key_t *this, chunk_t data) +{ + mpz_t m, c; + chunk_t encrypted; + + mpz_init(c); + mpz_init(m); + + mpz_import(m, data.len, 1, 1, 1, 0, data.ptr); + + mpz_powm(c, m, this->e, this->n); + + encrypted.len = this->k; + encrypted.ptr = mpz_export(NULL, NULL, 1, encrypted.len, 1, 0, c); + + mpz_clear(c); + mpz_clear(m); + + return encrypted; +} + +/** + * Implementation of rsa_public_key.verify_emsa_pkcs1_signature. + */ +static status_t verify_emsa_pkcs1_signature(private_rsa_public_key_t *this, chunk_t data, chunk_t signature) +{ + hasher_t *hasher = NULL; + chunk_t hash; + chunk_t em; + u_int8_t *pos; + + if (signature.len > this->k) + { + return INVALID_ARG; + } + + /* unpack signature */ + em = this->rsavp1(this, signature); + + /* result should look like this: + * EM = 0x00 || 0x01 || PS || 0x00 || T. + * PS = 0xFF padding, with length to fill em + * T = oid || hash + */ + + /* check magic bytes */ + if ((*(em.ptr) != 0x00) || + (*(em.ptr+1) != 0x01)) + { + allocator_free(em.ptr); + return FAILED; + } + + /* find magic 0x00 */ + pos = em.ptr + 2; + while (pos <= em.ptr + em.len) + { + if (*pos == 0x00) + { + /* found magic byte, stop */ + pos++; + break; + } + else if (*pos != 0xFF) + { + /* bad padding, decryption failed ?!*/ + allocator_free(em.ptr); + return FAILED; + } + pos++; + } + + if (pos + 20 > em.ptr + em.len) + { + /* not enought room for oid compare */ + allocator_free(em.ptr); + return FAILED; + } + + if (memcmp(md2_oid, pos, sizeof(md2_oid)) == 0) + { + hasher = hasher_create(HASH_MD2); + pos += sizeof(md2_oid); + } + else if (memcmp(md5_oid, pos, sizeof(md5_oid)) == 0) + { + hasher = hasher_create(HASH_MD5); + pos += sizeof(md5_oid); + } + else if (memcmp(sha1_oid, pos, sizeof(sha1_oid)) == 0) + { + hasher = hasher_create(HASH_SHA1); + pos += sizeof(sha1_oid); + } + else if (memcmp(sha256_oid, pos, sizeof(sha256_oid)) == 0) + { + hasher = hasher_create(HASH_SHA256); + pos += sizeof(sha256_oid); + } + else if (memcmp(sha384_oid, pos, sizeof(sha384_oid)) == 0) + { + hasher = hasher_create(HASH_SHA384); + pos += sizeof(sha384_oid); + } + else if (memcmp(sha512_oid, pos, sizeof(sha512_oid)) == 0) + { + hasher = hasher_create(HASH_SHA512); + pos += sizeof(sha512_oid); + } + + if (hasher == NULL) + { + /* not supported hash algorithm */ + allocator_free(em.ptr); + return NOT_SUPPORTED; + } + + if (pos + hasher->get_block_size(hasher) != em.ptr + em.len) + { + /* bad length */ + allocator_free(em.ptr); + hasher->destroy(hasher); + return FAILED; + } + + /* build own hash for a compare */ + hasher->allocate_hash(hasher, data, &hash); + hasher->destroy(hasher); + + if (memcmp(hash.ptr, pos, hash.len) != 0) + { + /* hash does not equal */ + allocator_free(hash.ptr); + allocator_free(em.ptr); + return FAILED; + + } + + /* seems good */ + allocator_free(hash.ptr); + allocator_free(em.ptr); + return SUCCESS; +} + +/** + * Implementation of rsa_public_key.get_key. + */ +static status_t get_key(private_rsa_public_key_t *this, chunk_t *key) +{ + chunk_t n, e; + + n.len = this->k; + n.ptr = mpz_export(NULL, NULL, 1, n.len, 1, 0, this->n); + e.len = this->k; + e.ptr = mpz_export(NULL, NULL, 1, e.len, 1, 0, this->e); + + key->len = this->k * 2; + key->ptr = allocator_alloc(key->len); + memcpy(key->ptr, n.ptr, n.len); + memcpy(key->ptr + n.len, e.ptr, e.len); + allocator_free(n.ptr); + allocator_free(e.ptr); + + return SUCCESS; +} + +/** + * Implementation of rsa_public_key.save_key. + */ +static status_t save_key(private_rsa_public_key_t *this, char *file) +{ + return NOT_SUPPORTED; +} + +/** + * Implementation of rsa_public_key.get_modulus. + */ +static mpz_t *get_modulus(private_rsa_public_key_t *this) +{ + return &this->n; +} + +/** + * Implementation of rsa_public_key.clone. + */ +static rsa_public_key_t* _clone(private_rsa_public_key_t *this) +{ + private_rsa_public_key_t *clone = rsa_public_key_create_empty(); + + mpz_init_set(clone->n, this->n); + mpz_init_set(clone->e, this->e); + clone->k = this->k; + + return &clone->public; +} + +/** + * Implementation of rsa_public_key.destroy. + */ +static void destroy(private_rsa_public_key_t *this) +{ + mpz_clear(this->n); + mpz_clear(this->e); + allocator_free(this); +} + +/** + * Generic private constructor + */ +private_rsa_public_key_t *rsa_public_key_create_empty() +{ + private_rsa_public_key_t *this = allocator_alloc_thing(private_rsa_public_key_t); + + /* public functions */ + this->public.verify_emsa_pkcs1_signature = (status_t (*) (rsa_public_key_t*,chunk_t,chunk_t))verify_emsa_pkcs1_signature; + this->public.get_key = (status_t (*) (rsa_public_key_t*,chunk_t*))get_key; + this->public.save_key = (status_t (*) (rsa_public_key_t*,char*))save_key; + this->public.get_modulus = (mpz_t *(*) (rsa_public_key_t*))get_modulus; + this->public.clone = (rsa_public_key_t* (*) (rsa_public_key_t*))_clone; + this->public.destroy = (void (*) (rsa_public_key_t*))destroy; + + /* private functions */ + this->rsaep = rsaep; + this->rsavp1 = rsaep; /* same algorithm */ + + return this; +} + +/* + * See header + */ +rsa_public_key_t *rsa_public_key_create_from_chunk(chunk_t chunk) +{ + der_decoder_t *dd; + status_t status; + private_rsa_public_key_t *this; + + this = rsa_public_key_create_empty(); + mpz_init(this->n); + mpz_init(this->e); + + dd = der_decoder_create(rsa_public_key_rules); + status = dd->decode(dd, chunk, this); + dd->destroy(dd); + if (status != SUCCESS) + { + destroy(this); + return NULL; + } + this->k = (mpz_sizeinbase(this->n, 2) + 7) / 8; + return &this->public; +} + +/* + * See header + */ +rsa_public_key_t *rsa_public_key_create_from_file(char *filename) +{ + struct stat stb; + FILE *file; + char *buffer; + chunk_t chunk; + rsa_public_key_info_t key_info = {CHUNK_INITIALIZER, CHUNK_INITIALIZER}; + der_decoder_t *dd; + status_t status; + rsa_public_key_t *public_key = NULL; + + if (stat(filename, &stb) == -1) + { + return NULL; + } + + buffer = alloca(stb.st_size); + + file = fopen(filename, "r"); + if (file == NULL) + { + return NULL; + } + + if (fread(buffer, stb.st_size, 1, file) != 1) + { + return NULL; + } + + chunk.ptr = buffer; + chunk.len = stb.st_size; + + /* parse public key info first */ + dd = der_decoder_create(rsa_public_key_info_rules); + status = dd->decode(dd, chunk, &key_info); + dd->destroy(dd); + allocator_free_chunk(&key_info.algorithm_oid); + if (status == SUCCESS) + { + public_key = rsa_public_key_create_from_chunk(chunk); + } + allocator_free_chunk(&key_info.public_key); + return public_key; +} -- cgit v1.2.3