2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
19 /** \file crypt.c openssl-based RSA encryption/decryption routines */
21 #include <openssl/pem.h>
26 /** \cond used to distinguish between loading of private/public key */
27 #define LOAD_PUBLIC_KEY 0
28 #define LOAD_PRIVATE_KEY 1
31 static EVP_PKEY *load_key(const char *file, int private)
34 EVP_PKEY *pkey = NULL;
36 key = BIO_new(BIO_s_file());
39 if (BIO_read_filename(key, file) > 0) {
40 if (private == LOAD_PRIVATE_KEY)
41 pkey = PEM_read_bio_PrivateKey(key, NULL, NULL, NULL);
43 pkey = PEM_read_bio_PUBKEY(key, NULL, NULL, NULL);
49 static int get_key(char *key_file, RSA **rsa, int private)
51 EVP_PKEY *key = load_key(key_file, private);
54 return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY : -E_PUBLIC_KEY;
55 *rsa = EVP_PKEY_get1_RSA(key);
59 return RSA_size(*rsa);
63 * decrypt a buffer using an RSA key
65 * \param key_file full path of the rsa key
66 * \param outbuf the output buffer
67 * \param inbuf the encrypted input buffer
68 * \param rsa_inlen the length of \a inbuf
70 * The \a outbuf must be large enough to hold at least \a rsa_inlen bytes.
72 * \return The size of the recovered plaintext on success, negative on errors.
74 * \sa RSA_private_decrypt(3)
76 int para_decrypt_buffer(char *key_file, unsigned char *outbuf, unsigned char *inbuf,
80 int ret = get_key(key_file, &rsa, LOAD_PRIVATE_KEY);
84 ret = RSA_private_decrypt(rsa_inlen, inbuf, outbuf, rsa, RSA_PKCS1_PADDING);
85 return (ret > 0)? ret : -E_DECRYPT;
89 * decrypt the challenge number sent by para_server
91 * \param key_file full path of the rsa key
92 * \param challenge_nr result is stored here
93 * \param inbuf the input buffer
94 * \param rsa_inlen the length of \a inbuf
96 * \return positive on success, negative on errors
98 * \sa para_decrypt_buffer()
100 int para_decrypt_challenge(char *key_file, long unsigned *challenge_nr,
101 unsigned char *inbuf, int rsa_inlen)
103 unsigned char *rsa_out = OPENSSL_malloc(128);
104 int ret = para_decrypt_buffer(key_file, rsa_out, inbuf, rsa_inlen);
107 ret = sscanf((char *)rsa_out, "%lu", challenge_nr) == 1?
109 OPENSSL_free(rsa_out);
114 * encrypt a buffer using an RSA key
116 * \param key_file full path of the rsa key
117 * \param inbuf the input buffer
118 * \param len the length of \a inbuf
119 * \param outbuf the output buffer
121 * \return The size of the encrypted data on success, negative on errors
123 * \sa RSA_public_encrypt(3)
125 int para_encrypt_buffer(char *key_file, unsigned char *inbuf,
126 const unsigned len, unsigned char *outbuf)
129 int ret = get_key(key_file, &rsa, LOAD_PUBLIC_KEY);
133 ret = RSA_public_encrypt(len, inbuf, outbuf, rsa, RSA_PKCS1_PADDING);
134 return ret < 0? -E_ENCRYPT : ret;
138 * encrypt the given challenge number
140 * \param key_file full path of the rsa key
141 * \param challenge_nr the number to be encrypted
142 * \param outbuf the output buffer
144 * \a outbuf must be at least 64 bytes long
146 * \return The size of the encrypted data on success, negative on errors
148 * \sa para_encrypt_buffer()
151 int para_encrypt_challenge(char *key_file, long unsigned challenge_nr,
152 unsigned char *outbuf)
154 unsigned char *inbuf = (unsigned char*) make_message("%lu", challenge_nr);
155 int ret = para_encrypt_buffer(key_file, inbuf, strlen((char *)inbuf), outbuf);