1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file openssl.c Openssl-based encryption/decryption routines. */
7 #include <sys/socket.h>
8 #include <openssl/rand.h>
9 #include <openssl/err.h>
10 #include <openssl/pem.h>
11 #include <openssl/sha.h>
12 #include <openssl/bn.h>
13 #include <openssl/aes.h>
19 #include "crypt_backend.h"
20 #include "portable_io.h"
22 struct asymmetric_key {
26 void get_random_bytes_or_die(unsigned char *buf, int num)
30 /* RAND_bytes() returns 1 on success, 0 otherwise. */
31 if (RAND_bytes(buf, num) == 1)
33 err = ERR_get_error();
34 PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err));
39 * Read 64 bytes from /dev/urandom and add them to the SSL PRNG. Seed the PRNG
40 * used by random(3) with a random seed obtained from SSL. If /dev/urandom is
41 * not readable, the function calls exit().
43 * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
44 * random(3), \ref para_random().
48 int seed, ret = RAND_load_file("/dev/urandom", 64);
51 PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
54 get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
58 static int get_private_key(const char *path, RSA **rsa)
61 BIO *bio = BIO_new(BIO_s_file());
65 return -E_PRIVATE_KEY;
66 if (BIO_read_filename(bio, path) <= 0)
68 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
71 *rsa = EVP_PKEY_get1_RSA(pkey);
75 return *rsa? RSA_size(*rsa) : -E_PRIVATE_KEY;
79 * The public key loading functions below were inspired by corresponding code
80 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
81 * Finland. However, not much of the original code remains.
84 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
86 const unsigned char *p = buf, *end = buf + len;
94 bnsize = read_u32_be(p);
95 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
103 bn = BN_bin2bn(p, bnsize, NULL);
110 static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
115 const unsigned char *p = blob, *end = blob + blen;
120 ret = read_bignum(p, end - p, &e);
124 ret = read_bignum(p, end - p, &n);
127 #ifdef HAVE_RSA_SET0_KEY
128 RSA_set0_key(rsa, n, e, NULL);
140 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
145 struct asymmetric_key *key = para_malloc(sizeof(*key));
147 ret = decode_ssh_key(key_file, &blob, &decoded_size);
150 ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
153 ret = RSA_size(key->rsa);
162 PARA_ERROR_LOG("can not load key %s\n", key_file);
167 void apc_free_pubkey(struct asymmetric_key *key)
175 int apc_priv_decrypt(const char *key_file, unsigned char *outbuf,
176 unsigned char *inbuf, int inlen)
178 struct asymmetric_key *priv;
181 ret = check_private_key_file(key_file);
186 priv = para_malloc(sizeof(*priv));
187 ret = get_private_key(key_file, &priv->rsa);
193 * RSA is vulnerable to timing attacks. Generate a random blinding
194 * factor to protect against this kind of attack.
197 if (RSA_blinding_on(priv->rsa, NULL) == 0)
199 ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
200 RSA_PKCS1_OAEP_PADDING);
201 RSA_blinding_off(priv->rsa);
210 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
211 unsigned len, unsigned char *outbuf)
213 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
217 ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
218 RSA_PKCS1_OAEP_PADDING);
219 return ret < 0? -E_ENCRYPT : ret;
222 struct stream_cipher {
226 struct stream_cipher *sc_new(const unsigned char *data, int len)
228 struct stream_cipher *sc = para_malloc(sizeof(*sc));
230 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
231 sc->aes = EVP_CIPHER_CTX_new();
232 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
233 data + AES_CRT128_BLOCK_SIZE);
237 void sc_free(struct stream_cipher *sc)
241 EVP_CIPHER_CTX_free(sc->aes);
245 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
248 int ret, inlen = src->iov_len, outlen, tmplen;
250 *dst = (typeof(*dst)) {
251 /* Add one for the terminating zero byte. */
252 .iov_base = para_malloc(inlen + 1),
255 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
257 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
260 ((char *)dst->iov_base)[outlen] = '\0';
261 dst->iov_len = outlen;
264 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
266 return aes_ctr128_crypt(sc->aes, src, dst);
269 void hash_function(const char *data, unsigned long len, unsigned char *hash)
273 SHA1_Update(&c, data, len);
274 SHA1_Final(hash, &c);