2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file crypt.c Openssl-based encryption/decryption routines. */
10 #include <sys/types.h>
11 #include <sys/socket.h>
12 #include <openssl/rand.h>
13 #include <openssl/err.h>
14 #include <openssl/pem.h>
15 #include <openssl/sha.h>
16 #include <openssl/bn.h>
17 #include <openssl/aes.h>
24 #include "crypt_backend.h"
27 struct asymmetric_key {
31 void get_random_bytes_or_die(unsigned char *buf, int num)
35 /* RAND_bytes() returns 1 on success, 0 otherwise. */
36 if (RAND_bytes(buf, num) == 1)
38 err = ERR_get_error();
39 PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err));
44 * Read 64 bytes from /dev/urandom and adds them to the SSL PRNG. Seed the PRNG
45 * used by random() with a random seed obtained from SSL. If /dev/random is not
46 * readable the function calls exit().
48 * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
49 * random(3), \ref para_random().
51 void init_random_seed_or_die(void)
53 int seed, ret = RAND_load_file("/dev/urandom", 64);
56 PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
59 get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
63 static int get_private_key(const char *path, RSA **rsa)
66 BIO *bio = BIO_new(BIO_s_file());
70 return -E_PRIVATE_KEY;
71 if (BIO_read_filename(bio, path) <= 0)
73 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
76 *rsa = EVP_PKEY_get1_RSA(pkey);
80 return *rsa? RSA_size(*rsa) : -E_PRIVATE_KEY;
84 * The public key loading functions below were inspired by corresponding code
85 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
86 * Finland. However, not much of the original code remains.
89 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
91 const unsigned char *p = buf, *end = buf + len;
99 bnsize = read_ssh_u32(p);
100 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
104 if (p + bnsize > end)
108 bn = BN_bin2bn(p, bnsize, NULL);
115 static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
120 const unsigned char *p = blob, *end = blob + blen;
125 ret = read_bignum(p, end - p, &e);
129 ret = read_bignum(p, end - p, &n);
132 #ifdef HAVE_RSA_SET0_KEY
133 RSA_set0_key(rsa, n, e, NULL);
145 int get_public_key(const char *key_file, struct asymmetric_key **result)
147 struct asymmetric_key *key = NULL;
149 unsigned char *blob = NULL;
150 size_t map_size, encoded_size, decoded_size;
154 key = para_malloc(sizeof(*key));
155 ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
158 ret = is_ssh_rsa_key(map, map_size);
160 para_munmap(map, map_size);
164 encoded_size = map_size - ret;
165 PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
166 ret = uudecode(cp, encoded_size, (char **)&blob, &decoded_size);
169 ret = check_ssh_key_header(blob, decoded_size);
172 ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
175 ret = RSA_size(key->rsa);
177 ret2 = para_munmap(map, map_size);
178 if (ret >= 0 && ret2 < 0)
184 PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
191 void free_public_key(struct asymmetric_key *key)
199 int priv_decrypt(const char *key_file, unsigned char *outbuf,
200 unsigned char *inbuf, int inlen)
202 struct asymmetric_key *priv;
205 ret = check_private_key_file(key_file);
210 priv = para_malloc(sizeof(*priv));
211 ret = get_private_key(key_file, &priv->rsa);
217 * RSA is vulnerable to timing attacks. Generate a random blinding
218 * factor to protect against this kind of attack.
221 if (RSA_blinding_on(priv->rsa, NULL) == 0)
223 ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
224 RSA_PKCS1_OAEP_PADDING);
225 RSA_blinding_off(priv->rsa);
234 int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
235 unsigned len, unsigned char *outbuf)
237 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
241 ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
242 RSA_PKCS1_OAEP_PADDING);
243 return ret < 0? -E_ENCRYPT : ret;
246 struct stream_cipher {
250 struct stream_cipher *sc_new(const unsigned char *data, int len)
252 struct stream_cipher *sc = para_malloc(sizeof(*sc));
254 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
255 sc->aes = EVP_CIPHER_CTX_new();
256 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
257 data + AES_CRT128_BLOCK_SIZE);
261 void sc_free(struct stream_cipher *sc)
265 EVP_CIPHER_CTX_free(sc->aes);
269 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
272 int ret, inlen = src->iov_len, outlen, tmplen;
274 *dst = (typeof(*dst)) {
275 /* Add one for the terminating zero byte. */
276 .iov_base = para_malloc(inlen + 1),
279 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
281 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
284 ((char *)dst->iov_base)[outlen] = '\0';
285 dst->iov_len = outlen;
288 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
290 return aes_ctr128_crypt(sc->aes, src, dst);
293 void hash_function(const char *data, unsigned long len, unsigned char *hash)
297 SHA1_Update(&c, data, len);
298 SHA1_Final(hash, &c);