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 void crypt_shutdown(void)
60 CRYPTO_cleanup_all_ex_data();
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_u32_be(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);
147 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
152 struct asymmetric_key *key = para_malloc(sizeof(*key));
154 ret = decode_ssh_key(key_file, &blob, &decoded_size);
157 ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
160 ret = RSA_size(key->rsa);
169 PARA_ERROR_LOG("can not load key %s\n", key_file);
174 void apc_free_pubkey(struct asymmetric_key *key)
182 int apc_priv_decrypt(const char *key_file, unsigned char *outbuf,
183 unsigned char *inbuf, int inlen)
185 struct asymmetric_key *priv;
188 ret = check_private_key_file(key_file);
193 priv = para_malloc(sizeof(*priv));
194 ret = get_private_key(key_file, &priv->rsa);
200 * RSA is vulnerable to timing attacks. Generate a random blinding
201 * factor to protect against this kind of attack.
204 if (RSA_blinding_on(priv->rsa, NULL) == 0)
206 ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
207 RSA_PKCS1_OAEP_PADDING);
208 RSA_blinding_off(priv->rsa);
217 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
218 unsigned len, unsigned char *outbuf)
220 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
224 ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
225 RSA_PKCS1_OAEP_PADDING);
226 return ret < 0? -E_ENCRYPT : ret;
229 struct stream_cipher {
233 struct stream_cipher *sc_new(const unsigned char *data, int len)
235 struct stream_cipher *sc = para_malloc(sizeof(*sc));
237 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
238 sc->aes = EVP_CIPHER_CTX_new();
239 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
240 data + AES_CRT128_BLOCK_SIZE);
244 void sc_free(struct stream_cipher *sc)
248 EVP_CIPHER_CTX_free(sc->aes);
252 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
255 int ret, inlen = src->iov_len, outlen, tmplen;
257 *dst = (typeof(*dst)) {
258 /* Add one for the terminating zero byte. */
259 .iov_base = para_malloc(inlen + 1),
262 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
264 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
267 ((char *)dst->iov_base)[outlen] = '\0';
268 dst->iov_len = outlen;
271 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
273 return aes_ctr128_crypt(sc->aes, src, dst);
276 void hash_function(const char *data, unsigned long len, unsigned char *hash)
280 SHA1_Update(&c, data, len);
281 SHA1_Final(hash, &c);