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>
14 #include <openssl/evp.h>
20 #include "crypt_backend.h"
21 #include "portable_io.h"
23 struct asymmetric_key {
27 static int openssl_perror(const char *pfx)
29 unsigned long err = ERR_get_error();
30 PARA_ERROR_LOG("%s: \"%s\"\n", pfx, ERR_reason_error_string(err));
34 void get_random_bytes_or_die(unsigned char *buf, int num)
38 if (RAND_bytes(buf, num) == 1) /* success */
40 ret = openssl_perror("RAND_bytes");
41 PARA_EMERG_LOG("%s\n", strerror(-ret));
46 * Read 64 bytes from /dev/urandom and add them to the SSL PRNG. Then seed the
47 * PRNG used by random(3) with a random seed obtained from SSL.
51 int seed, ret = RAND_load_file("/dev/urandom", 64);
54 PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
57 get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
61 void crypt_shutdown(void)
63 #ifdef HAVE_CRYPTO_CLEANUP_ALL_EX_DATA
64 CRYPTO_cleanup_all_ex_data();
66 #ifdef HAVE_OPENSSL_THREAD_STOP /* openssl-1.1 or later */
67 OPENSSL_thread_stop();
68 #else /* openssl-1.0 */
69 ERR_remove_thread_state(NULL);
75 * The public key loading functions below were inspired by corresponding code
76 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
77 * Finland. However, not much of the original code remains.
80 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
82 const unsigned char *p = buf, *end = buf + len;
90 bnsize = read_u32_be(p);
91 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
99 bn = BN_bin2bn(p, bnsize, NULL);
106 static int read_public_key(const unsigned char *blob, int blen,
107 struct asymmetric_key *result)
112 const unsigned char *p = blob, *end = blob + blen;
114 assert((rsa = RSA_new()));
115 ret = read_bignum(p, end - p, &e);
119 ret = read_bignum(p, end - p, &n);
122 #ifdef HAVE_RSA_SET0_KEY
123 RSA_set0_key(rsa, n, e, NULL);
137 static int read_pem_private_key(const char *path, struct asymmetric_key *priv)
142 assert((bio = BIO_new(BIO_s_file())));
144 if (BIO_read_filename(bio, path) <= 0)
146 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
149 priv->rsa = EVP_PKEY_get1_RSA(pkey);
153 return priv->rsa? RSA_size(priv->rsa) : -E_PRIVATE_KEY;
156 static int read_openssh_private_key(const unsigned char *blob,
157 const unsigned char *end, struct asymmetric_key *priv)
161 BIGNUM *n, *e, *d, *iqmp, *p, *q; /* stored in the key file */
162 const unsigned char *cp = blob;
164 assert((rsa = RSA_new()));
165 ret = read_bignum(cp, end - cp, &n);
169 ret = read_bignum(cp, end - cp, &e);
173 ret = read_bignum(cp, end - cp, &d);
177 ret = read_bignum(cp, end - cp, &iqmp);
181 ret = read_bignum(cp, end - cp, &p);
185 ret = read_bignum(cp, end - cp, &q);
188 #ifdef HAVE_RSA_SET0_KEY
189 RSA_set0_key(rsa, n, e, d);
190 RSA_set0_factors(rsa, p, q);
191 RSA_set0_crt_params(rsa, NULL, NULL, iqmp);
218 static int get_private_key(const char *path, struct asymmetric_key *priv)
221 unsigned char *blob, *end;
225 ret = decode_private_key(path, &blob, &blob_size);
228 end = blob + blob_size;
229 if (ret == PKT_OPENSSH) {
230 ret = find_openssh_bignum_offset(blob, blob_size);
233 PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
234 ret = read_openssh_private_key(blob + ret, end, priv);
236 ret = read_pem_private_key(path, priv);
242 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
247 struct asymmetric_key *pub = alloc(sizeof(*pub));
249 ret = decode_public_key(key_file, &blob, &decoded_size);
252 ret = read_public_key(blob + ret, decoded_size - ret, pub);
255 ret = RSA_size(pub->rsa);
264 PARA_ERROR_LOG("can not load key %s\n", key_file);
269 void apc_free_pubkey(struct asymmetric_key *pub)
277 int apc_priv_decrypt(const char *key_file, unsigned char **outbuf,
278 unsigned char *inbuf, int inlen)
280 struct asymmetric_key *priv;
284 ret = check_private_key_file(key_file);
289 priv = alloc(sizeof(*priv));
290 ret = get_private_key(key_file, priv);
296 * RSA is vulnerable to timing attacks. Generate a random blinding
297 * factor to protect against this kind of attack.
300 if (RSA_blinding_on(priv->rsa, NULL) == 0)
302 *outbuf = alloc(RSA_size(priv->rsa));
303 ret = RSA_private_decrypt(inlen, inbuf, *outbuf, priv->rsa,
304 RSA_PKCS1_OAEP_PADDING);
305 RSA_blinding_off(priv->rsa);
317 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
318 unsigned len, unsigned char **outbuf)
320 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
325 *outbuf = alloc(RSA_size(pub->rsa));
326 ret = RSA_public_encrypt(flen, inbuf, *outbuf, pub->rsa,
327 RSA_PKCS1_OAEP_PADDING);
336 struct stream_cipher {
340 struct stream_cipher *sc_new(const unsigned char *data, int len)
342 struct stream_cipher *sc = alloc(sizeof(*sc));
344 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
345 assert((sc->aes = EVP_CIPHER_CTX_new()));
346 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
347 data + AES_CRT128_BLOCK_SIZE);
351 void sc_free(struct stream_cipher *sc)
355 EVP_CIPHER_CTX_free(sc->aes);
359 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
362 int ret, inlen = src->iov_len, outlen, tmplen;
364 *dst = (typeof(*dst)) {
365 /* Add one for the terminating zero byte. */
366 .iov_base = alloc(inlen + 1),
369 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
371 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
374 ((char *)dst->iov_base)[outlen] = '\0';
375 dst->iov_len = outlen;
378 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
380 return aes_ctr128_crypt(sc->aes, src, dst);
383 void hash_function(const char *data, unsigned long len, unsigned char *hash)
388 assert((c = EVP_MD_CTX_new()));
389 ret = EVP_DigestInit_ex(c, EVP_sha1(), NULL);
391 ret = EVP_DigestUpdate(c, data, len);
393 ret = EVP_DigestFinal_ex(c, hash, NULL);
398 void hash2_function(const char *data, unsigned long len, unsigned char *hash)
403 assert((c = EVP_MD_CTX_new()));
404 ret = EVP_DigestInit_ex(c, EVP_sha256(), NULL);
406 ret = EVP_DigestUpdate(c, data, len);
408 ret = EVP_DigestFinal_ex(c, hash, NULL);