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 void get_random_bytes_or_die(unsigned char *buf, int num)
31 /* RAND_bytes() returns 1 on success, 0 otherwise. */
32 if (RAND_bytes(buf, num) == 1)
34 err = ERR_get_error();
35 PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err));
40 * Read 64 bytes from /dev/urandom and add them to the SSL PRNG. Then seed the
41 * PRNG used by random(3) with a random seed obtained from SSL.
45 int seed, ret = RAND_load_file("/dev/urandom", 64);
48 PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret);
51 get_random_bytes_or_die((unsigned char *)&seed, sizeof(seed));
55 void crypt_shutdown(void)
57 #ifdef HAVE_OPENSSL_THREAD_STOP /* openssl-1.1 or later */
58 OPENSSL_thread_stop();
59 #else /* openssl-1.0 */
60 ERR_remove_thread_state(NULL);
66 * The public key loading functions below were inspired by corresponding code
67 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
68 * Finland. However, not much of the original code remains.
71 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
73 const unsigned char *p = buf, *end = buf + len;
81 bnsize = read_u32_be(p);
82 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
90 bn = BN_bin2bn(p, bnsize, NULL);
97 static int read_public_key(const unsigned char *blob, int blen, RSA **result)
102 const unsigned char *p = blob, *end = blob + blen;
107 ret = read_bignum(p, end - p, &e);
111 ret = read_bignum(p, end - p, &n);
114 #ifdef HAVE_RSA_SET0_KEY
115 RSA_set0_key(rsa, n, e, NULL);
129 static int read_pem_private_key(const char *path, RSA **rsa)
132 BIO *bio = BIO_new(BIO_s_file());
136 return -E_PRIVATE_KEY;
137 if (BIO_read_filename(bio, path) <= 0)
139 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
142 *rsa = EVP_PKEY_get1_RSA(pkey);
146 return *rsa? RSA_size(*rsa) : -E_PRIVATE_KEY;
149 static int read_openssh_private_key(const unsigned char *blob,
150 const unsigned char *end, RSA **result)
155 BIGNUM *n, *e, *d, *iqmp, *p, *q; /* stored in the key file */
156 BIGNUM *dmp1, *dmq1; /* these will be computed */
158 const unsigned char *cp = blob;
176 ret = read_bignum(cp, end - cp, &n);
180 ret = read_bignum(cp, end - cp, &e);
184 ret = read_bignum(cp, end - cp, &d);
188 ret = read_bignum(cp, end - cp, &iqmp);
192 ret = read_bignum(cp, end - cp, &p);
196 ret = read_bignum(cp, end - cp, &q);
200 if (!BN_sub(tmp, q, BN_value_one()))
202 if (!BN_mod(dmp1, d, tmp, ctx))
204 if (!BN_sub(tmp, q, BN_value_one()))
206 if (!BN_mod(dmq1, d, tmp, ctx))
208 #ifdef HAVE_RSA_SET0_KEY
209 RSA_set0_key(rsa, n, e, d);
210 RSA_set0_factors(rsa, p, q);
211 RSA_set0_crt_params(rsa, dmp1, dmq1, iqmp);
251 static int get_private_key(const char *path, RSA **rsa)
254 unsigned char *blob, *end;
258 ret = decode_private_key(path, &blob, &blob_size);
261 end = blob + blob_size;
262 if (ret == PKT_OPENSSH) {
263 ret = find_openssh_bignum_offset(blob, blob_size);
266 PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
267 ret = read_openssh_private_key(blob + ret, end, rsa);
269 ret = read_pem_private_key(path, rsa);
275 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
280 struct asymmetric_key *pub = alloc(sizeof(*pub));
282 ret = decode_public_key(key_file, &blob, &decoded_size);
285 ret = read_public_key(blob + ret, decoded_size - ret, &pub->rsa);
288 ret = RSA_size(pub->rsa);
297 PARA_ERROR_LOG("can not load key %s\n", key_file);
302 void apc_free_pubkey(struct asymmetric_key *pub)
310 int apc_priv_decrypt(const char *key_file, unsigned char *outbuf,
311 unsigned char *inbuf, int inlen)
313 struct asymmetric_key *priv;
316 ret = check_private_key_file(key_file);
321 priv = alloc(sizeof(*priv));
322 ret = get_private_key(key_file, &priv->rsa);
328 * RSA is vulnerable to timing attacks. Generate a random blinding
329 * factor to protect against this kind of attack.
332 if (RSA_blinding_on(priv->rsa, NULL) == 0)
334 ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
335 RSA_PKCS1_OAEP_PADDING);
336 RSA_blinding_off(priv->rsa);
345 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
346 unsigned len, unsigned char *outbuf)
348 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
352 ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
353 RSA_PKCS1_OAEP_PADDING);
354 return ret < 0? -E_ENCRYPT : ret;
357 struct stream_cipher {
361 struct stream_cipher *sc_new(const unsigned char *data, int len)
363 struct stream_cipher *sc = alloc(sizeof(*sc));
365 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
366 sc->aes = EVP_CIPHER_CTX_new();
367 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
368 data + AES_CRT128_BLOCK_SIZE);
372 void sc_free(struct stream_cipher *sc)
376 EVP_CIPHER_CTX_free(sc->aes);
380 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
383 int ret, inlen = src->iov_len, outlen, tmplen;
385 *dst = (typeof(*dst)) {
386 /* Add one for the terminating zero byte. */
387 .iov_base = alloc(inlen + 1),
390 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
392 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
395 ((char *)dst->iov_base)[outlen] = '\0';
396 dst->iov_len = outlen;
399 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
401 return aes_ctr128_crypt(sc->aes, src, dst);
404 void hash_function(const char *data, unsigned long len, unsigned char *hash)
406 EVP_MD_CTX *c = EVP_MD_CTX_new();
407 int ret = EVP_DigestInit_ex(c, EVP_sha1(), NULL);
409 ret = EVP_DigestUpdate(c, data, len);
411 ret = EVP_DigestFinal_ex(c, hash, NULL);
416 void hash2_function(const char *data, unsigned long len, unsigned char *hash)
418 EVP_MD_CTX *c = EVP_MD_CTX_new();
419 int ret = EVP_DigestInit_ex(c, EVP_sha256(), NULL);
421 ret = EVP_DigestUpdate(c, data, len);
423 ret = EVP_DigestFinal_ex(c, hash, NULL);