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();
64 * The public key loading functions below were inspired by corresponding code
65 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
66 * Finland. However, not much of the original code remains.
69 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
71 const unsigned char *p = buf, *end = buf + len;
79 bnsize = read_u32_be(p);
80 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
88 bn = BN_bin2bn(p, bnsize, NULL);
95 static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
100 const unsigned char *p = blob, *end = blob + blen;
105 ret = read_bignum(p, end - p, &e);
109 ret = read_bignum(p, end - p, &n);
112 #ifdef HAVE_RSA_SET0_KEY
113 RSA_set0_key(rsa, n, e, NULL);
127 static int read_pem_private_key(const char *path, RSA **rsa)
130 BIO *bio = BIO_new(BIO_s_file());
134 return -E_PRIVATE_KEY;
135 if (BIO_read_filename(bio, path) <= 0)
137 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
140 *rsa = EVP_PKEY_get1_RSA(pkey);
144 return *rsa? RSA_size(*rsa) : -E_PRIVATE_KEY;
147 static int read_private_rsa_params(const unsigned char *blob,
148 const unsigned char *end, RSA **result)
153 BIGNUM *n, *e, *d, *iqmp, *p, *q; /* stored in the key file */
154 BIGNUM *dmp1, *dmq1; /* these will be computed */
156 const unsigned char *cp = blob;
174 ret = read_bignum(cp, end - cp, &n);
178 ret = read_bignum(cp, end - cp, &e);
182 ret = read_bignum(cp, end - cp, &d);
186 ret = read_bignum(cp, end - cp, &iqmp);
190 ret = read_bignum(cp, end - cp, &p);
194 ret = read_bignum(cp, end - cp, &q);
198 if (!BN_sub(tmp, q, BN_value_one()))
200 if (!BN_mod(dmp1, d, tmp, ctx))
202 if (!BN_sub(tmp, q, BN_value_one()))
204 if (!BN_mod(dmq1, d, tmp, ctx))
206 #ifdef HAVE_RSA_SET0_KEY
207 RSA_set0_key(rsa, n, e, d);
208 RSA_set0_factors(rsa, p, q);
209 RSA_set0_crt_params(rsa, dmp1, dmq1, iqmp);
249 static int get_private_key(const char *path, RSA **rsa)
252 unsigned char *blob, *end;
256 ret = decode_private_key(path, &blob, &blob_size);
259 end = blob + blob_size;
260 if (ret == PKT_OPENSSH) {
261 ret = find_openssh_bignum_offset(blob, blob_size);
264 PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
265 ret = read_private_rsa_params(blob + ret, end, rsa);
267 ret = read_pem_private_key(path, rsa);
273 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
278 struct asymmetric_key *key = para_malloc(sizeof(*key));
280 ret = decode_public_key(key_file, &blob, &decoded_size);
283 ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
286 ret = RSA_size(key->rsa);
295 PARA_ERROR_LOG("can not load key %s\n", key_file);
300 void apc_free_pubkey(struct asymmetric_key *key)
308 int apc_priv_decrypt(const char *key_file, unsigned char *outbuf,
309 unsigned char *inbuf, int inlen)
311 struct asymmetric_key *priv;
314 ret = check_private_key_file(key_file);
319 priv = para_malloc(sizeof(*priv));
320 ret = get_private_key(key_file, &priv->rsa);
326 * RSA is vulnerable to timing attacks. Generate a random blinding
327 * factor to protect against this kind of attack.
330 if (RSA_blinding_on(priv->rsa, NULL) == 0)
332 ret = RSA_private_decrypt(inlen, inbuf, outbuf, priv->rsa,
333 RSA_PKCS1_OAEP_PADDING);
334 RSA_blinding_off(priv->rsa);
343 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
344 unsigned len, unsigned char *outbuf)
346 int ret, flen = len; /* RSA_public_encrypt expects a signed int */
350 ret = RSA_public_encrypt(flen, inbuf, outbuf, pub->rsa,
351 RSA_PKCS1_OAEP_PADDING);
352 return ret < 0? -E_ENCRYPT : ret;
355 struct stream_cipher {
359 struct stream_cipher *sc_new(const unsigned char *data, int len)
361 struct stream_cipher *sc = para_malloc(sizeof(*sc));
363 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
364 sc->aes = EVP_CIPHER_CTX_new();
365 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
366 data + AES_CRT128_BLOCK_SIZE);
370 void sc_free(struct stream_cipher *sc)
374 EVP_CIPHER_CTX_free(sc->aes);
378 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
381 int ret, inlen = src->iov_len, outlen, tmplen;
383 *dst = (typeof(*dst)) {
384 /* Add one for the terminating zero byte. */
385 .iov_base = para_malloc(inlen + 1),
388 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
390 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
393 ((char *)dst->iov_base)[outlen] = '\0';
394 dst->iov_len = outlen;
397 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
399 return aes_ctr128_crypt(sc->aes, src, dst);
402 void hash_function(const char *data, unsigned long len, unsigned char *hash)
406 SHA1_Update(&c, data, len);
407 SHA1_Final(hash, &c);