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 {
29 static int openssl_perror(const char *pfx)
31 unsigned long err = ERR_get_error();
32 PARA_ERROR_LOG("%s: \"%s\"\n", pfx, ERR_reason_error_string(err));
36 void get_random_bytes_or_die(unsigned char *buf, int num)
40 if (RAND_bytes(buf, num) == 1) /* success */
42 ret = openssl_perror("RAND_bytes");
43 PARA_EMERG_LOG("%s\n", strerror(-ret));
48 * Read 64 bytes from /dev/urandom and add them to the SSL PRNG. Then seed the
49 * PRNG used by random(3) with a random seed obtained from SSL.
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 void crypt_shutdown(void)
65 #ifdef HAVE_CRYPTO_CLEANUP_ALL_EX_DATA
66 CRYPTO_cleanup_all_ex_data();
68 #ifdef HAVE_OPENSSL_THREAD_STOP /* openssl-1.1 or later */
69 OPENSSL_thread_stop();
70 #else /* openssl-1.0 */
71 ERR_remove_thread_state(NULL);
77 * The public key loading functions below were inspired by corresponding code
78 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
79 * Finland. However, not much of the original code remains.
82 static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
84 const unsigned char *p = buf, *end = buf + len;
92 bnsize = read_u32_be(p);
93 PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
101 bn = BN_bin2bn(p, bnsize, NULL);
108 #ifdef HAVE_OSSL_PARAM /* openssl-3 */
110 * Convert bignumns e and n to a pkey and context.
112 static int generate_public_pkey(struct asymmetric_key *pub,
113 const BIGNUM *e, const BIGNUM *n)
115 unsigned char *ebuf, *nbuf;
116 int ret, ebytes = BN_num_bytes(e), nbytes = BN_num_bytes(n);
117 OSSL_PARAM params[3];
119 /* Convert e and n to a buffer for OSSL_PARAM_construct_BN() */
120 ebuf = alloc(ebytes);
121 assert(BN_bn2nativepad(e, ebuf, ebytes) > 0);
122 nbuf = alloc(nbytes);
123 assert(BN_bn2nativepad(n, nbuf, nbytes) > 0);
124 /* Init params[] with {e,n}buf and create the pkey from it */
125 params[0] = OSSL_PARAM_construct_BN("e", ebuf, ebytes);
126 params[1] = OSSL_PARAM_construct_BN("n", nbuf, nbytes);
127 params[2] = OSSL_PARAM_construct_end();
128 pub->ctx = EVP_PKEY_CTX_new_from_name(NULL, "RSA", NULL);
130 assert(EVP_PKEY_fromdata_init(pub->ctx) > 0);
131 ret = EVP_PKEY_fromdata(pub->ctx, &pub->pkey, EVP_PKEY_PUBLIC_KEY,
136 EVP_PKEY_CTX_free(pub->ctx);
137 return openssl_perror("EVP_PKEY_fromdata()");
142 #endif /* HAVE_OSSL_PARAM */
144 static int read_public_key(const unsigned char *blob, size_t blen,
145 struct asymmetric_key *pub)
148 const unsigned char *p = blob, *end = blob + blen;
151 ret = read_bignum(p, end - p, &e);
155 ret = read_bignum(p, end - p, &n);
160 bits = BN_num_bytes(n) * 8;
161 PARA_DEBUG_LOG("modulus: %d bits\n", bits);
162 #ifdef HAVE_OSSL_PARAM /* openssl-3 */
163 ret = generate_public_pkey(pub, e, n);
168 #else /* openssl < 3.0 */
169 pub->rsa = RSA_new();
171 #if HAVE_RSA_SET0_KEY /* openssl-1.1 */
172 RSA_set0_key(pub->rsa, n, e, NULL);
173 #else /* openssl-1.0 */
177 /* e and n are now owned by openssl */
178 #endif /* HAVE_OSSL_PARAM */
182 static int read_pem_private_key(const char *path, struct asymmetric_key *priv)
187 assert((bio = BIO_new(BIO_s_file())));
189 if (BIO_read_filename(bio, path) <= 0)
191 pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
194 priv->rsa = EVP_PKEY_get1_RSA(pkey);
198 return priv->rsa? RSA_size(priv->rsa) : -E_PRIVATE_KEY;
201 static int read_openssh_private_key(const unsigned char *blob,
202 const unsigned char *end, struct asymmetric_key *priv)
206 BIGNUM *n, *e, *d, *iqmp, *p, *q; /* stored in the key file */
207 const unsigned char *cp = blob;
209 assert((rsa = RSA_new()));
210 ret = read_bignum(cp, end - cp, &n);
214 ret = read_bignum(cp, end - cp, &e);
218 ret = read_bignum(cp, end - cp, &d);
222 ret = read_bignum(cp, end - cp, &iqmp);
226 ret = read_bignum(cp, end - cp, &p);
230 ret = read_bignum(cp, end - cp, &q);
233 #ifdef HAVE_RSA_SET0_KEY
234 RSA_set0_key(rsa, n, e, d);
235 RSA_set0_factors(rsa, p, q);
236 RSA_set0_crt_params(rsa, NULL, NULL, iqmp);
263 static int get_private_key(const char *path, struct asymmetric_key *priv)
266 unsigned char *blob, *end;
270 ret = decode_private_key(path, &blob, &blob_size);
273 end = blob + blob_size;
274 if (ret == PKT_OPENSSH) {
275 ret = find_openssh_bignum_offset(blob, blob_size);
278 PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
279 ret = read_openssh_private_key(blob + ret, end, priv);
281 ret = read_pem_private_key(path, priv);
287 int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
292 struct asymmetric_key *pub;
294 ret = decode_public_key(key_file, &blob, &decoded_size);
297 pub = zalloc(sizeof(*pub)); /* ->pkey needs to start out zeroed */
298 ret = read_public_key(blob + ret, decoded_size - ret, pub);
303 PARA_ERROR_LOG("can not load key %s\n", key_file);
306 PARA_NOTICE_LOG("loaded %d bit key from %s\n", ret, key_file);
311 void apc_free_pubkey(struct asymmetric_key *pub)
315 #ifdef HAVE_OSSL_PARAM /* openssl-3 */
316 EVP_PKEY_CTX_free(pub->ctx);
317 EVP_PKEY_free(pub->pkey);
324 int apc_priv_decrypt(const char *key_file, unsigned char **outbuf,
325 unsigned char *inbuf, int inlen)
327 struct asymmetric_key *priv;
331 ret = check_private_key_file(key_file);
336 priv = alloc(sizeof(*priv));
337 ret = get_private_key(key_file, priv);
343 * RSA is vulnerable to timing attacks. Generate a random blinding
344 * factor to protect against this kind of attack.
347 if (RSA_blinding_on(priv->rsa, NULL) == 0)
349 *outbuf = alloc(RSA_size(priv->rsa));
350 ret = RSA_private_decrypt(inlen, inbuf, *outbuf, priv->rsa,
351 RSA_PKCS1_OAEP_PADDING);
352 RSA_blinding_off(priv->rsa);
364 int apc_pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
365 unsigned len, unsigned char **outbuf)
368 #ifdef HAVE_OSSL_PARAM /* openssl-3 */
373 assert((ctx = EVP_PKEY_CTX_new(pub->pkey, NULL)));
374 assert((EVP_PKEY_encrypt_init(ctx) > 0));
375 assert((EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) > 0));
376 if (EVP_PKEY_encrypt(ctx, NULL, &outlen, inbuf, len) <= 0) {
377 ret = openssl_perror("EVP_PKEY_encrypt()");
380 *outbuf = alloc(outlen);
381 assert((EVP_PKEY_encrypt(ctx, *outbuf, &outlen, inbuf, len) > 0));
382 PARA_INFO_LOG("wrote %zu encrypted data bytes\n", outlen);
385 EVP_PKEY_CTX_free(ctx);
387 #else /* openssl < 3.0 */
388 *outbuf = alloc(RSA_size(pub->rsa));
389 ret = RSA_public_encrypt((int)len, inbuf, *outbuf, pub->rsa,
390 RSA_PKCS1_OAEP_PADDING);
397 #endif /* HAVE_OSSL_PARAM */
400 struct stream_cipher {
404 struct stream_cipher *sc_new(const unsigned char *data, int len)
406 struct stream_cipher *sc = alloc(sizeof(*sc));
408 assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
409 assert((sc->aes = EVP_CIPHER_CTX_new()));
410 EVP_EncryptInit_ex(sc->aes, EVP_aes_128_ctr(), NULL, data,
411 data + AES_CRT128_BLOCK_SIZE);
415 void sc_free(struct stream_cipher *sc)
419 EVP_CIPHER_CTX_free(sc->aes);
423 static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
426 int ret, inlen = src->iov_len, outlen, tmplen;
428 *dst = (typeof(*dst)) {
429 /* Add one for the terminating zero byte. */
430 .iov_base = alloc(inlen + 1),
433 ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
435 ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
438 ((char *)dst->iov_base)[outlen] = '\0';
439 dst->iov_len = outlen;
442 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
444 return aes_ctr128_crypt(sc->aes, src, dst);
447 void hash_function(const char *data, unsigned long len, unsigned char *hash)
452 assert((c = EVP_MD_CTX_new()));
453 ret = EVP_DigestInit_ex(c, EVP_sha1(), NULL);
455 ret = EVP_DigestUpdate(c, data, len);
457 ret = EVP_DigestFinal_ex(c, hash, NULL);
462 void hash2_function(const char *data, unsigned long len, unsigned char *hash)
467 assert((c = EVP_MD_CTX_new()));
468 ret = EVP_DigestInit_ex(c, EVP_sha256(), NULL);
470 ret = EVP_DigestUpdate(c, data, len);
472 ret = EVP_DigestFinal_ex(c, hash, NULL);