2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file crypt.c Openssl-based encryption/decryption routines. */
10 #include <sys/types.h>
11 #include <sys/socket.h>
12 #include <openssl/rand.h>
13 #include <openssl/err.h>
14 #include <openssl/rc4.h>
15 #include <openssl/pem.h>
16 #include <openssl/sha.h>
17 #include <openssl/bn.h>
18 #include <openssl/aes.h>
25 #include "crypt_backend.h"
28 struct asymmetric_key
{
32 void get_random_bytes_or_die(unsigned char *buf
, int num
)
36 /* RAND_bytes() returns 1 on success, 0 otherwise. */
37 if (RAND_bytes(buf
, num
) == 1)
39 err
= ERR_get_error();
40 PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err
));
45 * Read 64 bytes from /dev/urandom and adds them to the SSL PRNG. Seed the PRNG
46 * used by random() with a random seed obtained from SSL. If /dev/random is not
47 * readable the function calls exit().
49 * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
50 * random(3), \ref para_random().
52 void init_random_seed_or_die(void)
54 int seed
, ret
= RAND_load_file("/dev/urandom", 64);
57 PARA_EMERG_LOG("could not seed PRNG (ret = %d)\n", ret
);
60 get_random_bytes_or_die((unsigned char *)&seed
, sizeof(seed
));
64 static EVP_PKEY
*load_key(const char *file
, int private)
67 EVP_PKEY
*pkey
= NULL
;
68 int ret
= check_key_file(file
, private);
71 PARA_ERROR_LOG("%s\n", para_strerror(-ret
));
74 key
= BIO_new(BIO_s_file());
77 if (BIO_read_filename(key
, file
) > 0) {
78 if (private == LOAD_PRIVATE_KEY
)
79 pkey
= PEM_read_bio_PrivateKey(key
, NULL
, NULL
, NULL
);
81 pkey
= PEM_read_bio_PUBKEY(key
, NULL
, NULL
, NULL
);
87 static int get_openssl_key(const char *key_file
, RSA
**rsa
, int private)
89 EVP_PKEY
*key
= load_key(key_file
, private);
92 return (private == LOAD_PRIVATE_KEY
)? -E_PRIVATE_KEY
94 *rsa
= EVP_PKEY_get1_RSA(key
);
98 return RSA_size(*rsa
);
102 * The public key loading functions below were inspired by corresponding code
103 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
104 * Finland. However, not much of the original code remains.
107 static int read_bignum(const unsigned char *buf
, size_t len
, BIGNUM
**result
)
109 const unsigned char *p
= buf
, *end
= buf
+ len
;
117 bnsize
= read_ssh_u32(p
);
118 PARA_DEBUG_LOG("bnsize: %u\n", bnsize
);
122 if (p
+ bnsize
> end
)
126 bn
= BN_bin2bn(p
, bnsize
, NULL
);
133 static int read_rsa_bignums(const unsigned char *blob
, int blen
, RSA
**result
)
138 const unsigned char *p
= blob
, *end
= blob
+ blen
;
143 ret
= read_bignum(p
, end
- p
, &e
);
147 ret
= read_bignum(p
, end
- p
, &n
);
150 #ifdef HAVE_RSA_SET0_KEY
151 RSA_set0_key(rsa
, n
, e
, NULL
);
163 int get_asymmetric_key(const char *key_file
, int private,
164 struct asymmetric_key
**result
)
166 struct asymmetric_key
*key
= NULL
;
168 unsigned char *blob
= NULL
;
169 size_t map_size
, encoded_size
, decoded_size
;
173 key
= para_malloc(sizeof(*key
));
175 ret
= get_openssl_key(key_file
, &key
->rsa
, LOAD_PRIVATE_KEY
);
178 ret
= mmap_full_file(key_file
, O_RDONLY
, &map
, &map_size
, NULL
);
181 ret
= is_ssh_rsa_key(map
, map_size
);
183 ret
= para_munmap(map
, map_size
);
187 ret
= get_openssl_key(key_file
, &key
->rsa
, LOAD_PUBLIC_KEY
);
191 encoded_size
= map_size
- ret
;
192 PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file
);
193 ret
= uudecode(cp
, encoded_size
, (char **)&blob
, &decoded_size
);
196 ret
= check_ssh_key_header(blob
, decoded_size
);
199 ret
= read_rsa_bignums(blob
+ ret
, decoded_size
- ret
, &key
->rsa
);
202 ret
= RSA_size(key
->rsa
);
204 ret2
= para_munmap(map
, map_size
);
205 if (ret
>= 0 && ret2
< 0)
211 PARA_ERROR_LOG("key %s: %s\n", key_file
, para_strerror(-ret
));
218 void free_asymmetric_key(struct asymmetric_key
*key
)
226 int priv_decrypt(const char *key_file
, unsigned char *outbuf
,
227 unsigned char *inbuf
, int inlen
)
229 struct asymmetric_key
*priv
;
234 ret
= get_asymmetric_key(key_file
, LOAD_PRIVATE_KEY
, &priv
);
238 * RSA is vulnerable to timing attacks. Generate a random blinding
239 * factor to protect against this kind of attack.
242 if (RSA_blinding_on(priv
->rsa
, NULL
) == 0)
244 ret
= RSA_private_decrypt(inlen
, inbuf
, outbuf
, priv
->rsa
,
245 RSA_PKCS1_OAEP_PADDING
);
246 RSA_blinding_off(priv
->rsa
);
250 free_asymmetric_key(priv
);
254 int pub_encrypt(struct asymmetric_key
*pub
, unsigned char *inbuf
,
255 unsigned len
, unsigned char *outbuf
)
257 int ret
, flen
= len
; /* RSA_public_encrypt expects a signed int */
261 ret
= RSA_public_encrypt(flen
, inbuf
, outbuf
, pub
->rsa
,
262 RSA_PKCS1_OAEP_PADDING
);
263 return ret
< 0? -E_ENCRYPT
: ret
;
266 struct stream_cipher
{
274 struct stream_cipher
*sc_new(const unsigned char *data
, int len
,
277 struct stream_cipher
*sc
= para_malloc(sizeof(*sc
));
279 sc
->use_aes
= use_aes
;
281 RC4_set_key(&sc
->context
.rc4_key
, len
, data
);
284 assert(len
>= 2 * AES_CRT128_BLOCK_SIZE
);
285 sc
->context
.aes
= EVP_CIPHER_CTX_new();
286 EVP_EncryptInit_ex(sc
->context
.aes
, EVP_aes_128_ctr(), NULL
, data
,
287 data
+ AES_CRT128_BLOCK_SIZE
);
291 void sc_free(struct stream_cipher
*sc
)
295 EVP_CIPHER_CTX_free(sc
->context
.aes
);
300 * The RC4() implementation of openssl apparently reads and writes data in
301 * blocks of 8 bytes. So we have to make sure our buffer sizes are a multiple
306 static void rc4_crypt(RC4_KEY
*key
, struct iovec
*src
, struct iovec
*dst
)
308 size_t len
= src
->iov_len
, l1
, l2
;
311 assert(len
< ((typeof(src
->iov_len
))-1) / 2);
312 l1
= ROUND_DOWN(len
, RC4_ALIGN
);
313 l2
= ROUND_UP(len
, RC4_ALIGN
);
315 *dst
= (typeof(*dst
)) {
316 /* Add one for the terminating zero byte. */
317 .iov_base
= para_malloc(l2
+ 1),
320 RC4(key
, l1
, src
->iov_base
, dst
->iov_base
);
322 unsigned char remainder
[RC4_ALIGN
] = "";
323 memcpy(remainder
, src
->iov_base
+ l1
, len
- l1
);
324 RC4(key
, len
- l1
, remainder
, dst
->iov_base
+ l1
);
326 ((char *)dst
->iov_base
)[len
] = '\0';
329 static void aes_ctr128_crypt(EVP_CIPHER_CTX
*ctx
, struct iovec
*src
,
332 int ret
, inlen
= src
->iov_len
, outlen
, tmplen
;
334 *dst
= (typeof(*dst
)) {
335 /* Add one for the terminating zero byte. */
336 .iov_base
= para_malloc(inlen
+ 1),
339 ret
= EVP_EncryptUpdate(ctx
, dst
->iov_base
, &outlen
, src
->iov_base
, inlen
);
341 ret
= EVP_EncryptFinal_ex(ctx
, dst
->iov_base
+ outlen
, &tmplen
);
344 ((char *)dst
->iov_base
)[outlen
] = '\0';
345 dst
->iov_len
= outlen
;
348 void sc_crypt(struct stream_cipher
*sc
, struct iovec
*src
, struct iovec
*dst
)
351 return aes_ctr128_crypt(sc
->context
.aes
, src
, dst
);
352 return rc4_crypt(&sc
->context
.rc4_key
, src
, dst
);
355 void hash_function(const char *data
, unsigned long len
, unsigned char *hash
)
359 SHA1_Update(&c
, data
, len
);
360 SHA1_Final(hash
, &c
);