610d2057947dba6757526127a317f8b87bf7eebc
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"
27 struct asymmetric_key
{
31 void get_random_bytes_or_die(unsigned char *buf
, int num
)
35 /* RAND_bytes() returns 1 on success, 0 otherwise. */
36 if (RAND_bytes(buf
, num
) == 1)
38 err
= ERR_get_error();
39 PARA_EMERG_LOG("%s\n", ERR_reason_error_string(err
));
44 * Read 64 bytes from /dev/urandom and adds them to the SSL PRNG. Seed the PRNG
45 * used by random() with a random seed obtained from SSL. If /dev/random is not
46 * readable the function calls exit().
48 * \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
49 * random(3), \ref para_random().
51 void init_random_seed_or_die(void)
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 static EVP_PKEY
*load_key(const char *file
, int private)
66 EVP_PKEY
*pkey
= NULL
;
67 int ret
= check_key_file(file
, private);
70 PARA_ERROR_LOG("%s\n", para_strerror(-ret
));
73 key
= BIO_new(BIO_s_file());
76 if (BIO_read_filename(key
, file
) > 0) {
77 if (private == LOAD_PRIVATE_KEY
)
78 pkey
= PEM_read_bio_PrivateKey(key
, NULL
, NULL
, NULL
);
80 pkey
= PEM_read_bio_PUBKEY(key
, NULL
, NULL
, NULL
);
86 static int get_openssl_key(const char *key_file
, RSA
**rsa
, int private)
88 EVP_PKEY
*key
= load_key(key_file
, private);
91 return (private == LOAD_PRIVATE_KEY
)? -E_PRIVATE_KEY
93 *rsa
= EVP_PKEY_get1_RSA(key
);
97 return RSA_size(*rsa
);
101 * The public key loading functions below were inspired by corresponding code
102 * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
103 * Finland. However, not much of the original code remains.
106 static int read_bignum(const unsigned char *buf
, size_t len
, BIGNUM
**result
)
108 const unsigned char *p
= buf
, *end
= buf
+ len
;
116 bnsize
= read_ssh_u32(p
);
117 PARA_DEBUG_LOG("bnsize: %u\n", bnsize
);
121 if (p
+ bnsize
> end
)
125 bn
= BN_bin2bn(p
, bnsize
, NULL
);
132 static int read_rsa_bignums(const unsigned char *blob
, int blen
, RSA
**result
)
136 const unsigned char *p
= blob
, *end
= blob
+ blen
;
141 ret
= read_bignum(p
, end
- p
, &rsa
->e
);
145 ret
= read_bignum(p
, end
- p
, &rsa
->n
);
155 int get_asymmetric_key(const char *key_file
, int private,
156 struct asymmetric_key
**result
)
158 struct asymmetric_key
*key
= NULL
;
160 unsigned char *blob
= NULL
;
161 size_t map_size
, blob_size
, decoded_size
;
165 key
= para_malloc(sizeof(*key
));
167 ret
= get_openssl_key(key_file
, &key
->rsa
, LOAD_PRIVATE_KEY
);
170 ret
= mmap_full_file(key_file
, O_RDONLY
, &map
, &map_size
, NULL
);
173 ret
= is_ssh_rsa_key(map
, map_size
);
175 ret
= para_munmap(map
, map_size
);
179 ret
= get_openssl_key(key_file
, &key
->rsa
, LOAD_PUBLIC_KEY
);
183 PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file
);
184 ret
= -ERRNO_TO_PARA_ERROR(EOVERFLOW
);
185 if (map_size
> INT_MAX
/ 4)
187 blob_size
= 2 * map_size
;
188 blob
= para_malloc(blob_size
);
189 ret
= uudecode(cp
, blob
, blob_size
);
193 ret
= check_ssh_key_header(blob
, decoded_size
);
196 ret
= read_rsa_bignums(blob
+ ret
, decoded_size
- ret
, &key
->rsa
);
199 ret
= RSA_size(key
->rsa
);
201 ret2
= para_munmap(map
, map_size
);
202 if (ret
>= 0 && ret2
< 0)
208 PARA_ERROR_LOG("key %s: %s\n", key_file
, para_strerror(-ret
));
215 void free_asymmetric_key(struct asymmetric_key
*key
)
223 int priv_decrypt(const char *key_file
, unsigned char *outbuf
,
224 unsigned char *inbuf
, int inlen
)
226 struct asymmetric_key
*priv
;
231 ret
= get_asymmetric_key(key_file
, LOAD_PRIVATE_KEY
, &priv
);
235 * RSA is vulnerable to timing attacks. Generate a random blinding
236 * factor to protect against this kind of attack.
239 if (RSA_blinding_on(priv
->rsa
, NULL
) == 0)
241 ret
= RSA_private_decrypt(inlen
, inbuf
, outbuf
, priv
->rsa
,
242 RSA_PKCS1_OAEP_PADDING
);
243 RSA_blinding_off(priv
->rsa
);
247 free_asymmetric_key(priv
);
251 int pub_encrypt(struct asymmetric_key
*pub
, unsigned char *inbuf
,
252 unsigned len
, unsigned char *outbuf
)
254 int ret
, flen
= len
; /* RSA_public_encrypt expects a signed int */
258 ret
= RSA_public_encrypt(flen
, inbuf
, outbuf
, pub
->rsa
,
259 RSA_PKCS1_OAEP_PADDING
);
260 return ret
< 0? -E_ENCRYPT
: ret
;
263 struct aes_ctr_128_context
{
265 unsigned char ivec
[AES_CRT128_BLOCK_SIZE
];
266 unsigned char ecount
[AES_CRT128_BLOCK_SIZE
];
270 struct stream_cipher
{
274 struct aes_ctr_128_context aes
;
278 struct stream_cipher
*sc_new(const unsigned char *data
, int len
,
282 struct stream_cipher
*sc
= para_malloc(sizeof(*sc
));
283 struct aes_ctr_128_context
*aes
;
285 sc
->use_aes
= use_aes
;
287 RC4_set_key(&sc
->context
.rc4_key
, len
, data
);
290 assert(len
>= 2 * AES_CRT128_BLOCK_SIZE
);
291 aes
= &sc
->context
.aes
;
292 ret
= AES_set_encrypt_key(data
, AES_CRT128_BLOCK_SIZE
* 8 /* bits */,
295 memcpy(aes
->ivec
, data
+ AES_CRT128_BLOCK_SIZE
, AES_CRT128_BLOCK_SIZE
);
300 void sc_free(struct stream_cipher
*sc
)
306 * The RC4() implementation of openssl apparently reads and writes data in
307 * blocks of 8 bytes. So we have to make sure our buffer sizes are a multiple
312 static void rc4_crypt(RC4_KEY
*key
, struct iovec
*src
, struct iovec
*dst
)
314 size_t len
= src
->iov_len
, l1
, l2
;
317 assert(len
< ((typeof(src
->iov_len
))-1) / 2);
318 l1
= ROUND_DOWN(len
, RC4_ALIGN
);
319 l2
= ROUND_UP(len
, RC4_ALIGN
);
321 *dst
= (typeof(*dst
)) {
322 /* Add one for the terminating zero byte. */
323 .iov_base
= para_malloc(l2
+ 1),
326 RC4(key
, l1
, src
->iov_base
, dst
->iov_base
);
328 unsigned char remainder
[RC4_ALIGN
] = "";
329 memcpy(remainder
, src
->iov_base
+ l1
, len
- l1
);
330 RC4(key
, len
- l1
, remainder
, dst
->iov_base
+ l1
);
332 ((char *)dst
->iov_base
)[len
] = '\0';
335 static void aes_ctr128_crypt(struct aes_ctr_128_context
*aes
, struct iovec
*src
,
338 size_t len
= src
->iov_len
;
340 *dst
= (typeof(*dst
)) {
341 /* Add one for the terminating zero byte. */
342 .iov_base
= para_malloc(len
+ 1),
345 AES_ctr128_encrypt(src
->iov_base
, dst
->iov_base
, len
,
346 &aes
->key
, aes
->ivec
, aes
->ecount
, &aes
->num
);
347 ((char *)dst
->iov_base
)[len
] = '\0';
350 void sc_crypt(struct stream_cipher
*sc
, struct iovec
*src
, struct iovec
*dst
)
353 return aes_ctr128_crypt(&sc
->context
.aes
, src
, dst
);
354 return rc4_crypt(&sc
->context
.rc4_key
, src
, dst
);
357 void hash_function(const char *data
, unsigned long len
, unsigned char *hash
)
361 SHA1_Update(&c
, data
, len
);
362 SHA1_Final(hash
, &c
);