/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
* Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* @file Data Channel Cryptography OpenSSL-specific backend interface
*/
#include "syshead.h"
#if defined(USE_CRYPTO) && defined(USE_OPENSSL)
#include "basic.h"
#include "buffer.h"
#include "integer.h"
#include "crypto_backend.h"
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/des.h>
/*
* Check for key size creepage.
*/
#if MAX_CIPHER_KEY_LENGTH < EVP_MAX_KEY_LENGTH
#warning Some OpenSSL EVP ciphers now support key lengths greater than MAX_CIPHER_KEY_LENGTH -- consider increasing MAX_CIPHER_KEY_LENGTH
#endif
#if MAX_HMAC_KEY_LENGTH < EVP_MAX_MD_SIZE
#warning Some OpenSSL HMAC message digests now support key lengths greater than MAX_HMAC_KEY_LENGTH -- consider increasing MAX_HMAC_KEY_LENGTH
#endif
/*
*
* Workarounds for incompatibilites between OpenSSL libraries.
* Right now we accept OpenSSL libraries from 0.9.5 to 0.9.7.
*
*/
#if SSLEAY_VERSION_NUMBER < 0x00907000L
/* Workaround: EVP_CIPHER_mode is defined wrong in OpenSSL 0.9.6 but is fixed in 0.9.7 */
#undef EVP_CIPHER_mode
#define EVP_CIPHER_mode(e) (((e)->flags) & EVP_CIPH_MODE)
#define DES_cblock des_cblock
#define DES_is_weak_key des_is_weak_key
#define DES_check_key_parity des_check_key_parity
#define DES_set_odd_parity des_set_odd_parity
#define HMAC_CTX_init(ctx) CLEAR (*ctx)
#define HMAC_Init_ex(ctx,sec,len,md,impl) HMAC_Init(ctx, sec, len, md)
#define HMAC_CTX_cleanup(ctx) HMAC_cleanup(ctx)
#define EVP_MD_CTX_cleanup(md) CLEAR (*md)
#define INFO_CALLBACK_SSL_CONST
#endif
#if SSLEAY_VERSION_NUMBER < 0x00906000
#undef EVP_CIPHER_mode
#define EVP_CIPHER_mode(x) 1
#define EVP_CIPHER_CTX_mode(x) 1
#define EVP_CIPHER_flags(x) 0
#define EVP_CIPH_CBC_MODE 1
#define EVP_CIPH_CFB_MODE 0
#define EVP_CIPH_OFB_MODE 0
#define EVP_CIPH_VARIABLE_LENGTH 0
#define OPENSSL_malloc(x) malloc(x)
#define OPENSSL_free(x) free(x)
static inline int
EVP_CipherInit_ov (EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, uint8_t *key, uint8_t *iv, int enc)
{
EVP_CipherInit (ctx, type, key, iv, enc);
return 1;
}
static inline int
EVP_CipherUpdate_ov (EVP_CIPHER_CTX *ctx, uint8_t *out, int *outl, uint8_t *in, int inl)
{
EVP_CipherUpdate (ctx, out, outl, in, inl);
return 1;
}
static inline bool
cipher_ok (const char* name)
{
const int i = strlen (name) - 4;
if (i >= 0)
return !strcmp (name + i, "-CBC");
else
return false;
}
#else
static inline int
EVP_CipherInit_ov (EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, uint8_t *key, uint8_t *iv, int enc)
{
return EVP_CipherInit (ctx, type, key, iv, enc);
}
static inline int
EVP_CipherUpdate_ov (EVP_CIPHER_CTX *ctx, uint8_t *out, int *outl, uint8_t *in, int inl)
{
return EVP_CipherUpdate (ctx, out, outl, in, inl);
}
static inline bool
cipher_ok (const char* name)
{
return true;
}
#endif
#if SSLEAY_VERSION_NUMBER < 0x0090581f
#undef DES_check_key_parity
#define DES_check_key_parity(x) 1
#endif /* SSLEAY_VERSION_NUMBER < 0x0090581f */
#ifndef EVP_CIPHER_name
#define EVP_CIPHER_name(e) OBJ_nid2sn(EVP_CIPHER_nid(e))
#endif
#ifndef EVP_MD_name
#define EVP_MD_name(e) OBJ_nid2sn(EVP_MD_type(e))
#endif
/*
*
* OpenSSL engine support. Allows loading/unloading of engines.
*
*/
#if defined(HAVE_OPENSSL_ENGINE_H) && defined(HAVE_ENGINE_LOAD_BUILTIN_ENGINES) && defined(HAVE_ENGINE_REGISTER_ALL_COMPLETE) && defined(HAVE_ENGINE_CLEANUP)
#define CRYPTO_ENGINE 1
#else
#define CRYPTO_ENGINE 0
#endif
#if CRYPTO_ENGINE
#include <openssl/engine.h>
static bool engine_initialized = false; /* GLOBAL */
static ENGINE *engine_persist = NULL; /* GLOBAL */
/* Try to load an engine in a shareable library */
static ENGINE *
try_load_engine (const char *engine)
{
ENGINE *e = ENGINE_by_id ("dynamic");
if (e)
{
if (!ENGINE_ctrl_cmd_string (e, "SO_PATH", engine, 0)
|| !ENGINE_ctrl_cmd_string (e, "LOAD", NULL, 0))
{
ENGINE_free (e);
e = NULL;
}
}
return e;
}
static ENGINE *
setup_engine (const char *engine)
{
ENGINE *e = NULL;
ENGINE_load_builtin_engines ();
if (engine)
{
if (strcmp (engine, "auto") == 0)
{
msg (M_INFO, "Initializing OpenSSL auto engine support");
ENGINE_register_all_complete ();
return NULL;
}
if ((e = ENGINE_by_id (engine)) == NULL
&& (e = try_load_engine (engine)) == NULL)
{
msg (M_FATAL, "OpenSSL error: cannot load engine '%s'", engine);
}
if (!ENGINE_set_default (e, ENGINE_METHOD_ALL))
{
msg (M_FATAL, "OpenSSL error: ENGINE_set_default failed on engine '%s'",
engine);
}
msg (M_INFO, "Initializing OpenSSL support for engine '%s'",
ENGINE_get_id (e));
}
return e;
}
#endif /* CRYPTO_ENGINE */
void
crypto_init_lib_engine (const char *engine_name)
{
#if CRYPTO_ENGINE
if (!engine_initialized)
{
ASSERT (engine_name);
ASSERT (!engine_persist);
engine_persist = setup_engine (engine_name);
engine_initialized = true;
}
#else
msg (M_WARN, "Note: OpenSSL hardware crypto engine functionality is not available");
#endif
}
/*
*
* Functions related to the core crypto library
*
*/
void
crypto_init_lib (void)
{
/*
* If you build the OpenSSL library and OpenVPN with
* CRYPTO_MDEBUG, you will get a listing of OpenSSL
* memory leaks on program termination.
*/
#ifdef CRYPTO_MDEBUG
CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON);
#endif
}
void
crypto_uninit_lib (void)
{
#ifdef CRYPTO_MDEBUG
FILE* fp = fopen ("sdlog", "w");
ASSERT (fp);
CRYPTO_mem_leaks_fp (fp);
fclose (fp);
#endif
#if CRYPTO_ENGINE
if (engine_initialized)
{
ENGINE_cleanup ();
engine_persist = NULL;
engine_initialized = false;
}
#endif
}
void
crypto_clear_error (void)
{
ERR_clear_error ();
}
/*
*
* OpenSSL memory debugging. If dmalloc debugging is enabled, tell
* OpenSSL to use our private malloc/realloc/free functions so that
* we can dispatch them to dmalloc.
*
*/
#ifdef DMALLOC
static void *
crypto_malloc (size_t size, const char *file, int line)
{
return dmalloc_malloc(file, line, size, DMALLOC_FUNC_MALLOC, 0, 0);
}
static void *
crypto_realloc (void *ptr, size_t size, const char *file, int line)
{
return dmalloc_realloc(file, line, ptr, size, DMALLOC_FUNC_REALLOC, 0);
}
static void
crypto_free (void *ptr)
{
dmalloc_free (__FILE__, __LINE__, ptr, DMALLOC_FUNC_FREE);
}
void
crypto_init_dmalloc (void)
{
CRYPTO_set_mem_ex_functions (crypto_malloc,
crypto_realloc,
crypto_free);
}
#endif /* DMALLOC */
void
show_available_ciphers ()
{
int nid;
#ifndef ENABLE_SMALL
printf ("The following ciphers and cipher modes are available\n"
"for use with " PACKAGE_NAME ". Each cipher shown below may be\n"
"used as a parameter to the --cipher option. The default\n"
"key size is shown as well as whether or not it can be\n"
"changed with the --keysize directive. Using a CBC mode\n"
"is recommended.\n\n");
#endif
for (nid = 0; nid < 10000; ++nid) /* is there a better way to get the size of the nid list? */
{
const EVP_CIPHER *cipher = EVP_get_cipherbynid (nid);
if (cipher && cipher_ok (OBJ_nid2sn (nid)))
{
const unsigned int mode = EVP_CIPHER_mode (cipher);
if (mode == EVP_CIPH_CBC_MODE
#ifdef ALLOW_NON_CBC_CIPHERS
|| mode == EVP_CIPH_CFB_MODE || mode == EVP_CIPH_OFB_MODE
#endif
)
printf ("%s %d bit default key (%s)\n",
OBJ_nid2sn (nid),
EVP_CIPHER_key_length (cipher) * 8,
((EVP_CIPHER_flags (cipher) & EVP_CIPH_VARIABLE_LENGTH) ?
"variable" : "fixed"));
}
}
printf ("\n");
}
void
show_available_digests ()
{
int nid;
#ifndef ENABLE_SMALL
printf ("The following message digests are available for use with\n"
PACKAGE_NAME ". A message digest is used in conjunction with\n"
"the HMAC function, to authenticate received packets.\n"
"You can specify a message digest as parameter to\n"
"the --auth option.\n\n");
#endif
for (nid = 0; nid < 10000; ++nid)
{
const EVP_MD *digest = EVP_get_digestbynid (nid);
if (digest)
{
printf ("%s %d bit digest size\n",
OBJ_nid2sn (nid), EVP_MD_size (digest) * 8);
}
}
printf ("\n");
}
void
show_available_engines ()
{
#if CRYPTO_ENGINE /* Only defined for OpenSSL */
ENGINE *e;
printf ("OpenSSL Crypto Engines\n\n");
ENGINE_load_builtin_engines ();
e = ENGINE_get_first ();
while (e)
{
printf ("%s [%s]\n",
ENGINE_get_name (e),
ENGINE_get_id (e));
e = ENGINE_get_next (e);
}
ENGINE_cleanup ();
#else
printf ("Sorry, OpenSSL hardware crypto engine functionality is not available.\n");
#endif
}
/*
*
* Random number functions, used in cases where we want
* reasonably strong cryptographic random number generation
* without depleting our entropy pool. Used for random
* IV values and a number of other miscellaneous tasks.
*
*/
int rand_bytes(uint8_t *output, int len)
{
return RAND_bytes (output, len);
}
/*
*
* Key functions, allow manipulation of keys.
*
*/
int
key_des_num_cblocks (const EVP_CIPHER *kt)
{
int ret = 0;
const char *name = OBJ_nid2sn (EVP_CIPHER_nid (kt));
if (name)
{
if (!strncmp (name, "DES-", 4))
{
ret = EVP_CIPHER_key_length (kt) / sizeof (DES_cblock);
}
else if (!strncmp (name, "DESX-", 5))
{
ret = 1;
}
}
dmsg (D_CRYPTO_DEBUG, "CRYPTO INFO: n_DES_cblocks=%d", ret);
return ret;
}
bool
key_des_check (uint8_t *key, int key_len, int ndc)
{
int i;
struct buffer b;
buf_set_read (&b, key, key_len);
for (i = 0; i < ndc; ++i)
{
DES_cblock *dc = (DES_cblock*) buf_read_alloc (&b, sizeof (DES_cblock));
if (!dc)
{
msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: insufficient key material");
goto err;
}
if (DES_is_weak_key(dc))
{
msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: weak key detected");
goto err;
}
if (!DES_check_key_parity (dc))
{
msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: bad parity detected");
goto err;
}
}
return true;
err:
ERR_clear_error ();
return false;
}
void
key_des_fixup (uint8_t *key, int key_len, int ndc)
{
int i;
struct buffer b;
buf_set_read (&b, key, key_len);
for (i = 0; i < ndc; ++i)
{
DES_cblock *dc = (DES_cblock*) buf_read_alloc(&b, sizeof(DES_cblock));
if (!dc)
{
msg (D_CRYPT_ERRORS, "CRYPTO INFO: fixup_key_DES: insufficient key material");
ERR_clear_error ();
return;
}
DES_set_odd_parity (dc);
}
}
/*
*
* Generic cipher key type functions
*
*/
const EVP_CIPHER *
cipher_kt_get (const char *ciphername)
{
const EVP_CIPHER *cipher = NULL;
ASSERT (ciphername);
cipher = EVP_get_cipherbyname (ciphername);
if ((NULL == cipher) || !cipher_ok (OBJ_nid2sn (EVP_CIPHER_nid (cipher))))
msg (M_SSLERR, "Cipher algorithm '%s' not found", ciphername);
if (EVP_CIPHER_key_length (cipher) > MAX_CIPHER_KEY_LENGTH)
msg (M_FATAL, "Cipher algorithm '%s' uses a default key size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum key size (%d bytes)",
ciphername,
EVP_CIPHER_key_length (cipher),
MAX_CIPHER_KEY_LENGTH);
return cipher;
}
const char *
cipher_kt_name (const EVP_CIPHER *cipher_kt)
{
if (NULL == cipher_kt)
return "[null-cipher]";
return EVP_CIPHER_name (cipher_kt);
}
int
cipher_kt_key_size (const EVP_CIPHER *cipher_kt)
{
return EVP_CIPHER_key_length (cipher_kt);
}
int
cipher_kt_iv_size (const EVP_CIPHER *cipher_kt)
{
return EVP_CIPHER_iv_length (cipher_kt);
}
int
cipher_kt_block_size (const EVP_CIPHER *cipher_kt)
{
return EVP_CIPHER_block_size (cipher_kt);
}
int
cipher_kt_mode (const EVP_CIPHER *cipher_kt)
{
ASSERT(NULL != cipher_kt);
return EVP_CIPHER_mode (cipher_kt);
}
/*
*
* Generic cipher context functions
*
*/
void
cipher_ctx_init (EVP_CIPHER_CTX *ctx, uint8_t *key, int key_len,
const EVP_CIPHER *kt, int enc)
{
ASSERT(NULL != kt && NULL != ctx);
CLEAR (*ctx);
EVP_CIPHER_CTX_init (ctx);
if (!EVP_CipherInit_ov (ctx, kt, NULL, NULL, enc))
msg (M_SSLERR, "EVP cipher init #1");
#ifdef HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH
if (!EVP_CIPHER_CTX_set_key_length (ctx, key_len))
msg (M_SSLERR, "EVP set key size");
#endif
if (!EVP_CipherInit_ov (ctx, NULL, key, NULL, enc))
msg (M_SSLERR, "EVP cipher init #2");
/* make sure we used a big enough key */
ASSERT (EVP_CIPHER_CTX_key_length (ctx) <= key_len);
}
void
cipher_ctx_cleanup (EVP_CIPHER_CTX *ctx)
{
EVP_CIPHER_CTX_cleanup (ctx);
}
int
cipher_ctx_iv_length (const EVP_CIPHER_CTX *ctx)
{
return EVP_CIPHER_CTX_iv_length (ctx);
}
int
cipher_ctx_block_size(const EVP_CIPHER_CTX *ctx)
{
return EVP_CIPHER_CTX_block_size (ctx);
}
int
cipher_ctx_mode (const EVP_CIPHER_CTX *ctx)
{
return EVP_CIPHER_CTX_mode (ctx);
}
int
cipher_ctx_reset (EVP_CIPHER_CTX *ctx, uint8_t *iv_buf)
{
return EVP_CipherInit_ov (ctx, NULL, NULL, iv_buf, -1);
}
int
cipher_ctx_update (EVP_CIPHER_CTX *ctx, uint8_t *dst, int *dst_len,
uint8_t *src, int src_len)
{
return EVP_CipherUpdate_ov (ctx, dst, dst_len, src, src_len);
}
int
cipher_ctx_final (EVP_CIPHER_CTX *ctx, uint8_t *dst, int *dst_len)
{
return EVP_CipherFinal (ctx, dst, dst_len);
}
void
cipher_des_encrypt_ecb (const unsigned char key[DES_KEY_LENGTH],
unsigned char *src,
unsigned char *dst)
{
DES_key_schedule sched;
DES_set_key_unchecked((DES_cblock*)key, &sched);
DES_ecb_encrypt((DES_cblock *)src, (DES_cblock *)dst, &sched, DES_ENCRYPT);
}
/*
*
* Generic message digest information functions
*
*/
const EVP_MD *
md_kt_get (const char *digest)
{
const EVP_MD *md = NULL;
ASSERT (digest);
md = EVP_get_digestbyname (digest);
if (!md)
msg (M_SSLERR, "Message hash algorithm '%s' not found", digest);
if (EVP_MD_size (md) > MAX_HMAC_KEY_LENGTH)
msg (M_FATAL, "Message hash algorithm '%s' uses a default hash size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum hash size (%d bytes)",
digest,
EVP_MD_size (md),
MAX_HMAC_KEY_LENGTH);
return md;
}
const char *
md_kt_name (const EVP_MD *kt)
{
if (NULL == kt)
return "[null-digest]";
return EVP_MD_name (kt);
}
int
md_kt_size (const EVP_MD *kt)
{
return EVP_MD_size(kt);
}
/*
*
* Generic message digest functions
*
*/
int
md_full (const EVP_MD *kt, const uint8_t *src, int src_len, uint8_t *dst)
{
unsigned int in_md_len = 0;
return EVP_Digest(src, src_len, dst, &in_md_len, kt, NULL);
}
void
md_ctx_init (EVP_MD_CTX *ctx, const EVP_MD *kt)
{
ASSERT(NULL != ctx && NULL != kt);
CLEAR (*ctx);
EVP_MD_CTX_init (ctx);
EVP_DigestInit(ctx, kt);
}
void
md_ctx_cleanup(EVP_MD_CTX *ctx)
{
EVP_MD_CTX_cleanup(ctx);
}
int
md_ctx_size (const EVP_MD_CTX *ctx)
{
return EVP_MD_CTX_size(ctx);
}
void
md_ctx_update (EVP_MD_CTX *ctx, const uint8_t *src, int src_len)
{
EVP_DigestUpdate(ctx, src, src_len);
}
void
md_ctx_final (EVP_MD_CTX *ctx, uint8_t *dst)
{
unsigned int in_md_len = 0;
EVP_DigestFinal(ctx, dst, &in_md_len);
}
/*
*
* Generic HMAC functions
*
*/
void
hmac_ctx_init (HMAC_CTX *ctx, const uint8_t *key, int key_len,
const EVP_MD *kt)
{
ASSERT(NULL != kt && NULL != ctx);
CLEAR(*ctx);
HMAC_CTX_init (ctx);
HMAC_Init_ex (ctx, key, key_len, kt, NULL);
/* make sure we used a big enough key */
ASSERT (HMAC_size (ctx) <= key_len);
}
void
hmac_ctx_cleanup(HMAC_CTX *ctx)
{
HMAC_CTX_cleanup (ctx);
}
int
hmac_ctx_size (const HMAC_CTX *ctx)
{
return HMAC_size (ctx);
}
void
hmac_ctx_reset (HMAC_CTX *ctx)
{
HMAC_Init_ex (ctx, NULL, 0, NULL, NULL);
}
void
hmac_ctx_update (HMAC_CTX *ctx, const uint8_t *src, int src_len)
{
HMAC_Update (ctx, src, src_len);
}
void
hmac_ctx_final (HMAC_CTX *ctx, uint8_t *dst)
{
unsigned int in_hmac_len = 0;
HMAC_Final (ctx, dst, &in_hmac_len);
}
#endif /* USE_CRYPTO && USE_OPENSSL */