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Drop keyschedule support

Browse Source 
- Legacy features are now moved to the legacy directory with readme
- Keyschedule feature is not supported anymore
This commit is contained in:
emanuele-f 2019-04-27 12:42:06 +02:00
parent e757f94efa
commit f577d997a7
12 changed files with 1351 additions and 160 deletions
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20
android/edge_android.c
View File

@ -137,6 +137,7 @@ static int scan_address(char * ip_addr, size_t addr_size,
/* *************************************************** */
//TODO use new API
int start_edge(const n2n_edge_cmd_t* cmd)
{
int keep_on_running = 0;
@ -177,13 +178,7 @@ int start_edge(const n2n_edge_cmd_t* cmd)
return 1;
}
eee.device.fd = cmd->vpn_fd;
if (cmd->enc_key_file)
{
strncpy(eee.keyschedule, cmd->enc_key_file, N2N_PATHNAME_MAXLEN-1);
eee.keyschedule[N2N_PATHNAME_MAXLEN-1]=0; /* strncpy does not add NULL if the source has no NULL. */
traceEvent(TRACE_DEBUG, "keyfile = '%s'\n", eee.keyschedule);
}
else if (cmd->enc_key)
if (cmd->enc_key)
{
encrypt_key = strdup(cmd->enc_key);
traceEvent(TRACE_DEBUG, "encrypt_key = '%s'\n", encrypt_key);
@ -242,7 +237,7 @@ int start_edge(const n2n_edge_cmd_t* cmd)
traceEvent(TRACE_NORMAL, "supernode %u => %s\n", i, (eee.sn_ip_array[i]));
}
supernode2addr(&(eee.supernode), eee.sn_ip_array[eee.sn_idx]);
if (encrypt_key == NULL && strlen(eee.keyschedule) == 0)
if (encrypt_key == NULL)
{
traceEvent(TRACE_WARNING, "Encryption is disabled in edge.");
eee.null_transop = 1;
@ -277,15 +272,6 @@ int start_edge(const n2n_edge_cmd_t* cmd)
free(encrypt_key);
encrypt_key = NULL;
}
else if (strlen(eee.keyschedule) > 0)
{
if (edge_init_keyschedule(&eee) != 0)
{
traceEvent(TRACE_ERROR, "keyschedule setup failed.\n");
free(encrypt_key);
return 1;
}
}
/* else run in NULL mode */
eee.udp_sock = open_socket(local_port, 1 /*bind ANY*/ );
if(eee.udp_sock < 0)

31
edge.c
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@ -143,7 +143,6 @@ static void help() {
printf("-a <mode:address> | Set interface address. For DHCP use '-r -a dhcp:0.0.0.0'\n");
printf("-c <community> | n2n community name the edge belongs to.\n");
printf("-k <encrypt key> | Encryption key (ASCII) - also N2N_KEY=<encrypt key>. Not with -K.\n");
printf("-K <key file> | Specify a key schedule file to load. Not with -k.\n");
printf("-s <netmask> | Edge interface netmask in dotted decimal notation (255.255.255.0).\n");
printf("-l <supernode host:port> | Supernode IP:port\n");
printf("-b | Periodically resolve supernode IP\n");
@ -179,21 +178,6 @@ static int setOption(int optkey, char *optargument, n2n_priv_config_t *ec, n2n_e
/* traceEvent(TRACE_NORMAL, "Option %c = %s", optkey, optargument ? optargument : ""); */
switch(optkey) {
case'K':
{
if(conf->encrypt_key) {
traceEvent(TRACE_ERROR, "Error: -K and -k options are mutually exclusive");
exit(1);
} else {
strncpy(conf->keyschedule, optargument, N2N_PATHNAME_MAXLEN-1);
/* strncpy does not add NULL if the source has no NULL. */
conf->keyschedule[N2N_PATHNAME_MAXLEN-1] = 0;
traceEvent(TRACE_NORMAL, "keyfile = '%s'\n", conf->keyschedule);
}
break;
}
case 'a': /* IP address and mode of TUNTAP interface */
{
scan_address(ec->ip_addr, N2N_NETMASK_STR_SIZE,
@ -252,14 +236,9 @@ static int setOption(int optkey, char *optargument, n2n_priv_config_t *ec, n2n_e
case 'k': /* encrypt key */
{
if(strlen(conf->keyschedule) > 0) {
traceEvent(TRACE_ERROR, "-K and -k options are mutually exclusive");
exit(1);
} else {
if(conf->encrypt_key) free(conf->encrypt_key);
conf->encrypt_key = strdup(optargument);
traceEvent(TRACE_DEBUG, "encrypt_key = '%s'\n", conf->encrypt_key);
}
if(conf->encrypt_key) free(conf->encrypt_key);
conf->encrypt_key = strdup(optargument);
traceEvent(TRACE_DEBUG, "encrypt_key = '%s'\n", conf->encrypt_key);
break;
}
@ -557,7 +536,7 @@ static void daemonize() {
/* *************************************************** */
void edge_conf_init_defaults(n2n_edge_conf_t *conf) {
void edge_init_conf_defaults(n2n_edge_conf_t *conf) {
memset(conf, 0, sizeof(*conf));
conf->local_port = 0 /* any port */;
@ -584,7 +563,7 @@ int main(int argc, char* argv[]) {
help();
/* Defaults */
edge_conf_init_defaults(&conf);
edge_init_conf_defaults(&conf);
ec.mtu = DEFAULT_MTU;
ec.daemon = 1; /* By default run in daemon mode. */
#ifndef WIN32

97
edge_utils.c
View File

@ -59,7 +59,6 @@ static void check_peer(n2n_edge_t * eee,
const n2n_mac_t mac,
const n2n_sock_t * peer);
static int edge_init_sockets(n2n_edge_t *eee, int udp_local_port, int mgmt_port);
static int edge_init_keyschedule(n2n_edge_t * eee);
/* ************************************** */
@ -162,7 +161,7 @@ n2n_edge_t* edge_init(const tuntap_dev *dev, const n2n_edge_conf_t *conf, int *r
supernode2addr(&(eee->supernode), conf->sn_ip_array[eee->sn_idx]);
/* Set active transop */
if((conf->encrypt_key == NULL) && (strlen(eee->conf.keyschedule) == 0))
if(conf->encrypt_key == NULL)
transop_id = N2N_TRANSFORM_ID_NULL;
switch(transop_id) {
@ -745,21 +744,6 @@ static const char * supernode_ip(const n2n_edge_t * eee) {
/* ************************************** */
/** Called periodically to roll keys and do any periodic maintenance in the
* tranform operations state machines. */
static int n2n_tick_transop(n2n_edge_t *eee, time_t now) {
n2n_tostat_t tst = eee->transop.tick(&eee->transop, now);
if(!tst.can_tx) {
traceEvent(TRACE_ERROR, "transop.tick can_tx=0, no packets can be sent!");
return(-1);
}
return 0;
}
/* ************************************** */
/** A PACKET has arrived containing an encapsulated ethernet datagram - usually
* encrypted. */
static int handle_PACKET(n2n_edge_t * eee,
@ -895,7 +879,6 @@ static void readFromMgmtSocket(n2n_edge_t * eee, int * keep_running) {
" help This help message\n"
" +verb Increase verbosity of logging\n"
" -verb Decrease verbosity of logging\n"
" reload Re-read the keyschedule\n"
" <enter> Display statistics\n\n");
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
@ -947,25 +930,6 @@ static void readFromMgmtSocket(n2n_edge_t * eee, int * keep_running) {
}
}
if(recvlen >= 6)
{
if(0 == memcmp(udp_buf, "reload", 6))
{
if(strlen(eee->conf.keyschedule) > 0)
{
if(edge_init_keyschedule(eee) == 0)
{
msg_len=0;
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"> OK\n");
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
}
return;
}
}
}
traceEvent(TRACE_DEBUG, "mgmt status rq");
msg_len=0;
@ -1518,8 +1482,8 @@ int run_edge_loop(n2n_edge_t * eee, int *keep_running) {
/* Make sure ciphers are updated before the packet is treated. */
if((nowTime - lastTransop) > TRANSOP_TICK_INTERVAL) {
lastTransop = nowTime;
n2n_tick_transop(eee, nowTime);
eee->transop.tick(&eee->transop, nowTime);
}
if(rc > 0) {
@ -1596,59 +1560,6 @@ int run_edge_loop(n2n_edge_t * eee, int *keep_running) {
/* ************************************** */
/** Read in a key-schedule file, parse the lines and pass each line to the
* appropriate trans_op for parsing of key-data and adding key-schedule
* entries. The lookup table of time->trans_op is constructed such that
* encoding can be passed to the correct trans_op. The trans_op internal table
* will then determine the best SA for that trans_op from the key schedule to
* use for encoding. */
// TODO call me
static int edge_init_keyschedule(n2n_edge_t *eee) {
#define N2N_NUM_CIPHERSPECS 32
int retval = -1;
ssize_t numSpecs=0;
n2n_cipherspec_t specs[N2N_NUM_CIPHERSPECS];
size_t i;
time_t now = time(NULL);
numSpecs = n2n_read_keyfile(specs, N2N_NUM_CIPHERSPECS, eee->conf.keyschedule);
if(numSpecs > 0)
{
traceEvent(TRACE_NORMAL, "keyfile = %s read -> %d specs.\n", optarg, (signed int)numSpecs);
for (i=0; i < (size_t)numSpecs; ++i)
{
n2n_transform_t idx = (n2n_transform_t) specs[i].t;
if(idx != eee->transop.transform_id) {
traceEvent(TRACE_ERROR, "changing transop in keyschedule is not supported");
retval = -1;
}
if(eee->transop.addspec != NULL)
retval = eee->transop.addspec(&eee->transop, &(specs[i]));
if (0 != retval)
{
traceEvent(TRACE_ERROR, "keyschedule failed to add spec[%u] to transop[%d].\n",
(unsigned int)i, idx);
return retval;
}
}
n2n_tick_transop(eee, now);
}
else
traceEvent(TRACE_ERROR, "Failed to process '%s'", eee->conf.keyschedule);
return retval;
}
/* ************************************** */
/** Deinitialise the edge and deallocate any owned memory. */
void edge_term(n2n_edge_t * eee) {
if(eee->udp_sock >= 0)
@ -1774,7 +1685,7 @@ int quick_edge_init(char *device_name, char *community_name,
int rv;
/* Setup the configuration */
edge_conf_init_defaults(&conf);
edge_init_conf_defaults(&conf);
conf.encrypt_key = encrypt_key;
snprintf((char*)conf.community_name, sizeof(conf.community_name), "%s", community_name);
edge_conf_add_supernode(&conf, supernode_ip_address_port);

33
legacy/README.md Normal file
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@ -0,0 +1,33 @@
# Removed Features
This folder contains a list N2N legacy features which have been dropped due to
maintainance cost versus effective use and benefits.
Multiple Transops
-----------------
N2N used to initialize all the available transops and use the "tick" function of
the transops to decide which transop to use before sending a packet. This however
has the following problems:
- It only works with the keyfile, whereas with normal encryption we inizialize and
keep structures that we don't need.
- It is unfeasable as an edge node is required to implement all the transops in order
to properly talk with other edge nodes (via keyfile).
- It rises the complexity of the code.
- It is not clear which transop will be used.
- Mixing multiple encyptions together is not necessarily a good idea to improve security
as a vulnerability in at least one encryption method will leak some information.
Keyfile and Key Rotation
------------------------
The keyfile mechanism allowed N2N users to specify a keyfile to be used to periodically
rotate keys and encryption methods. However, it has the following problems:
- This feature is obscure for most of the users and poorly documented.
- It is tightly integrated in the core whereas it is used by only a few people (if any).
In conclusion the main problem is the complexity that it adds to the code. In a possible
future rework this could be integrated as an extention (e.g. a specific trasop) without
rising the core complexity.

102
legacy/edge_keyschedule.c Normal file
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@ -0,0 +1,102 @@
typedef struct n2n_tostat {
uint8_t can_tx; /* Does this transop have a valid SA for encoding. */
n2n_cipherspec_t tx_spec; /* If can_tx, the spec used to encode. */
} n2n_tostat_t;
typedef int (*n2n_transaddspec_f)( struct n2n_trans_op * arg,
const n2n_cipherspec_t * cspec );
typedef n2n_tostat_t (*n2n_transtick_f)( struct n2n_trans_op * arg,
time_t now );
/** Read in a key-schedule file, parse the lines and pass each line to the
* appropriate trans_op for parsing of key-data and adding key-schedule
* entries. The lookup table of time->trans_op is constructed such that
* encoding can be passed to the correct trans_op. The trans_op internal table
* will then determine the best SA for that trans_op from the key schedule to
* use for encoding. */
static int edge_init_keyschedule(n2n_edge_t *eee) {
#define N2N_NUM_CIPHERSPECS 32
int retval = -1;
ssize_t numSpecs=0;
n2n_cipherspec_t specs[N2N_NUM_CIPHERSPECS];
size_t i;
time_t now = time(NULL);
numSpecs = n2n_read_keyfile(specs, N2N_NUM_CIPHERSPECS, eee->conf.keyschedule);
if(numSpecs > 0)
{
traceEvent(TRACE_NORMAL, "keyfile = %s read -> %d specs.\n", optarg, (signed int)numSpecs);
for (i=0; i < (size_t)numSpecs; ++i)
{
n2n_transform_t idx = (n2n_transform_t) specs[i].t;
if(idx != eee->transop.transform_id) {
traceEvent(TRACE_ERROR, "changing transop in keyschedule is not supported");
retval = -1;
}
if(eee->transop.addspec != NULL)
retval = eee->transop.addspec(&eee->transop, &(specs[i]));
if (0 != retval)
{
traceEvent(TRACE_ERROR, "keyschedule failed to add spec[%u] to transop[%d].\n",
(unsigned int)i, idx);
return retval;
}
}
n2n_tick_transop(eee, now);
}
else
traceEvent(TRACE_ERROR, "Failed to process '%s'", eee->conf.keyschedule);
return retval;
}
#if 0
if(recvlen >= 6)
{
if(0 == memcmp(udp_buf, "reload", 6))
{
if(strlen(eee->conf.keyschedule) > 0)
{
if(edge_init_keyschedule(eee) == 0)
{
msg_len=0;
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"> OK\n");
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
}
return;
}
}
}
#endif
#if 0
case'K':
{
if(conf->encrypt_key) {
traceEvent(TRACE_ERROR, "Error: -K and -k options are mutually exclusive");
exit(1);
} else {
strncpy(conf->keyschedule, optargument, N2N_PATHNAME_MAXLEN-1);
/* strncpy does not add NULL if the source has no NULL. */
conf->keyschedule[N2N_PATHNAME_MAXLEN-1] = 0;
traceEvent(TRACE_NORMAL, "keyfile = '%s'\n", conf->keyschedule);
}
break;
}
#endif
#if 0
printf("-K <key file> | Specify a key schedule file to load. Not with -k.\n");
#endif

0
gen_keyfile.py → legacy/gen_keyfile.py
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0
n2n_keyfile.c → legacy/n2n_keyfile.c
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0
n2n_keyfile.h → legacy/n2n_keyfile.h
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730
legacy/transform_aes.c Normal file
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@ -0,0 +1,730 @@
/**
* (C) 2007-18 - ntop.org and contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* 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; if not see see <http://www.gnu.org/licenses/>
*
*/
#include "n2n.h"
#include "n2n_transforms.h"
#if defined(N2N_HAVE_AES)
#include "openssl/aes.h"
#include "openssl/sha.h"
#ifndef _MSC_VER
/* Not included in Visual Studio 2008 */
#include <strings.h> /* index() */
#endif
#define N2N_AES_NUM_SA 32 /* space for SAa */
#define N2N_AES_TRANSFORM_VERSION 1 /* version of the transform encoding */
#define N2N_AES_IVEC_SIZE 32 /* Enough space for biggest AES ivec */
#define AES256_KEY_BYTES (256/8)
#define AES192_KEY_BYTES (192/8)
#define AES128_KEY_BYTES (128/8)
typedef unsigned char n2n_aes_ivec_t[N2N_AES_IVEC_SIZE];
struct sa_aes
{
n2n_cipherspec_t spec; /* cipher spec parameters */
n2n_sa_t sa_id; /* security association index */
AES_KEY enc_key; /* tx key */
AES_KEY dec_key; /* tx key */
AES_KEY iv_enc_key; /* key used to encrypt the IV */
uint8_t iv_ext_val[AES128_KEY_BYTES]; /* key used to extend the random IV seed to full block size */
};
typedef struct sa_aes sa_aes_t;
/** Aes transform state data.
*
* With a key-schedule in place this will be populated with a number of
* SAs. Each SA has a lifetime and some opque data. The opaque data for aes
* consists of the SA number and key material.
*
*/
struct transop_aes
{
ssize_t tx_sa;
size_t num_sa;
sa_aes_t sa[N2N_AES_NUM_SA];
u_int8_t psk_mode;
};
typedef struct transop_aes transop_aes_t;
static ssize_t aes_find_sa( const transop_aes_t * priv, const n2n_sa_t req_id );
static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_size, size_t sa_num);
static int transop_deinit_aes( n2n_trans_op_t * arg )
{
transop_aes_t * priv = (transop_aes_t *)arg->priv;
size_t i;
if ( priv )
{
/* Memory was previously allocated */
for (i=0; i<N2N_AES_NUM_SA; ++i )
{
sa_aes_t * sa = &(priv->sa[i]);
sa->sa_id=0;
}
priv->num_sa=0;
priv->tx_sa=-1;
free(priv);
}
arg->priv=NULL; /* return to fully uninitialised state */
return 0;
}
static size_t aes_choose_tx_sa( transop_aes_t * priv, const u_int8_t * peer_mac ) {
return priv->tx_sa; /* set in tick */
}
static ssize_t aes_choose_rx_sa( transop_aes_t * priv, const u_int8_t * peer_mac, ssize_t sa_rx) {
if(!priv->psk_mode)
return aes_find_sa(priv, sa_rx);
else
/* NOTE the sa_rx of the packet is ignored in this case */
return 0;
}
/* AES plaintext preamble */
#define TRANSOP_AES_VER_SIZE 1 /* Support minor variants in encoding in one module. */
#define TRANSOP_AES_SA_SIZE 4
#define TRANSOP_AES_IV_SEED_SIZE 8
#define TRANSOP_AES_PREAMBLE_SIZE (TRANSOP_AES_VER_SIZE + TRANSOP_AES_SA_SIZE + TRANSOP_AES_IV_SEED_SIZE)
/* AES ciphertext preamble */
#define TRANSOP_AES_NONCE_SIZE 4
/* Return the best acceptable AES key size (in bytes) given an input keysize.
*
* The value returned will be one of AES128_KEY_BYTES, AES192_KEY_BYTES or
* AES256_KEY_BYTES.
*/
static size_t aes_best_keysize(size_t numBytes)
{
if (numBytes >= AES256_KEY_BYTES )
{
return AES256_KEY_BYTES;
}
else if (numBytes >= AES192_KEY_BYTES)
{
return AES192_KEY_BYTES;
}
else
{
return AES128_KEY_BYTES;
}
}
static void set_aes_cbc_iv(sa_aes_t *sa, n2n_aes_ivec_t ivec, uint64_t iv_seed) {
uint8_t iv_full[AES_BLOCK_SIZE];
/* Extend the seed to full block size via the fixed ext value */
memcpy(iv_full, sa->iv_ext_val, sizeof(iv_seed)); // note: only 64bits used of 128 available
memcpy(iv_full + sizeof(iv_seed), &iv_seed, sizeof(iv_seed));
/* Encrypt the IV with secret key to make it unpredictable.
* As discussed in https://github.com/ntop/n2n/issues/72, it's important to
* have an unpredictable IV since the initial part of the packet plaintext
* can be easily reconstructed from plaintext headers and used by an attacker
* to perform differential analysis.
*/
AES_ecb_encrypt(iv_full, ivec, &sa->iv_enc_key, AES_ENCRYPT);
}
/** The aes packet format consists of:
*
* - a 8-bit aes encoding version in clear text
* - a 32-bit SA number in clear text
* - a 64-bit random IV seed
* - ciphertext encrypted from a 32-bit nonce followed by the payload.
*
* [V|SSSS|II|nnnnDDDDDDDDDDDDDDDDDDDDD]
* |<------ encrypted ------>|
*/
static int transop_encode_aes( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac)
{
int len2=-1;
transop_aes_t * priv = (transop_aes_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE] = {0};
uint32_t * pnonce;
if ( (in_len + TRANSOP_AES_NONCE_SIZE) <= N2N_PKT_BUF_SIZE )
{
if ( (in_len + TRANSOP_AES_NONCE_SIZE + TRANSOP_AES_PREAMBLE_SIZE) <= out_len )
{
int len=-1;
size_t idx=0;
sa_aes_t * sa;
size_t tx_sa_num = 0;
uint64_t iv_seed = 0;
uint8_t padding = 0;
n2n_aes_ivec_t enc_ivec = {0};
/* The transmit sa is periodically updated */
tx_sa_num = aes_choose_tx_sa( priv, peer_mac );
sa = &(priv->sa[tx_sa_num]); /* Proper Tx SA index */
traceEvent( TRACE_DEBUG, "encode_aes %lu with SA %lu.", in_len, sa->sa_id );
/* Encode the aes format version. */
encode_uint8( outbuf, &idx, N2N_AES_TRANSFORM_VERSION );
/* Encode the security association (SA) number */
encode_uint32( outbuf, &idx, sa->sa_id );
/* Generate and encode the IV seed.
* Using two calls to rand() because RAND_MAX is usually < 64bit
* (e.g. linux) and sometimes < 32bit (e.g. Windows).
*/
((uint32_t*)&iv_seed)[0] = rand();
((uint32_t*)&iv_seed)[1] = rand();
encode_buf(outbuf, &idx, &iv_seed, sizeof(iv_seed));
/* Encrypt the assembly contents and write the ciphertext after the SA. */
len = in_len + TRANSOP_AES_NONCE_SIZE;
/* The assembly buffer is a source for encrypting data. The nonce is
* written in first followed by the packet payload. The whole
* contents of assembly are encrypted. */
pnonce = (uint32_t *)assembly;
*pnonce = rand();
memcpy( assembly + TRANSOP_AES_NONCE_SIZE, inbuf, in_len );
/* Need at least one encrypted byte at the end for the padding. */
len2 = ( (len / AES_BLOCK_SIZE) + 1) * AES_BLOCK_SIZE; /* Round up to next whole AES adding at least one byte. */
padding = (len2-len);
assembly[len2 - 1] = padding;
traceEvent( TRACE_DEBUG, "padding = %u, seed = %016lx", padding, iv_seed );
set_aes_cbc_iv(sa, enc_ivec, iv_seed);
AES_cbc_encrypt( assembly, /* source */
outbuf + TRANSOP_AES_PREAMBLE_SIZE, /* dest */
len2, /* enc size */
&(sa->enc_key), enc_ivec, AES_ENCRYPT );
len2 += TRANSOP_AES_PREAMBLE_SIZE; /* size of data carried in UDP. */
}
else
{
traceEvent( TRACE_ERROR, "encode_aes outbuf too small." );
}
}
else
{
traceEvent( TRACE_ERROR, "encode_aes inbuf too big to encrypt." );
}
return len2;
}
/* Search through the array of SAs to find the one with the required ID.
*
* @return array index where found or -1 if not found
*/
static ssize_t aes_find_sa( const transop_aes_t * priv, const n2n_sa_t req_id )
{
size_t i;
for (i=0; i < priv->num_sa; ++i)
{
const sa_aes_t * sa=NULL;
sa = &(priv->sa[i]);
if (req_id == sa->sa_id)
{
return i;
}
}
return -1;
}
/* See transop_encode_aes for packet format */
static int transop_decode_aes( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac)
{
int len=0;
transop_aes_t * priv = (transop_aes_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE];
if ( ( (in_len - TRANSOP_AES_PREAMBLE_SIZE) <= N2N_PKT_BUF_SIZE ) /* Cipher text fits in assembly */
&& (in_len >= (TRANSOP_AES_PREAMBLE_SIZE + TRANSOP_AES_NONCE_SIZE) ) /* Has at least version, SA, iv seed and nonce */
)
{
n2n_sa_t sa_rx;
ssize_t sa_idx=-1;
size_t rem=in_len;
size_t idx=0;
uint8_t aes_enc_ver=0;
uint64_t iv_seed=0;
/* Get the encoding version to make sure it is supported */
decode_uint8( &aes_enc_ver, inbuf, &rem, &idx );
if ( N2N_AES_TRANSFORM_VERSION == aes_enc_ver )
{
/* Get the SA number and make sure we are decrypting with the right one. */
decode_uint32( &sa_rx, inbuf, &rem, &idx );
sa_idx = aes_choose_rx_sa(priv, peer_mac, sa_rx);
if ( sa_idx >= 0 )
{
sa_aes_t * sa = &(priv->sa[sa_idx]);
/* Get the IV seed */
decode_buf((uint8_t *)&iv_seed, sizeof(iv_seed), inbuf, &rem, &idx);
traceEvent( TRACE_DEBUG, "decode_aes %lu with SA %lu and seed %016lx", in_len, sa->sa_id, iv_seed );
len = (in_len - TRANSOP_AES_PREAMBLE_SIZE);
if ( 0 == (len % AES_BLOCK_SIZE ) )
{
uint8_t padding;
n2n_aes_ivec_t dec_ivec = {0};
set_aes_cbc_iv(sa, dec_ivec, iv_seed);
AES_cbc_encrypt( (inbuf + TRANSOP_AES_PREAMBLE_SIZE),
assembly, /* destination */
len,
&(sa->dec_key),
dec_ivec, AES_DECRYPT );
/* last byte is how much was padding: max value should be
* AES_BLOCKSIZE-1 */
padding = assembly[ len-1 ] & 0xff;
if ( len >= (padding + TRANSOP_AES_NONCE_SIZE))
{
/* strictly speaking for this to be an ethernet packet
* it is going to need to be even bigger; but this is
* enough to prevent segfaults. */
traceEvent( TRACE_DEBUG, "padding = %u", padding );
len -= padding;
len -= TRANSOP_AES_NONCE_SIZE; /* size of ethernet packet */
/* Step over 4-byte random nonce value */
memcpy( outbuf,
assembly + TRANSOP_AES_NONCE_SIZE,
len );
}
else
{
traceEvent( TRACE_WARNING, "UDP payload decryption failed." );
}
}
else
{
traceEvent( TRACE_WARNING, "Encrypted length %d is not a multiple of AES_BLOCK_SIZE (%d)", len, AES_BLOCK_SIZE );
len = 0;
}
}
else
{
/* Wrong security association; drop the packet as it is undecodable. */
traceEvent( TRACE_ERROR, "decode_aes SA number %lu not found.", sa_rx );
/* REVISIT: should be able to load a new SA at this point to complete the decoding. */
}
}
else
{
/* Wrong security association; drop the packet as it is undecodable. */
traceEvent( TRACE_ERROR, "decode_aes unsupported aes version %u.", aes_enc_ver );
/* REVISIT: should be able to load a new SA at this point to complete the decoding. */
}
}
else
{
traceEvent( TRACE_ERROR, "decode_aes inbuf wrong size (%ul) to decrypt.", in_len );
}
return len;
}
struct sha512_keybuf {
uint8_t enc_dec_key[AES256_KEY_BYTES]; /* The key to use for AES CBC encryption/decryption */
uint8_t iv_enc_key[AES128_KEY_BYTES]; /* The key to use to encrypt the IV with AES ECB */
uint8_t iv_ext_val[AES128_KEY_BYTES]; /* A value to extend the IV seed */
}; /* size: SHA512_DIGEST_LENGTH */
/* NOTE: the caller should adjust priv->num_sa accordingly */
static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_size, size_t sa_num) {
sa_aes_t * sa = &(priv->sa[sa_num]);
size_t aes_keysize_bytes;
size_t aes_keysize_bits;
struct sha512_keybuf keybuf;
/* Clear out any old possibly longer key matter. */
memset( &(sa->enc_key), 0, sizeof(sa->enc_key) );
memset( &(sa->dec_key), 0, sizeof(sa->dec_key) );
memset( &(sa->iv_enc_key), 0, sizeof(sa->iv_enc_key) );
memset( &(sa->iv_ext_val), 0, sizeof(sa->iv_ext_val) );
/* We still use aes_best_keysize (even not necessary since we hash the key
* into the 256bits enc_dec_key) to let the users choose the degree of encryption.
* Long keys will pick AES192 or AES256 with more robust but expensive encryption.
*/
aes_keysize_bytes = aes_best_keysize(key_size);
aes_keysize_bits = 8 * aes_keysize_bytes;
/* Hash the main key to generate subkeys */
SHA512(key, key_size, (u_char*)&keybuf);
/* setup of enc_key/dec_key, used for the CBC encryption */
AES_set_encrypt_key(keybuf.enc_dec_key, aes_keysize_bits, &(sa->enc_key));
AES_set_decrypt_key(keybuf.enc_dec_key, aes_keysize_bits, &(sa->dec_key));
/* setup of iv_enc_key and iv_ext_val, used for generating the CBC IV */
AES_set_encrypt_key(keybuf.iv_enc_key, sizeof(keybuf.iv_enc_key) * 8, &(sa->iv_enc_key));
memcpy(sa->iv_ext_val, keybuf.iv_ext_val, sizeof(keybuf.iv_ext_val));
traceEvent( TRACE_DEBUG, "transop_addspec_aes sa_id=%u, %u bits key=%s.\n",
priv->sa[sa_num].sa_id, aes_keysize_bits, key);
return(0);
}
/*
* priv: pointer to transform state
* keybuf: buffer holding the key
* pstat: length of keybuf
*/
static void add_aes_key(transop_aes_t *priv, uint8_t *keybuf, ssize_t pstat) {
setup_aes_key(priv, keybuf, pstat, priv->num_sa);
++(priv->num_sa);
}
static int transop_addspec_aes( n2n_trans_op_t * arg, const n2n_cipherspec_t * cspec )
{
int retval = 1;
ssize_t pstat=-1;
transop_aes_t * priv = (transop_aes_t *)arg->priv;
uint8_t keybuf[N2N_MAX_KEYSIZE];
if ( priv->num_sa < N2N_AES_NUM_SA )
{
const char * op = (const char *)cspec->opaque;
const char * sep = index( op, '_' );
if ( sep )
{
char tmp[256];
size_t s;
s = sep - op;
memcpy( tmp, cspec->opaque, s );
tmp[s]=0;
s = strlen(sep+1); /* sep is the _ which might be immediately followed by NULL */
priv->sa[priv->num_sa].spec = *cspec;
priv->sa[priv->num_sa].sa_id = strtoul(tmp, NULL, 10);
memset( keybuf, 0, N2N_MAX_KEYSIZE );
pstat = n2n_parse_hex( keybuf, N2N_MAX_KEYSIZE, sep+1, s );
if ( pstat > 0 )
{
add_aes_key(priv, keybuf, pstat);
retval = 0;
}
}
else
{
traceEvent( TRACE_ERROR, "transop_addspec_aes : bad key data - missing '_'.\n");
}
}
else
{
traceEvent( TRACE_ERROR, "transop_addspec_aes : full.\n");
}
return retval;
}
static n2n_tostat_t transop_tick_aes( n2n_trans_op_t * arg, time_t now )
{
transop_aes_t * priv = (transop_aes_t *)arg->priv;
size_t i;
int found=0;
n2n_tostat_t r;
memset( &r, 0, sizeof(r) );
traceEvent( TRACE_DEBUG, "transop_aes tick num_sa=%u now=%lu", priv->num_sa, now );
for ( i=0; i < priv->num_sa; ++i )
{
if ( 0 == validCipherSpec( &(priv->sa[i].spec), now ) )
{
time_t remaining = priv->sa[i].spec.valid_until - now;
traceEvent( TRACE_INFO, "transop_aes choosing tx_sa=%u (valid for %lu sec)", priv->sa[i].sa_id, remaining );
priv->tx_sa=i;
found=1;
break;
}
else
{
traceEvent( TRACE_DEBUG, "transop_aes tick rejecting sa=%u %lu -> %lu",
priv->sa[i].sa_id, priv->sa[i].spec.valid_from, priv->sa[i].spec.valid_until );
}
}
if ( 0==found)
{
traceEvent( TRACE_INFO, "transop_aes no keys are currently valid. Keeping tx_sa=%u", priv->tx_sa );
}
else
{
r.can_tx = 1;
r.tx_spec.t = N2N_TRANSFORM_ID_AESCBC;
r.tx_spec = priv->sa[priv->tx_sa].spec;
}
return r;
}
static n2n_tostat_t transop_tick_aes_psk(n2n_trans_op_t * arg, time_t now) {
transop_aes_t * priv = (transop_aes_t *)arg->priv;
n2n_tostat_t r;
memset(&r, 0, sizeof(r));
// Always tx
r.can_tx = 1;
r.tx_spec.t = N2N_TRANSFORM_ID_AESCBC;
r.tx_spec = priv->sa[priv->tx_sa].spec;
return r;
}
int transop_aes_init( n2n_trans_op_t * ttt )
{
int retval = 1;
transop_aes_t * priv = NULL;
if ( ttt->priv )
{
transop_deinit_aes( ttt );
}
memset( ttt, 0, sizeof( n2n_trans_op_t ) );
priv = (transop_aes_t *) calloc(1, sizeof(transop_aes_t));
if ( NULL != priv )
{
size_t i;
sa_aes_t * sa=NULL;
/* install the private structure. */
ttt->priv = priv;
priv->num_sa=0;
priv->tx_sa=0; /* We will use this sa index for encoding. */
priv->psk_mode = 0;
ttt->transform_id = N2N_TRANSFORM_ID_AESCBC;
ttt->addspec = transop_addspec_aes;
ttt->tick = transop_tick_aes; /* chooses a new tx_sa */
ttt->deinit = transop_deinit_aes;
ttt->fwd = transop_encode_aes;
ttt->rev = transop_decode_aes;
for(i=0; i<N2N_AES_NUM_SA; ++i)
{
sa = &(priv->sa[i]);
sa->sa_id=0;
memset( &(sa->spec), 0, sizeof(n2n_cipherspec_t) );
memset( &(sa->enc_key), 0, sizeof(sa->enc_key) );
memset( &(sa->dec_key), 0, sizeof(sa->dec_key) );
memset( &(sa->iv_enc_key), 0, sizeof(sa->iv_enc_key) );
memset( &(sa->iv_ext_val), 0, sizeof(sa->iv_ext_val) );
}
retval = 0;
}
else
{
memset( ttt, 0, sizeof(n2n_trans_op_t) );
traceEvent( TRACE_ERROR, "Failed to allocate priv for aes" );
}
return retval;
}
/* Setup AES in pre-shared key mode */
int transop_aes_setup_psk(n2n_trans_op_t *ttt,
n2n_sa_t sa_num,
uint8_t *encrypt_pwd,
uint32_t encrypt_pwd_len) {
int retval = 1;
transop_aes_t *priv = (transop_aes_t *)ttt->priv;
if(ttt->priv) {
/* Replace the tick function with the PSK version of it */
ttt->tick = transop_tick_aes_psk;
priv->psk_mode = 1;
priv->num_sa=0;
priv->tx_sa=0;
/* Setup the key to use for encryption/decryption */
add_aes_key(priv, encrypt_pwd, encrypt_pwd_len);
retval = 0;
} else
traceEvent(TRACE_ERROR, "AES priv is not allocated");
return retval;
}
#else /* #if defined(N2N_HAVE_AES) */
struct transop_aes
{
ssize_t tx_sa;
};
typedef struct transop_aes transop_aes_t;
static int transop_deinit_aes( n2n_trans_op_t * arg )
{
transop_aes_t * priv = (transop_aes_t *)arg->priv;
if ( priv )
{
free(priv);
}
arg->priv=NULL; /* return to fully uninitialised state */
return 0;
}
static int transop_encode_aes( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len )
{
return -1;
}
static int transop_decode_aes( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len )
{
return -1;
}
static int transop_addspec_aes( n2n_trans_op_t * arg, const n2n_cipherspec_t * cspec )
{
traceEvent( TRACE_DEBUG, "transop_addspec_aes AES not built into edge.\n");
return -1;
}
static n2n_tostat_t transop_tick_aes( n2n_trans_op_t * arg, time_t now )
{
n2n_tostat_t r;
memset( &r, 0, sizeof(r) );
return r;
}
int transop_aes_init( n2n_trans_op_t * ttt )
{
int retval = 1;
transop_aes_t * priv = NULL;
if ( ttt->priv )
{
transop_deinit_aes( ttt );
}
memset( ttt, 0, sizeof( n2n_trans_op_t ) );
priv = (transop_aes_t *) malloc( sizeof(transop_aes_t) );
if ( NULL != priv )
{
/* install the private structure. */
ttt->priv = priv;
priv->tx_sa=0; /* We will use this sa index for encoding. */
ttt->transform_id = N2N_TRANSFORM_ID_AESCBC;
ttt->addspec = transop_addspec_aes;
ttt->tick = transop_tick_aes; /* chooses a new tx_sa */
ttt->deinit = transop_deinit_aes;
ttt->fwd = transop_encode_aes;
ttt->rev = transop_decode_aes;
retval = 0;
}
else
{
memset( ttt, 0, sizeof(n2n_trans_op_t) );
traceEvent( TRACE_ERROR, "Failed to allocate priv for aes" );
}
return retval;
}
int transop_aes_setup_psk(n2n_trans_op_t *ttt,
n2n_sa_t sa_num,
uint8_t *encrypt_pwd,
uint32_t encrypt_pwd_len) {
return 0;
}
#endif /* #if defined(N2N_HAVE_AES) */

467
legacy/transform_tf.c Normal file
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@ -0,0 +1,467 @@
/**
* (C) 2007-18 - ntop.org and contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* 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; if not see see <http://www.gnu.org/licenses/>
*
*/
#include "n2n.h"
#include "n2n_transforms.h"
#include "twofish.h"
#ifndef _MSC_VER
/* Not included in Visual Studio 2008 */
#include <strings.h> /* index() */
#endif
#define N2N_TWOFISH_NUM_SA 32 /* space for SAa */
#define N2N_TWOFISH_TRANSFORM_VERSION 1 /* version of the transform encoding */
struct sa_twofish
{
n2n_cipherspec_t spec; /* cipher spec parameters */
n2n_sa_t sa_id; /* security association index */
TWOFISH * enc_tf; /* tx state */
TWOFISH * dec_tf; /* rx state */
};
typedef struct sa_twofish sa_twofish_t;
/** Twofish transform state data.
*
* With a key-schedule in place this will be populated with a number of
* SAs. Each SA has a lifetime and some opque data. The opaque data for twofish
* consists of the SA number and key material.
*
*/
struct transop_tf
{
ssize_t tx_sa;
size_t num_sa;
sa_twofish_t sa[N2N_TWOFISH_NUM_SA];
};
typedef struct transop_tf transop_tf_t;
static int transop_deinit_twofish( n2n_trans_op_t * arg )
{
transop_tf_t * priv = (transop_tf_t *)arg->priv;
size_t i;
if ( priv )
{
/* Memory was previously allocated */
for (i=0; i<N2N_TWOFISH_NUM_SA; ++i )
{
sa_twofish_t * sa = &(priv->sa[i]);
TwoFishDestroy(sa->enc_tf); /* deallocate TWOFISH */
sa->enc_tf=NULL;
TwoFishDestroy(sa->dec_tf); /* deallocate TWOFISH */
sa->dec_tf=NULL;
sa->sa_id=0;
}
priv->num_sa=0;
priv->tx_sa=-1;
free(priv);
}
arg->priv=NULL; /* return to fully uninitialised state */
return 0;
}
static size_t tf_choose_tx_sa( transop_tf_t * priv )
{
return priv->tx_sa; /* set in tick */
}
#define TRANSOP_TF_VER_SIZE 1 /* Support minor variants in encoding in one module. */
#define TRANSOP_TF_NONCE_SIZE 4
#define TRANSOP_TF_SA_SIZE 4
/** The twofish packet format consists of:
*
* - a 8-bit twofish encoding version in clear text
* - a 32-bit SA number in clear text
* - ciphertext encrypted from a 32-bit nonce followed by the payload.
*
* [V|SSSS|nnnnDDDDDDDDDDDDDDDDDDDDD]
* |<------ encrypted ------>|
*/
static int transop_encode_twofish( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac)
{
int len=-1;
transop_tf_t * priv = (transop_tf_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE];
uint32_t * pnonce;
if ( (in_len + TRANSOP_TF_NONCE_SIZE) <= N2N_PKT_BUF_SIZE )
{
if ( (in_len + TRANSOP_TF_NONCE_SIZE + TRANSOP_TF_SA_SIZE + TRANSOP_TF_VER_SIZE) <= out_len )
{
size_t idx=0;
sa_twofish_t * sa;
size_t tx_sa_num = 0;
/* The transmit sa is periodically updated */
tx_sa_num = tf_choose_tx_sa( priv );
sa = &(priv->sa[tx_sa_num]); /* Proper Tx SA index */
traceEvent( TRACE_DEBUG, "encode_twofish %lu with SA %lu.", in_len, sa->sa_id );
/* Encode the twofish format version. */
encode_uint8( outbuf, &idx, N2N_TWOFISH_TRANSFORM_VERSION );
/* Encode the security association (SA) number */
encode_uint32( outbuf, &idx, sa->sa_id );
/* The assembly buffer is a source for encrypting data. The nonce is
* written in first followed by the packet payload. The whole
* contents of assembly are encrypted. */
pnonce = (uint32_t *)assembly;
*pnonce = rand();
memcpy( assembly + TRANSOP_TF_NONCE_SIZE, inbuf, in_len );
/* Encrypt the assembly contents and write the ciphertext after the SA. */
len = TwoFishEncryptRaw( assembly, /* source */
outbuf + TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE,
in_len + TRANSOP_TF_NONCE_SIZE, /* enc size */
sa->enc_tf);
if ( len > 0 )
{
len += TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE; /* size of data carried in UDP. */
}
else
{
traceEvent( TRACE_ERROR, "encode_twofish encryption failed." );
}
}
else
{
traceEvent( TRACE_ERROR, "encode_twofish outbuf too small." );
}
}
else
{
traceEvent( TRACE_ERROR, "encode_twofish inbuf too big to encrypt." );
}
return len;
}
/* Search through the array of SAs to find the one with the required ID.
*
* @return array index where found or -1 if not found
*/
static ssize_t twofish_find_sa( const transop_tf_t * priv, const n2n_sa_t req_id )
{
size_t i;
for (i=0; i < priv->num_sa; ++i)
{
const sa_twofish_t * sa=NULL;
sa = &(priv->sa[i]);
if (req_id == sa->sa_id)
{
return i;
}
}
return -1;
}
/** The twofish packet format consists of:
*
* - a 8-bit twofish encoding version in clear text
* - a 32-bit SA number in clear text
* - ciphertext encrypted from a 32-bit nonce followed by the payload.
*
* [V|SSSS|nnnnDDDDDDDDDDDDDDDDDDDDD]
* |<------ encrypted ------>|
*/
static int transop_decode_twofish( n2n_trans_op_t * arg,
uint8_t * outbuf,
size_t out_len,
const uint8_t * inbuf,
size_t in_len,
const uint8_t * peer_mac)
{
int len=0;
transop_tf_t * priv = (transop_tf_t *)arg->priv;
uint8_t assembly[N2N_PKT_BUF_SIZE];
if ( ( (in_len - (TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE)) <= N2N_PKT_BUF_SIZE ) /* Cipher text fits in assembly */
&& (in_len >= (TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE + TRANSOP_TF_NONCE_SIZE) ) /* Has at least version, SA and nonce */
)
{
n2n_sa_t sa_rx;
ssize_t sa_idx=-1;
size_t rem=in_len;
size_t idx=0;
uint8_t tf_enc_ver=0;
/* Get the encoding version to make sure it is supported */
decode_uint8( &tf_enc_ver, inbuf, &rem, &idx );
if ( N2N_TWOFISH_TRANSFORM_VERSION == tf_enc_ver )
{
/* Get the SA number and make sure we are decrypting with the right one. */
decode_uint32( &sa_rx, inbuf, &rem, &idx );
sa_idx = twofish_find_sa(priv, sa_rx);
if ( sa_idx >= 0 )
{
sa_twofish_t * sa = &(priv->sa[sa_idx]);
traceEvent( TRACE_DEBUG, "decode_twofish %lu with SA %lu.", in_len, sa_rx, sa->sa_id );
len = TwoFishDecryptRaw( (void *)(inbuf + TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE),
assembly, /* destination */
(in_len - (TRANSOP_TF_VER_SIZE + TRANSOP_TF_SA_SIZE)),
sa->dec_tf);
if ( len > 0 )
{
/* Step over 4-byte random nonce value */
len -= TRANSOP_TF_NONCE_SIZE; /* size of ethernet packet */
memcpy( outbuf,
assembly + TRANSOP_TF_NONCE_SIZE,
len );
}
else
{
traceEvent( TRACE_ERROR, "decode_twofish decryption failed." );
}
}
else
{
/* Wrong security association; drop the packet as it is undecodable. */
traceEvent( TRACE_ERROR, "decode_twofish SA number %lu not found.", sa_rx );
/* REVISIT: should be able to load a new SA at this point to complete the decoding. */
}
}
else
{
/* Wrong security association; drop the packet as it is undecodable. */
traceEvent( TRACE_ERROR, "decode_twofish unsupported twofish version %u.", tf_enc_ver );
/* REVISIT: should be able to load a new SA at this point to complete the decoding. */
}
}
else
{
traceEvent( TRACE_ERROR, "decode_twofish inbuf wrong size (%ul) to decrypt.", in_len );
}
return len;
}
static int transop_addspec_twofish( n2n_trans_op_t * arg, const n2n_cipherspec_t * cspec )
{
int retval = 1;
ssize_t pstat=-1;
transop_tf_t * priv = (transop_tf_t *)arg->priv;
uint8_t keybuf[N2N_MAX_KEYSIZE];
if ( priv->num_sa < N2N_TWOFISH_NUM_SA )
{
const char * op = (const char *)cspec->opaque;
#ifdef __ANDROID_NDK__
const char *sep = strchr(op, '_');
#else
const char * sep = index( op, '_' );
#endif // __ANDROID_NDK__
if ( sep )
{
char tmp[256];
size_t s;
s = sep - op;
memcpy( tmp, cspec->opaque, s );
tmp[s]=0;
s = strlen(sep+1); /* sep is the _ which might be immediately followed by NULL */
priv->sa[priv->num_sa].spec = *cspec;
priv->sa[priv->num_sa].sa_id = strtoul(tmp, NULL, 10);
pstat = n2n_parse_hex( keybuf, N2N_MAX_KEYSIZE, sep+1, s );
if ( pstat > 0 )
{
priv->sa[priv->num_sa].enc_tf = TwoFishInit( keybuf, pstat);
priv->sa[priv->num_sa].dec_tf = TwoFishInit( keybuf, pstat);
traceEvent( TRACE_DEBUG, "transop_addspec_twofish sa_id=%u data=%s.\n",
priv->sa[priv->num_sa].sa_id, sep+1);
++(priv->num_sa);
retval = 0;
}
}
else
{
traceEvent( TRACE_ERROR, "transop_addspec_twofish : bad key data - missing '_'.\n");
}
}
else
{
traceEvent( TRACE_ERROR, "transop_addspec_twofish : full.\n");
}
return retval;
}
static n2n_tostat_t transop_tick_twofish( n2n_trans_op_t * arg, time_t now )
{
transop_tf_t * priv = (transop_tf_t *)arg->priv;
size_t i;
int found=0;
n2n_tostat_t r;
memset( &r, 0, sizeof(r) );
traceEvent( TRACE_DEBUG, "transop_tf tick num_sa=%u", priv->num_sa );
for ( i=0; i < priv->num_sa; ++i )
{
if ( 0 == validCipherSpec( &(priv->sa[i].spec), now ) )
{
time_t remaining = priv->sa[i].spec.valid_until - now;
traceEvent( TRACE_INFO, "transop_tf choosing tx_sa=%u (valid for %lu sec)", priv->sa[i].sa_id, remaining );
priv->tx_sa=i;
found=1;
break;
}
else
{
traceEvent( TRACE_DEBUG, "transop_tf tick rejecting sa=%u %lu -> %lu",
priv->sa[i].sa_id, priv->sa[i].spec.valid_from, priv->sa[i].spec.valid_until );
}
}
if ( 0==found)
{
traceEvent( TRACE_INFO, "transop_tf no keys are currently valid. Keeping tx_sa=%u", priv->tx_sa );
}
else
{
r.can_tx = 1;
r.tx_spec.t = N2N_TRANSFORM_ID_TWOFISH;
r.tx_spec = priv->sa[priv->tx_sa].spec;
}
return r;
}
int transop_twofish_setup_psk( n2n_trans_op_t * ttt,
n2n_sa_t sa_num,
uint8_t * encrypt_pwd,
uint32_t encrypt_pwd_len )
{
int retval = 1;
transop_tf_t * priv = (transop_tf_t *)ttt->priv;
if(priv) {
sa_twofish_t *sa;
priv->num_sa=1; /* There is one SA in the array. */
priv->tx_sa=0;
sa = &(priv->sa[priv->tx_sa]);
sa->sa_id=sa_num;
sa->spec.valid_until = 0x7fffffff;
/* This is a preshared key setup. Both Tx and Rx are using the same security association. */
sa->enc_tf = TwoFishInit(encrypt_pwd, encrypt_pwd_len);
sa->dec_tf = TwoFishInit(encrypt_pwd, encrypt_pwd_len);
if ( (sa->enc_tf) && (sa->dec_tf) )
retval = 0;
else
traceEvent( TRACE_ERROR, "transop_twofish_setup_psk" );
} else
traceEvent( TRACE_ERROR, "twofish priv is not allocated" );
return retval;
}
int transop_twofish_init( n2n_trans_op_t * ttt )
{
int retval = 1;
transop_tf_t * priv = NULL;
if ( ttt->priv )
{
transop_deinit_twofish( ttt );
}
memset( ttt, 0, sizeof( n2n_trans_op_t ) );
priv = (transop_tf_t *) malloc( sizeof(transop_tf_t) );
if ( NULL != priv ) {
size_t i;
sa_twofish_t * sa=NULL;
/* install the private structure. */
ttt->priv = priv;
priv->num_sa=0;
priv->tx_sa=0; /* We will use this sa index for encoding. */
ttt->transform_id = N2N_TRANSFORM_ID_TWOFISH;
ttt->addspec = transop_addspec_twofish;
ttt->tick = transop_tick_twofish; /* chooses a new tx_sa */
ttt->deinit = transop_deinit_twofish;
ttt->fwd = transop_encode_twofish;
ttt->rev = transop_decode_twofish;
for(i=0; i<N2N_TWOFISH_NUM_SA; ++i)
{
sa = &(priv->sa[i]);
sa->sa_id=0;
memset( &(sa->spec), 0, sizeof(n2n_cipherspec_t) );
sa->enc_tf=NULL;
sa->dec_tf=NULL;
}
retval = 0;
} else {
memset( ttt, 0, sizeof(n2n_trans_op_t) );
traceEvent( TRACE_ERROR, "Failed to allocate priv for twofish" );
}
return retval;
}

16
n2n.h
View File

@ -183,9 +183,7 @@ struct peer_info {
typedef char n2n_sn_name_t[N2N_EDGE_SN_HOST_SIZE];
typedef struct n2n_edge_conf {
char keyschedule[N2N_PATHNAME_MAXLEN];
n2n_sn_name_t sn_ip_array[N2N_EDGE_NUM_SUPERNODES];
n2n_community_t community_name; /**< The community. 16 full octets. */
n2n_transform_id_t transop_id; /**< The transop to use. */
@ -288,23 +286,19 @@ void update_peer_address(n2n_edge_t * eee,
time_t when);
/* Edge conf */
void edge_conf_init_defaults(n2n_edge_conf_t *conf);
void edge_init_conf_defaults(n2n_edge_conf_t *conf);
int edge_verify_conf(const n2n_edge_conf_t *conf);
int edge_conf_add_supernode(n2n_edge_conf_t *conf, const char *ip_and_port);
/* Public functions */
void send_packet2net(n2n_edge_t * eee,
uint8_t *tap_pkt, size_t len);
int edge_init_encryption(n2n_edge_t * eee, uint8_t *encrypt_pwd, uint32_t encrypt_pwd_len);
int edge_verify_conf(const n2n_edge_conf_t *conf);
n2n_edge_t* edge_init(const tuntap_dev *dev, const n2n_edge_conf_t *conf, int *rv);
void edge_term(n2n_edge_t *eee);
int run_edge_loop(n2n_edge_t * eee, int *keep_running);
int run_edge_loop(n2n_edge_t *eee, int *keep_running);
int quick_edge_init(char *device_name, char *community_name,
char *encrypt_key, char *device_mac,
char *local_ip_address,
char *supernode_ip_address_port,
int *keep_on_running);
void send_packet2net(n2n_edge_t * eee, uint8_t *tap_pkt, size_t len);
#endif /* _N2N_H_ */

15
n2n_transforms.h
View File

@ -19,7 +19,6 @@
#if !defined(N2N_TRANSFORMS_H_)
#define N2N_TRANSFORMS_H_
#include "n2n_keyfile.h"
#include "n2n_wire.h"
#define N2N_TRANSFORM_ID_USER_START 64
@ -34,17 +33,8 @@ typedef enum n2n_transform_id {
struct n2n_trans_op;
typedef struct n2n_tostat {
uint8_t can_tx; /* Does this transop have a valid SA for encoding. */
n2n_cipherspec_t tx_spec; /* If can_tx, the spec used to encode. */
} n2n_tostat_t;
typedef int (*n2n_transdeinit_f)( struct n2n_trans_op * arg );
typedef int (*n2n_transaddspec_f)( struct n2n_trans_op * arg,
const n2n_cipherspec_t * cspec );
typedef n2n_tostat_t (*n2n_transtick_f)( struct n2n_trans_op * arg,
time_t now );
typedef void (*n2n_transtick_f)( struct n2n_trans_op * arg, time_t now );
typedef int (*n2n_transform_f)( struct n2n_trans_op * arg,
uint8_t * outbuf,
size_t out_len,
@ -66,8 +56,7 @@ typedef struct n2n_trans_op {
size_t rx_cnt;
n2n_transdeinit_f deinit; /* destructor function */
n2n_transaddspec_f addspec; /* parse opaque data from a key schedule file. */
n2n_transtick_f tick; /* periodic maintenance */
n2n_transtick_f tick; /* periodic maintenance */
n2n_transform_f fwd; /* encode a payload */
n2n_transform_f rev; /* decode a payload */
} n2n_trans_op_t;