#include "cipher.h"
#include "connection.h"
#include "crypto.h"
+#include "ecdh.h"
#include "logger.h"
#include "net.h"
#include "netutl.h"
}
bool send_req_key(node_t *to) {
- return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
+ return send_request(to->nexthop->connection, "%d %s %s 1", REQ_KEY, myself->name, to->name);
}
bool req_key_h(connection_t *c, char *request) {
char from_name[MAX_STRING_SIZE];
char to_name[MAX_STRING_SIZE];
node_t *from, *to;
+ int kx_version = 0;
- if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
+ if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &kx_version) < 2) {
logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
c->hostname);
return false;
/* Check if this key request is for us */
if(to == myself) { /* Yes, send our own key back */
-
+ if(kx_version > 0) {
+ logger(LOG_DEBUG, "Got ECDH key request from %s", from->name);
+ from->status.ecdh = true;
+ }
send_ans_key(from);
} else {
if(tunnelserver)
return true;
}
+bool send_ans_key_ecdh(node_t *to) {
+ char key[ECDH_SIZE * 2 + 1];
+
+ ecdh_generate_public(&to->ecdh, key);
+
+ bin2hex(key, key, ECDH_SIZE);
+ key[ECDH_SIZE * 2] = '\0';
+
+ return send_request(to->nexthop->connection, "%d %s %s ECDH:%s %d %d %zu %d", ANS_KEY,
+ myself->name, to->name, key,
+ cipher_get_nid(&myself->incipher),
+ digest_get_nid(&myself->indigest),
+ digest_length(&myself->indigest),
+ myself->incompression);
+}
+
bool send_ans_key(node_t *to) {
+ if(to->status.ecdh)
+ return send_ans_key_ecdh(to);
+
size_t keylen = cipher_keylength(&myself->incipher);
char key[keylen * 2 + 1];
int cipher, digest, maclength, compression, keylen;
node_t *from, *to;
- if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
+ if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING" %d",
from_name, to_name, key, &cipher, &digest, &maclength,
&compression, address, port) < 7) {
logger(LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
return false;
}
- keylen = strlen(key) / 2;
-
- if(keylen != cipher_keylength(&from->outcipher)) {
- logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
- return false;
- }
-
if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
return false;
logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
return true;
}
-
+
from->outcompression = compression;
+ /* ECDH or old-style key exchange? */
+ /* TODO: look at SSH and TLS to see how they derive cipher and HMAC keys from shared secret properly */
+
+ if(!strncmp(key, "ECDH:", 5)) {
+ logger(LOG_DEBUG, "Got ECDH key from %s", from->name);
+
+ keylen = (strlen(key) - 5) / 2;
+
+ if(keylen != ECDH_SIZE) {
+ logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
+ return false;
+ }
+
+ if(ECDH_SHARED_SIZE < cipher_keylength(&from->outcipher)) {
+ logger(LOG_ERR, "ECDH key too short for cipher of %s!", from->name);
+ return false;
+ }
+
+ if(!from->ecdh) {
+ logger(LOG_DEBUG, "Woops, we didn't generate our public key yet");
+ from->status.ecdh = true;
+ if(!send_ans_key(from))
+ return false;
+ }
+
+ char shared[ECDH_SHARED_SIZE * 2 + 1];
+ char hex[ECDH_SHARED_SIZE * 2 + 1];
+ hex2bin(key + 5, key + 5, keylen);
+
+ if(!ecdh_compute_shared(&from->ecdh, key + 5, shared))
+ return false;
+
+ /* Update our crypto end */
+
+ char *mykey;
+ size_t mykeylen = cipher_keylength(&myself->incipher);
+ keylen = cipher_keylength(&from->outcipher);
+
+ if(ECDH_SHARED_SIZE < mykeylen) {
+ logger(LOG_ERR, "ECDH key too short for cipher of MYSELF!");
+ return false;
+ }
+
+ if(strcmp(myself->name, from->name) < 0) {
+ logger(LOG_DEBUG, "Using left half of shared secret");
+ mykey = shared;
+ memcpy(key, shared + ECDH_SHARED_SIZE - keylen, keylen);
+ } else {
+ logger(LOG_DEBUG, "Using right half of shared secret");
+ mykey = shared + ECDH_SHARED_SIZE - mykeylen;
+ memcpy(key, shared, keylen);
+ }
+
+ cipher_open_by_nid(&from->incipher, cipher_get_nid(&myself->incipher));
+ digest_open_by_nid(&from->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
+ from->incompression = myself->incompression;
+
+ cipher_set_key(&from->incipher, mykey, true);
+ digest_set_key(&from->indigest, mykey, mykeylen);
+
+ // Reset sequence number and late packet window
+ mykeyused = true;
+ from->received_seqno = 0;
+ if(replaywin)
+ memset(from->late, 0, replaywin);
+
+ bin2hex(shared, hex, ECDH_SHARED_SIZE);
+ hex[ECDH_SHARED_SIZE * 2] = 0;
+ logger(LOG_DEBUG, "Shared secret was %s", hex);
+
+ bin2hex(mykey, hex, mykeylen);
+ hex[mykeylen * 2] = 0;
+ logger(LOG_DEBUG, "My part is: %s (%d)", hex, mykeylen);
+
+ bin2hex(key, hex, keylen);
+ hex[keylen * 2] = 0;
+ logger(LOG_DEBUG, "His part is: %s (%d)", hex, keylen);
+ } else {
+ keylen = strlen(key) / 2;
+ hex2bin(key, key, keylen);
+ }
+
/* Update our copy of the origin's packet key */
- hex2bin(key, key, keylen);
+ if(keylen != cipher_keylength(&from->outcipher)) {
+ logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
+ return false;
+ }
+
cipher_set_key(&from->outcipher, key, false);
digest_set_key(&from->outdigest, key, keylen);
projects / tinc / blobdiff