Use PRF.

diff --git a/src/openssl/prf.c b/src/openssl/prf.c
index 2830d60..59e8a3a 100644 (file)
--- a/src/openssl/prf.c
+++ b/src/openssl/prf.c
@@ -22,14 +22,14 @@
 #include "digest.h"
 #include "prf.h"
 
-/* Generate key material from a master secret and a seed, based on RFC 2246.
+/* Generate key material from a master secret and a seed, based on RFC 4346 section 5.
    We use SHA512 and Whirlpool instead of MD5 and SHA1.
  */
 
 static bool prf_xor(int nid, char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
        digest_t digest;
        
-       if(!digest_open_by_nid(&digest, nid, 0))
+       if(!digest_open_by_nid(&digest, nid, -1))
                return false;
 
        if(!digest_set_key(&digest, secret, secretlen))

diff --git a/src/protocol_key.c b/src/protocol_key.c
index f52e896..8bbb6ad 100644 (file)
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -29,6 +29,7 @@
 #include "net.h"
 #include "netutl.h"
 #include "node.h"
+#include "prf.h"
 #include "protocol.h"
 #include "utils.h"
 #include "xalloc.h"
@@ -311,25 +312,27 @@ bool ans_key_h(connection_t *c, char *request) {
 
                /* 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;
-               }
-
+               char *mykey;
+               char *seed = NULL;
+               
                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);
+                       mykey = key;
+                       xasprintf(&seed, "tinc key expansion %s %s", myself->name, from->name);
                } else {
                        logger(LOG_DEBUG, "Using right half of shared secret");
-                       mykey = shared + ECDH_SHARED_SIZE - mykeylen;
-                       memcpy(key, shared, keylen);
+                       mykey = key + keylen;
+                       xasprintf(&seed, "tinc key expansion %s %s", from->name, myself->name);
                }
 
+               if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, keylen + mykeylen))
+                       return false;
+
+               free(seed);
+
                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;
@@ -343,17 +346,8 @@ bool ans_key_h(connection_t *c, char *request) {
                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);
+               if(strcmp(myself->name, from->name) < 0)
+                       memmove(key, key + mykeylen, keylen);
        } else {
                keylen = strlen(key) / 2;
                hex2bin(key, key, keylen);