Use CFB mode for meta-connections to improve security.

[oweals/tinc.git] / src / net_setup.c

diff --git a/src/net_setup.c b/src/net_setup.c
index a00a32109d9a3080c0a8ae6b13f5fa9151315c2a..d7668885e7f76ca6965f9bfbf3b6ab80a47bb1df 100644 (file)
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -1,7 +1,7 @@
 /*
     net_setup.c -- Setup.
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2014 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2016 Guus Sliepen <guus@tinc-vpn.org>
                   2006      Scott Lamb <slamb@slamb.org>
                   2010      Brandon Black <blblack@gmail.com>
 
@@ -39,6 +39,7 @@
 #include "netutl.h"
 #include "process.h"
 #include "protocol.h"
+#include "proxy.h"
 #include "route.h"
 #include "subnet.h"
 #include "utils.h"
@@ -47,17 +48,22 @@
 char *myport;
 devops_t devops;
 
-char *proxyhost;
-char *proxyport;
-char *proxyuser;
-char *proxypass;
-proxytype_t proxytype;
+#ifndef HAVE_RSA_SET0_KEY
+int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d) {
+       BN_free(r->n); r->n = n;
+       BN_free(r->e); r->e = e;
+       BN_free(r->d); r->d = d;
+       return 1;
+}
+#endif
 
 bool read_rsa_public_key(connection_t *c) {
        FILE *fp;
        char *pubname;
        char *hcfname;
        char *key;
+       BIGNUM *n = NULL;
+       BIGNUM *e = NULL;
 
        if(!c->rsa_key) {
                c->rsa_key = RSA_new();
@@ -67,12 +73,19 @@ bool read_rsa_public_key(connection_t *c) {
        /* First, check for simple PublicKey statement */
 
        if(get_config_string(lookup_config(c->config_tree, "PublicKey"), &key)) {
-               if(BN_hex2bn(&c->rsa_key->n, key) != strlen(key)) {
+               if(BN_hex2bn(&n, key) != strlen(key)) {
+                       free(key);
                        logger(LOG_ERR, "Invalid PublicKey for %s!", c->name);
                        return false;
                }
-               BN_hex2bn(&c->rsa_key->e, "FFFF");
                free(key);
+               BN_hex2bn(&e, "FFFF");
+               if(!n || !e || RSA_set0_key(c->rsa_key, n, e, NULL) != 1) {
+                       BN_free(e);
+                       BN_free(n);
+                       logger(LOG_ERR, "RSA_set0_key() failed with PublicKey for %s!", c->name);
+                       return false;
+               }
                return true;
        }
 
@@ -163,27 +176,39 @@ bool read_rsa_public_key(connection_t *c) {
 static bool read_rsa_private_key(void) {
        FILE *fp;
        char *fname, *key, *pubkey;
+       BIGNUM *n = NULL;
+       BIGNUM *e = NULL;
+       BIGNUM *d = NULL;
 
        if(get_config_string(lookup_config(config_tree, "PrivateKey"), &key)) {
                myself->connection->rsa_key = RSA_new();
 //             RSA_blinding_on(myself->connection->rsa_key, NULL);
-               if(BN_hex2bn(&myself->connection->rsa_key->d, key) != strlen(key)) {
+               if(BN_hex2bn(&d, key) != strlen(key)) {
                        logger(LOG_ERR, "Invalid PrivateKey for myself!");
                        free(key);
                        return false;
                }
                free(key);
                if(!get_config_string(lookup_config(config_tree, "PublicKey"), &pubkey)) {
+                       BN_free(d);
                        logger(LOG_ERR, "PrivateKey used but no PublicKey found!");
                        return false;
                }
-               if(BN_hex2bn(&myself->connection->rsa_key->n, pubkey) != strlen(pubkey)) {
-                       logger(LOG_ERR, "Invalid PublicKey for myself!");
+               if(BN_hex2bn(&n, pubkey) != strlen(pubkey)) {
                        free(pubkey);
+                       BN_free(d);
+                       logger(LOG_ERR, "Invalid PublicKey for myself!");
                        return false;
                }
                free(pubkey);
-               BN_hex2bn(&myself->connection->rsa_key->e, "FFFF");
+               BN_hex2bn(&e, "FFFF");
+               if(!n || !e || !d || RSA_set0_key(myself->connection->rsa_key, n, e, d) != 1) {
+                       BN_free(d);
+                       BN_free(e);
+                       BN_free(n);
+                       logger(LOG_ERR, "RSA_set0_key() failed with PrivateKey for myself!");
+                       return false;
+               }
                return true;
        }
 
@@ -539,7 +564,12 @@ static bool setup_myself(void) {
 
 #if !defined(SOL_IP) || !defined(IP_TOS)
        if(priorityinheritance)
-               logger(LOG_WARNING, "%s not supported on this platform", "PriorityInheritance");
+               logger(LOG_WARNING, "%s not supported on this platform for IPv4 connection", "PriorityInheritance");
+#endif
+
+#if !defined(IPPROTO_IPV6) || !defined(IPV6_TCLASS)
+       if(priorityinheritance)
+               logger(LOG_WARNING, "%s not supported on this platform for IPv6 connection", "PriorityInheritance");
 #endif
 
        if(!get_config_int(lookup_config(config_tree, "MACExpire"), &macexpire))
@@ -620,14 +650,25 @@ static bool setup_myself(void) {
                }
                free(cipher);
        } else
-               myself->incipher = EVP_bf_cbc();
+               myself->incipher = EVP_aes_256_cbc();
 
        if(myself->incipher)
-               myself->inkeylength = myself->incipher->key_len + myself->incipher->iv_len;
+               myself->inkeylength = EVP_CIPHER_key_length(myself->incipher) + EVP_CIPHER_iv_length(myself->incipher);
        else
                myself->inkeylength = 1;
 
-       myself->connection->outcipher = EVP_bf_ofb();
+       /* We need to use a stream mode for the meta protocol. Use AES for this,
+          but try to match the key size with the one from the cipher selected
+          by Cipher.
+       */
+
+       int keylen = EVP_CIPHER_key_length(myself->incipher);
+       if(keylen <= 16)
+               myself->connection->outcipher = EVP_aes_128_cfb();
+       else if(keylen <= 24)
+               myself->connection->outcipher = EVP_aes_192_cfb();
+       else
+               myself->connection->outcipher = EVP_aes_256_cfb();
 
        if(!get_config_int(lookup_config(config_tree, "KeyExpire"), &keylifetime))
                keylifetime = 3600;
@@ -651,13 +692,13 @@ static bool setup_myself(void) {
 
                free(digest);
        } else
-               myself->indigest = EVP_sha1();
+               myself->indigest = EVP_sha256();
 
-       myself->connection->outdigest = EVP_sha1();
+       myself->connection->outdigest = EVP_sha256();
 
        if(get_config_int(lookup_config(config_tree, "MACLength"), &myself->inmaclength)) {
                if(myself->indigest) {
-                       if(myself->inmaclength > myself->indigest->md_size) {
+                       if(myself->inmaclength > EVP_MD_size(myself->indigest)) {
                                logger(LOG_ERR, "MAC length exceeds size of digest!");
                                return false;
                        } else if(myself->inmaclength < 0) {
@@ -808,6 +849,10 @@ static bool setup_myself(void) {
                        hint.ai_protocol = IPPROTO_TCP;
                        hint.ai_flags = AI_PASSIVE;
 
+#if HAVE_DECL_RES_INIT
+                       // ensure glibc reloads /etc/resolv.conf.
+                       res_init();
+#endif
                        err = getaddrinfo(address && *address ? address : NULL, port, &hint, &ai);
                        free(address);