/*
protocol_auth.c -- handle the meta-protocol, authentication
Copyright (C) 1999-2005 Ivo Timmermans,
- 2000-2017 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2022 Guus Sliepen <guus@tinc-vpn.org>
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
#include "control.h"
#include "control_common.h"
#include "cipher.h"
-#include "crypto.h"
#include "digest.h"
#include "ecdsa.h"
#include "edge.h"
#include "sptps.h"
#include "utils.h"
#include "xalloc.h"
+#include "random.h"
+#include "compression.h"
#include "ed25519/sha512.h"
#include "keys.h"
+/* If nonzero, use null ciphers and skip all key exchanges. */
+bool bypass_security = false;
+
int invitation_lifetime;
ecdsa_t *invitation_key = NULL;
return false;
}
- uint8_t s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
+ const size_t s4reqlen = 9 + (proxyuser ? strlen(proxyuser) : 0);
+ uint8_t *s4req = alloca(s4reqlen);
s4req[0] = 4;
s4req[1] = 1;
memcpy(s4req + 2, &c->address.in.sin_port, 2);
memcpy(s4req + 8, proxyuser, strlen(proxyuser));
}
- s4req[sizeof(s4req) - 1] = 0;
+ s4req[s4reqlen - 1] = 0;
c->tcplen = 8;
- return send_meta(c, s4req, sizeof(s4req));
+ return send_meta(c, s4req, s4reqlen);
}
case PROXY_SOCKS5: {
len += 3 + strlen(proxyuser) + strlen(proxypass);
}
- uint8_t s5req[len];
+ uint8_t *s5req = alloca(len);
+
size_t i = 0;
s5req[i++] = 5;
s5req[i++] = 1;
abort();
}
- return send_meta(c, s5req, sizeof(s5req));
+ return send_meta(c, s5req, len);
}
case PROXY_SOCKS4A:
// Recover the filename from the cookie and the key
char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
- char hashbuf[18 + strlen(fingerprint)];
+ const size_t hashbuflen = 18 + strlen(fingerprint);
+ char *hashbuf = alloca(hashbuflen);
char cookie[64];
memcpy(hashbuf, data, 18);
- memcpy(hashbuf + 18, fingerprint, sizeof(hashbuf) - 18);
- sha512(hashbuf, sizeof(hashbuf), cookie);
+ memcpy(hashbuf + 18, fingerprint, hashbuflen - 18);
+ sha512(hashbuf, hashbuflen, cookie);
b64encode_tinc_urlsafe(cookie, cookie, 18);
free(fingerprint);
// Read the new node's Name from the file
char buf[1024] = "";
- fgets(buf, sizeof(buf), f);
+
+ if(!fgets(buf, sizeof(buf), f)) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Could not read invitation file %s\n", cookie);
+ fclose(f);
+ return false;
+ }
+
size_t buflen = strlen(buf);
// Strip whitespace at the end
sptps_send_record(&c->sptps, 0, buf, result);
}
+ if(!feof(f)) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Could not read invitation file %s\n", cookie);
+ fclose(f);
+ return false;
+ }
+
sptps_send_record(&c->sptps, 1, buf, 0);
fclose(f);
unlink(usedname);
if(c->protocol_minor >= 2) {
c->allow_request = ACK;
- char label[25 + strlen(myself->name) + strlen(c->name)];
+
+ const size_t labellen = 25 + strlen(myself->name) + strlen(c->name);
+ char *label = alloca(labellen);
if(c->outgoing) {
- snprintf(label, sizeof(label), "tinc TCP key expansion %s %s", myself->name, c->name);
+ snprintf(label, labellen, "tinc TCP key expansion %s %s", myself->name, c->name);
} else {
- snprintf(label, sizeof(label), "tinc TCP key expansion %s %s", c->name, myself->name);
+ snprintf(label, labellen, "tinc TCP key expansion %s %s", c->name, myself->name);
}
- return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof(label), send_meta_sptps, receive_meta_sptps);
+ return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, labellen, send_meta_sptps, receive_meta_sptps);
} else {
return send_metakey(c);
}
}
#ifndef DISABLE_LEGACY
+static const char *get_cipher_name(cipher_t *cipher) {
+ size_t keylen = cipher_keylength(cipher);
+
+ if(keylen <= 16) {
+ return "aes-128-cfb";
+ } else if(keylen <= 24) {
+ return "aes-192-cfb";
+ } else {
+ return "aes-256-cfb";
+ }
+}
+
bool send_metakey(connection_t *c) {
- if(!myself->connection->rsa) {
+ if(!myself->connection->legacy) {
logger(DEBUG_CONNECTIONS, LOG_ERR, "Peer %s (%s) uses legacy protocol which we don't support", c->name, c->hostname);
return false;
}
- if(!read_rsa_public_key(&c->rsa, c->config_tree, c->name)) {
+ rsa_t *rsa = read_rsa_public_key(c->config_tree, c->name);
+
+ if(!rsa) {
return false;
}
+ legacy_ctx_t *ctx = new_legacy_ctx(rsa);
+
/* 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.
*/
- size_t keylen = cipher_keylength(myself->incipher);
- const char *cipher_name;
+ const char *cipher_name = get_cipher_name(myself->incipher);
- if(keylen <= 16) {
- cipher_name = "aes-128-cfb";
- } else if(keylen <= 24) {
- cipher_name = "aes-192-cfb";
- } else {
- cipher_name = "aes-256-cfb";
- }
-
- if(!cipher_open_by_name(&c->outcipher, cipher_name)) {
+ if(!init_crypto_by_name(&ctx->out, cipher_name, "sha256")) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher or digest to %s (%s)", c->name, c->hostname);
+ free_legacy_ctx(ctx);
return false;
}
- c->outbudget = cipher_budget(&c->outcipher);
-
- if(!digest_open_by_name(&c->outdigest, "sha256", DIGEST_ALGO_SIZE)) {
- cipher_close(&c->outcipher);
- return false;
- }
-
- const size_t len = rsa_size(c->rsa);
- char key[len];
- char enckey[len];
- char hexkey[2 * len + 1];
+ const size_t len = rsa_size(ctx->rsa);
+ const size_t hexkeylen = HEX_SIZE(len);
+ char *key = alloca(len);
+ char *enckey = alloca(len);
+ char *hexkey = alloca(hexkeylen);
/* Create a random key */
key[0] &= 0x7F;
- if(!cipher_set_key_from_rsa(&c->outcipher, key, len, true)) {
+ if(!cipher_set_key_from_rsa(&ctx->out.cipher, key, len, true)) {
+ free_legacy_ctx(ctx);
+ memzero(key, len);
return false;
}
if(debug_level >= DEBUG_SCARY_THINGS) {
bin2hex(key, hexkey, len);
logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
+ memzero(hexkey, hexkeylen);
}
/* Encrypt the random data
with a length equal to that of the modulus of the RSA key.
*/
- if(!rsa_public_encrypt(c->rsa, key, len, enckey)) {
+ bool encrypted = rsa_public_encrypt(ctx->rsa, key, len, enckey);
+ memzero(key, len);
+
+ if(!encrypted) {
+ free_legacy_ctx(ctx);
logger(DEBUG_ALWAYS, LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
return false;
}
+ free_legacy_ctx(c->legacy);
+ c->legacy = ctx;
+
/* Convert the encrypted random data to a hexadecimal formatted string */
bin2hex(enckey, hexkey, len);
/* Send the meta key */
bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
- cipher_get_nid(&c->outcipher),
- digest_get_nid(&c->outdigest), c->outmaclength,
- c->outcompression, hexkey);
+ cipher_get_nid(&c->legacy->out.cipher),
+ digest_get_nid(&c->legacy->out.digest), c->outmaclength,
+ COMPRESS_NONE, hexkey);
c->status.encryptout = true;
return result;
}
bool metakey_h(connection_t *c, const char *request) {
- if(!myself->connection->rsa) {
+ if(!myself->connection->legacy || !c->legacy) {
return false;
}
char hexkey[MAX_STRING_SIZE];
- int cipher, digest, maclength, compression;
- const size_t len = rsa_size(myself->connection->rsa);
- char enckey[len];
- char key[len];
+ int cipher, digest;
+ const size_t len = rsa_size(myself->connection->legacy->rsa);
+ char *enckey = alloca(len);
+ char *key = alloca(len);
- if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
+ if(sscanf(request, "%*d %d %d %*d %*d " MAX_STRING, &cipher, &digest, hexkey) != 3) {
logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
return false;
}
+ if(!cipher || !digest) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): cipher %d, digest %d", c->name, c->hostname, cipher, digest);
+ return false;
+ }
+
/* Convert the challenge from hexadecimal back to binary */
- size_t inlen = hex2bin(hexkey, enckey, sizeof(enckey));
+ size_t inlen = hex2bin(hexkey, enckey, len);
/* Check if the length of the meta key is all right */
/* Decrypt the meta key */
- if(!rsa_private_decrypt(myself->connection->rsa, enckey, len, key)) {
+ if(!rsa_private_decrypt(myself->connection->legacy->rsa, enckey, len, key)) {
logger(DEBUG_ALWAYS, LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
return false;
}
if(debug_level >= DEBUG_SCARY_THINGS) {
bin2hex(key, hexkey, len);
logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
+ // Hopefully the user knew what he was doing leaking session keys into logs. We'll do the right thing here anyway.
+ memzero(hexkey, HEX_SIZE(len));
}
/* Check and lookup cipher and digest algorithms */
- if(cipher) {
- if(!cipher_open_by_nid(&c->incipher, cipher) || !cipher_set_key_from_rsa(&c->incipher, key, len, false)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
- return false;
- }
- } else {
- logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "null cipher");
+ if(!init_crypto_by_nid(&c->legacy->in, cipher, digest)) {
+ memzero(key, len);
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher or digest from %s (%s)", c->name, c->hostname);
return false;
}
- c->inbudget = cipher_budget(&c->incipher);
+ bool key_set = cipher_set_key_from_rsa(&c->legacy->in.cipher, key, len, false);
+ memzero(key, len);
- if(digest) {
- if(!digest_open_by_nid(&c->indigest, digest, DIGEST_ALGO_SIZE)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
- return false;
- }
- } else {
- logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "null digest");
+ if(!key_set) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error setting RSA key for %s (%s)", c->name, c->hostname);
return false;
}
}
bool send_challenge(connection_t *c) {
- const size_t len = rsa_size(c->rsa);
- char buffer[len * 2 + 1];
+ const size_t len = rsa_size(c->legacy->rsa);
+ char *buffer = alloca(len * 2 + 1);
c->hischallenge = xrealloc(c->hischallenge, len);
}
bool challenge_h(connection_t *c, const char *request) {
- if(!myself->connection->rsa) {
+ if(!myself->connection->legacy) {
return false;
}
char buffer[MAX_STRING_SIZE];
- const size_t len = rsa_size(myself->connection->rsa);
+ const size_t len = rsa_size(myself->connection->legacy->rsa);
if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
}
bool send_chal_reply(connection_t *c) {
- const size_t len = rsa_size(myself->connection->rsa);
- size_t digestlen = digest_length(&c->indigest);
- char digest[digestlen * 2 + 1];
+ const size_t len = rsa_size(myself->connection->legacy->rsa);
+ size_t digestlen = digest_length(&c->legacy->in.digest);
+ char *digest = alloca(digestlen * 2 + 1);
/* Calculate the hash from the challenge we received */
- if(!digest_create(&c->indigest, c->mychallenge, len, digest)) {
+ if(!digest_create(&c->legacy->in.digest, c->mychallenge, len, digest)) {
return false;
}
/* Check if the length of the hash is all right */
- if(inlen != digest_length(&c->outdigest)) {
+ if(inlen != digest_length(&c->legacy->out.digest)) {
logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
return false;
}
/* Verify the hash */
- if(!digest_verify(&c->outdigest, c->hischallenge, rsa_size(c->rsa), hishash)) {
+ if(!digest_verify(&c->legacy->out.digest, c->hischallenge, rsa_size(c->legacy->rsa), hishash)) {
logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
return false;
}
get_config_int(lookup_config(&config_tree, "Weight"), &c->estimated_weight);
}
- return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
+ return send_request(c, "%d %s %d %x", ACK, myport.udp, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
}
static void send_everything(connection_t *c) {
if(getsockname(c->socket, &local_sa.sa, &local_salen) < 0) {
logger(DEBUG_ALWAYS, LOG_WARNING, "Could not get local socket address for connection with %s", c->name);
} else {
- sockaddr_setport(&local_sa, myport);
+ sockaddr_setport(&local_sa, myport.udp);
c->edge->local_address = local_sa;
}
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