X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fprotocol_auth.c;h=b13d901a0dd2be92dd122ab84a364e9c9b0b8db5;hb=c44b08613508c993e7fd9f625e0b1b4775efffed;hp=12dc144a29501a05280f0d974ac93322f0c38f3a;hpb=b2701c7c54b11cda71461c5dbbc985476bf5b221;p=tinc

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index 12dc144a..b13d901a 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -1,7 +1,7 @@
 /*
     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
@@ -25,7 +25,6 @@
 #include "control.h"
 #include "control_common.h"
 #include "cipher.h"
-#include "crypto.h"
 #include "digest.h"
 #include "ecdsa.h"
 #include "edge.h"
@@ -42,10 +41,15 @@
 #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;
 
@@ -68,7 +72,8 @@ static bool send_proxyrequest(connection_t *c) {
 			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);
@@ -78,9 +83,9 @@ static bool send_proxyrequest(connection_t *c) {
 			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: {
@@ -91,7 +96,8 @@ static bool send_proxyrequest(connection_t *c) {
 			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;
@@ -137,7 +143,7 @@ static bool send_proxyrequest(connection_t *c) {
 			abort();
 		}
 
-		return send_meta(c, s5req, sizeof(s5req));
+		return send_meta(c, s5req, len);
 	}
 
 	case PROXY_SOCKS4A:
@@ -241,11 +247,12 @@ static bool receive_invitation_sptps(void *handle, uint8_t type, const void *dat
 
 	// 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);
 
@@ -287,7 +294,13 @@ static bool receive_invitation_sptps(void *handle, uint8_t type, const void *dat
 
 	// 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
@@ -325,6 +338,12 @@ static bool receive_invitation_sptps(void *handle, uint8_t type, const void *dat
 		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);
@@ -478,62 +497,67 @@ bool id_h(connection_t *c, const char *request) {
 
 	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 */
 
@@ -551,13 +575,16 @@ bool send_metakey(connection_t *c) {
 
 	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
@@ -567,11 +594,18 @@ bool send_metakey(connection_t *c) {
 	   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);
@@ -579,33 +613,38 @@ bool send_metakey(connection_t *c) {
 	/* 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 */
 
@@ -616,7 +655,7 @@ bool metakey_h(connection_t *c, const char *request) {
 
 	/* 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;
 	}
@@ -624,29 +663,23 @@ bool metakey_h(connection_t *c, const char *request) {
 	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;
 	}
 
@@ -658,8 +691,8 @@ bool metakey_h(connection_t *c, const char *request) {
 }
 
 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);
 
@@ -677,12 +710,12 @@ bool send_challenge(connection_t *c) {
 }
 
 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);
@@ -714,13 +747,13 @@ bool challenge_h(connection_t *c, const char *request) {
 }
 
 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;
 	}
 
@@ -751,7 +784,7 @@ bool chal_reply_h(connection_t *c, const char *request) {
 
 	/* 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;
 	}
@@ -759,7 +792,7 @@ bool chal_reply_h(connection_t *c, const char *request) {
 
 	/* 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;
 	}
@@ -874,7 +907,7 @@ bool send_ack(connection_t *c) {
 		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) {
@@ -1047,7 +1080,7 @@ bool ack_h(connection_t *c, const char *request) {
 	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;
 	}