X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fprotocol_auth.c;h=19859b7580f9829a58c1cbf246c4e86819edbdd1;hb=50c62f7235eacd3b88c59ead983e8be719fb7604;hp=d4bb4074f69efd82b90aaa94aa3f42198d709d6a;hpb=bcac314fe2d758e85335d499dbb4300bfa8a599e;p=tinc

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index d4bb4074..19859b75 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
@@ -46,6 +46,9 @@
 #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 +71,8 @@ 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 +82,9 @@ 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 +95,8 @@ 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 +142,7 @@ static bool send_proxyrequest(connection_t *c) {
 			abort();
 		}
 
-		return send_meta(c, s5req, sizeof(s5req));
+		return send_meta(c, s5req, len);
 	}
 
 	case PROXY_SOCKS4A:
@@ -241,12 +246,13 @@ 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);
-	b64encode_urlsafe(cookie, cookie, 18);
+	memcpy(hashbuf + 18, fingerprint, hashbuflen - 18);
+	sha512(hashbuf, hashbuflen, cookie);
+	b64encode_tinc_urlsafe(cookie, cookie, 18);
 	free(fingerprint);
 
 	char filename[PATH_MAX], usedname[PATH_MAX];
@@ -287,7 +293,12 @@ 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);
+		return false;
+	}
+
 	size_t buflen = strlen(buf);
 
 	// Strip whitespace at the end
@@ -478,15 +489,17 @@ 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);
 	}
@@ -531,9 +544,9 @@ bool send_metakey(connection_t *c) {
 	}
 
 	const size_t len = rsa_size(c->rsa);
-	char key[len];
-	char enckey[len];
-	char hexkey[2 * len + 1];
+	char *key = alloca(len);
+	char *enckey = alloca(len);
+	char *hexkey = alloca(2 * len + 1);
 
 	/* Create a random key */
 
@@ -595,8 +608,8 @@ bool metakey_h(connection_t *c, const char *request) {
 	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];
+	char *enckey = alloca(len);
+	char *key = alloca(len);
 
 	if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
@@ -605,7 +618,7 @@ bool metakey_h(connection_t *c, const char *request) {
 
 	/* 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 */
 
@@ -659,7 +672,7 @@ 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];
+	char *buffer = alloca(len * 2 + 1);
 
 	c->hischallenge = xrealloc(c->hischallenge, len);
 
@@ -716,7 +729,7 @@ 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];
+	char *digest = alloca(digestlen * 2 + 1);
 
 	/* Calculate the hash from the challenge we received */