From f06b208f3efd0d7e3cc8170cf415b8ae377b6517 Mon Sep 17 00:00:00 2001
From: Erik Ekman <yarrick@kryo.se>
Date: Tue, 5 Aug 2008 14:47:51 +0000
Subject: [PATCH] Reworked fix for #21

---
 src/iodined.c | 31 +++++++++++++++++++------------
 src/user.h    |  3 +--
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/iodined.c b/src/iodined.c
index f1e8538..85fb3d1 100644
--- a/src/iodined.c
+++ b/src/iodined.c
@@ -66,6 +66,15 @@ sigint(int sig)
 	running = 0;
 }
 
+static int
+ip_cmp(int userid, struct query *q)
+{
+	struct sockaddr_in *tempin;
+
+	tempin = (struct sockaddr_in *) &(q->from);
+	return memcmp(&(users[userid].host), &(tempin->sin_addr), sizeof(struct in_addr));
+}
+
 static int
 tunnel_tun(int tun_fd, int dns_fd)
 {
@@ -167,10 +176,14 @@ tunnel_dns(int tun_fd, int dns_fd)
 		if (version == VERSION) {
 			userid = find_available_user();
 			if (userid >= 0) {
+				struct sockaddr_in *tempin;
+
 				users[userid].seed = rand();
-				memcpy(&(users[userid].host), &(dummy.q.from), dummy.q.fromlen);
+				/* Store remote IP number */
+				tempin = (struct sockaddr_in *) &(dummy.q.from);
+				memcpy(&(users[userid].host), &(tempin->sin_addr), sizeof(struct in_addr));
+				
 				memcpy(&(users[userid].q), &(dummy.q), sizeof(struct query));
-				users[userid].addrlen = dummy.q.fromlen;
 				users[userid].encoder = get_base32_encoder();
 				send_version_response(dns_fd, VERSION_ACK, users[userid].seed, &users[userid]);
 				users[userid].q.id = 0;
@@ -192,8 +205,7 @@ tunnel_dns(int tun_fd, int dns_fd)
 		users[userid].last_pkt = time(NULL);
 		login_calculate(logindata, 16, password, users[userid].seed);
 
-		if (check_ip && (dummy.q.fromlen != users[userid].addrlen ||
-				memcmp(&(users[userid].host), &(dummy.q.from), dummy.q.fromlen) != 0)) {
+		if (check_ip && ip_cmp(userid, &(dummy.q)) != 0) {
 			write_dns(dns_fd, &(dummy.q), "BADIP", 5);
 		} else {
 			if (read >= 18 && (memcmp(logindata, unpacked+1, 16) == 0)) {
@@ -220,7 +232,7 @@ tunnel_dns(int tun_fd, int dns_fd)
 		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), read - 1, b32);
 		/* Ping packet, store userid */
 		userid = unpacked[0];
-		if (userid < 0 || userid >= USERS) {
+		if (userid < 0 || userid >= USERS || ip_cmp(userid, &(dummy.q)) != 0) {
 			write_dns(dns_fd, &(dummy.q), "BADIP", 5);
 			return 0; /* illegal id */
 		}
@@ -249,8 +261,7 @@ tunnel_dns(int tun_fd, int dns_fd)
 		}
 
 		/* Check sending ip number */
-		if (check_ip && (dummy.q.fromlen != users[userid].addrlen ||
-				memcmp(&(users[userid].host), &(dummy.q.from), dummy.q.fromlen) != 0)) {
+		if (check_ip && ip_cmp(userid, &(dummy.q)) != 0) {
 			write_dns(dns_fd, &(dummy.q), "BADIP", 5);
 		} else {
 			/* decode with this users encoding */
@@ -259,7 +270,6 @@ tunnel_dns(int tun_fd, int dns_fd)
 
 			users[userid].last_pkt = time(NULL);
 			memcpy(&(users[userid].q), &(dummy.q), sizeof(struct query));
-			users[userid].addrlen = dummy.q.fromlen;
 			memcpy(users[userid].inpacket.data + users[userid].inpacket.offset, unpacked, read);
 			users[userid].inpacket.len += read;
 			users[userid].inpacket.offset += read;
@@ -288,10 +298,7 @@ tunnel_dns(int tun_fd, int dns_fd)
 		}
 	}
 	/* userid must be set for a reply to be sent */
-	if (userid >= 0 && userid < USERS && dummy.q.fromlen == users[userid].addrlen &&
-			memcmp(&(users[userid].host), &(dummy.q.from), dummy.q.fromlen) == 0 &&
-			users[userid].outpacket.len > 0) {
-
+	if (userid >= 0 && userid < USERS && ip_cmp(userid, &(dummy.q)) == 0 &&	users[userid].outpacket.len > 0) {
 		write_dns(dns_fd, &(dummy.q), users[userid].outpacket.data, users[userid].outpacket.len);
 		users[userid].outpacket.len = 0;
 		users[userid].q.id = 0;
diff --git a/src/user.h b/src/user.h
index 2d0d2ad..b333bcb 100644
--- a/src/user.h
+++ b/src/user.h
@@ -25,8 +25,7 @@ struct user {
 	time_t last_pkt;
 	int seed;
 	in_addr_t tun_ip;
-	struct sockaddr host;
-	int addrlen;
+	struct in_addr host;
 	struct query q;
 	struct packet inpacket;
 	struct packet outpacket;