Added points in KKDCP connections to prevent DoS attacks.

doc/sample.config

@@ -55,7 +55,7 @@ auth = "plain[passwd=./sample.passwd]"
 # system calls allowed to a worker process, in order to reduce damage from a
 # bug in the worker process. It is available on Linux systems at a performance cost.
 # The performance cost is roughly 2% overhead at transfer time (tested on a Linux 3.17.8).
-isolate-workers = true
+#isolate-workers = true
 
 # A banner to be displayed on clients
 #banner = "Welcome"
@@ -216,7 +216,7 @@ min-reauth-time = 300
 # Banning clients in ocserv works with a point system. IP addresses
 # that get a score over that configured number are banned for
 # min-reauth-time seconds. A wrong password attempt is 10 points,
-# a connection is 1 point.
+# a KKDCP POST is 1 point, and a connection is 1 point.
 #
 # Set to zero to disable.
 max-ban-score = 50

src/ipc.proto

@@ -137,6 +137,13 @@ message session_info_msg
 	optional string dtls_compr = 5;
 }
 
+/* WORKER_BAN_IP: sent from worker to main */
+message ban_ip_msg
+{
+	required string ip = 1;
+	required uint32 score = 2;
+}
+
 
 /* Messages to and from the security module */
 
@@ -257,8 +264,4 @@ message sec_auth_session_reply_msg
 }
 
 /* SEC_BAN_IP: sent from sec-mod to main */
-message sec_auth_ban_ip
+/* same as: ban_ip_msg */
-{
-	required string ip = 1;
-	required uint32 score = 2;
-}

src/main-misc.c

@@ -55,6 +55,7 @@
 #include <cookies.h>
 #include <tun.h>
 #include <main.h>
+#include <main-ban.h>
 #include <ccan/list/list.h>
 
 int set_tun_mtu(main_server_st * s, struct proc_st *proc, unsigned mtu)
@@ -505,6 +506,21 @@ int handle_commands(main_server_st * s, struct proc_st *proc)
 	}
 
 	switch (cmd) {
+	case CMD_BAN_IP:{
+			BanIpMsg *tmsg;
+
+			tmsg = ban_ip_msg__unpack(&pa, raw_len, raw);
+			if (tmsg == NULL) {
+				mslog(s, NULL, LOG_ERR, "error unpacking sec-mod data");
+				ret = ERR_BAD_COMMAND;
+				goto cleanup;
+			}
+			add_ip_to_ban_list(s, tmsg->ip, tmsg->score);
+
+			ban_ip_msg__free_unpacked(tmsg, &pa);
+		}
+
+		break;
 	case CMD_TUN_MTU:{
 			TunMtuMsg *tmsg;
 

src/main-sec-mod-cmd.c

@@ -112,9 +112,9 @@ int handle_sec_mod_commands(main_server_st * s)
 
 	switch (cmd) {
 	case SM_CMD_AUTH_BAN_IP:{
-			SecAuthBanIp *tmsg;
+			BanIpMsg *tmsg;
 
-			tmsg = sec_auth_ban_ip__unpack(&pa, raw_len, raw);
+			tmsg = ban_ip_msg__unpack(&pa, raw_len, raw);
 			if (tmsg == NULL) {
 				mslog(s, NULL, LOG_ERR, "error unpacking sec-mod data");
 				ret = ERR_BAD_COMMAND;
@@ -122,7 +122,7 @@ int handle_sec_mod_commands(main_server_st * s)
 			}
 			add_ip_to_ban_list(s, tmsg->ip, tmsg->score);
 
-			sec_auth_ban_ip__free_unpacked(tmsg, &pa);
+			ban_ip_msg__free_unpacked(tmsg, &pa);
 		}
 
 		break;

src/ocserv-args.def

@@ -130,7 +130,7 @@ An example configuration file follows.
 # system calls allowed to a worker process, in order to reduce damage from a
 # bug in the worker process. It is available on Linux systems at a performance cost.
 # The performance cost is roughly 2% overhead at transfer time (tested on a Linux 3.17.8).
-#isolate-workers = true
+isolate-workers = true
 
 # A banner to be displayed on clients
 #banner = "Welcome"
@@ -291,7 +291,7 @@ min-reauth-time = 120
 # Banning clients in ocserv works with a point system. IP addresses
 # that get a score over that configured number are banned for
 # min-reauth-time seconds. A wrong password attempt is 10 points,
-# a connection is 1 point.
+# a KKDCP POST is 1 point, and a connection is 1 point.
 #
 # Set to zero to disable.
 max-ban-score = 50

src/sec-mod-auth.c

@@ -77,7 +77,7 @@ void sec_mod_add_score_to_ip(sec_mod_st *sec, void *pool, const char *ip, unsign
 {
 	void *lpool;
 	int ret, e;
-	SecAuthBanIp msg = SEC_AUTH_BAN_IP__INIT;
+	BanIpMsg msg = BAN_IP_MSG__INIT;
 
 	msg.ip = (char*)ip;
 	msg.score = points;
@@ -88,8 +88,8 @@ void sec_mod_add_score_to_ip(sec_mod_st *sec, void *pool, const char *ip, unsign
 	}
 
 	ret = send_msg(lpool, sec->cmd_fd, SM_CMD_AUTH_BAN_IP, &msg,
-				(pack_size_func) sec_auth_ban_ip__get_packed_size,
+				(pack_size_func) ban_ip_msg__get_packed_size,
-				(pack_func) sec_auth_ban_ip__pack);
+				(pack_func) ban_ip_msg__pack);
 	if (ret < 0) {
 		e = errno;
 		seclog(sec, LOG_WARNING, "error in sending BAN IP message: %s", strerror(e));

src/vpn.h

@@ -63,6 +63,7 @@ typedef enum {
  */
 #define PASSWORD_POINTS 10
 #define CONNECT_POINTS 1
+#define KKDCP_POINTS 1
 #define DEFAULT_MAX_BAN_SCORE (MAX_PASSWORD_TRIES*PASSWORD_POINTS)
 #define DEFAULT_BAN_RESET_TIME 300
 
@@ -143,6 +144,7 @@ typedef enum {
 	CMD_TERMINATE = 12,
 	CMD_SESSION_INFO = 13,
 	CMD_CLI_STATS = 15,
+	CMD_BAN_IP = 16,
 
 	/* from worker to sec-mod */
 	SM_CMD_AUTH_INIT = 120,

src/worker-kkdcp.c

@@ -30,6 +30,33 @@
 
 #ifdef HAVE_GSSAPI
 
+static
+void worker_add_score_to_ip(worker_st *ws, const char *ip, unsigned points)
+{
+	void *lpool;
+	int ret, e;
+	BanIpMsg msg = BAN_IP_MSG__INIT;
+
+	msg.ip = (char*)ip;
+	msg.score = points;
+
+	lpool = talloc_new(ws);
+	if (lpool == NULL) {
+		return;
+	}
+
+	ret = send_msg(lpool, ws->cmd_fd, CMD_BAN_IP, &msg,
+				(pack_size_func) ban_ip_msg__get_packed_size,
+				(pack_func) ban_ip_msg__pack);
+	if (ret < 0) {
+		e = errno;
+		oclog(ws, LOG_WARNING, "error in sending BAN IP message: %s", strerror(e));
+	}
+	talloc_free(lpool);
+
+	return;
+}
+
 int der_decode(const uint8_t *der, unsigned der_size, uint8_t *out, unsigned *out_size, 
 	       char *realm, unsigned realm_size, int *error)
 {
@@ -140,6 +167,9 @@ int post_kkdcp_handler(worker_st *ws, unsigned http_ver)
 		return -1;
 	}
 
+	if (human_addr2((void*)&ws->remote_addr, ws->remote_addr_len, realm, sizeof(realm), 0) != NULL)
+		worker_add_score_to_ip(ws, realm, KKDCP_POINTS);
+
 	oclog(ws, LOG_HTTP_DEBUG, "HTTP processing kkdcp framed request: %u bytes", (unsigned)req->body_length);