From: Sebastian Harl <sh@tokkee.org>
Date: Wed, 14 May 2014 18:55:29 +0000 (+0200)
Subject: frontend: Handle missing authentication early.
X-Git-Tag: sysdb-0.1.0~23
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=cb21eefec7a836927a2e313f83cda80c573f1b65;p=sysdb.git

frontend: Handle missing authentication early.

… and limit the max amount of buffered data for unauthenticated connections in
order reduce the impact of anonymous DoS attempts.
---

diff --git a/src/frontend/connection.c b/src/frontend/connection.c
index b913939..dba4310 100644
--- a/src/frontend/connection.c
+++ b/src/frontend/connection.c
@@ -265,14 +265,6 @@ command_handle(sdb_conn_t *conn)
 	sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
 			conn->cmd, conn->cmd_len);
 
-	if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
-		const char *errmsg = "Authentication required";
-		sdb_strbuf_sprintf(conn->errbuf, errmsg);
-		sdb_connection_send(conn, CONNECTION_ERROR,
-				(uint32_t)strlen(errmsg), errmsg);
-		return -1;
-	}
-
 	switch (conn->cmd) {
 		case CONNECTION_PING:
 			status = sdb_connection_ping(conn);
@@ -379,7 +371,16 @@ command_init(sdb_conn_t *conn)
 	conn->cmd = connection_get_int32(conn, 0);
 	conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
 
-	if (conn->cmd == CONNECTION_IDLE) {
+	if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
+		const char *errmsg = "Authentication required";
+		sdb_strbuf_sprintf(conn->errbuf, errmsg);
+		sdb_connection_send(conn, CONNECTION_ERROR,
+				(uint32_t)strlen(errmsg), errmsg);
+		conn->skip_len += conn->cmd_len;
+		conn->cmd = CONNECTION_IDLE;
+		conn->cmd_len = 0;
+	}
+	else if (conn->cmd == CONNECTION_IDLE) {
 		const char *errmsg = "Invalid command 0";
 		sdb_strbuf_sprintf(conn->errbuf, errmsg);
 		sdb_connection_send(conn, CONNECTION_ERROR,
diff --git a/t/unit/frontend/connection_test.c b/t/unit/frontend/connection_test.c
index 43322e0..a069903 100644
--- a/t/unit/frontend/connection_test.c
+++ b/t/unit/frontend/connection_test.c
@@ -169,7 +169,7 @@ mock_client(void *arg)
 } /* mock_client */
 
 static void
-connection_setup(sdb_conn_t *conn)
+connection_startup(sdb_conn_t *conn)
 {
 	ssize_t check, expected;
 
@@ -191,7 +191,7 @@ connection_setup(sdb_conn_t *conn)
 			"buffer; expected: 0", sdb_strbuf_len(conn->errbuf));
 
 	mock_conn_truncate(conn);
-} /* connection_setup */
+} /* connection_startup */
 
 /*
  * tests
@@ -238,7 +238,7 @@ START_TEST(test_conn_setup)
 	} golden_data[] = {
 		/* code == UINT32_MAX => no data will be sent */
 		{ UINT32_MAX,         NULL,       NULL },
-		{ CONNECTION_IDLE,    "fakedata", "Invalid command 0" },
+		{ CONNECTION_IDLE,    "fakedata", "Authentication required" },
 		{ CONNECTION_PING,    NULL,       "Authentication required" },
 		{ CONNECTION_STARTUP, "fakeuser", NULL },
 		{ CONNECTION_PING,    NULL,       NULL },
@@ -308,23 +308,28 @@ START_TEST(test_conn_io)
 		const char *err;
 	} golden_data[] = {
 		/* code == UINT32_MAX => this is a follow-up package */
-		{ CONNECTION_PING, 20, "9876543210", 10, NULL },
-		{ UINT32_MAX,      -1, "9876543210",  0, NULL },
-		{ CONNECTION_IDLE, 20, "9876543210",  0, "Invalid command 0" },
-		{ UINT32_MAX,      -1, "9876543210",  0, "Invalid command 0" },
-		{ CONNECTION_IDLE, 20, "9876543210",  0, "Invalid command 0" },
-		{ UINT32_MAX,      -1, "9876543210",  0, "Invalid command 0" },
-		{ CONNECTION_PING, 10, "9876543210",  0, NULL },
-		{ CONNECTION_PING, 20, "9876543210", 10, NULL },
-		{ UINT32_MAX,      -1, "9876543210",  0, NULL },
+		{ CONNECTION_PING,    20, "9876543210",  0, "Authentication required" },
+		{ UINT32_MAX,         -1, "9876543210",  0, "Authentication required" },
+		{ CONNECTION_PING,    10, "9876543210",  0, "Authentication required" },
+		{ CONNECTION_IDLE,    10, "9876543210",  0, "Authentication required" },
+		{ CONNECTION_IDLE,    20, "9876543210",  0, "Authentication required" },
+		{ UINT32_MAX,         -1, "9876543210",  0, "Authentication required" },
+		{ CONNECTION_STARTUP, -1, NULL,          0, NULL },
+		{ CONNECTION_PING,    20, "9876543210", 10, NULL },
+		{ UINT32_MAX,         -1, "9876543210",  0, NULL },
+		{ CONNECTION_IDLE,    20, "9876543210",  0, "Invalid command 0" },
+		{ UINT32_MAX,         -1, "9876543210",  0, "Invalid command 0" },
+		{ CONNECTION_IDLE,    20, "9876543210",  0, "Invalid command 0" },
+		{ UINT32_MAX,         -1, "9876543210",  0, "Invalid command 0" },
+		{ CONNECTION_PING,    10, "9876543210",  0, NULL },
+		{ CONNECTION_PING,    20, "9876543210", 10, NULL },
+		{ UINT32_MAX,         -1, "9876543210",  0, NULL },
 	};
 
 	size_t i;
 
-	connection_setup(conn);
-
 	for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
-		size_t msg_len = strlen(golden_data[i].msg);
+		size_t msg_len = golden_data[i].msg ? strlen(golden_data[i].msg) : 0;
 		char buffer[2 * sizeof(uint32_t) + msg_len];
 		size_t offset = 0;
 
@@ -332,6 +337,11 @@ START_TEST(test_conn_io)
 
 		mock_conn_truncate(conn);
 
+		if (golden_data[i].code == CONNECTION_STARTUP) {
+			connection_startup(conn);
+			continue;
+		}
+
 		if (golden_data[i].code != UINT32_MAX) {
 			uint32_t tmp;