Add extensive endpoints validation (#4019)

cmd/net.go

@@ -0,0 +1,167 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"sort"
+	"strconv"
+	"syscall"
+
+	"github.com/minio/minio-go/pkg/set"
+)
+
+// IPv4 addresses of local host.
+var localIP4 = mustGetLocalIP4()
+
+// mustSplitHostPort is a wrapper to net.SplitHostPort() where error is assumed to be a fatal.
+func mustSplitHostPort(hostPort string) (host, port string) {
+	host, port, err := net.SplitHostPort(hostPort)
+	fatalIf(err, "Unable to split host port %s", hostPort)
+	return host, port
+}
+
+// mustGetLocalIP4 returns IPv4 addresses of local host.  It panics on error.
+func mustGetLocalIP4() (ipList set.StringSet) {
+	ipList = set.NewStringSet()
+	addrs, err := net.InterfaceAddrs()
+	fatalIf(err, "Unable to get IP addresses of this host.")
+
+	for _, addr := range addrs {
+		var ip net.IP
+		switch v := addr.(type) {
+		case *net.IPNet:
+			ip = v.IP
+		case *net.IPAddr:
+			ip = v.IP
+		}
+
+		if ip.To4() != nil {
+			ipList.Add(ip.String())
+		}
+	}
+
+	return ipList
+}
+
+// getHostIP4 returns IPv4 address of given host.
+func getHostIP4(host string) (ipList set.StringSet, err error) {
+	ipList = set.NewStringSet()
+	ips, err := net.LookupIP(host)
+	if err != nil {
+		return ipList, err
+	}
+
+	for _, ip := range ips {
+		if ip.To4() != nil {
+			ipList.Add(ip.String())
+		}
+	}
+
+	return ipList, err
+}
+
+func getAPIEndpoints(serverAddr string) (apiEndpoints []string) {
+	host, port := mustSplitHostPort(serverAddr)
+
+	var ipList []string
+	if host == "" {
+		ipList = localIP4.ToSlice()
+	} else {
+		ipList = []string{host}
+	}
+
+	sort.Strings(ipList)
+
+	scheme := httpScheme
+	if globalIsSSL {
+		scheme = httpsScheme
+	}
+
+	for _, ip := range ipList {
+		apiEndpoints = append(apiEndpoints, fmt.Sprintf("%s://%s:%s", scheme, ip, port))
+	}
+
+	return apiEndpoints
+}
+
+// checkPortAvailability - check if given port is already in use.
+// Note: The check method tries to listen on given port and closes it.
+// It is possible to have a disconnected client in this tiny window of time.
+func checkPortAvailability(port string) (err error) {
+	// Return true if err is "address already in use" error.
+	isAddrInUseErr := func(err error) (b bool) {
+		if opErr, ok := err.(*net.OpError); ok {
+			if sysErr, ok := opErr.Err.(*os.SyscallError); ok {
+				if errno, ok := sysErr.Err.(syscall.Errno); ok {
+					b = (errno == syscall.EADDRINUSE)
+				}
+			}
+		}
+
+		return b
+	}
+
+	network := []string{"tcp", "tcp4", "tcp6"}
+	for _, n := range network {
+		l, err := net.Listen(n, net.JoinHostPort("", port))
+		if err == nil {
+			// As we are able to listen on this network, the port is not in use.
+			// Close the listener and continue check other networks.
+			if err = l.Close(); err != nil {
+				return err
+			}
+		} else if isAddrInUseErr(err) {
+			// As we got EADDRINUSE error, the port is in use by other process.
+			// Return the error.
+			return err
+		}
+	}
+
+	return nil
+}
+
+// CheckLocalServerAddr - checks if serverAddr is valid and local host.
+func CheckLocalServerAddr(serverAddr string) error {
+	host, port, err := net.SplitHostPort(serverAddr)
+	if err != nil {
+		return err
+	}
+
+	// Check whether port is a valid port number.
+	p, err := strconv.Atoi(port)
+	if err != nil {
+		return fmt.Errorf("invalid port number")
+	} else if p < 1 || p > 65535 {
+		return fmt.Errorf("port number must be between 1 to 65535")
+	}
+
+	if host != "" {
+		hostIPs, err := getHostIP4(host)
+		if err != nil {
+			return err
+		}
+
+		if localIP4.Intersection(hostIPs).IsEmpty() {
+			return fmt.Errorf("host in server address should be this server")
+		}
+	}
+
+	return nil
+}