More fixes in ipv6 parsing in get bucket location

Also fix the endpoint validation. The code was assuming that any address
has ':' in it means it has a port but this is not true.

bucket-cache.go

@@ -181,6 +181,9 @@ func (c *Client) getBucketLocationRequest(ctx context.Context, bucketName string
 	if h, p, err := net.SplitHostPort(targetURL.Host); err == nil {
 		if targetURL.Scheme == "http" && p == "80" || targetURL.Scheme == "https" && p == "443" {
 			targetURL.Host = h
+			if ip := net.ParseIP(h); ip != nil && ip.To16() != nil {
+				targetURL.Host = "[" + h + "]"
+			}
 		}
 	}
 

utils.go

@@ -105,21 +105,6 @@ func sumMD5Base64(data []byte) string {
 
 // getEndpointURL - construct a new endpoint.
 func getEndpointURL(endpoint string, secure bool) (*url.URL, error) {
-	if strings.Contains(endpoint, ":") {
-		host, _, err := net.SplitHostPort(endpoint)
-		if err != nil {
-			return nil, err
-		}
-		if !s3utils.IsValidIP(host) && !s3utils.IsValidDomain(host) {
-			msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
-			return nil, errInvalidArgument(msg)
-		}
-	} else {
-		if !s3utils.IsValidIP(endpoint) && !s3utils.IsValidDomain(endpoint) {
-			msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
-			return nil, errInvalidArgument(msg)
-		}
-	}
 	// If secure is false, use 'http' scheme.
 	scheme := "https"
 	if !secure {
@@ -176,6 +161,21 @@ func isValidEndpointURL(endpointURL url.URL) error {
 	if endpointURL.Path != "/" && endpointURL.Path != "" {
 		return errInvalidArgument("Endpoint url cannot have fully qualified paths.")
 	}
+
+	host, _, err := net.SplitHostPort(endpointURL.Host)
+	if err != nil {
+		if strings.Contains(err.Error(), "missing port in address") {
+			err = nil
+			host = endpointURL.Host
+		} else {
+			return err
+		}
+	}
+	if !s3utils.IsValidIP(host) && !s3utils.IsValidDomain(host) {
+		msg := "Endpoint: " + endpointURL.Host + " does not follow ip address or domain name standards."
+		return errInvalidArgument(msg)
+	}
+
 	if strings.Contains(endpointURL.Host, ".s3.amazonaws.com") {
 		if !s3utils.IsAmazonEndpoint(endpointURL) {
 			return errInvalidArgument("Amazon S3 endpoint should be 's3.amazonaws.com'.")

utils_test.go

@@ -153,7 +153,6 @@ func TestIsValidEndpointURL(t *testing.T) {
 		shouldPass bool
 	}{
 		{"", errInvalidArgument("Endpoint url cannot be empty."), false},
-		{"/", nil, true},
 		{"https://s3.amazonaws.com", nil, true},
 		{"https://s3.cn-north-1.amazonaws.com.cn", nil, true},
 		{"https://s3-us-gov-west-1.amazonaws.com", nil, true},
@@ -167,6 +166,7 @@ func TestIsValidEndpointURL(t *testing.T) {
 		{"https://amazon.googleapis.com/", errInvalidArgument("Google Cloud Storage endpoint should be 'storage.googleapis.com'."), false},
 		{"https://storage.googleapis.com/bucket/", errInvalidArgument("Endpoint url cannot have fully qualified paths."), false},
 		{"https://s3.amazonaws.com/bucket/object", errInvalidArgument("Endpoint url cannot have fully qualified paths."), false},
+		{"https://.s3server.example.com/", errInvalidArgument("Endpoint: .s3server.example.com does not follow ip address or domain name standards."), false},
 	}
 
 	for i, testCase := range testCases {