fix: set the minimum TLS version in the client to v1.2 (#156)

This commit sets the minimum required TLS version
by the client to 1.2.

v5/core/base_service.go

@@ -229,6 +229,7 @@ func (service *BaseService) SetDefaultHeaders(headers http.Header) {
 
 // SetHTTPClient updates the client handling the requests.
 func (service *BaseService) SetHTTPClient(client *http.Client) {
+	setMinimumTLSVersion(client)
 	service.Client = client
 }
 
@@ -303,6 +304,18 @@ func getClientTransportForSSL(client *http.Client) *http.Transport {
 	return nil
 }
 
+// setMinimumTLSVersion sets the minimum TLS version required by the client to TLS v1.2
+func setMinimumTLSVersion(client *http.Client) {
+	tr := getClientTransportForSSL(client)
+	if tr != nil {
+		if tr.TLSClientConfig == nil {
+			tr.TLSClientConfig = &tls.Config{} // #nosec G402
+		}
+
+		tr.TLSClientConfig.MinVersion = tls.VersionTLS12
+	}
+}
+
 // SetEnableGzipCompression sets the service's EnableGzipCompression field
 func (service *BaseService) SetEnableGzipCompression(enableGzip bool) {
 	service.Options.EnableGzipCompression = enableGzip
@@ -669,7 +682,9 @@ func (service *BaseService) DisableRetries() {
 
 // DefaultHTTPClient returns a non-retryable http client with default configuration.
 func DefaultHTTPClient() *http.Client {
-	return cleanhttp.DefaultPooledClient()
+	client := cleanhttp.DefaultPooledClient()
+	setMinimumTLSVersion(client)
+	return client
 }
 
 // httpLogger is a shim layer used to allow the Go core's logger to be used with the retryablehttp interfaces.
@@ -691,6 +706,7 @@ func NewRetryableHTTPClient() *retryablehttp.Client {
 	client.CheckRetry = IBMCloudSDKRetryPolicy
 	client.Backoff = IBMCloudSDKBackoffPolicy
 	client.ErrorHandler = retryablehttp.PassthroughErrorHandler
+	setMinimumTLSVersion(client.HTTPClient)
 	return client
 }
 

v5/core/base_service_test.go

@@ -1,3 +1,4 @@
+//go:build all || fast || basesvc
 // +build all fast basesvc
 
 package core
@@ -18,6 +19,7 @@ package core
 
 import (
 	"bytes"
+	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -1966,3 +1968,33 @@ func TestErrorMessage(t *testing.T) {
 		`{"errorMessage":{"statusCode":500,"message":"Internal Server Error"}}`,
 		"Internal Server Error")
 }
+
+func TestMinSSLVersion(t *testing.T) {
+	service, err := NewBaseService(
+		&ServiceOptions{
+			Authenticator: &NoAuthAuthenticator{},
+		})
+	assert.Nil(t, err)
+	assert.NotNil(t, service)
+	assert.NotNil(t, service.Client)
+
+	// Check the default config.
+	minTLS := int(getClientTransportForSSL(service.Client).TLSClientConfig.MinVersion)
+	assert.Equal(t, minTLS, tls.VersionTLS12)
+
+	// Set a insecureClient with different value.
+	insecureClient := &http.Client{}
+	insecureClient.Transport = &http.Transport{
+		TLSClientConfig: &tls.Config{
+			MinVersion: tls.VersionTLS10,
+		},
+	}
+	service.SetHTTPClient(insecureClient)
+	minTLS = int(getClientTransportForSSL(service.Client).TLSClientConfig.MinVersion)
+	assert.Equal(t, minTLS, tls.VersionTLS12)
+
+	// Check retryable client config.
+	service.EnableRetries(3, 30*time.Second)
+	minTLS = int(getClientTransportForSSL(service.Client).TLSClientConfig.MinVersion)
+	assert.Equal(t, minTLS, tls.VersionTLS12)
+}

v5/core/common_test.go

@@ -1,4 +1,5 @@
-// +build all
+//go:build all || fast || basesvc
+// +build all fast basesvc
 
 package core