Implement fmt.Stringer on rest.Config to sanitize sensitive fields

staging/src/k8s.io/client-go/plugin/pkg/client/auth/exec/BUILD

@@ -18,6 +18,7 @@ go_library(
         "//staging/src/k8s.io/client-go/tools/clientcmd/api:go_default_library",
         "//staging/src/k8s.io/client-go/transport:go_default_library",
         "//staging/src/k8s.io/client-go/util/connrotation:go_default_library",
+        "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
         "//vendor/golang.org/x/crypto/ssh/terminal:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
     ],

staging/src/k8s.io/client-go/plugin/pkg/client/auth/exec/exec.go

@@ -31,6 +31,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/davecgh/go-spew/spew"
 	"golang.org/x/crypto/ssh/terminal"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -73,8 +74,10 @@ func newCache() *cache {
 	return &cache{m: make(map[string]*Authenticator)}
 }
 
+var spewConfig = &spew.ConfigState{DisableMethods: true, Indent: " "}
+
 func cacheKey(c *api.ExecConfig) string {
-	return fmt.Sprintf("%#v", c)
+	return spewConfig.Sprint(c)
 }
 
 type cache struct {

staging/src/k8s.io/client-go/rest/config.go

@@ -129,6 +129,47 @@ type Config struct {
 	// Version string
 }
 
+var _ fmt.Stringer = new(Config)
+var _ fmt.GoStringer = new(Config)
+
+type sanitizedConfig *Config
+
+type sanitizedAuthConfigPersister struct{ AuthProviderConfigPersister }
+
+func (sanitizedAuthConfigPersister) GoString() string {
+	return "rest.AuthProviderConfigPersister(--- REDACTED ---)"
+}
+func (sanitizedAuthConfigPersister) String() string {
+	return "rest.AuthProviderConfigPersister(--- REDACTED ---)"
+}
+
+// GoString implements fmt.GoStringer and sanitizes sensitive fields of Config
+// to prevent accidental leaking via logs.
+func (c *Config) GoString() string {
+	return c.String()
+}
+
+// String implements fmt.Stringer and sanitizes sensitive fields of Config to
+// prevent accidental leaking via logs.
+func (c *Config) String() string {
+	if c == nil {
+		return "<nil>"
+	}
+	cc := sanitizedConfig(CopyConfig(c))
+	// Explicitly mark non-empty credential fields as redacted.
+	if cc.Password != "" {
+		cc.Password = "--- REDACTED ---"
+	}
+	if cc.BearerToken != "" {
+		cc.BearerToken = "--- REDACTED ---"
+	}
+	if cc.AuthConfigPersister != nil {
+		cc.AuthConfigPersister = sanitizedAuthConfigPersister{cc.AuthConfigPersister}
+	}
+
+	return fmt.Sprintf("%#v", cc)
+}
+
 // ImpersonationConfig has all the available impersonation options
 type ImpersonationConfig struct {
 	// UserName is the username to impersonate on each request.
@@ -168,6 +209,40 @@ type TLSClientConfig struct {
 	CAData []byte
 }
 
+var _ fmt.Stringer = TLSClientConfig{}
+var _ fmt.GoStringer = TLSClientConfig{}
+
+type sanitizedTLSClientConfig TLSClientConfig
+
+// GoString implements fmt.GoStringer and sanitizes sensitive fields of
+// TLSClientConfig to prevent accidental leaking via logs.
+func (c TLSClientConfig) GoString() string {
+	return c.String()
+}
+
+// String implements fmt.Stringer and sanitizes sensitive fields of
+// TLSClientConfig to prevent accidental leaking via logs.
+func (c TLSClientConfig) String() string {
+	cc := sanitizedTLSClientConfig{
+		Insecure:   c.Insecure,
+		ServerName: c.ServerName,
+		CertFile:   c.CertFile,
+		KeyFile:    c.KeyFile,
+		CAFile:     c.CAFile,
+		CertData:   c.CertData,
+		KeyData:    c.KeyData,
+		CAData:     c.CAData,
+	}
+	// Explicitly mark non-empty credential fields as redacted.
+	if len(cc.CertData) != 0 {
+		cc.CertData = []byte("--- TRUNCATED ---")
+	}
+	if len(cc.KeyData) != 0 {
+		cc.KeyData = []byte("--- REDACTED ---")
+	}
+	return fmt.Sprintf("%#v", cc)
+}
+
 type ContentConfig struct {
 	// AcceptContentTypes specifies the types the client will accept and is optional.
 	// If not set, ContentType will be used to define the Accept header

staging/src/k8s.io/client-go/rest/config_test.go

@@ -19,6 +19,7 @@ package rest
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
@@ -26,6 +27,7 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+	"time"
 
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -381,3 +383,140 @@ func TestCopyConfig(t *testing.T) {
 		}
 	}
 }
+
+func TestConfigStringer(t *testing.T) {
+	formatBytes := func(b []byte) string {
+		// %#v for []byte always pre-pends "[]byte{".
+		// %#v for struct with []byte field always pre-pends "[]uint8{".
+		return strings.Replace(fmt.Sprintf("%#v", b), "byte", "uint8", 1)
+	}
+	tests := []struct {
+		desc            string
+		c               *Config
+		expectContent   []string
+		prohibitContent []string
+	}{
+		{
+			desc:          "nil config",
+			c:             nil,
+			expectContent: []string{"<nil>"},
+		},
+		{
+			desc: "non-sensitive config",
+			c: &Config{
+				Host:      "localhost:8080",
+				APIPath:   "v1",
+				UserAgent: "gobot",
+			},
+			expectContent: []string{"localhost:8080", "v1", "gobot"},
+		},
+		{
+			desc: "sensitive config",
+			c: &Config{
+				Host:        "localhost:8080",
+				Username:    "gopher",
+				Password:    "g0ph3r",
+				BearerToken: "1234567890",
+				TLSClientConfig: TLSClientConfig{
+					CertFile: "a.crt",
+					KeyFile:  "a.key",
+					CertData: []byte("fake cert"),
+					KeyData:  []byte("fake key"),
+				},
+				AuthProvider: &clientcmdapi.AuthProviderConfig{
+					Config: map[string]string{"secret": "s3cr3t"},
+				},
+				ExecProvider: &clientcmdapi.ExecConfig{
+					Args: []string{"secret"},
+					Env:  []clientcmdapi.ExecEnvVar{{Name: "secret", Value: "s3cr3t"}},
+				},
+			},
+			expectContent: []string{
+				"localhost:8080",
+				"gopher",
+				"a.crt",
+				"a.key",
+				"--- REDACTED ---",
+				formatBytes([]byte("--- REDACTED ---")),
+				formatBytes([]byte("--- TRUNCATED ---")),
+			},
+			prohibitContent: []string{
+				"g0ph3r",
+				"1234567890",
+				formatBytes([]byte("fake cert")),
+				formatBytes([]byte("fake key")),
+				"secret",
+				"s3cr3t",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			got := tt.c.String()
+			t.Logf("formatted config: %q", got)
+
+			for _, expect := range tt.expectContent {
+				if !strings.Contains(got, expect) {
+					t.Errorf("missing expected string %q", expect)
+				}
+			}
+			for _, prohibit := range tt.prohibitContent {
+				if strings.Contains(got, prohibit) {
+					t.Errorf("found prohibited string %q", prohibit)
+				}
+			}
+		})
+	}
+}
+
+func TestConfigSprint(t *testing.T) {
+	c := &Config{
+		Host:    "localhost:8080",
+		APIPath: "v1",
+		ContentConfig: ContentConfig{
+			AcceptContentTypes: "application/json",
+			ContentType:        "application/json",
+		},
+		Username:    "gopher",
+		Password:    "g0ph3r",
+		BearerToken: "1234567890",
+		Impersonate: ImpersonationConfig{
+			UserName: "gopher2",
+		},
+		AuthProvider: &clientcmdapi.AuthProviderConfig{
+			Name:   "gopher",
+			Config: map[string]string{"secret": "s3cr3t"},
+		},
+		AuthConfigPersister: fakeAuthProviderConfigPersister{},
+		ExecProvider: &clientcmdapi.ExecConfig{
+			Command: "sudo",
+			Args:    []string{"secret"},
+			Env:     []clientcmdapi.ExecEnvVar{{Name: "secret", Value: "s3cr3t"}},
+		},
+		TLSClientConfig: TLSClientConfig{
+			CertFile: "a.crt",
+			KeyFile:  "a.key",
+			CertData: []byte("fake cert"),
+			KeyData:  []byte("fake key"),
+		},
+		UserAgent:     "gobot",
+		Transport:     &fakeRoundTripper{},
+		WrapTransport: fakeWrapperFunc,
+		QPS:           1,
+		Burst:         2,
+		RateLimiter:   &fakeLimiter{},
+		Timeout:       3 * time.Second,
+		Dial:          fakeDialFunc,
+	}
+	want := fmt.Sprintf(
+		`&rest.Config{Host:"localhost:8080", APIPath:"v1", ContentConfig:rest.ContentConfig{AcceptContentTypes:"application/json", ContentType:"application/json", GroupVersion:(*schema.GroupVersion)(nil), NegotiatedSerializer:runtime.NegotiatedSerializer(nil)}, Username:"gopher", Password:"--- REDACTED ---", BearerToken:"--- REDACTED ---", BearerTokenFile:"", Impersonate:rest.ImpersonationConfig{UserName:"gopher2", Groups:[]string(nil), Extra:map[string][]string(nil)}, AuthProvider:api.AuthProviderConfig{Name: "gopher", Config: map[string]string{--- REDACTED ---}}, AuthConfigPersister:rest.AuthProviderConfigPersister(--- REDACTED ---), ExecProvider:api.AuthProviderConfig{Command: "sudo", Args: []string{"--- REDACTED ---"}, Env: []ExecEnvVar{--- REDACTED ---}, APIVersion: ""}, TLSClientConfig:rest.sanitizedTLSClientConfig{Insecure:false, ServerName:"", CertFile:"a.crt", KeyFile:"a.key", CAFile:"", CertData:[]uint8{0x2d, 0x2d, 0x2d, 0x20, 0x54, 0x52, 0x55, 0x4e, 0x43, 0x41, 0x54, 0x45, 0x44, 0x20, 0x2d, 0x2d, 0x2d}, KeyData:[]uint8{0x2d, 0x2d, 0x2d, 0x20, 0x52, 0x45, 0x44, 0x41, 0x43, 0x54, 0x45, 0x44, 0x20, 0x2d, 0x2d, 0x2d}, CAData:[]uint8(nil)}, UserAgent:"gobot", Transport:(*rest.fakeRoundTripper)(%p), WrapTransport:(transport.WrapperFunc)(%p), QPS:1, Burst:2, RateLimiter:(*rest.fakeLimiter)(%p), Timeout:3000000000, Dial:(func(context.Context, string, string) (net.Conn, error))(%p)}`,
+		c.Transport, fakeWrapperFunc, c.RateLimiter, fakeDialFunc,
+	)
+
+	for _, f := range []string{"%s", "%v", "%+v", "%#v"} {
+		if got := fmt.Sprintf(f, c); want != got {
+			t.Errorf("fmt.Sprintf(%q, c)\ngot:  %q\nwant: %q", f, got, want)
+		}
+	}
+}

staging/src/k8s.io/client-go/tools/clientcmd/api/types.go

@@ -17,6 +17,8 @@ limitations under the License.
 package api
 
 import (
+	"fmt"
+
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
@@ -150,6 +152,25 @@ type AuthProviderConfig struct {
 	Config map[string]string `json:"config,omitempty"`
 }
 
+var _ fmt.Stringer = new(AuthProviderConfig)
+var _ fmt.GoStringer = new(AuthProviderConfig)
+
+// GoString implements fmt.GoStringer and sanitizes sensitive fields of
+// AuthProviderConfig to prevent accidental leaking via logs.
+func (c AuthProviderConfig) GoString() string {
+	return c.String()
+}
+
+// String implements fmt.Stringer and sanitizes sensitive fields of
+// AuthProviderConfig to prevent accidental leaking via logs.
+func (c AuthProviderConfig) String() string {
+	cfg := "<nil>"
+	if c.Config != nil {
+		cfg = "--- REDACTED ---"
+	}
+	return fmt.Sprintf("api.AuthProviderConfig{Name: %q, Config: map[string]string{%s}}", c.Name, cfg)
+}
+
 // ExecConfig specifies a command to provide client credentials. The command is exec'd
 // and outputs structured stdout holding credentials.
 //
@@ -172,6 +193,29 @@ type ExecConfig struct {
 	APIVersion string `json:"apiVersion,omitempty"`
 }
 
+var _ fmt.Stringer = new(ExecConfig)
+var _ fmt.GoStringer = new(ExecConfig)
+
+// GoString implements fmt.GoStringer and sanitizes sensitive fields of
+// ExecConfig to prevent accidental leaking via logs.
+func (c ExecConfig) GoString() string {
+	return c.String()
+}
+
+// String implements fmt.Stringer and sanitizes sensitive fields of ExecConfig
+// to prevent accidental leaking via logs.
+func (c ExecConfig) String() string {
+	var args []string
+	if len(c.Args) > 0 {
+		args = []string{"--- REDACTED ---"}
+	}
+	env := "[]ExecEnvVar(nil)"
+	if len(c.Env) > 0 {
+		env = "[]ExecEnvVar{--- REDACTED ---}"
+	}
+	return fmt.Sprintf("api.AuthProviderConfig{Command: %q, Args: %#v, Env: %s, APIVersion: %q}", c.Command, args, env, c.APIVersion)
+}
+
 // ExecEnvVar is used for setting environment variables when executing an exec-based
 // credential plugin.
 type ExecEnvVar struct {

staging/src/k8s.io/sample-cli-plugin/Godeps/Godeps.json

@@ -7,6 +7,10 @@
 	],
 	"Deps": [
 		{
+			"ImportPath": "github.com/davecgh/go-spew/spew",
+			"Rev": "782f4967f2dc4564575ca782fe2d04090b5faca8"
+		},
+		{
 			"ImportPath": "github.com/evanphx/json-patch",
 			"Rev": "36442dbdb585210f8d5a1b45e67aa323c197d5c4"
 		},