Move cookie to pkg/encryption

pkg/apis/options/sessions.go

@@ -1,13 +1,11 @@
 package options
 
-import (
-	"github.com/pusher/oauth2_proxy/cookie"
-)
+import "github.com/pusher/oauth2_proxy/pkg/encryption"
 
 // SessionOptions contains configuration options for the SessionStore providers.
 type SessionOptions struct {
 	Type   string `flag:"session-store-type" cfg:"session_store_type" env:"OAUTH2_PROXY_SESSION_STORE_TYPE"`
-	Cipher *cookie.Cipher
+	Cipher *encryption.Cipher
 	CookieStoreOptions
 	RedisStoreOptions
 }

pkg/apis/sessions/session_state.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pusher/oauth2_proxy/cookie"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 )
 
 // SessionState is used to store information about the currently authenticated user session
@@ -66,7 +66,7 @@ func (s *SessionState) String() string {
 }
 
 // EncodeSessionState returns string representation of the current session
-func (s *SessionState) EncodeSessionState(c *cookie.Cipher) (string, error) {
+func (s *SessionState) EncodeSessionState(c *encryption.Cipher) (string, error) {
 	var ss SessionState
 	if c == nil {
 		// Store only Email and User when cipher is unavailable
@@ -133,7 +133,7 @@ func legacyDecodeSessionStatePlain(v string) (*SessionState, error) {
 
 // legacyDecodeSessionState attempts to decode the session state string
 // generated by v3.1.0 or older
-func legacyDecodeSessionState(v string, c *cookie.Cipher) (*SessionState, error) {
+func legacyDecodeSessionState(v string, c *encryption.Cipher) (*SessionState, error) {
 	chunks := strings.Split(v, "|")
 
 	if c == nil {
@@ -176,7 +176,7 @@ func legacyDecodeSessionState(v string, c *cookie.Cipher) (*SessionState, error)
 }
 
 // DecodeSessionState decodes the session cookie string into a SessionState
-func DecodeSessionState(v string, c *cookie.Cipher) (*SessionState, error) {
+func DecodeSessionState(v string, c *encryption.Cipher) (*SessionState, error) {
 	var ssj SessionStateJSON
 	var ss *SessionState
 	err := json.Unmarshal([]byte(v), &ssj)

pkg/apis/sessions/session_state_test.go

@@ -5,8 +5,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/pusher/oauth2_proxy/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/apis/sessions"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -14,9 +14,9 @@ const secret = "0123456789abcdefghijklmnopqrstuv"
 const altSecret = "0000000000abcdefghijklmnopqrstuv"
 
 func TestSessionStateSerialization(t *testing.T) {
-	c, err := cookie.NewCipher([]byte(secret))
+	c, err := encryption.NewCipher([]byte(secret))
 	assert.Equal(t, nil, err)
-	c2, err := cookie.NewCipher([]byte(altSecret))
+	c2, err := encryption.NewCipher([]byte(altSecret))
 	assert.Equal(t, nil, err)
 	s := &sessions.SessionState{
 		Email:        "user@domain.com",
@@ -54,9 +54,9 @@ func TestSessionStateSerialization(t *testing.T) {
 }
 
 func TestSessionStateSerializationWithUser(t *testing.T) {
-	c, err := cookie.NewCipher([]byte(secret))
+	c, err := encryption.NewCipher([]byte(secret))
 	assert.Equal(t, nil, err)
-	c2, err := cookie.NewCipher([]byte(altSecret))
+	c2, err := encryption.NewCipher([]byte(altSecret))
 	assert.Equal(t, nil, err)
 	s := &sessions.SessionState{
 		User:         "just-user",
@@ -146,7 +146,7 @@ func TestExpired(t *testing.T) {
 type testCase struct {
 	sessions.SessionState
 	Encoded string
-	Cipher  *cookie.Cipher
+	Cipher  *encryption.Cipher
 	Error   bool
 }
 
@@ -203,7 +203,7 @@ func TestDecodeSessionState(t *testing.T) {
 	eString := string(eJSON)
 	eUnix := e.Unix()
 
-	c, err := cookie.NewCipher([]byte(secret))
+	c, err := encryption.NewCipher([]byte(secret))
 	assert.NoError(t, err)
 
 	testCases := []testCase{

pkg/encryption/cipher.go

@@ -0,0 +1,128 @@
+package encryption
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha1"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// cookies are stored in a 3 part (value + timestamp + signature) to enforce that the values are as originally set.
+// additionally, the 'value' is encrypted so it's opaque to the browser
+
+// Validate ensures a cookie is properly signed
+func Validate(cookie *http.Cookie, seed string, expiration time.Duration) (value string, t time.Time, ok bool) {
+	// value, timestamp, sig
+	parts := strings.Split(cookie.Value, "|")
+	if len(parts) != 3 {
+		return
+	}
+	sig := cookieSignature(seed, cookie.Name, parts[0], parts[1])
+	if checkHmac(parts[2], sig) {
+		ts, err := strconv.Atoi(parts[1])
+		if err != nil {
+			return
+		}
+		// The expiration timestamp set when the cookie was created
+		// isn't sent back by the browser. Hence, we check whether the
+		// creation timestamp stored in the cookie falls within the
+		// window defined by (Now()-expiration, Now()].
+		t = time.Unix(int64(ts), 0)
+		if t.After(time.Now().Add(expiration*-1)) && t.Before(time.Now().Add(time.Minute*5)) {
+			// it's a valid cookie. now get the contents
+			rawValue, err := base64.URLEncoding.DecodeString(parts[0])
+			if err == nil {
+				value = string(rawValue)
+				ok = true
+				return
+			}
+		}
+	}
+	return
+}
+
+// SignedValue returns a cookie that is signed and can later be checked with Validate
+func SignedValue(seed string, key string, value string, now time.Time) string {
+	encodedValue := base64.URLEncoding.EncodeToString([]byte(value))
+	timeStr := fmt.Sprintf("%d", now.Unix())
+	sig := cookieSignature(seed, key, encodedValue, timeStr)
+	cookieVal := fmt.Sprintf("%s|%s|%s", encodedValue, timeStr, sig)
+	return cookieVal
+}
+
+func cookieSignature(args ...string) string {
+	h := hmac.New(sha1.New, []byte(args[0]))
+	for _, arg := range args[1:] {
+		h.Write([]byte(arg))
+	}
+	var b []byte
+	b = h.Sum(b)
+	return base64.URLEncoding.EncodeToString(b)
+}
+
+func checkHmac(input, expected string) bool {
+	inputMAC, err1 := base64.URLEncoding.DecodeString(input)
+	if err1 == nil {
+		expectedMAC, err2 := base64.URLEncoding.DecodeString(expected)
+		if err2 == nil {
+			return hmac.Equal(inputMAC, expectedMAC)
+		}
+	}
+	return false
+}
+
+// Cipher provides methods to encrypt and decrypt cookie values
+type Cipher struct {
+	cipher.Block
+}
+
+// NewCipher returns a new aes Cipher for encrypting cookie values
+func NewCipher(secret []byte) (*Cipher, error) {
+	c, err := aes.NewCipher(secret)
+	if err != nil {
+		return nil, err
+	}
+	return &Cipher{Block: c}, err
+}
+
+// Encrypt a value for use in a cookie
+func (c *Cipher) Encrypt(value string) (string, error) {
+	ciphertext := make([]byte, aes.BlockSize+len(value))
+	iv := ciphertext[:aes.BlockSize]
+	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
+		return "", fmt.Errorf("failed to create initialization vector %s", err)
+	}
+
+	stream := cipher.NewCFBEncrypter(c.Block, iv)
+	stream.XORKeyStream(ciphertext[aes.BlockSize:], []byte(value))
+	return base64.StdEncoding.EncodeToString(ciphertext), nil
+}
+
+// Decrypt a value from a cookie to it's original string
+func (c *Cipher) Decrypt(s string) (string, error) {
+	encrypted, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return "", fmt.Errorf("failed to decrypt cookie value %s", err)
+	}
+
+	if len(encrypted) < aes.BlockSize {
+		return "", fmt.Errorf("encrypted cookie value should be "+
+			"at least %d bytes, but is only %d bytes",
+			aes.BlockSize, len(encrypted))
+	}
+
+	iv := encrypted[:aes.BlockSize]
+	encrypted = encrypted[aes.BlockSize:]
+	stream := cipher.NewCFBDecrypter(c.Block, iv)
+	stream.XORKeyStream(encrypted, encrypted)
+
+	return string(encrypted), nil
+}

pkg/encryption/cipher_test.go

@@ -0,0 +1,43 @@
+package encryption
+
+import (
+	"encoding/base64"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEncodeAndDecodeAccessToken(t *testing.T) {
+	const secret = "0123456789abcdefghijklmnopqrstuv"
+	const token = "my access token"
+	c, err := NewCipher([]byte(secret))
+	assert.Equal(t, nil, err)
+
+	encoded, err := c.Encrypt(token)
+	assert.Equal(t, nil, err)
+
+	decoded, err := c.Decrypt(encoded)
+	assert.Equal(t, nil, err)
+
+	assert.NotEqual(t, token, encoded)
+	assert.Equal(t, token, decoded)
+}
+
+func TestEncodeAndDecodeAccessTokenB64(t *testing.T) {
+	const secretBase64 = "A3Xbr6fu6Al0HkgrP1ztjb-mYiwmxgNPP-XbNsz1WBk="
+	const token = "my access token"
+
+	secret, err := base64.URLEncoding.DecodeString(secretBase64)
+	assert.Equal(t, nil, err)
+	c, err := NewCipher([]byte(secret))
+	assert.Equal(t, nil, err)
+
+	encoded, err := c.Encrypt(token)
+	assert.Equal(t, nil, err)
+
+	decoded, err := c.Decrypt(encoded)
+	assert.Equal(t, nil, err)
+
+	assert.NotEqual(t, token, encoded)
+	assert.Equal(t, token, decoded)
+}

pkg/encryption/nonce.go

@@ -0,0 +1,17 @@
+package encryption
+
+import (
+	"crypto/rand"
+	"fmt"
+)
+
+// Nonce generates a random 16 byte string to be used as a nonce
+func Nonce() (nonce string, err error) {
+	b := make([]byte, 16)
+	_, err = rand.Read(b)
+	if err != nil {
+		return
+	}
+	nonce = fmt.Sprintf("%x", b)
+	return
+}

pkg/sessions/cookie/session_store.go

@@ -8,10 +8,10 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pusher/oauth2_proxy/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/apis/options"
 	"github.com/pusher/oauth2_proxy/pkg/apis/sessions"
 	"github.com/pusher/oauth2_proxy/pkg/cookies"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 	"github.com/pusher/oauth2_proxy/pkg/sessions/utils"
 )
 
@@ -28,7 +28,7 @@ var _ sessions.SessionStore = &SessionStore{}
 // interface that stores sessions in client side cookies
 type SessionStore struct {
 	CookieOptions *options.CookieOptions
-	CookieCipher  *cookie.Cipher
+	CookieCipher  *encryption.Cipher
 }
 
 // Save takes a sessions.SessionState and stores the information from it
@@ -53,7 +53,7 @@ func (s *SessionStore) Load(req *http.Request) (*sessions.SessionState, error) {
 		// always http.ErrNoCookie
 		return nil, fmt.Errorf("Cookie %q not present", s.CookieOptions.CookieName)
 	}
-	val, _, ok := cookie.Validate(c, s.CookieOptions.CookieSecret, s.CookieOptions.CookieExpire)
+	val, _, ok := encryption.Validate(c, s.CookieOptions.CookieSecret, s.CookieOptions.CookieExpire)
 	if !ok {
 		return nil, errors.New("Cookie Signature not valid")
 	}
@@ -96,7 +96,7 @@ func (s *SessionStore) setSessionCookie(rw http.ResponseWriter, req *http.Reques
 // authentication details
 func (s *SessionStore) makeSessionCookie(req *http.Request, value string, now time.Time) []*http.Cookie {
 	if value != "" {
-		value = cookie.SignedValue(s.CookieOptions.CookieSecret, s.CookieOptions.CookieName, value, now)
+		value = encryption.SignedValue(s.CookieOptions.CookieSecret, s.CookieOptions.CookieName, value, now)
 	}
 	c := s.makeCookie(req, s.CookieOptions.CookieName, value, s.CookieOptions.CookieExpire, now)
 	if len(c.Value) > 4096-len(s.CookieOptions.CookieName) {

pkg/sessions/redis/redis_store.go

@@ -13,10 +13,10 @@ import (
 	"time"
 
 	"github.com/go-redis/redis"
-	"github.com/pusher/oauth2_proxy/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/apis/options"
 	"github.com/pusher/oauth2_proxy/pkg/apis/sessions"
 	"github.com/pusher/oauth2_proxy/pkg/cookies"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 )
 
 // TicketData is a structure representing the ticket used in server session storage
@@ -28,7 +28,7 @@ type TicketData struct {
 // SessionStore is an implementation of the sessions.SessionStore
 // interface that stores sessions in redis
 type SessionStore struct {
-	CookieCipher  *cookie.Cipher
+	CookieCipher  *encryption.Cipher
 	CookieOptions *options.CookieOptions
 	Client        *redis.Client
 }
@@ -106,7 +106,7 @@ func (store *SessionStore) Load(req *http.Request) (*sessions.SessionState, erro
 		return nil, fmt.Errorf("error loading session: %s", err)
 	}
 
-	val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
+	val, _, ok := encryption.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
 	if !ok {
 		return nil, fmt.Errorf("Cookie Signature not valid")
 	}
@@ -166,7 +166,7 @@ func (store *SessionStore) Clear(rw http.ResponseWriter, req *http.Request) erro
 		return fmt.Errorf("error retrieving cookie: %v", err)
 	}
 
-	val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
+	val, _, ok := encryption.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
 	if !ok {
 		return fmt.Errorf("Cookie Signature not valid")
 	}
@@ -186,7 +186,7 @@ func (store *SessionStore) Clear(rw http.ResponseWriter, req *http.Request) erro
 // makeCookie makes a cookie, signing the value if present
 func (store *SessionStore) makeCookie(req *http.Request, value string, expires time.Duration, now time.Time) *http.Cookie {
 	if value != "" {
-		value = cookie.SignedValue(store.CookieOptions.CookieSecret, store.CookieOptions.CookieName, value, now)
+		value = encryption.SignedValue(store.CookieOptions.CookieSecret, store.CookieOptions.CookieName, value, now)
 	}
 	return cookies.MakeCookieFromOptions(
 		req,
@@ -230,7 +230,7 @@ func (store *SessionStore) getTicket(requestCookie *http.Cookie) (*TicketData, e
 	}
 
 	// An existing cookie exists, try to retrieve the ticket
-	val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
+	val, _, ok := encryption.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire)
 	if !ok {
 		// Cookie is invalid, create a new ticket
 		return newTicket()

pkg/sessions/session_store_test.go

@@ -13,10 +13,10 @@ import (
 	"github.com/alicebob/miniredis"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-	"github.com/pusher/oauth2_proxy/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/apis/options"
 	sessionsapi "github.com/pusher/oauth2_proxy/pkg/apis/sessions"
 	"github.com/pusher/oauth2_proxy/pkg/cookies"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 	"github.com/pusher/oauth2_proxy/pkg/sessions"
 	sessionscookie "github.com/pusher/oauth2_proxy/pkg/sessions/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/sessions/redis"
@@ -158,7 +158,7 @@ var _ = Describe("NewSessionStore", func() {
 				BeforeEach(func() {
 					By("Using a valid cookie with a different providers session encoding")
 					broken := "BrokenSessionFromADifferentSessionImplementation"
-					value := cookie.SignedValue(cookieOpts.CookieSecret, cookieOpts.CookieName, broken, time.Now())
+					value := encryption.SignedValue(cookieOpts.CookieSecret, cookieOpts.CookieName, broken, time.Now())
 					cookie := cookies.MakeCookieFromOptions(request, cookieOpts.CookieName, value, cookieOpts, cookieOpts.CookieExpire, time.Now())
 					request.AddCookie(cookie)
 
@@ -354,7 +354,7 @@ var _ = Describe("NewSessionStore", func() {
 				_, err := rand.Read(secret)
 				Expect(err).ToNot(HaveOccurred())
 				cookieOpts.CookieSecret = base64.URLEncoding.EncodeToString(secret)
-				cipher, err := cookie.NewCipher(utils.SecretBytes(cookieOpts.CookieSecret))
+				cipher, err := encryption.NewCipher(utils.SecretBytes(cookieOpts.CookieSecret))
 				Expect(err).ToNot(HaveOccurred())
 				Expect(cipher).ToNot(BeNil())
 				opts.Cipher = cipher

pkg/sessions/utils/utils.go

@@ -3,17 +3,17 @@ package utils
 import (
 	"encoding/base64"
 
-	"github.com/pusher/oauth2_proxy/cookie"
 	"github.com/pusher/oauth2_proxy/pkg/apis/sessions"
+	"github.com/pusher/oauth2_proxy/pkg/encryption"
 )
 
 // CookieForSession serializes a session state for storage in a cookie
-func CookieForSession(s *sessions.SessionState, c *cookie.Cipher) (string, error) {
+func CookieForSession(s *sessions.SessionState, c *encryption.Cipher) (string, error) {
 	return s.EncodeSessionState(c)
 }
 
 // SessionFromCookie deserializes a session from a cookie value
-func SessionFromCookie(v string, c *cookie.Cipher) (s *sessions.SessionState, err error) {
+func SessionFromCookie(v string, c *encryption.Cipher) (s *sessions.SessionState, err error) {
 	return sessions.DecodeSessionState(v, c)
 }