oauth2_proxy/pkg/sessions/cookie/session_store.go
2019-06-08 07:46:06 +01:00

212 lines
6.0 KiB
Go

package cookie
import (
"errors"
"fmt"
"net/http"
"regexp"
"strings"
"time"
"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"
)
const (
// Cookies are limited to 4kb including the length of the cookie name,
// the cookie name can be up to 256 bytes
maxCookieLength = 3840
)
// Ensure CookieSessionStore implements the interface
var _ sessions.SessionStore = &SessionStore{}
// SessionStore is an implementation of the sessions.SessionStore
// interface that stores sessions in client side cookies
type SessionStore struct {
CookieOptions *options.CookieOptions
CookieCipher *encryption.Cipher
}
// Save takes a sessions.SessionState and stores the information from it
// within Cookies set on the HTTP response writer
func (s *SessionStore) Save(rw http.ResponseWriter, req *http.Request, ss *sessions.SessionState) error {
if ss.CreatedAt.IsZero() {
ss.CreatedAt = time.Now()
}
value, err := utils.CookieForSession(ss, s.CookieCipher)
if err != nil {
return err
}
s.setSessionCookie(rw, req, value, ss.CreatedAt)
return nil
}
// Load reads sessions.SessionState information from Cookies within the
// HTTP request object
func (s *SessionStore) Load(req *http.Request) (*sessions.SessionState, error) {
c, err := loadCookie(req, s.CookieOptions.CookieName)
if err != nil {
// always http.ErrNoCookie
return nil, fmt.Errorf("Cookie %q not present", s.CookieOptions.CookieName)
}
val, _, ok := encryption.Validate(c, s.CookieOptions.CookieSecret, s.CookieOptions.CookieExpire)
if !ok {
return nil, errors.New("Cookie Signature not valid")
}
session, err := utils.SessionFromCookie(val, s.CookieCipher)
if err != nil {
return nil, err
}
return session, nil
}
// Clear clears any saved session information by writing a cookie to
// clear the session
func (s *SessionStore) Clear(rw http.ResponseWriter, req *http.Request) error {
var cookies []*http.Cookie
// matches CookieName, CookieName_<number>
var cookieNameRegex = regexp.MustCompile(fmt.Sprintf("^%s(_\\d+)?$", s.CookieOptions.CookieName))
for _, c := range req.Cookies() {
if cookieNameRegex.MatchString(c.Name) {
clearCookie := s.makeCookie(req, c.Name, "", time.Hour*-1, time.Now())
http.SetCookie(rw, clearCookie)
cookies = append(cookies, clearCookie)
}
}
return nil
}
// setSessionCookie adds the user's session cookie to the response
func (s *SessionStore) setSessionCookie(rw http.ResponseWriter, req *http.Request, val string, created time.Time) {
for _, c := range s.makeSessionCookie(req, val, created) {
http.SetCookie(rw, c)
}
}
// makeSessionCookie creates an http.Cookie containing the authenticated user's
// authentication details
func (s *SessionStore) makeSessionCookie(req *http.Request, value string, now time.Time) []*http.Cookie {
if value != "" {
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) {
return splitCookie(c)
}
return []*http.Cookie{c}
}
func (s *SessionStore) makeCookie(req *http.Request, name string, value string, expiration time.Duration, now time.Time) *http.Cookie {
return cookies.MakeCookieFromOptions(
req,
name,
value,
s.CookieOptions,
expiration,
now,
)
}
// NewCookieSessionStore initialises a new instance of the SessionStore from
// the configuration given
func NewCookieSessionStore(opts *options.SessionOptions, cookieOpts *options.CookieOptions) (sessions.SessionStore, error) {
return &SessionStore{
CookieCipher: opts.Cipher,
CookieOptions: cookieOpts,
}, nil
}
// splitCookie reads the full cookie generated to store the session and splits
// it into a slice of cookies which fit within the 4kb cookie limit indexing
// the cookies from 0
func splitCookie(c *http.Cookie) []*http.Cookie {
if len(c.Value) < maxCookieLength {
return []*http.Cookie{c}
}
cookies := []*http.Cookie{}
valueBytes := []byte(c.Value)
count := 0
for len(valueBytes) > 0 {
new := copyCookie(c)
new.Name = fmt.Sprintf("%s_%d", c.Name, count)
count++
if len(valueBytes) < maxCookieLength {
new.Value = string(valueBytes)
valueBytes = []byte{}
} else {
newValue := valueBytes[:maxCookieLength]
valueBytes = valueBytes[maxCookieLength:]
new.Value = string(newValue)
}
cookies = append(cookies, new)
}
return cookies
}
// loadCookie retreieves the sessions state cookie from the http request.
// If a single cookie is present this will be returned, otherwise it attempts
// to reconstruct a cookie split up by splitCookie
func loadCookie(req *http.Request, cookieName string) (*http.Cookie, error) {
c, err := req.Cookie(cookieName)
if err == nil {
return c, nil
}
cookies := []*http.Cookie{}
err = nil
count := 0
for err == nil {
var c *http.Cookie
c, err = req.Cookie(fmt.Sprintf("%s_%d", cookieName, count))
if err == nil {
cookies = append(cookies, c)
count++
}
}
if len(cookies) == 0 {
return nil, fmt.Errorf("Could not find cookie %s", cookieName)
}
return joinCookies(cookies)
}
// joinCookies takes a slice of cookies from the request and reconstructs the
// full session cookie
func joinCookies(cookies []*http.Cookie) (*http.Cookie, error) {
if len(cookies) == 0 {
return nil, fmt.Errorf("list of cookies must be > 0")
}
if len(cookies) == 1 {
return cookies[0], nil
}
c := copyCookie(cookies[0])
for i := 1; i < len(cookies); i++ {
c.Value += cookies[i].Value
}
c.Name = strings.TrimRight(c.Name, "_0")
return c, nil
}
func copyCookie(c *http.Cookie) *http.Cookie {
return &http.Cookie{
Name: c.Name,
Value: c.Value,
Path: c.Path,
Domain: c.Domain,
Expires: c.Expires,
RawExpires: c.RawExpires,
MaxAge: c.MaxAge,
Secure: c.Secure,
HttpOnly: c.HttpOnly,
Raw: c.Raw,
Unparsed: c.Unparsed,
}
}