Split large cookies

This commit is contained in:
Joel Speed 2018-01-27 22:48:52 +00:00
parent 6aa35a9ecf
commit d4b588dbe9
No known key found for this signature in database
GPG Key ID: 6E80578D6751DEFB
2 changed files with 111 additions and 15 deletions

View File

@ -26,6 +26,10 @@ const (
httpScheme = "http"
httpsScheme = "https"
// Cookies are limited to 4kb including the length of the cookie name,
// the cookie name can be up to 256 bytes
maxCookieLength = 3840
)
// SignatureHeaders contains the headers to be signed by the hmac algorithm
@ -282,15 +286,100 @@ func (p *OAuthProxy) redeemCode(host, code string) (s *providers.SessionState, e
// MakeSessionCookie creates an http.Cookie containing the authenticated user's
// authentication details
func (p *OAuthProxy) MakeSessionCookie(req *http.Request, value string, expiration time.Duration, now time.Time) *http.Cookie {
func (p *OAuthProxy) MakeSessionCookie(req *http.Request, value string, expiration time.Duration, now time.Time) []*http.Cookie {
if value != "" {
value = cookie.SignedValue(p.CookieSeed, p.CookieName, value, now)
if len(value) > 4096 {
// Cookies cannot be larger than 4kb
log.Printf("WARNING - Cookie Size: %d bytes", len(value))
}
c := p.makeCookie(req, p.CookieName, value, expiration, now)
if len(c.Value) > 4096 {
return splitCookie(c)
}
return []*http.Cookie{c}
}
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,
}
}
return p.makeCookie(req, p.CookieName, value, expiration, now)
// 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
}
// 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
}
// 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)
}
// MakeCSRFCookie creates a cookie for CSRF
@ -334,12 +423,14 @@ func (p *OAuthProxy) SetCSRFCookie(rw http.ResponseWriter, req *http.Request, va
// ClearSessionCookie creates a cookie to unset the user's authentication cookie
// stored in the user's session
func (p *OAuthProxy) ClearSessionCookie(rw http.ResponseWriter, req *http.Request) {
clr := p.MakeSessionCookie(req, "", time.Hour*-1, time.Now())
cookies := p.MakeSessionCookie(req, "", time.Hour*-1, time.Now())
for _, clr := range cookies {
http.SetCookie(rw, clr)
}
// ugly hack because default domain changed
if p.CookieDomain == "" {
clr2 := *clr
if p.CookieDomain == "" && len(cookies) > 0 {
clr2 := *cookies[0]
clr2.Domain = req.Host
http.SetCookie(rw, &clr2)
}
@ -347,13 +438,15 @@ func (p *OAuthProxy) ClearSessionCookie(rw http.ResponseWriter, req *http.Reques
// SetSessionCookie adds the user's session cookie to the response
func (p *OAuthProxy) SetSessionCookie(rw http.ResponseWriter, req *http.Request, val string) {
http.SetCookie(rw, p.MakeSessionCookie(req, val, p.CookieExpire, time.Now()))
for _, c := range p.MakeSessionCookie(req, val, p.CookieExpire, time.Now()) {
http.SetCookie(rw, c)
}
}
// LoadCookiedSession reads the user's authentication details from the request
func (p *OAuthProxy) LoadCookiedSession(req *http.Request) (*providers.SessionState, time.Duration, error) {
var age time.Duration
c, err := req.Cookie(p.CookieName)
c, err := loadCookie(req, p.CookieName)
if err != nil {
// always http.ErrNoCookie
return nil, age, fmt.Errorf("Cookie %q not present", p.CookieName)

View File

@ -502,7 +502,7 @@ func NewProcessCookieTestWithDefaults() *ProcessCookieTest {
})
}
func (p *ProcessCookieTest) MakeCookie(value string, ref time.Time) *http.Cookie {
func (p *ProcessCookieTest) MakeCookie(value string, ref time.Time) []*http.Cookie {
return p.proxy.MakeSessionCookie(p.req, value, p.opts.CookieExpire, ref)
}
@ -511,7 +511,9 @@ func (p *ProcessCookieTest) SaveSession(s *providers.SessionState, ref time.Time
if err != nil {
return err
}
p.req.AddCookie(p.proxy.MakeSessionCookie(p.req, value, p.proxy.CookieExpire, ref))
for _, c := range p.proxy.MakeSessionCookie(p.req, value, p.proxy.CookieExpire, ref) {
p.req.AddCookie(c)
}
return nil
}
@ -800,8 +802,9 @@ func (st *SignatureTest) MakeRequestWithExpectedKey(method, body, key string) {
if err != nil {
panic(err)
}
cookie := proxy.MakeSessionCookie(req, value, proxy.CookieExpire, time.Now())
req.AddCookie(cookie)
for _, c := range proxy.MakeSessionCookie(req, value, proxy.CookieExpire, time.Now()) {
req.AddCookie(c)
}
// This is used by the upstream to validate the signature.
st.authenticator.auth = hmacauth.NewHmacAuth(
crypto.SHA1, []byte(key), SignatureHeader, SignatureHeaders)