Add configurable cookie name prefix for the OIDC filter (#3234)

Allow specifying cookie name prefix for OIDC filters

Signed-off-by: Carl Zhou <czhou@brex.com>

docs/reference/filters.md

@@ -1844,6 +1844,7 @@ The filter needs the following parameters:
 * **Auth Code Options** (optional) Passes key/value parameters to a provider's authorization endpoint. The value can be dynamically set by a query parameter with the same key name if the placeholder `skipper-request-query` is used.
 * **Upstream Headers** (optional) The upstream endpoint will receive these headers which values are parsed from the OIDC information. The header definition can be one or more header-query pairs, space delimited. The query syntax is [GJSON](https://github.com/tidwall/gjson/blob/master/SYNTAX.md).
 * **SubdomainsToRemove** (optional, default "1") Configures number of subdomains to remove from the request hostname to derive OIDC cookie domain. By default one subdomain is removed, e.g. for the www.example.com request hostname the OIDC cookie domain will be example.com (to support SSO for all subdomains of the example.com). Configure "0" to use the same hostname. Note that value is a string.
+* **Custom Cookie Name** (optional) Defines a constant cookie name generated by the OIDC filter. By default the cookie name is SkipperOauthOidc{hash}, where {hash} is a generated value.
 
 #### oauthOidcAnyClaims
 

filters/auth/oidc.go

@@ -85,6 +85,7 @@ const (
 	paramAuthCodeOpts
 	paramUpstrHeaders
 	paramSubdomainsToRemove
+	paramCookieName
 )
 
 type OidcOptions struct {
@@ -201,22 +202,27 @@ func (s *tokenOidcSpec) CreateFilter(args []interface{}) (filters.Filter, error)
 		return nil, filters.ErrInvalidFilterParameters
 	}
 
-	h := sha256.New()
-	for i, s := range sargs {
-		// CallbackURL not taken into account for cookie hashing for additional sub path ingresses
-		if i == paramCallbackURL {
-			continue
-		}
-		// SubdomainsToRemove not taken into account for cookie hashing for additional sub-domain ingresses
-		if i == paramSubdomainsToRemove {
-			continue
+	var cookieName string
+	if len(sargs) > paramCookieName && sargs[paramCookieName] != "" {
+		cookieName = sargs[paramCookieName]
+	} else {
+		h := sha256.New()
+		for i, s := range sargs {
+			// CallbackURL not taken into account for cookie hashing for additional sub path ingresses
+			if i == paramCallbackURL {
+				continue
+			}
+			// SubdomainsToRemove not taken into account for cookie hashing for additional sub-domain ingresses
+			if i == paramSubdomainsToRemove {
+				continue
+			}
+			h.Write([]byte(s))
 		}
-		h.Write([]byte(s))
+		byteSlice := h.Sum(nil)
+		sargsHash := fmt.Sprintf("%x", byteSlice)[:8]
+		cookieName = oauthOidcCookieName + sargsHash + "-"
 	}
-	byteSlice := h.Sum(nil)
-	sargsHash := fmt.Sprintf("%x", byteSlice)[:8]
-	generatedCookieName := oauthOidcCookieName + sargsHash + "-"
-	log.Debugf("Generated Cookie Name: %s", generatedCookieName)
+	log.Debugf("Cookie Name: %s", cookieName)
 
 	redirectURL, err := url.Parse(sargs[paramCallbackURL])
 	if err != nil || sargs[paramCallbackURL] == "" {
@@ -269,7 +275,7 @@ func (s *tokenOidcSpec) CreateFilter(args []interface{}) (filters.Filter, error)
 			ClientID: oidcClientId,
 		}),
 		validity:           validity,
-		cookiename:         generatedCookieName,
+		cookiename:         cookieName,
 		encrypter:          encrypter,
 		compressor:         newDeflatePoolCompressor(flate.BestCompression),
 		subdomainsToRemove: subdomainsToRemove,

filters/auth/oidc_test.go

@@ -711,6 +711,7 @@ func TestOIDCSetup(t *testing.T) {
 		expectCookieDomain string
 		filterCookies      []string
 		extraClaims        jwt.MapClaims
+		expectCookieName   string
 	}{{
 		msg:             "wrong provider",
 		filter:          `oauthOidcAnyClaims("no url", "", "", "{{ .RedirectURL }}", "", "")`,
@@ -848,6 +849,16 @@ func TestOIDCSetup(t *testing.T) {
 		expected:           200,
 		expectCookieDomain: "bar.foo.skipper.test",
 		filterCookies:      []string{"badheader", "malformed"},
+	}, {
+		msg:              "custom cookie name",
+		filter:           `oauthOidcUserInfo("{{ .OIDCServerURL }}", "valid-client", "mysec", "{{ .RedirectURL }}", "", "", "", "", "", "custom-cookie")`,
+		expected:         200,
+		expectCookieName: "custom-cookie",
+	}, {
+		msg:              "default cookie name when not specified",
+		filter:           `oauthOidcUserInfo("{{ .OIDCServerURL }}", "valid-client", "mysec", "{{ .RedirectURL }}", "", "")`,
+		expected:         200,
+		expectCookieName: "skipperOauthOidc",
 	}} {
 		t.Run(tc.msg, func(t *testing.T) {
 			backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -976,6 +987,12 @@ func TestOIDCSetup(t *testing.T) {
 							assert.True(t, c.Value == "")
 						}
 					}
+
+					// Check for custom cookie name
+					if tc.expectCookieName != "" {
+						assert.True(t, strings.HasPrefix(c.Name, tc.expectCookieName),
+							"Cookie name should start with %s, but got %s", tc.expectCookieName, c.Name)
+					}
 				}
 			}
 		})