Case Sensitivity of Email Addresses in Whitelist (Issue #324)

.defaults.yml

@@ -10,6 +10,8 @@ vouch:
   listen: 0.0.0.0
   port: 9090
   # domains:
+  case_insensitive_emails: false
+  # case_insensitive_email_domains:
   allowAllUsers: false
   publicAccess: false
   # whiteList:

config/config.yml_example

@@ -32,6 +32,19 @@ vouch:
   - yourdomain.com
   - yourotherdomain.com
 
+  # case_insensitive_emails - VOUCH_CASE_INSENSITIVE_EMAILS
+  # Setting this to true will treat all email-based usernames returned by the
+  # service provider case insensitively when validating against the whitelist
+  case_insensitive_emails: false
+
+  # case_insensitive_email_domains - VOUCH_CASE_INSENSITIVE_EMAIL_DOMAINS
+  # Any email-based username returned by the service provider that belongs to
+  # any of the following domains will be treated case insensitively when
+  # validating against the whitelist. Subdomains of a case insensitive domain
+  # will not be assumed case insensitive.
+  # Comment `case_insensitive_email_domains:` out if you set case_insensitive_emails:true
+  # case_insensitive_email_domains:
+
   # Set allowAllUsers: true to use Vouch Proxy to just accept anyone who can authenticate at the configured provider - VOUCH_ALLOWALLUSERS
   # allowAllUsers: false
   # vouch.cookie.domain must be set below when enabling allowAllUsers

config/testing/handler_case_insensitive_email_domains.yml

@@ -0,0 +1,23 @@
+vouch:
+  logLevel: debug
+
+  case_insensitive_emails: false
+
+  case_insensitive_email_domains:
+    - example1.com
+
+  whiteList:
+    # these should work if cases do not match with incoming email
+    - [email protected]
+    - [email protected]
+    # these should not work if cases do not match with incoming email
+    - [email protected]
+
+  jwt:
+    secret: testingsecret
+
+oauth:
+  provider: indieauth
+  client_id: http://vouch.github.io
+  auth_url: https://indielogin.com/auth
+  callback_url: http://vouch.github.io:9090/auth

config/testing/handler_case_insensitive_emails.yml

@@ -0,0 +1,19 @@
+vouch:
+  logLevel: debug
+
+  case_insensitive_emails: true
+
+  whiteList:
+    # these should work if cases do not match with incoming email
+    - [email protected]
+    - [email protected]
+    - test_username
+
+  jwt:
+    secret: testingsecret
+
+oauth:
+  provider: indieauth
+  client_id: http://vouch.github.io
+  auth_url: https://indielogin.com/auth
+  callback_url: http://vouch.github.io:9090/auth

handlers/auth.go

@@ -13,6 +13,8 @@ package handlers
 import (
 	"fmt"
 	"net/http"
+	"regexp"
+	"strings"
 
 	"github.com/vouch/vouch-proxy/pkg/cfg"
 	"github.com/vouch/vouch-proxy/pkg/cookie"
@@ -24,6 +26,17 @@ import (
 	"golang.org/x/oauth2"
 )
 
+// From https://golangcode.com/validate-an-email-address/
+var emailRegex = regexp.MustCompile("^[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$")
+
+// isEmailValid checks if the email provided passes the required structure and length.
+func isEmailValid(e string) bool {
+	if len(e) < 3 || len(e) > 254 {
+		return false
+	}
+	return emailRegex.MatchString(e)
+}
+
 // CallbackHandler /auth
 // - redirects to /auth/{state}/ with the state coming from the query parameter
 func CallbackHandler(w http.ResponseWriter, r *http.Request) {
@@ -125,6 +138,24 @@ func AuthStateHandler(w http.ResponseWriter, r *http.Request) {
 	responses.RenderIndex(w, "/auth "+tokenstring)
 }
 
+func isUsernameCaseInsensitive(user *structs.User) bool {
+	if cfg.Cfg.CaseInsensitiveEmails {
+		return true
+	}
+
+	lowerUsername := strings.ToLower(user.Username)
+	for _, caseInsensitiveDomain := range cfg.Cfg.CaseInsensitiveEmailDomains {
+		// Guarantees that
+		// 1) the username is an email
+		// 2) the username should be treated case-insensitively
+		if strings.HasSuffix(lowerUsername, "@"+strings.ToLower(caseInsensitiveDomain)) {
+			return true
+		}
+	}
+
+	return false
+}
+
 // verifyUser validates that the domains match for the user
 func verifyUser(u interface{}) (bool, error) {
 
@@ -139,8 +170,12 @@ func verifyUser(u interface{}) (bool, error) {
 
 	// WhiteList
 	case len(cfg.Cfg.WhiteList) != 0:
+		// If the username is from a case insensitive domain then we should perform case insensitive checks on the whitelist
+		usernameIsCaseInsensitive := isUsernameCaseInsensitive(&user)
+
 		for _, wl := range cfg.Cfg.WhiteList {
-			if user.Username == wl {
+			// Case sensitivity should only apply to email-based usernames
+			if user.Username == wl || (isEmailValid(user.Username) && usernameIsCaseInsensitive && strings.ToLower(user.Username) == strings.ToLower(wl)) {
 				log.Debugf("verifyUser: Success! found user.Username in WhiteList: %s", user.Username)
 				return true, nil
 			}

handlers/handlers_test.go

@@ -111,6 +111,82 @@ func TestVerifyUserNegative(t *testing.T) {
 	assert.False(t, ok)
 	assert.NotNil(t, err)
 }
+func TestVerifyUserPositiveCaseInsensitiveEmailDomains(t *testing.T) {
+	setUp("/config/testing/handler_case_insensitive_email_domains.yml")
+	tests := []struct {
+		name string
+		user *structs.User
+	}{
+		{name: "case insensitive domain having caps domain", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+		{name: "case insensitive subdomain having caps email", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ok, err := verifyUser(*tt.user)
+			assert.True(t, ok)
+			assert.Nil(t, err)
+		})
+	}
+}
+
+func TestVerifyUserNegativeCaseInsensitiveEmailDomains(t *testing.T) {
+	setUp("/config/testing/handler_case_insensitive_email_domains.yml")
+	tests := []struct {
+		name string
+		user *structs.User
+	}{
+		{name: "case sensitive domain having mixed case", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+		{name: "case sensitive subdomain having mixed case", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ok, err := verifyUser(*tt.user)
+			assert.False(t, ok)
+			assert.NotNil(t, err)
+		})
+	}
+}
+
+func TestVerifyUserPositiveCaseInsensitiveEmails(t *testing.T) {
+	setUp("/config/testing/handler_case_insensitive_emails.yml")
+
+	tests := []struct {
+		name string
+		user *structs.User
+	}{
+		{name: "email is caps", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+		{name: "email is caps with subdomain", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+		{name: "email is caps with mixed submain", user: &structs.User{Username: "[email protected]", Email: "[email protected]", Name: "Test Name"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ok, err := verifyUser(*tt.user)
+			assert.True(t, ok)
+			assert.Nil(t, err)
+		})
+	}
+}
+
+func TestVerifyUserNegativeCaseInsensitiveEmails(t *testing.T) {
+	setUp("/config/testing/handler_case_insensitive_emails.yml")
+	tests := []struct {
+		name string
+		user *structs.User
+	}{
+		{name: "non-email username is caps", user: &structs.User{Username: "TEST_USERNAME", Email: "[email protected]", Name: "Test Name"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ok, err := verifyUser(*tt.user)
+			assert.False(t, ok)
+			assert.NotNil(t, err)
+		})
+	}
+}
 
 // copied from jwtmanager_test.go
 // it should live there but circular imports are resolved if it lives here

pkg/cfg/cfg.go

@@ -35,16 +35,17 @@ import (
 // as well as a `envconfig` tag used by https://github.com/kelseyhightower/envconfig
 // though most of the time envconfig will use the struct key's name: VOUCH_PORT VOUCH_JWT_MAXAGE
 type Config struct {
-	LogLevel      string   `mapstructure:"logLevel"`
-	Listen        string   `mapstructure:"listen"`
-	Port          int      `mapstructure:"port"`
-	Domains       []string `mapstructure:"domains"`
-	WhiteList     []string `mapstructure:"whitelist"`
-	TeamWhiteList []string `mapstructure:"teamWhitelist"`
-	AllowAllUsers bool     `mapstructure:"allowAllUsers"`
-	PublicAccess  bool     `mapstructure:"publicAccess"`
-
-	TLS struct {
+	LogLevel                    string   `mapstructure:"logLevel"`
+	Listen                      string   `mapstructure:"listen"`
+	Port                        int      `mapstructure:"port"`
+	Domains                     []string `mapstructure:"domains"`
+	CaseInsensitiveEmails       bool     `mapstructure:"case_insensitive_emails" envconfig:"case_insensitive_emails"`
+	CaseInsensitiveEmailDomains []string `mapstructure:"case_insensitive_email_domains" envconfig:"case_insensitive_email_domains"`
+	WhiteList                   []string `mapstructure:"whitelist"`
+	TeamWhiteList               []string `mapstructure:"teamWhitelist"`
+	AllowAllUsers               bool     `mapstructure:"allowAllUsers"`
+	PublicAccess                bool     `mapstructure:"publicAccess"`
+	TLS                         struct {
 		Cert    string `mapstructure:"cert"`
 		Key     string `mapstructure:"key"`
 		Profile string `mapstructure:"profile"`
@@ -378,6 +379,11 @@ func basicTest() error {
 		return fmt.Errorf("configuration error: either one of %s or %s needs to be set (but not both)", Branding.LCName+".domains", Branding.LCName+".allowAllUsers")
 	}
 
+	// Email case insensitive list should be empty if the global case insensitivity flag is set
+	if Cfg.CaseInsensitiveEmails && len(Cfg.CaseInsensitiveEmailDomains) > 0 {
+		return fmt.Errorf("configuration error: either one of %s or %s needs to be set (but not both)", Branding.LCName+".case_insensitive_emails", Branding.LCName+".case_insensitive_email_domains")
+	}
+
 	// issue a warning if the secret is too small
 	log.Debugf("vouch.jwt.secret is %d characters long", len(Cfg.JWT.Secret))
 	if len(Cfg.JWT.Secret) < minBase64Length {

pkg/cfg/cfg_test.go

@@ -130,12 +130,12 @@ func Test_configureFromEnvCfg(t *testing.T) {
 		"VOUCH_HEADERS_CLAIMHEADER", "VOUCH_HEADERS_ACCESSTOKEN", "VOUCH_HEADERS_IDTOKEN", "VOUCH_COOKIE_NAME", "VOUCH_COOKIE_DOMAIN",
 		"VOUCH_COOKIE_SAMESITE", "VOUCH_TESTURL", "VOUCH_SESSION_NAME", "VOUCH_SESSION_KEY"}
 	// array of strings
-	saenv := []string{"VOUCH_DOMAINS", "VOUCH_WHITELIST", "VOUCH_TEAMWHITELIST", "VOUCH_HEADERS_CLAIMS", "VOUCH_TESTURLS", "VOUCH_POST_LOGOUT_REDIRECT_URIS"}
+	saenv := []string{"VOUCH_DOMAINS", "VOUCH_WHITELIST", "VOUCH_TEAMWHITELIST", "VOUCH_HEADERS_CLAIMS", "VOUCH_TESTURLS", "VOUCH_POST_LOGOUT_REDIRECT_URIS", "VOUCH_CASE_INSENSITIVE_EMAIL_DOMAINS"}
 	// int
 	ienv := []string{"VOUCH_PORT", "VOUCH_JWT_MAXAGE", "VOUCH_COOKIE_MAXAGE"}
 	// bool
 	benv := []string{"VOUCH_ALLOWALLUSERS", "VOUCH_PUBLICACCESS", "VOUCH_JWT_COMPRESS", "VOUCH_COOKIE_SECURE",
-		"VOUCH_COOKIE_HTTPONLY", "VOUCH_TESTING"}
+		"VOUCH_COOKIE_HTTPONLY", "VOUCH_TESTING", "VOUCH_CASE_INSENSITIVE_EMAILS"}
 
 	// populate environmental variables
 	svalue := "svalue"
@@ -168,12 +168,13 @@ func Test_configureFromEnvCfg(t *testing.T) {
 		Cfg.Cookie.SameSite, Cfg.TestURL, Cfg.Session.Name, Cfg.Session.Key,
 	}
 
-	sacfg := [][]string{Cfg.Domains, Cfg.WhiteList, Cfg.TeamWhiteList, Cfg.Headers.Claims, Cfg.TestURLs, Cfg.LogoutRedirectURLs}
+	sacfg := [][]string{Cfg.Domains, Cfg.WhiteList, Cfg.TeamWhiteList, Cfg.Headers.Claims, Cfg.TestURLs, Cfg.LogoutRedirectURLs, Cfg.CaseInsensitiveEmailDomains,}
 	icfg := []int{Cfg.Port, Cfg.JWT.MaxAge, Cfg.Cookie.MaxAge}
 	bcfg := []bool{Cfg.AllowAllUsers, Cfg.PublicAccess, Cfg.JWT.Compress,
 		Cfg.Cookie.Secure,
 		Cfg.Cookie.HTTPOnly,
 		Cfg.Testing,
+		Cfg.CaseInsensitiveEmails,
 	}
 
 	tests := []struct {