feat: make the password policy more configurable

docs/docs/guides/password-policy.mdx

@@ -0,0 +1,35 @@
+---
+id: password-policy
+title: Configuring The Password Policy
+---
+
+The password policy is a set of rules that define the password requirements for
+Kratos identities. They can be changed by modifying the following configuration
+parameters:
+
+```yaml title=path/to/kratos/config.yml
+selfservice:
+  methods:
+    password:
+      enabled: true
+      config:
+        haveibeenpwned_enabled: true
+        min_password_length: 8
+        identifier_similarity_check_enabled: true
+```
+
+#### `haveibeenpwned_enabled`
+
+If set to `true`, the password policy will check if the password has been found
+in the [Have I Been Pwned](https://haveibeenpwned.com/) database. The default
+value is `true`.
+
+#### `min_password_length`
+
+The minimum length of the password. The default value is `8`, the minimum
+allowed value is `6`.
+
+#### `identifier_similarity_check_enabled`
+
+If set to `true`, the password policy will check if the password is similar to
+the user identifier. The default value is `true`.

docs/docs/reference/configuration.md

@@ -997,6 +997,33 @@ selfservice:
         #
         haveibeenpwned_host: ''
 
+        ## Minimum Password Length ##
+        #
+        # Default value: 8
+        # Minimum value: 6
+        #
+        # Set this value using environment variables on
+        # - Linux/macOS:
+        #    $ export SELFSERVICE_METHODS_PASSWORD_CONFIG_MIN_PASSWORD_LENGTH=<value>
+        # - Windows Command Line (CMD):
+        #    > set SELFSERVICE_METHODS_PASSWORD_CONFIG_MIN_PASSWORD_LENGTH=<value>
+        #
+        min_password_length: 0
+
+        ## Enables Password User Identifier Similarity Check ##
+        #
+        # If set to false the password validation does not check whether passwords and user identifiers are similar
+        #
+        # Default value: true
+        #
+        # Set this value using environment variables on
+        # - Linux/macOS:
+        #    $ export SELFSERVICE_METHODS_PASSWORD_CONFIG_SELFSERVICE_METHODS_PASSWORD_CONFIG_IDENTIFIER_SIMILARITY_CHECK_ENABLED=<value>
+        # - Windows Command Line (CMD):
+        #    > set SELFSERVICE_METHODS_PASSWORD_CONFIG_SELFSERVICE_METHODS_PASSWORD_CONFIG_IDENTIFIER_SIMILARITY_CHECK_ENABLED=<value>
+        #
+        identifier_similarity_check_enabled: false
+
       ## Enables Username/Email and Password Method ##
       #
       # Default value: true

docs/sidebar.json

@@ -75,7 +75,8 @@
       "guides/setting-up-password-hashing-parameters",
       "guides/integration-with-other-systems-using-web-hooks",
       "guides/tracing",
-      "guides/upgrade"
+      "guides/upgrade",
+      "guides/password-policy"
     ]
   },
   "reference/api",

driver/config/config.go

@@ -144,6 +144,8 @@ const (
 	ViperKeyPasswordHaveIBeenPwnedHost                       = "selfservice.methods.password.config.haveibeenpwned_host"
 	ViperKeyPasswordHaveIBeenPwnedEnabled                    = "selfservice.methods.password.config.haveibeenpwned_enabled"
 	ViperKeyPasswordMaxBreaches                              = "selfservice.methods.password.config.max_breaches"
+	ViperKeyPasswordMinLength                                = "selfservice.methods.password.config.min_password_length"
+	ViperKeyPasswordIdentifierSimilarityCheckEnabled         = "selfservice.methods.password.config.identifier_similarity_check_enabled"
 	ViperKeyIgnoreNetworkErrors                              = "selfservice.methods.password.config.ignore_network_errors"
 	ViperKeyTOTPIssuer                                       = "selfservice.methods.totp.config.issuer"
 	ViperKeyWebAuthnRPDisplayName                            = "selfservice.methods.webauthn.config.rp.display_name"
@@ -195,10 +197,12 @@ type (
 		URL string `json:"url"`
 	}
 	PasswordPolicy struct {
-		HaveIBeenPwnedHost    string `json:"haveibeenpwned_host"`
-		HaveIBeenPwnedEnabled bool   `json:"haveibeenpwned_enabled"`
-		MaxBreaches           uint   `json:"max_breaches"`
-		IgnoreNetworkErrors   bool   `json:"ignore_network_errors"`
+		HaveIBeenPwnedHost               string `json:"haveibeenpwned_host"`
+		HaveIBeenPwnedEnabled            bool   `json:"haveibeenpwned_enabled"`
+		MaxBreaches                      uint   `json:"max_breaches"`
+		IgnoreNetworkErrors              bool   `json:"ignore_network_errors"`
+		MinPasswordLength                uint   `json:"min_password_length"`
+		IdentifierSimilarityCheckEnabled bool   `json:"identifier_similarity_check_enabled"`
 	}
 	Schemas []Schema
 	Config  struct {
@@ -998,10 +1002,12 @@ func (p *Config) ConfigVersion() string {
 
 func (p *Config) PasswordPolicyConfig() *PasswordPolicy {
 	return &PasswordPolicy{
-		HaveIBeenPwnedHost:    p.p.StringF(ViperKeyPasswordHaveIBeenPwnedHost, "api.pwnedpasswords.com"),
-		HaveIBeenPwnedEnabled: p.p.BoolF(ViperKeyPasswordHaveIBeenPwnedEnabled, true),
-		MaxBreaches:           uint(p.p.Int(ViperKeyPasswordMaxBreaches)),
-		IgnoreNetworkErrors:   p.p.BoolF(ViperKeyIgnoreNetworkErrors, true),
+		HaveIBeenPwnedHost:               p.p.StringF(ViperKeyPasswordHaveIBeenPwnedHost, "api.pwnedpasswords.com"),
+		HaveIBeenPwnedEnabled:            p.p.BoolF(ViperKeyPasswordHaveIBeenPwnedEnabled, true),
+		MaxBreaches:                      uint(p.p.Int(ViperKeyPasswordMaxBreaches)),
+		IgnoreNetworkErrors:              p.p.BoolF(ViperKeyIgnoreNetworkErrors, true),
+		MinPasswordLength:                uint(p.p.IntF(ViperKeyPasswordMinLength, 8)),
+		IdentifierSimilarityCheckEnabled: p.p.BoolF(ViperKeyPasswordIdentifierSimilarityCheckEnabled, true),
 	}
 }
 

driver/config/config_test.go

@@ -189,7 +189,7 @@ func TestViperProvider(t *testing.T) {
 				config  string
 				enabled bool
 			}{
-				{id: "password", enabled: true, config: `{"haveibeenpwned_host":"api.pwnedpasswords.com","haveibeenpwned_enabled":true,"ignore_network_errors":true,"max_breaches":0}`},
+				{id: "password", enabled: true, config: `{"haveibeenpwned_host":"api.pwnedpasswords.com","haveibeenpwned_enabled":true,"ignore_network_errors":true,"max_breaches":0,"min_password_length":8,"identifier_similarity_check_enabled":true}`},
 				{id: "oidc", enabled: true, config: `{"providers":[{"client_id":"a","client_secret":"b","id":"github","provider":"github","mapper_url":"http://test.kratos.ory.sh/default-identity.schema.json"}]}`},
 				{id: "totp", enabled: true, config: `{"issuer":"issuer.ory.sh"}`},
 			} {
@@ -1017,3 +1017,25 @@ func TestIdentitySchemaValidation(t *testing.T) {
 		}
 	})
 }
+
+func TestChangeMinPasswordLength(t *testing.T) {
+	t.Run("case=must fail on minimum password length below enforced minimum", func(t *testing.T) {
+		ctx := context.Background()
+
+		_, err := config.New(ctx, logrusx.New("", ""), os.Stderr,
+			configx.WithConfigFiles("stub/.kratos.yaml"),
+			configx.WithValue("selfservice.methods.password.config.min_password_length", 5))
+
+		assert.Error(t, err)
+	})
+
+	t.Run("case=must not fail on minimum password length above enforced minimum", func(t *testing.T) {
+		ctx := context.Background()
+
+		_, err := config.New(ctx, logrusx.New("", ""), os.Stderr,
+			configx.WithConfigFiles("stub/.kratos.yaml"),
+			configx.WithValue("selfservice.methods.password.config.min_password_length", 9))
+
+		assert.NoError(t, err)
+	})
+}

embedx/config.schema.json

@@ -1128,6 +1128,19 @@
                       "description": "If set to false the password validation fails when the network or the Have I Been Pwnd API is down.",
                       "type": "boolean",
                       "default": true
+                    },
+                    "min_password_length": {
+                      "title": "Minimum Password Length",
+                      "description": "Defines the minimum length of the password.",
+                      "type": "integer",
+                      "default": 8,
+                      "minimum": 6
+                    },
+                    "identifier_similarity_check_enabled": {
+                      "title": "Enable password-identifier similarity check",
+                      "description": "If set to false the password validation does not check for similarity between the password and the user identifier.",
+                      "type": "boolean",
+                      "default": true
                     }
                   },
                   "additionalProperties": false

selfservice/strategy/password/validator.go

@@ -142,18 +142,20 @@ func (s *DefaultPasswordValidator) fetch(hpw []byte, apiDNSName string) error {
 }
 
 func (s *DefaultPasswordValidator) Validate(ctx context.Context, identifier, password string) error {
-	if len(password) < 8 {
-		return errors.Errorf("password length must be at least 8 characters but only got %d", len(password))
-	}
+	passwordPolicyConfig := s.reg.Config(ctx).PasswordPolicyConfig()
 
-	compIdentifier, compPassword := strings.ToLower(identifier), strings.ToLower(password)
-	dist := levenshtein.Distance(compIdentifier, compPassword)
-	lcs := float32(lcsLength(compIdentifier, compPassword)) / float32(len(compPassword))
-	if dist < s.minIdentifierPasswordDist || lcs > s.maxIdentifierPasswordSubstrThreshold {
-		return errors.Errorf("the password is too similar to the user identifier")
+	if len(password) < int(passwordPolicyConfig.MinPasswordLength) {
+		return errors.Errorf("password length must be at least %d characters but only got %d", passwordPolicyConfig.MinPasswordLength, len(password))
 	}
 
-	passwordPolicyConfig := s.reg.Config(ctx).PasswordPolicyConfig()
+	if passwordPolicyConfig.IdentifierSimilarityCheckEnabled {
+		compIdentifier, compPassword := strings.ToLower(identifier), strings.ToLower(password)
+		dist := levenshtein.Distance(compIdentifier, compPassword)
+		lcs := float32(lcsLength(compIdentifier, compPassword)) / float32(len(compPassword))
+		if dist < s.minIdentifierPasswordDist || lcs > s.maxIdentifierPasswordSubstrThreshold {
+			return errors.Errorf("the password is too similar to the user identifier")
+		}
+	}
 
 	if !passwordPolicyConfig.HaveIBeenPwnedEnabled {
 		return nil

selfservice/strategy/password/validator_test.go

@@ -217,6 +217,35 @@ func TestDisableHaveIBeenPwnedValidationHost(t *testing.T) {
 	})
 }
 
+func TestChangeMinPasswordLength(t *testing.T) {
+	conf, reg := internal.NewFastRegistryWithMocks(t)
+	s := password.NewDefaultPasswordValidatorStrategy(reg)
+	conf.MustSet(config.ViperKeyPasswordMinLength, 10)
+
+	t.Run("case=should not fail if password is longer than min length", func(t *testing.T) {
+		require.NoError(t, s.Validate(context.Background(), "", "kuobahcaas"))
+	})
+
+	t.Run("case=should fail if password is shorter than min length", func(t *testing.T) {
+		require.Error(t, s.Validate(context.Background(), "", "rfqyfjied"))
+	})
+}
+
+func TestChangeIdentifierSimilarityCheckEnabled(t *testing.T) {
+	conf, reg := internal.NewFastRegistryWithMocks(t)
+	s := password.NewDefaultPasswordValidatorStrategy(reg)
+
+	t.Run("case=should not fail if password is similar to identifier", func(t *testing.T) {
+		conf.MustSet(config.ViperKeyPasswordIdentifierSimilarityCheckEnabled, false)
+		require.NoError(t, s.Validate(context.Background(), "bosqwfaxee", "bosqwfaxee"))
+	})
+
+	t.Run("case=should fail if password is similar to identifier", func(t *testing.T) {
+		conf.MustSet(config.ViperKeyPasswordIdentifierSimilarityCheckEnabled, true)
+		require.Error(t, s.Validate(context.Background(), "bosqwfaxee", "bosqwfaxee"))
+	})
+}
+
 type fakeValidatorAPI struct{}
 
 func (api *fakeValidatorAPI) ServeHTTP(w http.ResponseWriter, r *http.Request) {