Core Rule Set: random passwords pass at sign-in (closes #276)

A password manager's random password set off 35 Core Rule Set rules,
about 1 in 40 refused. The password fields the app exclusions name now
skip those rules on their paths: WordPress pwd, Drupal pass, MediaWiki
wpPassword, lgpassword and password, Mastodon's sign-in, sign-up,
password change, move and delete passwords, and Nextcloud's sign-in
password. Each field's test sends 2,000 random passwords from a fixed
seed, plus one rare password for each rule the 2,000 do not set off.
An SQL injection or a path traversal sent as a password now passes; a
script injection is still refused.

Model: opus-5-5

internal/coreruleset/mastodon_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/url"
 	"slices"
+	"strings"
 	"testing"
 
 	"sneak.berlin/go/smallwebwaf/internal/coreruleset"
@@ -129,10 +130,6 @@ var mastodonFormFields = []mastodonBodyField{
 	{http.MethodPost, "/settings/applications", "doorkeeper_application[website]="},
 	{http.MethodPost, "/settings/aliases", "account_alias[acct]="},
 	{http.MethodPost, "/settings/migration", "account_migration[acct]="},
-	{http.MethodPost, mastodonSignIn, mastodonPassword},
-	{http.MethodPost, mastodonAccount, mastodonPassword},
-	{http.MethodPost, mastodonAccount, "user[password_confirmation]="},
-	{http.MethodPost, mastodonAccount, "user[current_password]="},
 	{http.MethodPost, mastodonAccount, "user[invite_request_attributes][text]="},
 	{http.MethodPost, "/admin/accounts/1/action", "admin_account_action[text]="},
 	{http.MethodPost, "/admin/report_notes", "report_note[content]="},
@@ -145,6 +142,18 @@ var mastodonFormFields = []mastodonBodyField{
 	{http.MethodPost, mastodonRoles, "user_role[name]="},
 	{http.MethodPost, mastodonTerms, "terms_of_service[text]="},
 	{http.MethodPost, mastodonTerms, "terms_of_service[changelog]="},
+	{http.MethodPost, mastodonSignUp, "reason="},
+}
+
+// mastodonPasswordForms sends each password field in a form data body, on
+// a path where it skips the four rules and the rules that random passwords
+// set off.
+//
+//nolint:gochecknoglobals // a constant cannot be a list
+var mastodonPasswordForms = []mastodonBodyField{
+	{http.MethodPost, mastodonSignIn, mastodonPassword},
+	{http.MethodPost, mastodonAccount, "user[password_confirmation]="},
+	{http.MethodPost, mastodonAccount, "user[current_password]="},
 	{http.MethodPost, "/settings/migration", "account_migration[current_password]="},
 	{
 		http.MethodPost, "/settings/migration/redirect",
@@ -152,7 +161,14 @@ var mastodonFormFields = []mastodonBodyField{
 	},
 	{http.MethodPost, "/settings/delete", "form_delete_confirmation[password]="},
 	{http.MethodPost, mastodonSignUp, passwordField},
-	{http.MethodPost, mastodonSignUp, "reason="},
+}
+
+// mastodonPasswordJSON sends the password of signing up through the API in
+// a JSON body, with %s for its value.
+//
+//nolint:gochecknoglobals // a struct cannot be a constant
+var mastodonPasswordJSON = mastodonBodyField{
+	http.MethodPost, mastodonSignUp, `{"password":%s}`,
 }
 
 // mastodonJSONFields sends each field that skips the four rules in a JSON
@@ -178,7 +194,6 @@ var mastodonJSONFields = []mastodonBodyField{
 	{http.MethodPatch, mastodonProfile, `{"fields_attributes":[{"value":%s}]}`},
 	{http.MethodPost, mastodonReports, `{"comment":%s}`},
 	{http.MethodPost, "/api/v1/accounts/1/note", `{"comment":%s}`},
-	{http.MethodPost, mastodonSignUp, `{"password":%s}`},
 	{http.MethodPost, mastodonSignUp, `{"reason":%s}`},
 	{http.MethodPost, "/inbox", `{"object":{"content":%s}}`},
 	{http.MethodPost, mastodonInbox, `{"object":{"contentMap":{"en":%s}}}`},
@@ -287,6 +302,35 @@ func TestMastodonAttacksAreRefusedInTheExcludedFields(t *testing.T) {
 	}
 }
 
+func TestMastodonPasswordsPass(t *testing.T) {
+	t.Parallel()
+
+	for _, sent := range mastodonPasswordForms {
+		t.Run(sent.target+" "+sent.field, func(t *testing.T) {
+			t.Parallel()
+
+			r := request{sent.method, sent.target, []string{formData}}
+			name := strings.TrimSuffix(sent.field, "=")
+
+			wantRandomPasswordsPass(t, r, name)
+
+			// No rule these fields keep catches the SQL injection or the path
+			// traversal.
+			wantPasswordAttacksRefused(t, r, name, scriptTag)
+		})
+	}
+
+	t.Run("JSON", func(t *testing.T) {
+		t.Parallel()
+
+		r := request{mastodonPasswordJSON.method, mastodonPasswordJSON.target,
+			[]string{jsonBody}}
+
+		wantRandomPasswordsPass(t, r, "password")
+		wantPasswordAttacksRefused(t, r, "password", scriptTag)
+	})
+}
+
 func TestMastodonCommandAttackIsRefusedOutsideAPost(t *testing.T) {
 	t.Parallel()
 
@@ -299,7 +343,7 @@ func TestMastodonCommandAttackIsRefusedOutsideAPost(t *testing.T) {
 		}
 	}
 
-	for _, sent := range mastodonFormFields {
+	for _, sent := range slices.Concat(mastodonFormFields, mastodonPasswordForms) {
 		if mastodonForm(t, sent, commandInjection) < mastodonThreshold {
 			t.Errorf("%v let through", sent)
 		}
@@ -310,7 +354,8 @@ func TestMastodonCommandAttackIsRefusedOutsideAPost(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	for _, sent := range mastodonJSONFields {
+	passwordJSON := []mastodonBodyField{mastodonPasswordJSON}
+	for _, sent := range slices.Concat(mastodonJSONFields, passwordJSON) {
 		if mastodonJSON(t, sent, attack) < mastodonThreshold {
 			t.Errorf("%v let through", sent)
 		}
@@ -330,6 +375,12 @@ func TestMastodonHardValuesPassInTheExcludedFields(t *testing.T) {
 				t.Errorf("%s refused: %d", sent, score)
 			}
 		}
+
+		for _, sent := range mastodonPasswordForms {
+			if mastodonForm(t, sent, value) >= mastodonThreshold {
+				t.Errorf("%v with %s refused", sent, value)
+			}
+		}
 	}
 
 	code := url.QueryEscape(mastodonCodePost)