feat(registration): add email domain whitelist policy

2026-03-02 23:13:39 +08:00
parent ba6de4c4d4
commit bd0801a887
25 changed files with 1113 additions and 267 deletions
--- a/backend/internal/service/registration_email_policy.go
+++ b/backend/internal/service/registration_email_policy.go
@@ -0,0 +1,123 @@
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var registrationEmailDomainPattern = regexp.MustCompile(
+	`^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?(?:\.[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)+$`,
+)
+
+// RegistrationEmailSuffix extracts normalized suffix in "@domain" form.
+func RegistrationEmailSuffix(email string) string {
+	_, domain, ok := splitEmailForPolicy(email)
+	if !ok {
+		return ""
+	}
+	return "@" + domain
+}
+
+// IsRegistrationEmailSuffixAllowed checks whether an email is allowed by suffix whitelist.
+// Empty whitelist means allow all.
+func IsRegistrationEmailSuffixAllowed(email string, whitelist []string) bool {
+	if len(whitelist) == 0 {
+		return true
+	}
+	suffix := RegistrationEmailSuffix(email)
+	if suffix == "" {
+		return false
+	}
+	for _, allowed := range whitelist {
+		if suffix == allowed {
+			return true
+		}
+	}
+	return false
+}
+
+// NormalizeRegistrationEmailSuffixWhitelist normalizes and validates suffix whitelist items.
+func NormalizeRegistrationEmailSuffixWhitelist(raw []string) ([]string, error) {
+	return normalizeRegistrationEmailSuffixWhitelist(raw, true)
+}
+
+// ParseRegistrationEmailSuffixWhitelist parses persisted JSON into normalized suffixes.
+// Invalid entries are ignored to keep old misconfigurations from breaking runtime reads.
+func ParseRegistrationEmailSuffixWhitelist(raw string) []string {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return []string{}
+	}
+	var items []string
+	if err := json.Unmarshal([]byte(raw), &items); err != nil {
+		return []string{}
+	}
+	normalized, _ := normalizeRegistrationEmailSuffixWhitelist(items, false)
+	if len(normalized) == 0 {
+		return []string{}
+	}
+	return normalized
+}
+
+func normalizeRegistrationEmailSuffixWhitelist(raw []string, strict bool) ([]string, error) {
+	if len(raw) == 0 {
+		return nil, nil
+	}
+
+	seen := make(map[string]struct{}, len(raw))
+	out := make([]string, 0, len(raw))
+	for _, item := range raw {
+		normalized, err := normalizeRegistrationEmailSuffix(item)
+		if err != nil {
+			if strict {
+				return nil, err
+			}
+			continue
+		}
+		if normalized == "" {
+			continue
+		}
+		if _, ok := seen[normalized]; ok {
+			continue
+		}
+		seen[normalized] = struct{}{}
+		out = append(out, normalized)
+	}
+
+	if len(out) == 0 {
+		return nil, nil
+	}
+	return out, nil
+}
+
+func normalizeRegistrationEmailSuffix(raw string) (string, error) {
+	value := strings.ToLower(strings.TrimSpace(raw))
+	if value == "" {
+		return "", nil
+	}
+
+	domain := value
+	if strings.Contains(value, "@") {
+		if !strings.HasPrefix(value, "@") || strings.Count(value, "@") != 1 {
+			return "", fmt.Errorf("invalid email suffix: %q", raw)
+		}
+		domain = strings.TrimPrefix(value, "@")
+	}
+
+	if domain == "" || strings.Contains(domain, "@") || !registrationEmailDomainPattern.MatchString(domain) {
+		return "", fmt.Errorf("invalid email suffix: %q", raw)
+	}
+
+	return "@" + domain, nil
+}
+
+func splitEmailForPolicy(raw string) (local string, domain string, ok bool) {
+	email := strings.ToLower(strings.TrimSpace(raw))
+	local, domain, found := strings.Cut(email, "@")
+	if !found || local == "" || domain == "" || strings.Contains(domain, "@") {
+		return "", "", false
+	}
+	return local, domain, true
+}