feat: Add ext-auth plugin support for authentication blacklists/whitelists (#1694)

plugins/wasm-go/extensions/ext-auth/expr/match_rules.go

@@ -0,0 +1,79 @@
+package expr
+
+import (
+	"strings"
+
+	regexp "github.com/wasilibs/go-re2"
+)
+
+const (
+	ModeWhitelist = "whitelist"
+	ModeBlacklist = "blacklist"
+)
+
+type MatchRules struct {
+	Mode     string
+	RuleList []Rule
+}
+
+type Rule struct {
+	Domain string
+	Path   Matcher
+}
+
+func MatchRulesDefaults() MatchRules {
+	return MatchRules{
+		Mode:     ModeWhitelist,
+		RuleList: []Rule{},
+	}
+}
+
+// IsAllowedByMode checks if the given domain and path are allowed based on the configuration mode.
+func (config *MatchRules) IsAllowedByMode(domain, path string) bool {
+	switch config.Mode {
+	case ModeWhitelist:
+		for _, rule := range config.RuleList {
+			if rule.matchDomainAndPath(domain, path) {
+				return true
+			}
+		}
+		return false
+	case ModeBlacklist:
+		for _, rule := range config.RuleList {
+			if rule.matchDomainAndPath(domain, path) {
+				return false
+			}
+		}
+		return true
+	default:
+		return false
+	}
+}
+
+// matchDomainAndPath checks if the given domain and path match the rule.
+// If rule.Domain is empty, it only checks rule.Path.
+// If rule.Path is empty, it only checks rule.Domain.
+// If both are empty, it returns false.
+func (rule *Rule) matchDomainAndPath(domain, path string) bool {
+	if rule.Domain == "" && rule.Path == nil {
+		return false
+	}
+	domainMatch := rule.Domain == "" || matchDomain(domain, rule.Domain)
+	pathMatch := rule.Path == nil || rule.Path.Match(path)
+	return domainMatch && pathMatch
+}
+
+// matchDomain checks if the given domain matches the pattern.
+func matchDomain(domain string, pattern string) bool {
+	// Convert wildcard pattern to regex pattern
+	regexPattern := convertWildcardToRegex(pattern)
+	matched, _ := regexp.MatchString(regexPattern, domain)
+	return matched
+}
+
+// convertWildcardToRegex converts a wildcard pattern to a regex pattern.
+func convertWildcardToRegex(pattern string) string {
+	pattern = regexp.QuoteMeta(pattern)
+	pattern = "^" + strings.ReplaceAll(pattern, "\\*", ".*") + "$"
+	return pattern
+}