pilot/pkg/security/trustdomain/util.go

// Copyright Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package trustdomain

import (
	"strings"
)

// stringMatch checks if a string is in a list, it supports four types of string matches:
// 1. Exact match.
// 2. Wild character match. "*" matches any string.
// 3. Prefix match. For example, "book*" matches "bookstore", "bookshop", etc.
// 4. Suffix match. For example, "*/review" matches "/bookstore/review", "/products/review", etc.
// This is an extensive version of model.stringMatch(). The pattern can be in the string or the list.
func stringMatch(a string, list []string) bool {
	for _, s := range list {
		if a == s || s == "*" || prefixMatch(a, s) || prefixMatch(s, a) || suffixMatch(a, s) || suffixMatch(s, a) {
			return true
		}
	}
	return false
}

// prefixMatch checks if pattern is a prefix match and if string a has the given prefix.
func prefixMatch(a string, pattern string) bool {
	if !strings.HasSuffix(pattern, "*") {
		return false
	}
	pattern = strings.TrimSuffix(pattern, "*")
	return strings.HasPrefix(a, pattern)
}

// suffixMatch checks if pattern is a suffix match and if string a has the given suffix.
func suffixMatch(a string, pattern string) bool {
	if !strings.HasPrefix(pattern, "*") {
		return false
	}
	pattern = strings.TrimPrefix(pattern, "*")
	return strings.HasSuffix(a, pattern)
}

// isKeyInList it's fine to use this naive implementation for searching in a very short list.
func isKeyInList(key string, list []string) bool {
	for _, l := range list {
		if key == l {
			return true
		}
	}
	return false
}