istio.io/istio@v0.0.0-20240520182934-d79c90f27776/pilot/pkg/security/trustdomain/util.go (about)

     1  // Copyright Istio Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package trustdomain
    16  
    17  import "strings"
    18  
    19  // stringMatch checks if a string is in a list, it supports four types of string matches:
    20  // 1. Exact match.
    21  // 2. Wild character match. "*" matches any string.
    22  // 3. Prefix match. For example, "book*" matches "bookstore", "bookshop", etc.
    23  // 4. Suffix match. For example, "*/review" matches "/bookstore/review", "/products/review", etc.
    24  // This is an extensive version of model.stringMatch(). The pattern can be in the string or the list.
    25  func stringMatch(a string, list []string) bool {
    26  	for _, s := range list {
    27  		if a == s || s == "*" || prefixMatch(a, s) || prefixMatch(s, a) || suffixMatch(a, s) || suffixMatch(s, a) {
    28  			return true
    29  		}
    30  	}
    31  	return false
    32  }
    33  
    34  // prefixMatch checks if pattern is a prefix match and if string a has the given prefix.
    35  func prefixMatch(a string, pattern string) bool {
    36  	if !strings.HasSuffix(pattern, "*") {
    37  		return false
    38  	}
    39  	pattern = strings.TrimSuffix(pattern, "*")
    40  	return strings.HasPrefix(a, pattern)
    41  }
    42  
    43  // suffixMatch checks if pattern is a suffix match and if string a has the given suffix.
    44  func suffixMatch(a string, pattern string) bool {
    45  	if !strings.HasPrefix(pattern, "*") {
    46  		return false
    47  	}
    48  	pattern = strings.TrimPrefix(pattern, "*")
    49  	return strings.HasSuffix(a, pattern)
    50  }
    51  
    52  // isKeyInList it's fine to use this naive implementation for searching in a very short list.
    53  func isKeyInList(key string, list []string) bool {
    54  	for _, l := range list {
    55  		if key == l {
    56  			return true
    57  		}
    58  	}
    59  	return false
    60  }