k8s.io/apiserver@v0.31.1/pkg/authorization/path/path.go (about)

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package path
    18  
    19  import (
    20  	"context"
    21  	"fmt"
    22  	"strings"
    23  
    24  	"k8s.io/apimachinery/pkg/util/sets"
    25  	"k8s.io/apiserver/pkg/authorization/authorizer"
    26  )
    27  
    28  // NewAuthorizer returns an authorizer which accepts a given set of paths.
    29  // Each path is either a fully matching path or it ends in * in case a prefix match is done. A leading / is optional.
    30  func NewAuthorizer(alwaysAllowPaths []string) (authorizer.Authorizer, error) {
    31  	var prefixes []string
    32  	paths := sets.NewString()
    33  	for _, p := range alwaysAllowPaths {
    34  		p = strings.TrimPrefix(p, "/")
    35  		if len(p) == 0 {
    36  			// matches "/"
    37  			paths.Insert(p)
    38  			continue
    39  		}
    40  		if strings.ContainsRune(p[:len(p)-1], '*') {
    41  			return nil, fmt.Errorf("only trailing * allowed in %q", p)
    42  		}
    43  		if strings.HasSuffix(p, "*") {
    44  			prefixes = append(prefixes, p[:len(p)-1])
    45  		} else {
    46  			paths.Insert(p)
    47  		}
    48  	}
    49  
    50  	return authorizer.AuthorizerFunc(func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
    51  		if a.IsResourceRequest() {
    52  			return authorizer.DecisionNoOpinion, "", nil
    53  		}
    54  
    55  		pth := strings.TrimPrefix(a.GetPath(), "/")
    56  		if paths.Has(pth) {
    57  			return authorizer.DecisionAllow, "", nil
    58  		}
    59  
    60  		for _, prefix := range prefixes {
    61  			if strings.HasPrefix(pth, prefix) {
    62  				return authorizer.DecisionAllow, "", nil
    63  			}
    64  		}
    65  
    66  		return authorizer.DecisionNoOpinion, "", nil
    67  	}), nil
    68  }