github.com/zmap/zlint@v1.1.0/lints/lint_ext_duplicate_extension.go (about)

     1  package lints
     2  
     3  /*
     4   * ZLint Copyright 2018 Regents of the University of Michigan
     5   *
     6   * Licensed under the Apache License, Version 2.0 (the "License"); you may not
     7   * use this file except in compliance with the License. You may obtain a copy
     8   * of the License at 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
    13   * implied. See the License for the specific language governing
    14   * permissions and limitations under the License.
    15   */
    16  
    17  /************************************************
    18  "A certificate MUST NOT include more than one instance of a particular extension."
    19  ************************************************/
    20  
    21  import (
    22  	"github.com/zmap/zcrypto/x509"
    23  	"github.com/zmap/zlint/util"
    24  )
    25  
    26  type ExtDuplicateExtension struct{}
    27  
    28  func (l *ExtDuplicateExtension) Initialize() error {
    29  	return nil
    30  }
    31  
    32  func (l *ExtDuplicateExtension) CheckApplies(cert *x509.Certificate) bool {
    33  	return cert.Version == 3
    34  }
    35  
    36  func (l *ExtDuplicateExtension) Execute(cert *x509.Certificate) *LintResult {
    37  	// O(n^2) is not terrible here because n is capped around 10
    38  	for i := 0; i < len(cert.Extensions); i++ {
    39  		for j := i + 1; j < len(cert.Extensions); j++ {
    40  			if i != j && cert.Extensions[i].Id.Equal(cert.Extensions[j].Id) {
    41  				return &LintResult{Status: Error}
    42  			}
    43  		}
    44  	}
    45  	// Nested loop will return if it finds a duplicate, so safe to assume pass
    46  	return &LintResult{Status: Pass}
    47  }
    48  
    49  func init() {
    50  	RegisterLint(&Lint{
    51  		Name:          "e_ext_duplicate_extension",
    52  		Description:   "A certificate MUST NOT include more than one instance of a particular extension",
    53  		Citation:      "RFC 5280: 4.2",
    54  		Source:        RFC5280,
    55  		EffectiveDate: util.RFC2459Date,
    56  		Lint:          &ExtDuplicateExtension{},
    57  	})
    58  }