github.com/zmap/zlint@v1.1.0/lints/lint_idn_dnsname_malformed_unicode.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  import (
    18  	"strings"
    19  
    20  	"github.com/zmap/zcrypto/x509"
    21  	"github.com/zmap/zlint/util"
    22  	"golang.org/x/net/idna"
    23  )
    24  
    25  type IDNMalformedUnicode struct{}
    26  
    27  func (l *IDNMalformedUnicode) Initialize() error {
    28  	return nil
    29  }
    30  
    31  func (l *IDNMalformedUnicode) CheckApplies(c *x509.Certificate) bool {
    32  	return util.IsExtInCert(c, util.SubjectAlternateNameOID)
    33  }
    34  
    35  func (l *IDNMalformedUnicode) Execute(c *x509.Certificate) *LintResult {
    36  	for _, dns := range c.DNSNames {
    37  		labels := strings.Split(dns, ".")
    38  		for _, label := range labels {
    39  			if strings.HasPrefix(label, "xn--") {
    40  				_, err := idna.ToUnicode(label)
    41  				if err != nil {
    42  					return &LintResult{Status: Error}
    43  				}
    44  			}
    45  		}
    46  	}
    47  	return &LintResult{Status: Pass}
    48  }
    49  
    50  func init() {
    51  	RegisterLint(&Lint{
    52  		Name:          "e_international_dns_name_not_unicode",
    53  		Description:   "Internationalized DNSNames punycode not valid unicode",
    54  		Citation:      "RFC 3490",
    55  		EffectiveDate: util.RFC3490Date,
    56  		Source:        RFC5280,
    57  		Lint:          &IDNMalformedUnicode{},
    58  	})
    59  }