Merge pull request #107 from arj-singh/master

Basic Constraints extension

Author: Ephenodrom

lib/src/X509Utils.dart

@@ -290,6 +290,8 @@ class X509Utils {
   /// * [sans] = Subject alternative names to place within the certificate
   /// * [keyUsage] = The key usage definition extension
   /// * [extKeyUsage] = The extended key usage definition
+  /// * [cA] = The cA boolean of the basic constraints extension, which indicates whether the certificate is a CA
+  /// * [pathLenConstraint] = The pathLenConstraint field of the basic constraints extension. This is ignored if cA is null or false, or if pathLenConstraint is less than 0.
   /// * [serialNumber] = The serialnumber. If not set the default will be 1.
   /// * [issuer] = The issuer. If null, the issuer will be the subject of the given csr.
   /// * [notBefore] = The Timestamp after when the certificate is valid. If null, this will be [DateTime.now].
@@ -302,6 +304,8 @@ class X509Utils {
     List<String>? sans,
     List<KeyUsage>? keyUsage,
     List<ExtendedKeyUsage>? extKeyUsage,
+    bool? cA,
+    int? pathLenConstraint,
     String serialNumber = '1',
     Map<String, String>? issuer,
     DateTime? notBefore,
@@ -397,7 +401,8 @@ class X509Utils {
     // Add Extensions
     if (IterableUtils.isNotNullOrEmpty(sans) ||
         IterableUtils.isNotNullOrEmpty(keyUsage) ||
-        IterableUtils.isNotNullOrEmpty(extKeyUsage)) {
+        IterableUtils.isNotNullOrEmpty(extKeyUsage) ||
+        cA != null) {
       var extensionTopSequence = ASN1Sequence();
 
       if (IterableUtils.isNotNullOrEmpty(keyUsage)) {
@@ -484,6 +489,30 @@ class X509Utils {
         extensionTopSequence.add(sanSequence);
       }
 
+      if (cA != null) {
+        var basicConstraintsSequence = ASN1Sequence();
+
+        basicConstraintsSequence
+            .add(ASN1ObjectIdentifier.fromIdentifierString("2.5.29.19"));
+        basicConstraintsSequence.add(ASN1Boolean(true));
+
+        var basicConstraintsList = ASN1Sequence();
+
+        if (cA) {
+          basicConstraintsList.add(ASN1Boolean(cA));
+        }
+
+        // check if CA to allow pathLenConstraint
+        if (pathLenConstraint != null && cA && pathLenConstraint >= 0) {
+          basicConstraintsList.add(ASN1Integer.fromtInt(pathLenConstraint));
+        }
+
+        basicConstraintsSequence
+            .add(ASN1OctetString(octets: basicConstraintsList.encode()));
+
+        extensionTopSequence.add(basicConstraintsSequence);
+      }
+
       var extObj = ASN1Object(tag: 0xA3);
       extObj.valueBytes = extensionTopSequence.encode();
 
@@ -1417,6 +1446,28 @@ class X509Utils {
     return extKeyUsage;
   }
 
+  ///
+  /// Parses the given ASN1Object to the two basic constraint
+  /// fields cA and pathLenConstraint. Returns a list of types [bool, int] if
+  /// cA is true and a valid pathLenConstraint is specified, else the
+  /// corresponding element will be null.
+  ///
+  static List<dynamic> _fetchBasicConstraintsFromExtension(ASN1Object extData) {
+    var basicConstraints = <dynamic>[null, null];
+    var octet = extData as ASN1OctetString;
+    var constraintParser = ASN1Parser(octet.valueBytes);
+    var constraintSeq = constraintParser.nextObject() as ASN1Sequence;
+    constraintSeq.elements!.forEach((ASN1Object obj) {
+      if (obj is ASN1Boolean) {
+        basicConstraints[0] = obj.boolValue;
+      }
+      if (obj is ASN1Integer) {
+        basicConstraints[1] = obj.integer!.toInt();
+      }
+    });
+    return basicConstraints;
+  }
+
   ///
   /// Parses the given object identifier values to the internal enum
   ///
@@ -1926,6 +1977,7 @@ class X509Utils {
     List<String>? sans;
     List<KeyUsage>? keyUsage;
     List<ExtendedKeyUsage>? extKeyUsage;
+    List<dynamic> basicConstraints;
     var extensions = X509CertificateDataExtensions();
     extSequence.elements!.forEach(
       (ASN1Object subseq) {
@@ -1962,6 +2014,17 @@ class X509Utils {
           }
           extensions.extKeyUsage = extKeyUsage;
         }
+        if (oi.objectIdentifierAsString == '2.5.29.19') {
+          if (seq.elements!.length == 3) {
+            basicConstraints =
+                _fetchBasicConstraintsFromExtension(seq.elements!.elementAt(2));
+          } else {
+            basicConstraints = [null, null];
+          }
+
+          extensions.cA = basicConstraints[0];
+          extensions.pathLenConstraint = basicConstraints[1];
+        }
         if (oi.objectIdentifierAsString == '1.3.6.1.5.5.7.1.12') {
           var vmcData = _fetchVmcLogo(seq.elements!.elementAt(1));
           extensions.vmc = vmcData;

lib/src/model/x509/X509CertificateDataExtensions.dart

@@ -19,6 +19,12 @@ class X509CertificateDataExtensions {
   /// The key usage extension
   List<KeyUsage>? keyUsage;
 
+  /// The cA field of the basic constraints extension
+  bool? cA;
+
+  /// The pathLenConstraint field of the basic constraints extension
+  int? pathLenConstraint;
+
   /// The base64 encoded VMC logo
   VmcData? vmc;
 
@@ -29,6 +35,8 @@ class X509CertificateDataExtensions {
     this.subjectAlternativNames,
     this.extKeyUsage,
     this.keyUsage,
+    this.cA,
+    this.pathLenConstraint,
     this.vmc,
     this.cRLDistributionPoints,
   });

lib/src/model/x509/X509CertificateDataExtensions.g.dart

@@ -1652,10 +1652,16 @@ SEQUENCE (1 elem)
       notBefore: notBefore,
     );
     var x509 = X509Utils.x509CertificateFromPem(pem);
-    expect(x509.tbsCertificate?.validity.notBefore.toIso8601String().substring(0, 10),
+    expect(
+        x509.tbsCertificate?.validity.notBefore
+            .toIso8601String()
+            .substring(0, 10),
         notBefore.toUtc().toIso8601String().substring(0, 10),
         reason: "notBefore match except milliseconds as utc");
-    expect(x509.tbsCertificate?.validity.notAfter.toIso8601String().substring(0, 10),
+    expect(
+        x509.tbsCertificate?.validity.notAfter
+            .toIso8601String()
+            .substring(0, 10),
         notAfter.toUtc().toIso8601String().substring(0, 10),
         reason: "notAfter match except milliseconds as utc");
   });
@@ -1707,6 +1713,93 @@ SEQUENCE (1 elem)
         KeyUsage.DECIPHER_ONLY);
   });
 
+  test('Test generateSelfSignedCertificate with cA true and valid pathlen', () {
+    var pair = CryptoUtils.generateEcKeyPair();
+    var dn = {
+      'CN': 'basic-utils.dev',
+      'O': 'Magic Company',
+      'L': 'Fakecity',
+      'S': 'FakeState',
+      'C': 'DE',
+    };
+    var csr = X509Utils.generateEccCsrPem(
+        dn, pair.privateKey as ECPrivateKey, pair.publicKey as ECPublicKey,
+        san: ['san1.basic-utils.dev', 'san2.basic-utils.dev']);
+
+    var pem = X509Utils.generateSelfSignedCertificate(pair.privateKey, csr, 365,
+        cA: true, pathLenConstraint: 10);
+    var x509 = X509Utils.x509CertificateFromPem(pem);
+
+    expect(x509.tbsCertificate?.extensions?.cA, true);
+    expect(x509.tbsCertificate?.extensions?.pathLenConstraint, 10);
+  });
+
+  test('Test generateSelfSignedCertificate with cA false and valid pathLen',
+      () {
+    var pair = CryptoUtils.generateEcKeyPair();
+    var dn = {
+      'CN': 'basic-utils.dev',
+      'O': 'Magic Company',
+      'L': 'Fakecity',
+      'S': 'FakeState',
+      'C': 'DE',
+    };
+    var csr = X509Utils.generateEccCsrPem(
+        dn, pair.privateKey as ECPrivateKey, pair.publicKey as ECPublicKey,
+        san: ['san1.basic-utils.dev', 'san2.basic-utils.dev']);
+
+    var pem = X509Utils.generateSelfSignedCertificate(pair.privateKey, csr, 365,
+        cA: false, pathLenConstraint: 10);
+    var x509 = X509Utils.x509CertificateFromPem(pem);
+
+    expect(x509.tbsCertificate?.extensions?.cA, null);
+    expect(x509.tbsCertificate?.extensions?.pathLenConstraint, null);
+  });
+
+  test('Test generateSelfSignedCertificate with cA true and invalid pathLen',
+      () {
+    var pair = CryptoUtils.generateEcKeyPair();
+    var dn = {
+      'CN': 'basic-utils.dev',
+      'O': 'Magic Company',
+      'L': 'Fakecity',
+      'S': 'FakeState',
+      'C': 'DE',
+    };
+    var csr = X509Utils.generateEccCsrPem(
+        dn, pair.privateKey as ECPrivateKey, pair.publicKey as ECPublicKey,
+        san: ['san1.basic-utils.dev', 'san2.basic-utils.dev']);
+
+    var pem = X509Utils.generateSelfSignedCertificate(pair.privateKey, csr, 365,
+        cA: true, pathLenConstraint: -10);
+    var x509 = X509Utils.x509CertificateFromPem(pem);
+
+    expect(x509.tbsCertificate?.extensions?.cA, true);
+    expect(x509.tbsCertificate?.extensions?.pathLenConstraint, null);
+  });
+
+  test('Test generateSelfSignedCertificate with cA false and invalid pathLen',
+      () {
+    var pair = CryptoUtils.generateEcKeyPair();
+    var dn = {
+      'CN': 'basic-utils.dev',
+      'O': 'Magic Company',
+      'L': 'Fakecity',
+      'S': 'FakeState',
+      'C': 'DE',
+    };
+    var csr = X509Utils.generateEccCsrPem(
+        dn, pair.privateKey as ECPrivateKey, pair.publicKey as ECPublicKey,
+        san: ['san1.basic-utils.dev', 'san2.basic-utils.dev']);
+
+    var pem = X509Utils.generateSelfSignedCertificate(pair.privateKey, csr, 365,
+        cA: false, pathLenConstraint: -10);
+    var x509 = X509Utils.x509CertificateFromPem(pem);
+
+    expect(x509.tbsCertificate?.extensions?.cA, null);
+    expect(x509.tbsCertificate?.extensions?.pathLenConstraint, null);
+  });
+
   test('Test x509CertificateFromPem with vmc', () {
     var data = X509Utils.x509CertificateFromPem(vmc);