Add lint to check Authority Key Identifier in CRL Extension (#892)

Co-authored-by: Christopher Henderson <chris@chenderson.org>

v3/lints/rfc/lint_crl_has_authority_key_identifier.go

@@ -0,0 +1,54 @@
+package rfc
+
+/*
+ * ZLint Copyright 2024 Regents of the University of Michigan
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+/*
+ * Contributed by Adriano Santoni <adriano.santoni@staff.aruba.it>
+ * of ACTALIS S.p.A. (www.actalis.com).
+ */
+
+import (
+	"github.com/zmap/zcrypto/x509"
+	"github.com/zmap/zlint/v3/lint"
+	"github.com/zmap/zlint/v3/util"
+)
+
+func init() {
+	lint.RegisterRevocationListLint(&lint.RevocationListLint{
+		LintMetadata: lint.LintMetadata{
+			Name:          "e_crl_has_authority_key_identifier",
+			Description:   "The CRL must include Authority Key Identifier extension.",
+			Citation:      "RFC5280 §5.2,1",
+			Source:        lint.RFC5280,
+			EffectiveDate: util.RFC5280Date,
+		},
+		Lint: func() lint.RevocationListLintInterface { return &crlAuthKeyID{} },
+	})
+}
+
+type crlAuthKeyID struct{}
+
+func (l *crlAuthKeyID) CheckApplies(_ *x509.RevocationList) bool {
+	return true
+}
+
+func (l *crlAuthKeyID) Execute(c *x509.RevocationList) *lint.LintResult {
+	for _, ext := range c.Extensions {
+		if ext.Id.Equal(util.AuthkeyOID) {
+			return &lint.LintResult{Status: lint.Pass}
+		}
+	}
+	return &lint.LintResult{Status: lint.Error, Details: "The CRL lacks the mandatory Authority Key Identifier extension."}
+}

v3/lints/rfc/lint_crl_has_authority_key_identifier_test.go

@@ -0,0 +1,49 @@
+package rfc
+
+/*
+ * ZLint Copyright 2024 Regents of the University of Michigan
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+import (
+	"testing"
+
+	"github.com/zmap/zlint/v3/lint"
+	"github.com/zmap/zlint/v3/test"
+)
+
+func TestExecute(t *testing.T) {
+	tests := []struct {
+		name string
+		path string
+		want lint.LintStatus
+	}{
+		{
+			name: "crlWithMissingAuthKeyID",
+			path: "crlWithMissingAuthKeyID.pem",
+			want: lint.Error,
+		},
+		{
+			name: "crlWithAuthKeyID",
+			path: "crlWithAuthKeyID.pem",
+			want: lint.Pass,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := test.TestRevocationListLint(t, "e_crl_has_authority_key_identifier", tc.path)
+			if got.Status != tc.want {
+				t.Errorf("Execute() = %v, want %v", got.Status, tc.want)
+			}
+		})
+	}
+}

v3/testdata/crlWithAuthKeyID.pem

@@ -0,0 +1,12 @@
+-----BEGIN X509 CRL-----
+MIIBvDCBpQIBATANBgkqhkiG9w0BAQsFADASMRAwDgYDVQQDEwdSb290IENBFxEy
+NDEwMjgyMzI5MzErMDEwMBcRMjUxMDI4MjMyOTMxKzAxMDAwJjAkAgEBFxEyNDEw
+MjgyMzI5MzErMDEwMDAMMAoGA1UdFQQDCgEFoC8wLTAKBgNVHRQEAwIBATAfBgNV
+HSMEGDAWgBRUsHutRbjiQH/7Cm77vjPJPKOE1TANBgkqhkiG9w0BAQsFAAOCAQEA
+lz8TEEYTSCY633weMHkCMjJZoPgOmM5kIGBMg8Mgl6GNJA3pZYfwUhxpa+eb+M7U
+WBo3JtXLWrIsu++YitTw16kLWIsUg2iEtDDZnPVagw+qtrYnifsihF+aSjbOUBQr
+oaT5wnPbf3tG5I84TZ5/rTtkG7wtuU7bbSc2GdaG1x33cIG/EXMzgwxNWwoKSo2w
+Z2spALtQFyPLTGxf9jhS7mYMDEAxu7njw5/10/BLGOWzmQhlkHaqdeqZqMk/y9gX
+45y0z7F4T7SqpafacQHk4v6TD8vWVtCIU8gp0vNJTkJITZpdjm9IwgHexXsQXXrF
+DXk+Gj9jgl9PQefJwSGTSg==
+-----END X509 CRL-----

v3/testdata/crlWithMissingAuthKeyID.pem

@@ -0,0 +1,11 @@
+-----BEGIN X509 CRL-----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+-----END X509 CRL-----