fix bug in the email address checking in the smime package to allow m…

…ultiple email address subject fields, but dsisallow multiple values in a single email address field

fixes a comment on zmap#753

v3/lints/cabf_smime_br/lint_single_email_if_present.go

@@ -16,6 +16,7 @@ package cabf_smime_br
 
 import (
 	"fmt"
+	"net/mail"
 
 	"github.com/zmap/zcrypto/x509"
 	"github.com/zmap/zlint/v3/lint"
@@ -46,15 +47,18 @@ func (l *singleEmailIfPresent) CheckApplies(c *x509.Certificate) bool {
 }
 
 func (l *singleEmailIfPresent) Execute(c *x509.Certificate) *lint.LintResult {
-	if len(c.EmailAddresses) == 1 {
-		return &lint.LintResult{
-			Status: lint.Pass,
-		}
-	} else {
-		return &lint.LintResult{
-			Status:       lint.Error,
-			Details:      fmt.Sprintf("subject:emailAddress was present and contained %d names (%s)", len(c.EmailAddresses), c.EmailAddresses),
-			LintMetadata: lint.LintMetadata{},
+	for _, email := range c.EmailAddresses {
+		_, err := mail.ParseAddress(email)
+		if err != nil {
+			return &lint.LintResult{
+				Status:       lint.Error,
+				Details:      fmt.Sprintf("subject:emailAddress was present and contained an invalid email address (%s)", email),
+				LintMetadata: lint.LintMetadata{},
+			}
 		}
 	}
+
+	return &lint.LintResult{
+		Status: lint.Pass,
+	}
 }

v3/lints/cabf_smime_br/lint_single_email_if_present_test.go

@@ -24,8 +24,13 @@ func TestSingleEmailIfPresent(t *testing.T) {
 			ExpectedResult: lint.NA,
 		},
 		{
-			Name:           "Error - cert with multiple email addresses",
+			Name:           "Pass - cert with multiple email addresses",
 			InputFilename:  "smime/multiple_email_present.pem",
+			ExpectedResult: lint.Pass,
+		},
+		{
+			Name:           "Error - email address present with mutliple values",
+			InputFilename:  "smime/email_with_multiple_values.pem",
 			ExpectedResult: lint.Error,
 		},
 	}

v3/testdata/smime/email_with_multiple_values.pem

@@ -0,0 +1,44 @@
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number: 3 (0x3)
+        Signature Algorithm: ecdsa-with-SHA256
+        Issuer: 
+        Validity
+            Not Before: Sep 30 00:00:00 2023 GMT
+            Not After : Nov 30 00:00:00 9998 GMT
+        Subject: 
+        Subject Public Key Info:
+            Public Key Algorithm: id-ecPublicKey
+                Public-Key: (256 bit)
+                pub:
+                    04:b1:40:22:c1:13:22:0c:f6:64:60:55:a0:3c:7d:
+                    3f:e5:81:49:00:bd:36:9f:ef:d6:29:c6:eb:28:e5:
+                    d7:25:98:9b:f5:a5:e4:b3:95:0f:f6:af:bf:f5:b1:
+                    32:39:3c:5e:6b:bc:0e:2d:cf:ea:39:55:50:25:55:
+                    74:bd:e8:5e:f5
+                ASN1 OID: prime256v1
+                NIST CURVE: P-256
+        X509v3 extensions:
+            X509v3 Extended Key Usage: 
+                E-mail Protection
+            X509v3 Subject Alternative Name: 
+                email:[email protected] [email protected], email:[email protected]
+            X509v3 Certificate Policies: 
+                Policy: 2.23.140.1.5.1.1
+    Signature Algorithm: ecdsa-with-SHA256
+    Signature Value:
+        30:44:02:20:0a:ad:0d:13:2f:8d:f2:ea:66:17:2d:d2:6a:63:
+        ff:4b:3f:01:0a:32:00:74:ce:cd:ea:e2:9f:0d:21:14:55:64:
+        02:20:6c:6a:fb:1b:64:88:d8:67:fe:39:a9:e7:77:29:a6:a3:
+        77:a5:34:8f:60:1a:85:e6:db:18:5b:e7:00:41:30:fb
+-----BEGIN CERTIFICATE-----
+MIIBYzCCAQqgAwIBAgIBAzAKBggqhkjOPQQDAjAAMCAXDTIzMDkzMDAwMDAwMFoY
+Dzk5OTgxMTMwMDAwMDAwWjAAMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEsUAi
+wRMiDPZkYFWgPH0/5YFJAL02n+/WKcbrKOXXJZib9aXks5UP9q+/9bEyOTxea7wO
+Lc/qOVVQJVV0vehe9aNzMHEwEwYDVR0lBAwwCgYIKwYBBQUHAwQwRAYDVR0RBD0w
+O4EldGVzdCsxQGV4YW1wbGUuY29tIHRlc3QrMkBleGFtcGxlLmNvbYESdGVzdCsz
+QGV4YW1wbGUuY29tMBQGA1UdIAQNMAswCQYHZ4EMAQUBATAKBggqhkjOPQQDAgNH
+ADBEAiAKrQ0TL43y6mYXLdJqY/9LPwEKMgB0zs3q4p8NIRRVZAIgbGr7G2SI2Gf+
+Oanndymmo3elNI9gGoXm2xhb5wBBMPs=
+-----END CERTIFICATE-----