better error handling for csrs (#211)

Error when no valid certs are found when verifying instead of accessing oob.
Warn when CSRs are found instead of silently ignoring them.

Co-authored-by: Mat Byczkowski <mbyczkowski@gmail.com>

lib/certs.go

@@ -183,6 +183,8 @@ func pemToX509(callback func(*x509.Certificate, error) error) func(*pem.Block) e
 			} else {
 				return callback(nil, err)
 			}
+		case "CERTIFICATE REQUEST":
+			fmt.Println(red.SprintfFunc()("warning: certificate requests are not supported"))
 		}
 		return nil
 	}

lib/verify.go

@@ -114,6 +114,11 @@ func VerifyChain(certs []*x509.Certificate, ocspStaple []byte, dnsName, caPath s
 		OCSPWasStapled: ocspStaple != nil,
 	}
 
+	if len(certs) == 0 {
+		result.Error = "no certificates found"
+		return result
+	}
+
 	intermediates := x509.NewCertPool()
 	for i := 1; i < len(certs); i++ {
 		intermediates.AddCert(certs[i])

tests/dump-csr-to-text.t

@@ -0,0 +1,27 @@
+Set up test data.
+
+  $ cat > example-leaf.csr <<EOF
+  > -----BEGIN CERTIFICATE REQUEST-----
+  > MIICmjCCAYICAQAwVTELMAkGA1UEBhMCVVMxCzAJBgNVBAgTAkNBMRAwDgYDVQQK
+  > EwdjZXJ0aWdvMRAwDgYDVQQLEwdleGFtcGxlMRUwEwYDVQQDEwxleGFtcGxlLWxl
+  > YWYwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC7stSvfQyGuHw3v34f
+  > isqIdDXberrFoFk9ht/WdXgYzX2uLNKdsR/J5sbWSl8K/5djpzj31eIzqU69w8v7
+  > SChM5x9bouDsABHz3kZucx5cSafEgJojysBkcrq3VY+aJanzbL+qErYX+lhRpPcZ
+  > K6JMWIwar8Y3B2la4yWwieecw2/WfEVvG0M/DOYKnR8QHFsfl3US1dnBM84czKPy
+  > t9r40gDk2XiH/lGts5a94rAGvbr8IMCtq0mA5aH3Fx3mDSi3+4MZwygCAHrF5O5i
+  > SV9rEI+m2+7j2S+jHDUnvV+nqcpb9m6ENECnYX8FD2KcqlOjTmw8smDy09N2Np6i
+  > 464lAgMBAAGgADANBgkqhkiG9w0BAQUFAAOCAQEAZW13CST8BtPCINS0CiIv9BMv
+  > zXpkCRz3riPvrPkllnOY3Dp0NQzQkdj3aE4at5GSN9fOTWCQ0tGnjOLAZ8tqHcyg
+  > FLgU3MjDcsRvyeQ8mYpCqeUbwq/nHIs33jM/x087lTP7aNXGH4sncxZdIv71+sqF
+  > f4WnumxsJUARaeb0AnUZmtAC/OR+9vpiUw+wMMhMbDNCboKYANqnFhWkTKp5/85f
+  > eC21haSG55pT7bGvlG9WNawgXJ3WX48yw29dSyDKd/buVM5Andrp7hYVuC57wz0u
+  > wng/cxCCQrENS4qSvxOgFiLK2j1LHccMuChPFFGyOyXqBNs9pr8F4/2qPJ7tOw==
+  > -----END CERTIFICATE REQUEST-----
+  > EOF
+
+Dump an example certificate request (example-leaf.csr)
+
+  $ certigo --verbose dump example-leaf.csr
+  warning: certificate requests are not supported
+  warning: no certificates found in input
+