Display SANs in output

helpers.go

@@ -108,6 +108,8 @@ type CertInfo struct {
 	SubjectParseError	error
 	Issuer			RDNSequence
 	IssuerParseError	error
+	SANs			[]SubjectAltName
+	SANsParseError		error
 	SerialNumber		*big.Int
 	SerialNumberParseError	error
 	Validity		*CertValidity
@@ -122,6 +124,7 @@ func MakeCertInfoFromTBS (tbs *TBSCertificate) *CertInfo {
 	info.Identifiers, info.IdentifiersParseError = tbs.ParseIdentifiers()
 	info.Subject, info.SubjectParseError = tbs.ParseSubject()
 	info.Issuer, info.IssuerParseError = tbs.ParseIssuer()
+	info.SANs, info.SANsParseError = tbs.ParseSubjectAltNames()
 	info.SerialNumber, info.SerialNumberParseError = tbs.ParseSerialNumber()
 	info.Validity, info.ValidityParseError = tbs.ParseValidity()
 	info.IsCA, info.IsCAParseError = tbs.ParseBasicConstraints()
@@ -244,6 +247,8 @@ func (info *CertInfo) Environ () []string {
 		env = append(env, "ISSUER_DN=" + info.Issuer.String())
 	}
 
+	// TODO: include SANs in environment
+
 	return env
 }
 
@@ -252,6 +257,7 @@ func (info *EntryInfo) HasParseErrors () bool {
 		info.CertInfo.IdentifiersParseError != nil ||
 		info.CertInfo.SubjectParseError != nil ||
 		info.CertInfo.IssuerParseError != nil ||
+		info.CertInfo.SANsParseError != nil ||
 		info.CertInfo.SerialNumberParseError != nil ||
 		info.CertInfo.ValidityParseError != nil ||
 		info.CertInfo.IsCAParseError != nil
@@ -345,6 +351,13 @@ func (info *EntryInfo) Write (out io.Writer) {
 		}
 		writeField(out, "Pubkey", info.CertInfo.PubkeyHash(), nil)
 		writeField(out, "Subject", info.CertInfo.Subject, info.CertInfo.SubjectParseError)
+		if info.CertInfo.SANsParseError != nil {
+			writeField(out, "Alt Names", nil, info.CertInfo.SANsParseError)
+		} else {
+			for _, san := range info.CertInfo.SANs {
+				writeField(out, "Alt Name", san.String(), nil)
+			}
+		}
 		writeField(out, "Issuer", info.CertInfo.Issuer, info.CertInfo.IssuerParseError)
 		writeField(out, "Serial", info.CertInfo.SerialNumber, info.CertInfo.SerialNumberParseError)
 		writeField(out, "Not Before", info.CertInfo.NotBefore(), info.CertInfo.ValidityParseError)

x509.go

@@ -7,6 +7,7 @@ import (
 	"encoding/asn1"
 	"math/big"
 	"time"
+	"net"
 )
 
 var (
@@ -146,6 +147,22 @@ func (rdns RDNSequence) String () string {
 	return buf.String()
 }
 
+func (san SubjectAltName) String () string {
+	switch san.Type {
+	case sanDNSName:
+		return "DNS:" + string(san.Value) // TODO: escape non-printable characters, '\', and ','
+	case sanIPAddress:
+		if len(san.Value) == 4 || len(san.Value) == 16 {
+			return "IP:" + net.IP(san.Value).String()
+		} else {
+			return fmt.Sprintf("IP:%v", san.Value)
+		}
+	default:
+		// TODO: support other types of SANs
+		return fmt.Sprintf("%d:%v", san.Type, san.Value)
+	}
+}
+
 func ParseTBSCertificate (tbsBytes []byte) (*TBSCertificate, error) {
 	var tbs TBSCertificate
 	if rest, err := asn1.Unmarshal(tbsBytes, &tbs); err != nil {