I tried to generate a CSR using "crypto/x509" package and didn't find the way to add a "emailAddress" field into its Subject.
According to the documentation CertificateRequest structure has a "EmailAddresses []string" field but it's serialized into SAN extension. Here is a test code i used: http://play.golang.org/p/OtObaTyuTM
Also I created a CSR using "openssl req" program and compared results:
% openssl req -in openssl.csr -noout -text
Certificate Request:
Data:
Version: 0 (0x0)
Subject: C=AU, ST=Some-State, L=MyCity, O=Company Ltd, OU=IT, CN=domain.com/[email protected]
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (512 bit)
Modulus:
00:a3:05:e3:37:63:f9:8b:d0:37:46:2d:a8:d9:26:
4e:be:83:1d:b9:30:88:2b:80:4b:53:cc:7c:01:86:
b0:9b:1d:3b:0a:05:c4:56:47:4e:5d:90:f9:5a:29:
8b:9a:7f:fa:4b:5e:e4:5d:dd:c6:8b:87:33:c4:b4:
fa:6b:b4:67:bd
Exponent: 65537 (0x10001)
Attributes:
a0:00
Signature Algorithm: sha1WithRSAEncryption
0b:24:6e:0a:f9:bf:23:d7:41:5f:96:da:78:d1:99:18:fb:d6:
71:7e:79:f0:02:e9:8a:50:a9:00:32:df:26:14:2f:f4:3e:c4:
22:c9:5c:4e:79:c1:c2:22:1b:2a:da:79:6f:51:ba:8a:12:63:
27:02:4a:b3:22:97:59:f7:6e:d6
===============================================================
% openssl req -in golang.csr -noout -text
Certificate Request:
Data:
Version: 0 (0x0)
Subject: C=AU, O=Company Ltd, OU=IT, L=MyCity, ST=Some-State, CN=domain.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (512 bit)
Modulus:
00:ac:b6:51:5b:53:44:44:20:91:da:01:45:72:49:
95:83:78:74:7c:05:f9:a7:77:88:02:3a:23:5f:04:
c3:69:45:b9:5a:bb:fd:e7:d3:24:5f:46:14:b8:7d:
30:ce:a0:c6:ea:e3:3b:ec:4c:75:24:cc:ce:60:1d:
e9:33:57:ae:21
Exponent: 65537 (0x10001)
Attributes:
Requested Extensions:
X509v3 Subject Alternative Name:
email:[email protected]
Signature Algorithm: sha256WithRSAEncryption
a1:c1:b7:80:a0:f0:c3:b6:44:06:f4:ad:12:3a:67:19:fa:84:
34:22:2a:d9:56:d9:8b:c9:a4:d0:cf:8d:a1:36:87:fa:75:b7:
05:40:0a:15:1f:72:61:85:a8:09:bc:f4:13:e6:24:5e:2e:b7:
99:e3:93:53:4e:2d:d5:0c:22:fc
To my mind I should build RawSubject field myself with emainAddress oid but I didn't find any code samples. UPD: I've found the solution. As I mentioned above, the RawSubject field must be prepared manually:
subj := pkix.Name{
CommonName: cn,
Country: []string{c},
Organization: []string{o},
OrganizationalUnit: []string{ou},
Locality: []string{l},
Province: []string{s},
}
rawSubj := subj.ToRDNSequence()
rawSubj = appendRDNs(rawSubj, []string{e}, oidEmailAddress)
asn1Subj, err := asn1.Marshal(rawSubj)
template := x509.CertificateRequest{
RawSubject: asn1Subj,
SignatureAlgorithm: x509.SHA1WithRSA,
}
where:
I know mephist answered his own question, but he left a few things to piece together. So, for the sake of completeness (and because I've landed here twice in the past 2 years...) Here's a complete working example: https://play.golang.org/p/YL_qfPe4Zz
package main
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"os"
)
var oidEmailAddress = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}
func main() {
keyBytes, _ := rsa.GenerateKey(rand.Reader, 1024)
emailAddress := "[email protected]"
subj := pkix.Name{
CommonName: "example.com",
Country: []string{"AU"},
Province: []string{"Some-State"},
Locality: []string{"MyCity"},
Organization: []string{"Company Ltd"},
OrganizationalUnit: []string{"IT"},
}
rawSubj := subj.ToRDNSequence()
rawSubj = append(rawSubj, []pkix.AttributeTypeAndValue{
{Type: oidEmailAddress, Value: emailAddress},
})
asn1Subj, _ := asn1.Marshal(rawSubj)
template := x509.CertificateRequest{
RawSubject: asn1Subj,
EmailAddresses: []string{emailAddress},
SignatureAlgorithm: x509.SHA256WithRSA,
}
csrBytes, _ := x509.CreateCertificateRequest(rand.Reader, &template, keyBytes)
pem.Encode(os.Stdout, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: csrBytes})
}