如何使用Go从专有名称中提取通用名称？

Question

I have an x509 certificate's subject distinguished name (DN) from an X.509 certificate. I want to extract common name (CN) from it. Is there a way to do it via crypto/x509 or any other library in Go?

For Example, if the subject's distinguished name is:

CN=AMA AMI SA APB MDE MADB MDS LE.AXVD-04954-19-17.,OU=Abc,O=DA.CB.AcbDinema.com,dnQualifier=PY0aT8abfcQeUyquTe4w5RVasfY=

then I want to extract common name (CN) part (AMA AMI SA APB MDE MADB MDS LE.AXVD-04954-19-17.) out of it.

Answer 1

There is nothing in the Go standard library to parse it for you (it only handles ASN.1 encoded distinguished names), but you treat it as just a string and parse it yourself.

Here is an example using regexps. A word of warning: there is no guarantee that this will work in all cases. For example, I've seen cases of lowercase CN, or ordering may change, or just bad formatting.

package main

import (
    "fmt"
    "regexp"
    "strings"
)

func main() {
    subjectString := "CN=AMA AMI SA APB MDE MADB MDS LE.AXVD-04954-19-17.,OU=Abc,O=DA.CB.AcbDinema.com,dnQualifier=PY0aT8abfcQeUyquTe4w5RVasfY="
    re := regexp.MustCompile("CN=([^,]+)")
    matches := re.FindStringSubmatch(subjectString)

    fmt.Println(matches[1])

    commonNameParts := strings.Split(matches[1], " ")
    fmt.Println(commonNameParts)
}

Outputs the full CN string and a slice of the individual components of the CommonName:

AMA AMI SA APB MDE MADB MDS LE.AXVD-04954-19-17.
[AMA AMI SA APB MDE MADB MDS LE.AXVD-04954-19-17.]