How can i pass the base64 string as a input certificate for Openssl? - node.js

Question

I have a certificate which i am getting in string . I just want that string to be directly pass as -in in the openssl command.
But i don't see any method in openssl , can you help.
my code
const { exec } = require('child_process');
exec('openssl x509 -noout -issuer -in '+certificateString , (err, stdout, stderr) => {
if (err) {
console.log(err);
}else{
console.log(studout);
}
});
If i directly pass certificate file url it works, like this
openssl x509 -noout -issuer -in certificate.pem
this work
but how can i pass the certificate string directly in openssl ?
Any help?

Answer 1

First, do you have base64 or PEM? Those are not the same thing; although PEM includes base64, it is not only base64. If you have a file that works with openssl x509 -in file then it is PEM, NOT only base64. People seem to look at PEM, see more than 40 base64 characters, and their brains shut down and become unable to see the dashes-BEGIN line, the dashes-END line, and the line breaks, all of which are REQUIRED.
Second, certificate.pem is a filename or pathname, not a URL. A filename or pathname is not a URL, and a URL is not a filename or pathname, although some URL schemes (and particularly the only ones most people notice) include some elements in common with pathnames.
The certificate input to openssl x509 must be either a (named) file, or standard input (commonly abbreviated stdin). If you don't want to supply it as a named file, nodejs can provide data to a child's stdin, but not with the higher-level exec* methods, only the more basic spawn:
const{ spawn } = require('child_process');
const pem = `-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
`;
const p = spawn("/path/to/openssl", ["x509","-noout","-issuer"]);
// options.stdio defaults to ['pipe','pipe','pipe']
p.stdout.on('data',(data)=> {console.log(data.toString())} );
p.stderr.on('data',(data)=> {console.log("ERROR:"+data.toString())} );
p.on('close',()=> {} );
p.stdin.write(pem); p.stdin.end();
However, you don't need to run an external program to parse a certificate; there are lots of JS libraries to do it. For example, with the second one npmjs finds for me:
const { Certificate } = require('#fidm/x509');
const { ASN1 } = require('#fidm/asn1');
var iss = Certificate.fromPEM(pem).issuer.attributes;
var s = ""; for(var a of iss){ s += "/" + a.shortName + "=" + a.value; }
console.log(s);
If you actually did have base64 and not PEM, replace the third line with
const bin = Buffer.from(b64,'base64');
var iss = new Certificate(ASN1.fromDER(bin)).issuer.attributes;