Openssl : error "self signed certificate in certificate chain"

Question

When I used openssl APIs to validate server certificate (self signed), I got following error :

error 19 at 1 depth lookup:self signed certificate in certificate chain

As per openssl documentation, this error (19) is

"X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in certificate chain - the certificate chain could be built up using the untrusted certificates but the root could not be found locally."

Why this error occurs ? Any problems with my server certificate ?

Answer 1

You have a certificate which is self-signed, so it's non-trusted by default, that's why OpenSSL complains. This warning is actually a good thing, because this scenario might also rise due to a man-in-the-middle attack.

To solve this, you'll need to install it as a trusted server. If it's signed by a non-trusted CA, you'll have to install that CA's certificate as well.

Have a look at this link about installing self-signed certificates.

Answer 2

Here is one-liner to verify certificate to be signed by specific CA:

openssl verify -verbose -x509_strict -CAfile ca.pem certificate.pem

This doesn't require to install CA anywhere.

See How does an SSL certificate chain bundle work? for details and correct certificate chain handling.