PEM_read_bio: bad end line error error after TLS 1.2 upgrade

Issue Description:

To configure TLS 1.2 with EBS 12.1.3, we would need to generate csr request and request for CA signed SHA2 certificate. Once we received the server certificate and certificate chain files from the CA, we need to merge them to create a certificate file for OPMN using below command:

cat server.crt intermediate.crt ca.crt > opmn.crt

Then the opmn.crt needs to be placed in $INST_TOP/certs/Apache directory along with the files: server.key, new.csr, server.crt, intermediate.crt, ca.crt

After the above step and rest of the TLS configurations steps were performed, we encountered the below issue while starting the EBS services

Starting OPMN managed Oracle HTTP Server (OHS) instance …
sslSecureInit: SSL_CTX_use_certificate_chain_file($INST_TOP/certs/Apache/server.key): failed
4149028608:error:0906D066:PEM routines:PEM_read_bio:bad end line:pem_lib.c:805:
4149028608:error:140DC009:SSL routines:SSL_CTX_use_certificate_chain_file:PEM lib:ssl_rsa.c:708:
opmnctl: opmn start failed.
opmnctl: opmn is not running.

On reviewing the log $INST_TOP/logs/appl/admin/log/adopmnctl.txt and each of the individual certificates, I noticed the opmn.crt file had some junk characters like ^M & the separators of the mark certificate were together on the same line like below instead of on separate lines

—-END CERTIFICATE———-BEGIN CERTIFICATE—–

This caused the error while starting opmn.

Resolution:

We need to separate the lines with line breaks like below. That will also take care of the M^ characters.

—–END CERTIFICATE—–
—–BEGIN CERTIFICATE—–

So, I manually copied the contents of the certificates(server.crt, intermediate.crt, ca.crt) in a notepad, merged them one after another and copied the merged contents into opmn.crt on the server.

Finally, I was able to start the opmn services without any issue.