On Tue, 19 Apr 2016, david wrote:
At 09:09 AM 4/18/2016, you wrote:
On Mon, 18 Apr 2016, david wrote:
FOLLOWUP & REPORT
I had lots of suggestions, and the most persuasive was to try OpenVPN. I already had a CA working, so issuing certificates was easy. The HOW-TO guides were less helpful than I could hope, but comparing several of them, applying common sense, and trying things out, I arrived at a dead-end. Here's essentially what happened:
- None of the HOW-TOs were very clear about the need to add some
attributes to a certificate, keyUsage and extendedKeyUsage. They had different values for server and client. OpenSSL documentation was a big vague on how to add them, but I think I did - the print out of the entity certificates showed the values. The attempt to connect failed. The client log is below. I think it's complaining that the CA certificate doesn't have the ke Usage extension, which makes no sense to me. Such an extension should be in the end-entity certificate, not the CA's, unless I'm wrong. I checked the server and really think that the certificates are in the right place.
Here's how I managed that in my openssl.cnf file. Lots of bits ellided for clarity's sake:
### start ### [ ca ] default_ca = CA_default
[ CA_default ] x509_extensions = server_cert
[ server_cert ] basicConstraints=CA:FALSE keyUsage = nonRepudiation, dataEncipherment, digitalSignature, keyEncipherment extendedKeyUsage = serverAuth, clientAuth nsCertType = server, client ### end ###
I think the nsCertType directive may be unnecessary these days, but I keep it around because it doesn't hurt anything.
The important bit is the extendedKeyUsage line; I'm pretty sure that an OpenVPN server needs the serverAuth extension. For instance, here is the X509 extensions configuration for a server used by EasyRSA:
basicConstraints = CA:FALSE subjectKeyIdentifier = hash authorityKeyIdentifier = keyid,issuer:always extendedKeyUsage = serverAuth,clientAuth keyUsage = digitalSignature,keyEncipherment
You can ask openssl to tell you the purpose of a certificate:
[bash]$ openssl x509 -noout -purpose -in cert.pem | grep SSL SSL client : Yes SSL client CA : No SSL server : Yes SSL server CA : No Netscape SSL server : Yes Netscape SSL server CA : No
Anyway, those are the extensions that should do away with these errors:
Mon Apr 18 05:34:50 2016 VERIFY OK: depth=1, C=US, ST=California, L=San Francisco, OU=Certificate Authority, O=XXXX, CN=X.X.X Mon Apr 18 05:34:50 2016 Certificate does not have key usage extension
-- Paul Heinlein <> heinlein@madboa.com <> http://www.madboa.com/
Paul Two things...
First, the diagnostic I got referenced the server's CA certificate. And that confuses me.
I'm not sure that's actually what the log is indicating. I think there's a mismatch between what extensions the server certificate says it can provide and what the client is expecting.
Can you provide the SSL/TLS parts of your client configuration?
In particular, I expect you'll have a "remote-cert-tls server" directive. I'd suggest commenting that out (or replacing it with "ns-cert-type server") and trying again.
If that succeeds, you'll probably need to review your CA configuration.