Support for client certificate fingerprint whitelist #62
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client_ca_file is used to validate client certificate. However, in tests, client never present any. Signed-off-by: WGH <wgh@torlan.ru>
Add tests cases when the client actually sends a certificate, and check
how the server responds to it.
The client certificates were generated with this command:
openssl req -x509 -newkey ec:<(openssl ecparam -name secp384r1) -keyout client2_selfsigned.key -out client2_selfsigned.pem -nodes -subj '/CN=test2' -days 36500 -addext "extendedKeyUsage = clientAuth"
Signed-off-by: WGH <wgh@torlan.ru>
This is useful for simple setups that don't require full-blown CAs for mutual authentication. Signed-off-by: WGH <wgh@torlan.ru>
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Wouldn't putting client cert as CA work instead? This looks uncommon. |
I think not, because it might lack the flag allowing it to be a CA. |
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This is useful for simple setups that don't require full-blown CAs for mutual authentication.
An example of a program that support this type of client auth is Postfix (see
permit_tls_clientcerts).This introduces a footgun in a way: using
client_fingerprintspractially requires usingRequireAnyClientCert, so it invites a mistake of settingRequireAnyClientCertand forgetting aboutclient_fingerprints. Luckily, it's possible to discern empty list from a nil one (not set), but it still requires the user to carefully replace multiline YAML list withclient_fingerprints: []if he wants to delete all certificates for some reason. Maybe that's not really a problem, but I still want to mention it.Alternatively, we might introduce a new custom
client_auth_type(say,FingerprintWhitelist) that would behave likeRequireAnyClientCert, but would treat a nil set like an empty one (i.e. reject any certificate). This diverges a bit fromtls.ClientAuthTypeenumeration list, but it's less error-prone this way.Currently based on top of #61, hence draft.