4 tlsproxy is a TLS proxy for HTTPS which intercepts the connections and ensures
5 the server certificate doesn't change. Normally this isn't detected if a
6 trusted CA for the new server certificate is installed.
8 tlsproxy is licensed under GPL 3 (or later).
14 - GnuTLS library including development headers
15 - certtool (from by GnuTLS) to create TLS certificates
21 To use tlsproxy you must first run `tlsproxy-setup` in an (empty) directory.
22 This creates the following files:
24 - `proxy-ca.pem`: CA which is used for all connections to the client
25 - `proxy-ca-key.pem`: private key for the CA
26 - `proxy-key.pem`: private key for the server
27 - `proxy-invalid.pem`: special certificate used for invalid pages
29 Then import the CA file `proxy-ca.pem` in your browser so it can validate the
30 pages sent by the proxy.
32 For each page you want to visit securely you must first obtain its server
33 certificate (in PEM format) (for example with `gnutls-cli --print-cert server`
34 - you need the first certificate). The next step is to _validate_ it. The
35 proxy doesn't perform any validation thus it's important that you make sure
36 the server certificate is the correct one!
38 Then run `tlsproxy-add hostname path-to-certificate` in the same directory as
39 above. This creates the following files:
41 - `certificate-example.org-proxy.pem`: certificate used by the proxy for the
42 connection to the client
43 - `certificate-example.org-server.pem`: original server certificate, used to
44 check if the current server certificate changed
46 If the validation is successful the proxy uses the `certificate-*-proxy.pem`
47 certificate to secure the connection to the client (signed by `proxy-ca.pem`).
49 If an error occurs in the validation (missing `certificate-*.pem` files,
50 fingerprint changed, etc.) it's logged by the proxy (stdout) and the special
51 `proxy-invalid.pem` certificate is used to send a 500 error message to the
52 client. The connection to the server is closed so there's no chance that any
53 client data is sent to the (possible) evil server. The invalide certificate is
54 also easy to spot in the browser because it uses an invalid hostname
55 ("invalid") and is self-signed.
57 If an internal error occurs before the TLS connection can be established a 503
58 Forwarding failure is sent to the client (unencrypted).