auth-gen-token: Inform client why auth-token was rejected

Previously when a client connection got closed due to the auth-token being rejected, the client did not receive any indication why. This patch-set ensures the client will receive such an indication.

The AUTH_FAILED statement which is used to reject and close client connections can contain a text string with a message aimed at the user. Some clients (like OpenVPN Connect) have also some kind of categorization. For this use-case, the SESSION category was chosen.

The rejection message to the client is sent using the send_auth_failed() function. This ensures the formatting is proper. The only detail we need to ensure is that the category and the message is separated by a colon (:).

This patch-set is split into two parts. The first parts refactors the code to provide the struct context object the whole way into key_method_2_read(). This is the place where verify_user_pass() is called. The reason we need the struct context object is that send_auth_failed() needs that to prepare a message to be pushed to the client.

The second patch just implements the rejection message and calling send_auth_failed() with the appropriate messages.

David Sommerseth (2):
Refactor to provide struct context object inside key_method_2_read()
auth-gen-token: Provide a rejection message back to the client on
failure

 src/openvpn/forward.c    |  2 +-
 src/openvpn/ssl.c        | 30 +++++++++++++++++-------------
 src/openvpn/ssl.h        |  6 +-----
 src/openvpn/ssl_verify.c | 13 +++++++++----
 src/openvpn/ssl_verify.h |  2 +-
 5 files changed, 29 insertions(+), 24 deletions(-)

1.8.3.1