[gssproxy] [gssapi/gssproxy] c2484e: Add a hidden debug tool to gssproxy

[Simo Sorce]

  Branch: refs/heads/main
  Home:   https://github.com/gssapi/gssproxy
  Commit: c2484eed03b97962be86ab1aa7d7bd182e1bdcc9
      https://github.com/gssapi/gssproxy/commit/c2484eed03b97962be86ab1aa7d7bd1...
  Author: Simo Sorce <simo(a)redhat.com&gt;
  Date:   2020-09-10 (Thu, 10 Sep 2020)

  Changed paths:
    M Makefile.am
    A src/extract_ccache.c
    M src/gp_common.h
    M src/gp_export.c
    M src/gp_proxy.h
    M src/gssproxy.c
    M src/mechglue/gpp_creds.c

  Log Message:
  -----------
  Add a hidden debug tool to gssproxy

Sometimes it is really valuable to be able to extract the ccaches that a
client may be storing encrypted.

This special tool allows that and can be used as follow:

KRB5_KTNAME=/path/to/service.keytab ./gssproxy -d --extract-ccache
/path/to/encrypted.ccache --into-ccache ~/decryptedccache

Signed-off-by: Simo Sorce <simo(a)redhat.com&gt;
Reviewed-by: Robbie Harwood <rharwood(a)redhat.com&gt;