KCM: Adjust REPLY_MAX to the one used in krb5 krb5 has its MAX_REPLY_SIZE set as 10*1024*1024, as seen in: https://github.com/krb5/krb5/blob/master/src/lib/krb5/ccache/cc_kcm.c#L53 Related: https://pagure.io/SSSD/sssd/issue/3386 Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com> Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

KCM: temporary increase hardcoded buffers Temporary workaround: https://pagure.io/SSSD/sssd/issue/3386 Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

KCM: Queue requests by the same UID In order to avoid race conditions, we queue requests towards the KCM responder coming from the same client UID. Reviewed-by: Michal Židek <mzidek@redhat.com> Reviewed-by: Simo Sorce <simo@redhat.com> Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>

KCM: Implement KCM server operations Implements the actual KCM server operations. On a high level, each operation unmarhalls the needed data from the input buffer, calls into the ccache db and marshalls a response. Only the operations that are also implemented by the MIT client are implemented by our KCM server. Resolves: https://pagure.io/SSSD/sssd/issue/2887 Reviewed-by: Michal Židek <mzidek@redhat.com> Reviewed-by: Simo Sorce <simo@redhat.com>