Heimdal at least up through 1.2 incorrectly encrypts the TGS response
in the session key not the subkey when a subkey is supplied.  See RFC
4120 page 35.  Work around this by trying decryption using the session
key after the subkey fails.

* decode_kdc_rep.c: rename to krb5int_decode_tgs_rep; only used for
  TGS and now needs to take keyusage
* gc_via_tkt: pass in session key and appropriate usage if subkey
  fails.

Note that the dead code to process AS responses in decode_kdc_rep is
not removed by this commit.  That will be removed as FAST TGS client
support is integrated post 1.7.

https://github.com/krb5/krb5/commit/56e9c98f2871f78130baf3f7c63ce2abe76e02f6
Commit By: hartmans
Revision: 22325
Changed Files:
U   trunk/src/include/k5-int.h
U   trunk/src/lib/krb5/krb/decode_kdc.c
U   trunk/src/lib/krb5/krb/gc_via_tkt.c
U   trunk/src/lib/krb5/libkrb5.exports