[krbdev.mit.edu #8767] git commit

[Greg Hudson via RT]

Remove incorrect KDC assertion

The assertion in return_enc_padata() is reachable because
kdc_make_s4u2self_rep() may have previously added encrypted padata.
It is no longer necessary because the code uses add_pa_data_element()
instead of allocating a new list.

CVE-2018-20217:

In MIT krb5 1.8 or later, an authenticated user who can obtain a TGT
using an older encryption type (DES, DES3, or RC4) can cause an
assertion failure in the KDC by sending an S4U2Self request.

[ghudson at mit.edu: rewrote commit message with CVE description]

(cherry picked from commit 94e5eda5bb94d1d44733a49c3d9b6d1e42c74def)

https://github.com/krb5/krb5/commit/56870f9456da78d77a667dfc03a6d90f948dc3a5
Author: Isaac Boukris <iboukris at gmail.com>
Committer: Greg Hudson <ghudson at mit.edu>
Commit: 56870f9456da78d77a667dfc03a6d90f948dc3a5
Branch: krb5-1.16
 src/kdc/kdc_preauth.c     |    1 -
 src/tests/gssapi/t_s4u.py |    7 +++++++
 2 files changed, 7 insertions(+), 1 deletions(-)