[krbdev.mit.edu #8953] git commit

[Greg Hudson via RT]

Thu Oct 29 19:28:40 2020: Request 8953 was acted upon.
 Transaction: Ticket created by ghudson at mit.edu
       Queue: krb5
     Subject: git commit
       Owner: ghudson at mit.edu
  Requestors: 
      Status: new
 Ticket <URL: https://krbdev.mit.edu/rt/Ticket/Display.html?id=8953 >



Move more KDC checks to validate_tgs_request()

Move the following validity checks:

* the INVALID ticket flag check from kdc_process_tgs_req()
* the lineage check from process_tgs_req()
* the user-to-user second ticket client check from process_tgs_req()
* all S4U2Self validity checks from kdc_process_s4u2self_req()
* S4U2Proxy validity checks (but not KDB authorization checks) from
  kdc_process_s4u2proxy_req()

In process_tgs_req(), call validate_tgs_request() after
kdc_process_s4u2self_req() and decrypt_2ndtkt() so that their outputs
can be used as validation inputs.  Add stkt and is_crossrealm locals
for convenience, and remove st_idx.

There are some minor behavior changes:

* For invalid S4U2Self request options, the status string is changed
  from "INVALID AS OPTIONS" to "INVALID S4U2SELF OPTIONS".

* For a header ticket with the INVALID flag, the reply code is changed
  to KRB_AP_ERR_TKT_NYV (as specified in RFC 4120) and the status
  string to "TICKET NOT VALID".

* For a lineage check failure, the explicit KDC log is removed, and
  the status string is changed to "INVALID LINEAGE".

* For a user-to-user second ticket client mismatch, the explicit audit
  call is removed, and the log message does not include the second
  ticket client.

* e_data returned from the KDB check_policy_as() method will be
  included in the error for S4U2Self requests.

https://github.com/krb5/krb5/commit/3b163eed1cf1f55dd4a7bc6d6fffc34f55695b00
Author: Greg Hudson <ghudson at mit.edu>
Commit: 3b163eed1cf1f55dd4a7bc6d6fffc34f55695b00
Branch: master
 src/kdc/do_tgs_req.c |  137 +++++++++++++------------------
 src/kdc/kdc_util.c   |  141 +++-----------------------------
 src/kdc/kdc_util.h   |   17 +++--
 src/kdc/tgs_policy.c |  225 +++++++++++++++++++++++++++++++++++++++++++------
 4 files changed, 275 insertions(+), 245 deletions(-)