SA-2010-007 Checksum vulnerabilities (CVE-2010-1324 and others)

SA-2010-007 Checksum vulnerabilities (CVE-2010-1324 and others)

Fix multiple checksum handling bugs, as described in:
  CVE-2010-1324
  CVE-2010-1323
  CVE-2010-4020
  CVE-2010-4021

* Return the correct (keyed) checksums as the mandatory checksum type
  for DES enctypes.
* Restrict simplified-profile checksums to their corresponding etypes.
* Add internal checks to reduce the risk of stream ciphers being used
  with simplified-profile key derivation or other algorithms relying
  on the block encryption primitive.
* Use the mandatory checksum type for the PKINIT KDC signature,
  instead of the first-listed keyed checksum.
* Use the mandatory checksum type when sending KRB-SAFE messages by
  default, instead of the first-listed keyed checksum.
* Use the mandatory checksum type for the t_kperf test program.
* Use the mandatory checksum type (without additional logic) for the
  FAST request checksum.
* Preserve the existing checksum choices (unkeyed checksums for DES
  enctypes) for the authenticator checksum, using explicit logic.
* Ensure that SAM checksums received from the KDC are keyed.
* Ensure that PAC checksums are keyed.

ticket: 6827

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@24538 dc483132-0cff-0310-8789-dd5450dbe970