heimdal: Fix multiple security vulnerabilities

The following issues are patched:

• CVE-2022-42898 PAC parse integer overflows
• CVE-2022-3437 Overflows and non-constant time leaks in DES{,3} and arcfour
• CVE-2021-44758 NULL dereference DoS in SPNEGO acceptors
• CVE-2022-44640 Heimdal KDC: invalid free in ASN.1 codec
  
  Note that CVE-2022-44640 is a severe vulnerability, possibly a 10.0 on the Common Vulnerability Scoring System (CVSS) v3, as we believe it should be possible to get an RCE on a KDC, which means that credentials can be compromised that can be used to impersonate anyone in a realm or forest of realms.
  
  Heimdal's ASN.1 compiler generates code that allows specially crafted DER encodings of CHOICEs to invoke the wrong free function on the decoded structure upon decode error. This is known to impact the Heimdal KDC, leading to an invalid free() of an address partly or wholly under the control of the attacker, in turn leading to a potential remote code execution (RCE) vulnerability.
  
  This error affects the DER codec for all extensible CHOICE types used in Heimdal, though not all cases will be exploitable. We have not completed a thorough analysis of all the Heimdal components affected, thus the Kerberos client, the X.509 library, and other parts, may be affected as well.
  
  This bug has been in Heimdal's ASN.1 compiler since 2005, but it may only affect Heimdal 1.6 and up. It was first reported by Douglas Bagnall, though it had been found independently by the Heimdal maintainers via fuzzing a few weeks earlier.
  
  While no zero-day exploit is known, such an exploit will likely be available soon after public disclosure.
• CVE-2019-14870: Validate client attributes in protocol-transition
• CVE-2019-14870: Apply forwardable policy in protocol-transition
• CVE-2019-14870: Always lookup impersonate client in DB

Sponsored by: so (philip)
Obtained from: so (philip)
Tested by: philip, cy
MFC after: immediately