OPENAFS-SA-2024-002: viced: Free ACL on acl_Internalize_pr error

OPENAFS-SA-2024-002: viced: Free ACL on acl_Internalize_pr error

CVE-2024-10396

Currently, we don't free 'newACL' if acl_Internalize_pr() fails. If
acl_Internalize_pr() has already allocated 'newACL', then the memory
associated with newACL will be leaked. This can happen if parsing the
given ACL fails at any point after successfully parsing the first
couple of lines in the ACL.

Change acl_FreeACL() to make freeing a NULL acl a no-op, to make it
easier to make sure the acl has been freed.

FIXES 135445

Reviewed-on: https://gerrit.openafs.org/15909
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit f4dfc2d7183f126bc4a45b5cabc78c3de020925f)

Change-Id: If1554aa899542761ec6e6611394f2ee4f9379f22
Reviewed-on: https://gerrit.openafs.org/15930
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>