[Heimdal-source-changes] [heimdal/heimdal] 545b5b: Fix race condition with global _gsskrb5_keytab

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/heimdal/heimdal
  Commit: 545b5b41cedb1f76565e541c68f0562e07ec78d5
      https://github.com/heimdal/heimdal/commit/545b5b41cedb1f76565e541c68f0562e07ec78d5
  Author: Heath Kehoe <heath at digitalartefacts.com>
  Date:   2016-11-10 (Thu, 10 Nov 2016)

  Changed paths:
    M lib/gssapi/krb5/accept_sec_context.c

  Log Message:
  -----------
  Fix race condition with global _gsskrb5_keytab

gsskrb5_acceptor_start() was making a copy of the global pointer
_gsskrb5_keytab to use later. This invites a race condition where
another thread could call gsskrb5_register_acceptor_identity()
(thus invalidating the target of the copied pointer) before it is
used by gsskrb5_acceptor_start().

So instead, clone the keytab to a new one while protected by the
mutex lock (similar to get_keytab() in acquire_cred.c).

Signed-off-by: Nicolas Williams <nico at twosigma.com>