[Heimdal-source-changes] [heimdal/heimdal] 49861e: Delay KRB5_KTNAME lookup until keytab resolution.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/heimdal/heimdal
  Commit: 49861eb2c5012a6508af461f4e6397d61b1e1fda
      https://github.com/heimdal/heimdal/commit/49861eb2c5012a6508af461f4e6397d61b1e1fda
  Author: Viktor Dukhovni <viktor at twosigma.com>
  Date:   2015-02-06 (Fri, 06 Feb 2015)

  Changed paths:
    M lib/krb5/context.c
    M lib/krb5/keytab.c

  Log Message:
  -----------
  Delay KRB5_KTNAME lookup until keytab resolution.

Previously getenv("KRB5_KTNAME") happened in

    init_context_from_config_file()

which would capture the environment value as an override without
using strdup() to get a private copy, so it would get trashed in
applications that dynamically update the environment (e.g. Perl
code that has a tied %ENV).

The patch delays getenv("KRB5_KTNAME") until the context's value
of default_keytab is actually needed, and the environment can preempt
the context's default at that time.

[ Do we need to worry about issuid() being true initially when the
  context is created, but not later, because the application changes
  both the real and effective uid?  If so the issuid() state should
  be saved when the context is created and the saved value queried. ]