[Midnightbsd-cvs] [MidnightBSD/src] 34ade9: initialize oifp to avoid bogus results/panics in e...

[Lucas Holt]

  Branch: refs/heads/master
  Home:   https://github.com/MidnightBSD/src
  Commit: 34ade9084c7e53ca0e3a4f2f21848d34848e7d7e
      https://github.com/MidnightBSD/src/commit/34ade9084c7e53ca0e3a4f2f21848d34848e7d7e
  Author: Lucas Holt <luke at foolishgames.com>
  Date:   2020-11-15 (Sun, 15 Nov 2020)

  Changed paths:
    M sys/netinet6/mld6.c

  Log Message:
  -----------
  initialize oifp to avoid bogus results/panics in edge cases

  In certain cases (probably not during normal operation but observed in
  the lab during development) ip6_ouput() could return without error
  and ifpp (&oifp) not updated.
  Given oifp was never initialized we would take the later branch
  as oifp was not NULL, and when calling icmp6_ifstat_inc() we would
  panic dereferencing a garbage pointer.
  For code stability initialize oifp to NULL before first use to always
  have a deterministic value and not rely on a called function to behave
  and always and for ever do the work for us as we hope for.