Merge rev 1.96 of NetBSD's net/if_spppsubr.c:

Merge rev 1.96 of NetBSD's net/if_spppsubr.c:
  A problem has been identified in the in-kernel PPP code shared by ISDN PPP
  interfaces ippp(4) and pppoe(4). Insufficient checking of options presented
  by the peer may cause writing of copies of the malicious input beyond the
  end of a buffer allocated for that purpose.

  Issue found by pavel@
  Fix from martin@

  This is SA2006-019 (CVE-2006-4304)