[Midnightbsd-cvs] [MidnightBSD/src] 9617b9: Fix a potential memory overflow in cron.

[Lucas Holt]

  Branch: refs/heads/master
  Home:   https://github.com/MidnightBSD/src
  Commit: 9617b9e20af41c60fb7ba8eff94ad2ec03caeb45
      https://github.com/MidnightBSD/src/commit/9617b9e20af41c60fb7ba8eff94ad2ec03caeb45
  Author: Lucas Holt <luke at foolishgames.com>
  Date:   2023-05-29 (Mon, 29 May 2023)

  Changed paths:
    M usr.sbin/cron/lib/entry.c

  Log Message:
  -----------
  Fix a potential memory overflow in cron.

bit_nset is used to set bits [start, stop], which the stop position
is included, so we should pass `bitstring size - 1` as the stop,
or it will potentially overflow. It is ok with the month and dom,
because their allocted byte was not fully used, but for dow and
hour, they use 8 bits and 24bits, the following statement will
write the next byte.

bit_nset(e->hour, 0, (LAST_HOUR-FIRST_HOUR+1));
bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));

See https://github.com/vixie/cron/pull/14/commits/fac29ab04ba02f4b4923c9d2c2e4ce111f60d252