[Pkg-shadow-devel] Bug#621810: shadow: usermod and passwd man pages wrongly suggest `usermod -e 1` to expire account

[enok srd]

On Fri, Apr 8, 2011 at 7:46 PM, enok srd <enoksrd at gmail.com> wrote:

> Suggested fix: `change usermod --expiredate` to handle numeric
> arguments the same way chage does, and update the usermod man page
> accordingly.
>
> Here's some relevant code from usermod and chage in the most recent
> source I could find
> (ftp://pkg-shadow.alioth.debian.org/pub/pkg-shadow/shadow-4.1.4.3.tar.bz).
> Note the isnum check in chage:
>
> shadow-4.1.4.3/src/usermod.c:
>    937                         case 'e':
>    938                                 if ('\0' != *optarg) {
>    939                                         user_newexpire =
> strtoday (optarg);
>    940                                         if (user_newexpire == -1) {
>    941                                                 fprintf (stderr,
>    942
> _("%s: invalid date '%s'\n"),
>    943                                                          Prog, optarg);
>    944                                                 exit (E_BAD_ARG);
>    945                                         }
>    946                                         user_newexpire *= DAY / SCALE;
>    947                                 } else {
>    948                                         user_newexpire = -1;
>    949                                 }
>    950                                 eflg = true;
>    951                                 break;
>
> shadow-4.1.4.3/src/chage.c:
>    419                 case 'E':
>    420                         Eflg = true;
>    421                         if (!isnum (optarg)) {
>    422                                 expdate = strtoday (optarg);
>    423                         } else if (   (getlong (optarg, &expdate) == 0)
>    424                                    || (expdate < -1)) {
>    425                                 fprintf (stderr,
>    426                                          _("%s: invalid date '%s'\n"),
>    427                                          Prog, optarg);
>    428                                 usage ();
>    429                         }
>    430                         break;

Oh, and notice the `expdate < -1` check in the isnum branch of the
chage case: that check also needs to be made on the strtoday results,
since currently both chage and usermod are happy to write negative
values into /etc/shadow, but then they are unable to parse those
values.  Subsequent `usermod --expiredate` calls do nothing, and
`chage --expiredate` calls add new entries to /etc/shadow.  Only way I
know to fix these is to edit /etc/shadow (with vipw -s).  The pwck
command suggests the corrupted /etc/shadow entries be deleted.