Bug in the [non-]propagation of control messages

[Julien ÉLIE]

En réponse à Russ Allbery :
>> There is a bug when I send a newgroup control article to local.example:
>> if the newsfeeds pattern of a site is "*, at local.*", the control article
>> is sent to that site!  Such a leak is not very good...
>
> What was the control message for?  If it wasn't for a local.* group, that
> sounds correct to me.  Control messages should propagate according to the
> superset of the affected group and the Newsgroups header.

It was a control message for the creation of local.example
(Newsgroups: local.example).

It is sent by art.c at line 2136:

  /* Control messages not filed in "to" get filed only in control.name
   * or control. */
  if (IsControl && Accepted && !ToGroup) {
    ControlStore = true;
    controlgroup = concat("control.", ControlWord, (char *) 0);
    if ((ngp = NGfind(controlgroup)) == NULL)
      ngp = NGfind(ARTctl);
    free(controlgroup);
    ngp->PostCount = 0;
    ngptr = GroupPointers;
    *ngptr++ = ngp;
    for (isp = ngp->Sites, i = ngp->nSites; --i >= 0; isp++) {
      if (*isp >= 0) {
        sp = &Sites[*isp];
        SITEmark(sp, ngp);
      }
    }
  }

Indeed, control.newgroup is in the pattern "*, at local.*" so it is sent.
It does not care about the poison pattern here.



> The best way to keep control messages local to a site is with a
> distribution.

Sure.



> I don't think the checkgroups part is right.  That code requires that
> there be an argument to the control command specifying the affected group,
> and it does article propagation based on that argument.  checkgroups takes
> no argument, so that doesn't work.

The article propagation is based on what there is in "groups" thanks
to ARTsendthegroup(*groups).  And it is set by:
    groups = data->Newsgroups.List;
just before.

Note that the definition of LikeNewgroup is not done as the same time.
Perhaps the whole code would be better to understand:


  groups = data->Newsgroups.List;
  /* Parse the Control header. */
  LikeNewgroup = false;
  if (HDR_FOUND(HDR__CONTROL)) {
    IsControl = true;

    /* Nip off the first word into lowercase. */
    strlcpy(ControlWord, HDR(HDR__CONTROL), sizeof(ControlWord));
    for (p = ControlWord; *p && !ISWHITE(*p); p++)
      if (CTYPE(isupper, *p))
    *p = tolower(*p);
    *p = '\0';
    LikeNewgroup = (strcmp(ControlWord, "newgroup") == 0
                    || strcmp(ControlWord, "rmgroup") == 0);

    if (innconf->ignorenewsgroups && LikeNewgroup) {
      for (p++; *p && ISWHITE(*p); p++);
      groupbuff[0] = p;
      for (p++; *p; p++) {
    if (NG_ISSEP(*p)) {
      *p = '\0';
      break;
    }
      }
      p = groupbuff[0];
      for (p++; *p; p++) {
    if (ISWHITE(*p)) {
      *p = '\0';
      break;
    }
      }
      groupbuff[1] = NULL;
      groups = groupbuff;
      data->Groupcount = 2;
      if (data->Followcount == 0)
    data->Followcount = data->Groupcount;
    }

    LikeNewgroup = (LikeNewgroup || strcmp(ControlWord, "checkgroups") == 0);

[...]

-- 
Julien ÉLIE

« Le style est l'homme même. » (Buffon)