[libvirt] [PATCH 1/5] util: simplify virSetUIDGIDWithCaps

[Paolo Bonzini]

> >      /* Change to the temp capabilities */
> > -    if ((capng_ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
> > +    if ((capng_ret = capng_apply(CAPNG_SELECT_CAPS)) < 0) {
> 
> Beforehand, we limited both caps and bounding set, with an overlarge
> set, now you are limiting just caps...
> 
> >          virReportError(VIR_ERR_INTERNAL_ERROR,
> >                         _("cannot apply process capabilities %d"),
> >                         capng_ret);
> >          goto cleanup;
> > @@ -3063,12 +3061,18 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid,
> > unsigned long long capBits,
> >          goto cleanup;
> >  
> >      /* Tell it we are done keeping capabilities */
> > -    if (need_prctl && prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0)) {
> > +    if (prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0)) {
> >          virReportSystemError(errno, "%s",
> >                               _("prctl failed to reset KEEPCAPS"));
> >          goto cleanup;
> >      }
> >  
> > +    /* Set bounding set while we have CAP_SETPCAP.  Unfortunately we cannot
> > +     * do this if we failed to get the capability above, so ignore the
> > +     * return value.
> > +     */
> > +    capng_apply(CAPNG_SELECT_BOUNDS);
> 
> ...and then separately limiting bounds, but still while having an
> overlarge set.
> 
> > +
> >      /* Drop the caps that allow setuid/gid (unless they were
> >      requested) */
> >      if (need_setgid)
> >          capng_update(CAPNG_DROP, CAPNG_EFFECTIVE|CAPNG_PERMITTED,
> >          CAP_SETGID);
> > @@ -3078,7 +3082,7 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid,
> > unsigned long long capBits,
> >      if (need_setpcap)
> >          capng_update(CAPNG_DROP, CAPNG_EFFECTIVE|CAPNG_PERMITTED,
> >          CAP_SETPCAP);
> 
> Here, the set is now pruned to size...
> 
> >  
> > -    if (need_prctl && ((capng_ret =
> > capng_apply(CAPNG_SELECT_BOTH)) < 0)) {
> > +    if (((capng_ret = capng_apply(CAPNG_SELECT_CAPS)) < 0)) {
> 
> ...but you are now only limiting caps, not the bounding set.  Is that
> correct?

Yes, the code after capng(CAPNG_SELECT_BOUNDS) does not affect the
bounding set.

> Does this need to be considered for 1.0.4, or can we delay it to
> post-release?

Post-release, absolutely.

Paolo