On Fri, 2013-04-05 at 12:26 +0200, Lukas Slebodnik wrote:
> On (04/04/13 12:24), Simo Sorce wrote:
> >Commit should say it all.
> >We do not have any security issue (that I know off) with the current
> >code, but I want to tighten up the privileges more given we do not need
> >the additional capabilities in the krb5_child anyway.
> >
> >Simo.
> >
> >--
> >Simo Sorce * Red Hat, Inc * New York
> Nack
>
> Patch make impossible user authentication.
>
> sh-4.2$ su - usersssd02
> Password:
> su: incorrect password
>
>
> From krb5_child.log:
> [become_user] (0x0200): Trying to become user [325600012][325600012].
> [create_ccache_in_dir] (0x0200): Creating ccache at
> [DIR:/run/user/325600012/krb5cc]
> [become_user] (0x0200): Trying to become user [325600012][325600012].
> [become_user] (0x0020): setgroups failed [1][Operation not permitted].
> ^^^^^
> The second call of function become_user fail with EPERM
>
> [create_ccache_in_dir] (0x0020): become_user failed.
> [get_and_save_tgt] (0x0020): 1140: [1][Operation not permitted]
> [map_krb5_error] (0x0020): 1160: [1][Operation not permitted]
>
> > errno_t become_user(uid_t uid, gid_t gid)
> > {
> > int ret;
> >
> > DEBUG(SSSDBG_FUNC_DATA, ("Trying to become user [%d][%d].\n", uid,
> > gid));
> >- ret = setgid(gid);
> >- if (ret == -1) {
> >- ret = errno;
> >- DEBUG(SSSDBG_CRIT_FAILURE,
> >- ("setgid failed [%d][%s].\n", ret, strerror(ret)));
> >- return ret;
> >- }
> >
> >- ret = setuid(uid);
> >+ /* drop supplmentary groups first */
> >+ ret = setgroups(0, NULL);
> > if (ret == -1) {
> > ret = errno;
> If errno is EPERM, than we should ignore this error and continue.
>
> > DEBUG(SSSDBG_CRIT_FAILURE,
> >- ("setuid failed [%d][%s].\n", ret, strerror(ret)));
> >+ ("setgroups failed [%d][%s].\n", ret, strerror(ret)));
> > return ret;
> > }
> >
It is very odd that we get EPERM .. is this function beeing called
twice ? Once as root before the fork, and then again in the code ?
Simo.
--
Simo Sorce * Red Hat, Inc * New York
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