Samba Segfault on NT Login when /etc/group contains user not in /etc/passwd or .../smbpasswd (PR#21228)

[Alex Satrapa]

But it gets worse...

If I have a non-magic-named user (eg: "fred") associated with a group in
/etc/group, but that user is not present in /etc/passwd or
.../smbpasswd, then smbd will "fix" the group to not include that user.

If I have a magic-named users (eg: "uucp") associated with a group, smbd
will *not* fix the group. At least, that's my reading of the debug messages.

Which probably only serves as a surface symptom of the clompexity you're
talking about. ;)

Sorry I can't figure out a patch for you - one day I'll learn to read C.

Regards
Alex

Gerald Carter wrote:
> 
> Alex Satrapa wrote:
> >
> > It appears that smbd will segfault (why?) when a system user is present
> > in a /etc/group group, but not in /etc/passwd. The same is not true for
> > a non-system user. As a side effect of this bug, I've cleaned up our
> > /etc/group file, so I guess I'm a little thankful.
> 
> Nice work.  I remember this bug.  Been there for a while.  If I
> remember correctly (now that you reminded me), the problem is because
> of a NULL pointer returned when trying to setup group membership
> and executing a getpwnam() call on members of group in /etc/qroup.
> Therefore if you lookup a nonexistent account, we don;t check the
> return value.  My memory is fuzzy here, and to be honest, I'm not
> sure I remember why I didn;t fix this when I found it.  Maybe
> because the group code was so complex in the 2.1 code.
> 
> I should go back and look at this again.
> Nice work.
> 
> Cheers,
> jerry
> ________________________________________________________________________
>                             Gerald ( Jerry ) Carter
> Engineering Network Services                           Auburn University
> jerry at eng.auburn.edu             http://www.eng.auburn.edu/users/cartegw
> 
>        "...a hundred billion castaways looking for a home."
>                                   - Sting "Message in a Bottle" ( 1979 )