[ts-7000] Re: Creating a working ftp account on my TS-7400 (proftpd)

["inakizi" <>]

Hello Jim,

OK This is in the TS-7400 (where the login doesn't work)

$ ls -ld / /home /home/testuser
drw-rw-rw-    1 root     root          512 Jan  1  1970 /
drwxrwxrwx    1 root     root          512 Jan 15 11:14 /home
drwxr-sr-x    1 testuser testuser      512 Jan 25 04:13 /home/testuser


$ grep testuser /etc/passwd
testuser:$1$$dZY0EB48u3cuRp7JFyg68.:508:508:Linux 
User:/home/testuser:/bin/sh

I also have a TS-7250 where the login works fine:

$ ls -ld / /home /home/testuser
drwxr-xr-x    1 root     root          512 Jan  1  1970 /
drwxr-xr-x    1 root     root          512 Dec 12 04:02 /home
drwxr-sr-x    1 testuser testuser      512 Dec 12 04:02 /home/testuser

$ grep testuser /etc/passwd
testuser:$1$$dZY0EB48u3cuRp7JFyg68.:507:507:Linux 
User:/home/testuser:/bin/sh

OK so let me give you some more info:
this is the error I get when I try to login with this user:
$ login testuser
Password:
login: cannot cd to home directory or /

So I searched that inBusybox and found this piece of code that is
executed every time a user is logged on:

/* Become the user and group(s) specified by PW.  */
const char *change_identity_e2str ( const struct passwd *pw )
{
   printf("Inside Change_identity_e2str\n");
   printf("pw_name: %s pw_gid: %d\n",pw->pw_name,pw->pw_gid);



       long int initgresult = initgroups ( pw-> pw_name, pw-> 
pw_gid );
       printf("initgroups result: %d\n",initgresult);
       if ( initgresult == -1 )
               return "cannot set groups";
       endgrent ( );

       if ( setgid ( pw-> pw_gid ))
               return "cannot set group id";
       if ( setuid ( pw->pw_uid ))
               return "cannot set user id";

       // Modified by Me to simulate a whoami instruction
       char user[10];
       uid_t uid;

   printf("Now I try to get the user ID that I just set\n");
       uid = geteuid();
   printf("uid: %d\n",uid);
       if (my_getpwuid(user, uid)) {
               user[9] = 0;
               printf("user: %s\n",user);
       } else {
               printf("cannot find username for UID %u\n", (unsigned) 
uid);
       }

       return NULL;
}

All the printf are added by me. and the code to get whoami at the end
of the function.

When I run this on the TS-7400:

$ ./busybox login testuser
Password:
Inside Change_identity_e2str
pw_name: testuser pw_gid: 508
initgroups result: 0
Now I try to get the user ID that I just set
uid: 508
cannot find username for UID 508
After Calling ChangeIdentity e2str
shell: /bin/sh
pw_name: testuser
pw_passwd: $1$$dZY0EB48u3cuRp7JFyg68.
pw_dir: /home/testuser
login: cannot run /bin/sh: Permission denied
$

If I run exactly same executable on the TS-7250 I get:

$ ./busybox login testuser
Password:
Inside Change_identity_e2str
pw_name: testuser pw_gid: 507
initgroups result: 0
Now I try to get the user ID that I just set
uid: 507
user: testuser
After Calling ChangeIdentity e2str
shell: /bin/sh
pw_name: testuser
pw_passwd: $1$$dZY0EB48u3cuRp7JFyg68.
pw_dir: /home/testuser


BusyBox v1.00-rc2 (2004.08.05-21:44+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

$

So in some weird way looks like the functions setgid  and setuid  are
not working.




--- In  Jim Jackson <> wrote:
>
> 
> 
> 
> On Mon, 11 Dec 2006, inakizi wrote:
> 
> > Correct, I guess I din't explain myself correctly. I followed the 
code
> > of the Login process (puting some printf instructions on the 
busybox
> > code) for an already created user. Everything went perfect until 
the
> > setgid and setuid functions. Just after that, the busybox login 
tries
> > to change current dir to the user folder (/home/testuser) and
> 
> What does
> 
>   ls -ld / /home /home/testuser
> 
>   grep testuser /etc/passwd
> 
> give?
> 
> Jim
> 
> > everything is correct when the chdir function is called but it 
couldn't
> > change to that folder, is like it has not enough permissions to 
do it.
> > Samething happens a little bit after that when it tries to create 
a
> > shell.
> > This leads me to believe that there's some kind of problem when 
this
> > functions are called but you are right there are probably 
hundreds of
> > reasons to make those function fails that had nothing to do with 
the
> > kernel code.
> > Everything works perfect if the user that is logged in is root.
> > --- In  Jim Jackson <jj@> wrote:
> > >
> > >
> > > > and using users on the TS-7400,
> > > > ....... I guess the problem is with the
> > > > kernel but I haven't figured out what it is yet but I think 
that the
> > > > kernel functions setgid and setuid are not working in the TS-
7400.
> > >
> > > I would assume this ONLY after every other possibility is 
exhausted.
> > > The chances of these kernel functions not working are 
infinitessimally
> > > small.
> > >
> >
> >
> >
>




 
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