lkml.org 
[lkml]   [1999]   [Jul]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Serial Port COM1 under Linux on IBM ThinkPad 770X
Alan Cox wrote:
>
> > 0 crw-rw---- 1 root dialout 4, 64 Feb 23 04:42 /dev/ttyS0
> > 0 crw-rw---- 1 root dialout 4, 65 Feb 23 04:42 /dev/ttyS1
> > root@ibmtop:pts/0 ~ # cu -l /dev/ttyS0
> > cu: open (/dev/ttyS0): Permission denied
> > cu: /dev/ttyS0: Line in use
> > zsh: 5731 exit 1 cu -l /dev/ttyS0
> >
> > >From strace cu:
> > open("/dev/ttyS0", O_RDWR|O_NONBLOCK) = -1 EACCES (Permission denied)
> >
> > But this is as superuser (root). How is this possible at all?
>
> cu is setuid to uucp on some systems. Unless you have a deep desire to
> inflict cu on yourself in the name of tradition try playing with minicom.
> If you want to suffer cu then chmod it so its not setuid uucp

root@ibmtop:pts/0 ~ # ll =cu
120 -rwxr-xr-x 1 root root 121156 Apr 21 22:22 /usr/bin/cu*

The cu binary is from Debian 2.2 (potato)

root@ibmtop:pts/0 ~ # dpkg -S =cu
uucp: /usr/bin/cu

As you can see, cu is not suid root. But you were
still right in a sense:

root@ibmtop:pts/0 ~ # strace cu -l /dev/ttyS0 |& grep setuid
setuid(10) = 0

Uid 10 is uucp. I do consider this strange behaviour.

Anyway, I prefer a simple command line tool like cu to a
menu-driven thing like minicom.

All of this still doesn't solve my problem, though.

Thanks for the help, anyway,

Dirk

--
Dipl.-Ing. Dirk W. Steinberg
__________________________________________________
Consultant Technologieberatung Informationssysteme
DETECON GmbH, Oberkasseler Strasse 2, 53227 Bonn
Tel.: (0228) 700-1277 Fax: (0228) 700-1157
Mobil: (0171) 221 6585 Internet: www.detecon.de

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:52    [W:0.047 / U:0.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site