Bug 219048 - pty opened by XTerm is not owned by group `tty' and is world writable
Summary: pty opened by XTerm is not owned by group `tty' and is world writable
Alias: None
Product: Fedora
Classification: Fedora
Component: xterm   
(Show other bugs)
Version: 5
Hardware: All Linux
Target Milestone: ---
Assignee: Miroslav Lichvar
QA Contact:
Whiteboard: impact=low,source=redhat,reported=200...
Keywords: Reopened, Security
Depends On:
Blocks: 220153
TreeView+ depends on / blocked
Reported: 2006-12-10 02:31 UTC by Kasper Dupont
Modified: 2007-11-30 22:11 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-01-09 17:08:04 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

Description Kasper Dupont 2006-12-10 02:31:43 UTC
Description of problem:
mesg n does not actually prevent messages, and mesg y consistently produce an
error message.

Version-Release number of selected component (if applicable):

How reproducible:
Happens every time

Steps to Reproduce:
1. Open xterm
2. Type "mesg y"
Actual results:
mesg: error: tty device is not owned by group `tty'

Expected results:
No errors

Steps to Reproduce:
1. Open xterm
2. Type "mesg n"
3. ls -l $(tty)
Actual results:
crw-----w- 1 kasperd kasperd 136, 14 Dec  9 18:26 /dev/pts/14

Expected results:
No write permission for others

Additional info:
Even when messages are enabled, it is a bad idea to allow every user to write
the device directly. The write command makes it clear that a message was send,
and who did it. Direct writes can be used to fake tty output.

Comment 1 Bill Nottingham 2006-12-11 20:27:17 UTC
I can't reproduce this, although this is on FC6:

[notting@nostromo: ~]$ ls -l $(tty)
crw--w---- 1 notting tty 136, 2 Dec 11 15:23 /dev/pts/2
[notting@nostromo: ~]$ mesg n
[notting@nostromo: ~]$ ls -l $(tty)
crw------- 1 notting tty 136, 2 Dec 11 15:23 /dev/pts/2
[notting@nostromo: ~]$ mesg y
[notting@nostromo: ~]$ ls -l $(tty)
crw--w---- 1 notting tty 136, 2 Dec 11 15:23 /dev/pts/2

What sort of tty rules do you have in /etc/udev/rules.d?

Comment 2 Kasper Dupont 2006-12-12 04:44:18 UTC
I have just the /etc/udev/rules.d/50-udev.rules from udev-084-13.fc5.2

Comment 3 Harald Hoyer 2006-12-12 15:33:15 UTC
ownership and permissions of ptys are not set by udev, afaik

Comment 4 Bill Nottingham 2006-12-12 16:47:26 UTC
What's your line for /dev/pts in /etc/fstab?

Comment 5 Kasper Dupont 2006-12-13 06:19:44 UTC
[kasperd@localhost:pts/7:~] grep pts /etc/fstab
/dev/devpts             /dev/pts                devpts  gid=5,mode=620  0 0

Comment 6 Harald Hoyer 2006-12-13 10:45:01 UTC
/dev/pts is not managed by udev

Comment 7 Kasper Dupont 2006-12-14 04:55:12 UTC
I just noticed that I can only reproduce the problem in xterm. Konsole, script,
and screen are not affected by this.

Comment 8 Lubomir Kundrak 2006-12-19 10:50:53 UTC
mlichvar reported that only FC6, FC5 and RHEL5 are affected.
The problem is caused by obsolete patch for configure script that is no longer

Comment 9 Lubomir Kundrak 2007-01-09 11:55:02 UTC
Fixed in


Removing "Security sensitive" flag.

Comment 10 Fedora Update System 2007-01-09 16:54:04 UTC
xterm-223-1.fc5 has been pushed for fc5, which should resolve this issue.  If these problems are still present in this version, then please make note of it in this bug report.

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