Bug 454252 – Problem with who,write and tty permissions

Bug 454252 - Problem with who,write and tty permissions

Summary:	Problem with who,write and tty permissions

Status:	CLOSED NEXTRELEASE

Aliases:	None

Product:	Fedora
Classification:	Fedora
Component:	util-linux-ng (Show other bugs)
Sub Component:
Version:	8
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Karel Zak
QA Contact:	Fedora Extras Quality Assurance
Docs Contact:

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Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2008-07-07 05:32 EDT by Piotr Gackiewicz
Modified:	2008-09-10 03:11 EDT (History)
CC List:	0 users

See Also:
Fixed In Version:
Doc Type:	Bug Fix
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Last Closed:	2008-09-10 03:11:31 EDT
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oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
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Attachments	(Terms of Use)
Added check of tty gid against process egid in write (561 bytes, patch) 2008-07-07 06:28 EDT, Piotr Gackiewicz	no flags	Details \| Diff
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Piotr Gackiewicz 2008-07-07 05:32:33 EDT

Description of problem:
"write", "who" do mistakes when determining users' message status.
These utils only check "group writable" bit on tty, but not "group tty" ownership.

Version-Release number of selected component (if applicable):
util-linux-ng-2.13.1-2.fc8

How reproducible:
Change group on tty and check:
who -wu
write 

This bug does hit when user logs in with gdm (look at the status of /dev/tty7):
root     - tty1         2008-07-07 11:08 00:17        2443
user_a   + tty7         2008-07-07 11:13   .         15676 (:0)
user_a   + pts/0        2008-07-07 11:13   .         15748
user_a   + pts/1        2008-07-07 11:15 00:10       16002
user_a   + pts/2        2008-07-07 11:17 00:11       16132
user_b   + pts/6        2008-07-07 09:32 01:55        8453 (xxx.xxx.x.xx)

then:
$ ls -l /dev/tty7
crw--w---- 1 root root 4, 7 lip  7 08:12 /dev/tty7

$ write user_a
write: user_a is logged in more than once; writing to tty7
write: /dev/tty7: Permission denied

Comment 1 Piotr Gackiewicz 2008-07-07 06:28:20 EDT

Created attachment 311135 [details]
Added check of tty gid against process egid in write

Comment 2 Karel Zak 2008-07-07 16:28:05 EDT

Thanks a lot. The patch (with a minor change) has been committed (
bf09b61a3283ddce337700e791c0c02aa2265aae) to the upstream repository.

I'm going to backport the patch to F8 and F9 ASAP.

Comment 3 Karel Zak 2008-08-12 10:07:38 EDT

The patch applied to F9.

Comment 4 Fedora Update System 2008-08-12 16:08:45 EDT

util-linux-ng-2.13.1-8.3.fc9 has been submitted as an update for Fedora 9

Comment 5 Fedora Update System 2008-09-10 03:11:22 EDT

util-linux-ng-2.13.1-8.3.fc9 has been pushed to the Fedora 9 stable repository.  If problems still persist, please make note of it in this bug report.

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