Red Hat Bugzilla – Bug 454252
Problem with who,write and tty permissions
Last modified: 2008-09-10 03:11:31 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):
Change group on tty and check:
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)
$ 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
Created attachment 311135 [details]
Added check of tty gid against process egid in write
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.
The patch applied to F9.
util-linux-ng-2.13.1-8.3.fc9 has been submitted as an update for Fedora 9
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.