linux-kernel - Re: 2.6.25.3: su gets stuck for root

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 2 Jun 2008 09:10:16 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Willy Tarreau <w@....eu>
Cc:	Harald Dunkel <harald.dunkel@...nline.de>,
	Joe Peterson <joe@...rush.com>, linux-kernel@...r.kernel.org,
	Alan Cox <alan@...hat.com>
Subject: Re: 2.6.25.3: su gets stuck for root

> Guys, you should test if "kill -CONT $pid" wakes the process up.
> It might be possible that some obscure bug appeared in the tty
> code resulting in SIGTTOU sometimes being sent to the caller,
> although that seems rather strange :-/

Not really. The task would get suspended if it attempted to change the
tty settings while not being session leader. This is part of the POSIX
and BSD job control. A race (either kernel or in something like
sshd/bash) would do that and could have been caused by any of the timing
changes recently.

That would also explain why I can't duplicate it, and the sleep
observation.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/