linux-kernel - Re: [PATCH 1/1] ptrace: do_notify_parent_cldstop: fix the wrong ->nsproxy usage

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]

Message-ID: <20090602045418.GB8219@us.ibm.com>
Date:	Mon, 1 Jun 2009 21:54:18 -0700
From:	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
To:	Roland McGrath <roland@...hat.com>
Cc:	Oleg Nesterov <oleg@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Hellwig <hch@...radead.org>,
	Ingo Molnar <mingo@...e.hu>,
	Pavel Emelyanov <xemul@...nvz.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] ptrace: do_notify_parent_cldstop: fix the wrong
	->nsproxy usage

Roland McGrath [roland@...hat.com] wrote:
| > Yes. Perhaps it would be nice to add a helper,
| 
| I agree.
| 
| > > sys_kill, do_tkill all look wrong to me.
| > 
| > They should be fine, note the
| > 
| > 	if (from_ancestor_ns)
| > 		q->info.si_pid = 0;
| > 
| > in __send_signal(). If we send the signal "down" to the sub-namespace,
| > si_pid == 0 is correct. And, unlike do_notify_parent/ptrace_notify/etc
| > kill/tkill can't send the signal "up".
| 
| Ah, right.  I knew there was something around this I was forgetting.

Setting si_pid to task_tgid_vnr(current); in places like do_tkill() is
slightly misleading bc, it can get modified later in send_signal().  We
can't set si_pid correctly in do_tkill() since we must first establish
pid-namespace relationship and that can mess up control flow.

Maybe a comment will help.
--
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/