From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bastian Blank Subject: Re: [RFC][PATCH 3/5] Determine if sender is from ancestor ns+ Date: Thu, 4 Dec 2008 13:45:11 +0100 Message-ID: <20081204124511.GA31061@wavehammer.waldi.eu.org> References: <20081126034242.GA23120@us.ibm.com> <20081126034611.GC23238@us.ibm.com> <20081127010101.GA13545@wavehammer.waldi.eu.org> <20081201201506.GB12493@us.ibm.com> <20081202114833.GA1132@wavehammer.waldi.eu.org> <20081202195904.GA20077@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20081202195904.GA20077@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: Sukadev Bhattiprolu Cc: oleg@redhat.com, ebiederm@xmission.com, roland@redhat.com, containers@lists.osdl.org, linux-kernel@vger.kernel.org, xemul@openvz.org List-Id: containers.vger.kernel.org On Tue, Dec 02, 2008 at 11:59:04AM -0800, Sukadev Bhattiprolu wrote: > Bastian Blank [bastian@waldi.eu.org] wrote: > | sys_rt_sigqueueinfo disallows setting si_code to any value which > | describes kernel signals from userspace. So using SI_FROMUSER should be > | sufficient. > SI_ASYNCIO qualifies as SI_FROMUSER() even when it originates from > kernel (usb/core/devio.c async_completed())... SI_ASYNCIO currently qualifies as user signal, it is sent in the context of the pid issuing the async io request. It is never used as a kernel originated signal in any way. The code sending it even seems to do a full permission check. If you think this is wrong, maybe this should be fixed first. > If we know that it came from rt_sigqueueinfo(), we can safely check > the namespace. If it came from driver we should skip the ns check. If it have a sender pid attached, this should be checked. > Yes, (Eric Biederman, Dec 2007) > https://lists.linux-foundation.org/pipermail/containers/2007-December/009152.html > Oleg Nesterov, Aug 2007: > http://marc.info/?l=linux-kernel&m=118753610515859 > I had sent out a summary of the above attempts to Containers list recently: > https://lists.linux-foundation.org/pipermail/containers/2008-November/013991.html Okay. > | Please add a complete comment to the function which describes the > | function. And don't us "it" for not defined entities. > Ah, I see the problem now. The 't' refers to the task parameter - how > about changing comment to: No, I meant a real comment, defining the complete behaviour, each parameter with constraints and the possible return values. Bastian -- Insufficient facts always invite danger. -- Spock, "Space Seed", stardate 3141.9