From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753822Ab2ATAx1 (ORCPT ); Thu, 19 Jan 2012 19:53:27 -0500 Received: from mail-we0-f174.google.com ([74.125.82.174]:57638 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751718Ab2ATAxY (ORCPT ); Thu, 19 Jan 2012 19:53:24 -0500 MIME-Version: 1.0 In-Reply-To: <930b350b8504fa9e1272f93bf21dde49.squirrel@webmail.greenhost.nl> References: <20120117170512.GB17070@redhat.com> <49017bd7edab7010cd9ac767e39d99e4.squirrel@webmail.greenhost.nl> <20120118015013.GR11715@one.firstfloor.org> <20120118020453.GL7180@jl-vm1.vm.bytemark.co.uk> <20120118023114.GA9643@alboin.amr.corp.intel.com> <20120118182411.GT11715@one.firstfloor.org> <20120119160429.GO7180@jl-vm1.vm.bytemark.co.uk> <930b350b8504fa9e1272f93bf21dde49.squirrel@webmail.greenhost.nl> From: Linus Torvalds Date: Thu, 19 Jan 2012 16:53:01 -0800 X-Google-Sender-Auth: _6xtwSovvhdk1GrtGGtbdRm8KIA Message-ID: Subject: Re: Compat 32-bit syscall entry from 64-bit task!? [was: Re: [RFC,PATCH 1/2] seccomp_filters: system call filtering using BPF] To: Indan Zupancic Cc: Jamie Lokier , Andi Kleen , Martin Mares , Andi Kleen , Andrew Lutomirski , Oleg Nesterov , Will Drewry , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, olofj@chromium.org, mhalcrow@google.com, dlaor@redhat.com, Roland McGrath Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2012 at 4:21 PM, Indan Zupancic wrote: > > With current ptrace you can do exactly that. It's just very slow, because > you have to copy the data word by word via PTRACE_PEEKDATA. But if Linux > would support something like BSD's PT_IO ptrace request, then it could be > limited to one extra ptrace command. (PTRACE_STRNCPY would be handy.) Actually, you could use the new "process_vm_readv/writev()" system calls. No need to do the crazy slow ptrace stuff. I dunno. It got merged through Andrew, and the code looks sane, but I've never actually seen anybody *use* it. So maybe there is something wrong there. And no, it doesn't have a "strncpy" interface, I'm afraid. Linus From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: Compat 32-bit syscall entry from 64-bit task!? [was: Re: [RFC,PATCH 1/2] seccomp_filters: system call filtering using BPF] Date: Thu, 19 Jan 2012 16:53:01 -0800 Message-ID: References: <20120117170512.GB17070@redhat.com> <49017bd7edab7010cd9ac767e39d99e4.squirrel@webmail.greenhost.nl> <20120118015013.GR11715@one.firstfloor.org> <20120118020453.GL7180@jl-vm1.vm.bytemark.co.uk> <20120118023114.GA9643@alboin.amr.corp.intel.com> <20120118182411.GT11715@one.firstfloor.org> <20120119160429.GO7180@jl-vm1.vm.bytemark.co.uk> <930b350b8504fa9e1272f93bf21dde49.squirrel@webmail.greenhost.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Jamie Lokier , Andi Kleen , Martin Mares , Andi Kleen , Andrew Lutomirski , Oleg Nesterov , Will Drewry , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, olofj@chromium.org, mhalcrow@google.com, dlaor@redhat. To: Indan Zupancic Return-path: Received: from mail-we0-f174.google.com ([74.125.82.174]:57638 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751718Ab2ATAxY (ORCPT ); Thu, 19 Jan 2012 19:53:24 -0500 In-Reply-To: <930b350b8504fa9e1272f93bf21dde49.squirrel@webmail.greenhost.nl> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Jan 19, 2012 at 4:21 PM, Indan Zupancic wrote: > > With current ptrace you can do exactly that. It's just very slow, because > you have to copy the data word by word via PTRACE_PEEKDATA. But if Linux > would support something like BSD's PT_IO ptrace request, then it could be > limited to one extra ptrace command. (PTRACE_STRNCPY would be handy.) Actually, you could use the new "process_vm_readv/writev()" system calls. No need to do the crazy slow ptrace stuff. I dunno. It got merged through Andrew, and the code looks sane, but I've never actually seen anybody *use* it. So maybe there is something wrong there. And no, it doesn't have a "strncpy" interface, I'm afraid. Linus