Received: by 2002:a05:6a11:4021:0:0:0:0 with SMTP id ky33csp767514pxb; Wed, 22 Sep 2021 12:24:06 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzoedGKXSO974HB/VjUawQwu0bBrVDTRlzR1alYEWMETYlcgUbS8R6oEZi5EGSXSOs4U4pZ X-Received: by 2002:a6b:e309:: with SMTP id u9mr532752ioc.39.1632338646387; Wed, 22 Sep 2021 12:24:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1632338646; cv=none; d=google.com; s=arc-20160816; b=i+vsIqQSDxAqrQFdOlUqvQRkYf37c+7fb8MEAwRs/c2u/3/6iJW/1LwORnJTo7nwYq EzBWEfx5S5P7WtKfVFkw29p1WExsQ49NPP7Z3YWU5RK4aH9BmPN01kv+vGNdk4l5kfQR YUmd/VZoL7tTrZE4tf8tddZftaolzqO2nMUU0DXj3xfvcc17ttQT9WYh812md6Eo2mwc 1hmhPcyNc567JQ9H9iEgEB5kzSWY69DC1GMVISPgdBVQhV0m0A7hris25IzgFE71Gthh YNBsCg6AUQMSuj+ju8dn8HgkUYagUrJgTsP3Tdiiqj1tP6ZK7Og6l1nocPaQ1xmbO06v 1vUw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date; bh=trt9LWfIxIfy7RcFs581ryhPg3VyGtRy8aqGZgNYAZ4=; b=TRDtNoEGXa+3gFAM2qenHIqaZTAbzlU3zLY3FuGRFwUcaahnZHQOOXEsTDw3ohZOTB iTjSuQFm8ehorlaU0WxbYcjfmP2h7hSzKdSXWGXkXj3hJGnRP2NvSDSZ4DkuMvvEwhK2 +VBA0MZ6WOMEu1+658h35q6ZGOEj6LSWlAD0SiILHDRiRRLU1daSzID+eBn0R7C1QcDf T8tIc+X0QgoTJfLm6bl6jFLzGXgWxvlR5LeKu/VZjK5spjV1/d0lVVrOP6y2xakrzMxM 8bzKTBGmNH1kVT/GLc4JdVdwc/9ZvWfG1BNWCO70D00M7fNQwd0Yn7STngdUhf95fc20 LFAg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id l11si3659630ilv.110.2021.09.22.12.23.54; Wed, 22 Sep 2021 12:24:06 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237169AbhIVTY1 (ORCPT + 99 others); Wed, 22 Sep 2021 15:24:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:59376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233678AbhIVTY1 (ORCPT ); Wed, 22 Sep 2021 15:24:27 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 61F6561038; Wed, 22 Sep 2021 19:22:53 +0000 (UTC) Date: Wed, 22 Sep 2021 15:22:50 -0400 From: Steven Rostedt To: David Hildenbrand Cc: Peter Collingbourne , Catalin Marinas , Will Deacon , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Thomas Gleixner , Andy Lutomirski , Kees Cook , Andrew Morton , Masahiro Yamada , Sami Tolvanen , YiFei Zhu , Colin Ian King , Mark Rutland , Frederic Weisbecker , Viresh Kumar , Andrey Konovalov , Gabriel Krisman Bertazi , Balbir Singh , Chris Hyser , Daniel Vetter , Chris Wilson , Arnd Bergmann , Dmitry Vyukov , Christian Brauner , "Eric W. Biederman" , Alexey Gladkov , Ran Xiaokai , Xiaofeng Cao , Cyrill Gorcunov , Thomas Cedeno , Marco Elver , Alexander Potapenko , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Evgenii Stepanov Subject: Re: [PATCH] kernel: introduce prctl(PR_LOG_UACCESS) Message-ID: <20210922152250.4e7c869a@gandalf.local.home> In-Reply-To: <29f1822d-e4cd-eedb-bea8-619db1d56335@redhat.com> References: <20210922061809.736124-1-pcc@google.com> <29f1822d-e4cd-eedb-bea8-619db1d56335@redhat.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 22 Sep 2021 19:46:47 +0200 David Hildenbrand wrote: > > All signals except SIGKILL and SIGSTOP are masked for the interval > > between the prctl() and the next syscall in order to prevent handlers > > for intervening asynchronous signals from issuing syscalls that may > > cause uaccesses from the wrong syscall to be logged. > > Stupid question: can this be exploited from user space to effectively > disable SIGKILL for a long time ... and do we care? I first misread it too, but then caught my mistake reading it a second time. It says "except SIGKILL". So no, it does not disable SIGKILL. -- Steve