From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18F59C38A24 for ; Thu, 7 May 2020 18:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9A9C221F7 for ; Thu, 7 May 2020 18:47:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TWz6Vqjj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728534AbgEGSrY (ORCPT ); Thu, 7 May 2020 14:47:24 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:55045 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726467AbgEGSrW (ORCPT ); Thu, 7 May 2020 14:47:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588877240; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fA/ECm0zhQEdUp/fUbA73B0nJs5vbdkbZsQ0b4cogDo=; b=TWz6Vqjj8SBvEKBx1vLPZ+I1DGcKCa4G+y4nV2bm5DF3FyqhBCXJtSDWthw1Bn4lfbPPND GpvV8mPueQCWwaE0Mv/ySdiuNnJfV+w30W7IpzUQnv/vyglM7fOBwZboc8k5ivv1Aw0oVC sjZ3yk1ojO3h0yFMM+x/KLU3jWGVXT0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-271-MgJVVsgDOfqwYGQcSYPLlA-1; Thu, 07 May 2020 14:47:16 -0400 X-MC-Unique: MgJVVsgDOfqwYGQcSYPLlA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BAF3919200C0; Thu, 7 May 2020 18:47:14 +0000 (UTC) Received: from optiplex-lnx (unknown [10.3.128.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CCBBF70559; Thu, 7 May 2020 18:47:08 +0000 (UTC) Date: Thu, 7 May 2020 14:47:05 -0400 From: Rafael Aquini To: Luis Chamberlain Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, dyoung@redhat.com, bhe@redhat.com, corbet@lwn.net, keescook@chromium.org, akpm@linux-foundation.org, cai@lca.pw, rdunlap@infradead.org Subject: Re: [PATCH v2] kernel: add panic_on_taint Message-ID: <20200507184705.GG205881@optiplex-lnx> References: <20200507180631.308441-1-aquini@redhat.com> <20200507182257.GX11244@42.do-not-panic.com> <20200507184307.GF205881@optiplex-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200507184307.GF205881@optiplex-lnx> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 07, 2020 at 02:43:16PM -0400, Rafael Aquini wrote: > On Thu, May 07, 2020 at 06:22:57PM +0000, Luis Chamberlain wrote: > > On Thu, May 07, 2020 at 02:06:31PM -0400, Rafael Aquini wrote: > > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > > > index 8a176d8727a3..b80ab660d727 100644 > > > --- a/kernel/sysctl.c > > > +++ b/kernel/sysctl.c > > > @@ -1217,6 +1217,13 @@ static struct ctl_table kern_table[] = { > > > .extra1 = SYSCTL_ZERO, > > > .extra2 = SYSCTL_ONE, > > > }, > > > + { > > > + .procname = "panic_on_taint", > > > + .data = &panic_on_taint, > > > + .maxlen = sizeof(unsigned long), > > > + .mode = 0644, > > > + .proc_handler = proc_doulongvec_minmax, > > > + }, > > > > You sent this out before I could reply to the other thread on v1. > > My thoughts on the min / max values, or lack here: > > > > Valid range doesn't mean "currently allowed defined" masks. > > > > For example, if you expect to panic due to a taint, but a new taint type > > you want was not added on an older kernel you would be under a very > > *false* sense of security that your kernel may not have hit such a > > taint, but the reality of the situation was that the kernel didn't > > support that taint flag only added in future kernels. > > > > You may need to define a new flag (MAX_TAINT) which should be the last > > value + 1, the allowed max values would be > > > > (2^MAX_TAINT)-1 > > > > or > > > > (1< > > > Since this is to *PANIC* I think we do want to test ranges and ensure > > only valid ones are allowed. > > > > Ok. I'm thinking in: > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 8a176d8727a3..ee492431e7b0 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1217,6 +1217,15 @@ static struct ctl_table kern_table[] = { > .extra1 = SYSCTL_ZERO, > .extra2 = SYSCTL_ONE, > }, > + { > + .procname = "panic_on_taint", > + .data = &panic_on_taint, > + .maxlen = sizeof(unsigned long), > + .mode = 0644, > + .proc_handler = proc_doulongvec_minmax, > + .extra1 = SYSCTL_ZERO, > + .extra2 = (1 << TAINT_FLAGS_COUNT << 1) - 1, ^^^^^^^^ Without that crap, obviously. Sorry. That was a screw up on my side, when copyin' and pasting. -- Rafael > + }, > > > Would that address your concerns wrt this one? > > Cheers! > -- Rafael