Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965003AbVI0Qiz (ORCPT ); Tue, 27 Sep 2005 12:38:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965004AbVI0Qiz (ORCPT ); Tue, 27 Sep 2005 12:38:55 -0400 Received: from tierw.net.avaya.com ([198.152.13.100]:44029 "EHLO tierw.net.avaya.com") by vger.kernel.org with ESMTP id S965003AbVI0Qiy convert rfc822-to-8bit (ORCPT ); Tue, 27 Sep 2005 12:38:54 -0400 X-MimeOLE: Produced By Microsoft Exchange V6.0.6603.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: [RFC PATCH] New SA_NOPRNOTIF sigaction flag Date: Tue, 27 Sep 2005 10:24:23 -0600 Message-ID: <21FFE0795C0F654FAD783094A9AE1DFC086EFBEB@cof110avexu4.global.avaya.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [RFC PATCH] New SA_NOPRNOTIF sigaction flag Thread-Index: AcXDfHSDezXjog24QIy5xVH9CqLpkQAAlAzA From: "Davda, Bhavesh P \(Bhavesh\)" To: "Daniel Jacobowitz" Cc: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1649 Lines: 45 > Also, this is far from the only problem you're going to have > if you run > your debugger with lower priority than your debuggee. About the priority inversion and running the debugger at higher priority then the debuggee, that's a moot point. You're still doing too many pointless context switches to the debugger only to do nothing and switch back to the debuggee. > > > > IMHO this is a perfectly safe capability... > > No. Ptrace is considered a security barrier; the tracee should not be > able to control what the tracer sees. > Since when did ptrace become a security barrier? If security is the only concern, then we can always add a capability check to only allow root to set SA_NOPRNOTIF on sigaction() for a particular signal. Besides, putting this responsibility (ignore SIGCHLDs for signal X from Task Y) in the debugger requires the debugger to have information about the debuggee, like Task Y is special for handling signal X, and I'm going to ptrace() ignore SIGCHLD's from Task Y. See where I'm going with this? That's why I specifically put the responsibility on the debuggee to say: I know what I'm doing and I don't want the debugger to be notified about this specific signal. - Bhavesh Bhavesh P. Davda | Distinguished Member of Technical Staff | Avaya | 1300 West 120th Avenue | B3-B03 | Westminster, CO 80234 | U.S.A. | Voice/Fax: 303.538.4438 | bhavesh@avaya.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/