From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) by sourceware.org (Postfix) with ESMTP id 19AC2384B13D for ; Thu, 9 Jul 2020 18:16:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 19AC2384B13D 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-73-vRmG0rbtOmWWul2fP_IL9w-1; Thu, 09 Jul 2020 14:15:54 -0400 X-MC-Unique: vRmG0rbtOmWWul2fP_IL9w-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 859BC80BCAD; Thu, 9 Jul 2020 18:15:52 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-114-125.ams2.redhat.com [10.36.114.125]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B2A4C7981F; Thu, 9 Jul 2020 18:15:50 +0000 (UTC) From: Florian Weimer To: Gian-Carlo Pascutto Cc: Szabolcs Nagy , mathieu.desnoyers@efficios.com, libc-alpha@sourceware.org, Christian Brauner , Jed Davis , Emilio Cobos =?utf-8?Q?=C3=81lvarez?= , Rich Felker Subject: Re: glibc 2.32 rseq support incompatible with Firefox sandbox References: <87pn94688t.fsf@oldenburg2.str.redhat.com> <20200709163407.GB26482@arm.com> Date: Thu, 09 Jul 2020 20:15:49 +0200 In-Reply-To: (Gian-Carlo Pascutto's message of "Thu, 9 Jul 2020 20:10:10 +0200") Message-ID: <87d0545zca.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Jul 2020 18:16:06 -0000 * Gian-Carlo Pascutto: > If all we need to do here is allow rseq, then it's not really a > problem. If it's a more fundamental issue with the signal blocking, > we'll need to figure out a workaround until sandboxed browsers can add > support for and add the entirely new seccomp implementation. rseq and rt_sigprocmask are the only new system call after clone in glibc 2.32. rt_sigprocmask should be fine, so only rseq needs to be permitted. It would be be best not to deny rseq on specific threads if it has already succeeded on the main thread. Thanks, Florian