From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id A30C0385735A for ; Wed, 20 Apr 2022 18:57:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A30C0385735A Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-257-C-Q--0luPTyMT8ZNd1CcIg-1; Wed, 20 Apr 2022 14:57:22 -0400 X-MC-Unique: C-Q--0luPTyMT8ZNd1CcIg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 041E3100BAA6; Wed, 20 Apr 2022 18:57:22 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3369440E8114; Wed, 20 Apr 2022 18:57:20 +0000 (UTC) From: Florian Weimer To: Jonathon Anderson Cc: libc-alpha@sourceware.org, Carlos O'Donell Subject: Re: RFC: Auditor access to program headers References: <975db62c-dd23-9dbf-ba91-d41e04282961@rice.edu> <87v8wcoc9z.fsf@oldenburg.str.redhat.com> Date: Wed, 20 Apr 2022 20:57:19 +0200 In-Reply-To: (Jonathon Anderson's message of "Thu, 17 Mar 2022 15:16:11 -0500") Message-ID: <87ilr3wpkg.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-5.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Wed, 20 Apr 2022 18:57:26 -0000 * Jonathon Anderson: > The current implementation does error on unsupported requests, and > AFAICT has since the initial implementation in 2003: > > switch (args->request) > { > case RTLD_DI_CONFIGADDR: > default: > _dl_signal_error (0, NULL, NULL, N_("unsupported dlinfo request"))= ; > break; Oops, I had missed that. > Adding a new dlinfo request should work well enough for our purposes, > we'll keep a runtime fallback in case the request isn't supported. I've posted a patch: [PATCH] dlfcn: Implement the RTLD_DI_PHDR request type for dlinfo I couldn't find precedent for this in other loaders, so I made something up from scratch. > For my own curiosity, what would you consider for a longer-term > solution? Separate function calls instead of a type-polymorphic multiplexer. (A while back, I tried to write type-safety diagnostics for fcntl, but gave up because of the complexity, but the diagnostics would have been worth it=E2=80=94this was before the separate fcntl64 function.) [rtld_active () crash] > Great! We'll be happy to test when it's available. I'll try to work on this next. Thanks, Florian