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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id B3C203896811 for ; Mon, 28 Jun 2021 08:31:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B3C203896811 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-594-HNIH-ZffOU6lP5Yx6axIRQ-1; Mon, 28 Jun 2021 04:31:28 -0400 X-MC-Unique: HNIH-ZffOU6lP5Yx6axIRQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 605791084F54 for ; Mon, 28 Jun 2021 08:31:27 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-228.ams2.redhat.com [10.36.112.228]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 11ED25D9CA; Mon, 28 Jun 2021 08:31:22 +0000 (UTC) From: Florian Weimer To: Carlos O'Donell Cc: libc-alpha@sourceware.org Subject: Re: [PATCH] elf: Assert range of ns argument in _dl_debug_initialize References: <87y2b04us6.fsf@oldenburg.str.redhat.com> <1517d682-9f16-6daf-b2b3-ab716a222a0b@redhat.com> <87pmw6zzt7.fsf@oldenburg.str.redhat.com> <251374b9-857b-b5a7-d315-6847b159923d@redhat.com> Date: Mon, 28 Jun 2021 10:31:21 +0200 In-Reply-To: <251374b9-857b-b5a7-d315-6847b159923d@redhat.com> (Carlos O'Donell's message of "Sun, 27 Jun 2021 22:15:45 -0400") Message-ID: <874kdiz8yu.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 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-12.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, 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: Mon, 28 Jun 2021 08:31:32 -0000 * Carlos O'Donell: > On 6/27/21 6:51 PM, Florian Weimer wrote: >> * Carlos O'Donell: >> >>>> diff --git a/elf/dl-debug.c b/elf/dl-debug.c >>>> index 2cd5f09753..85b087455e 100644 >>>> --- a/elf/dl-debug.c >>>> +++ b/elf/dl-debug.c >>>> @@ -16,6 +16,8 @@ >>>> License along with the GNU C Library; if not, see >>>> . */ >>>> >>>> +#include >>>> +#include >>>> #include >>>> >>>> >>>> @@ -49,7 +51,11 @@ _dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns) >>>> if (ns == LM_ID_BASE) >>>> r = &_r_debug; >>>> else >>>> - r = &GL(dl_ns)[ns]._ns_debug; >>>> + { >>>> + assert (ns >= 0); >>>> + assert (ns < array_length (GL (dl_ns))); >>> >>> The check in _dl_map_object is: >>> assert (nsid >= 0); >>> assert (nsid < GL(dl_nns)); >>> >>> Should we be consistent one way or the other? >> >> I wasn't sure if _dl_debug_initialize can be called with a >> not-yet-allocated (or already-deallocated) namespace ID. _dl_map_object >> is somewhat higher-level, so it's not surprising that it expects an >> active ID. An out-of-bounds array access is clearly invalid, though. > > Assert on the tighter bound and we'll see? :-) Do we do things this way? I'm mainly interested in catching the LM_ID_NEWLM case, to be honest. Thanks, Florian