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 596973857702 for ; Wed, 19 Jul 2023 09:15:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 596973857702 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689758131; 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=tnPlnrD7L9pA9D6ualGRmLOhLgAow9HEUJR329flCiQ=; b=B7XzS5d4BYjgN3BIrmvQnQfFdfzKa6cBCzHmZNPjbG3/l/d/k4zeFBCZ8sXyJ8Ao2vh8CE HefCjFI4Mx9SRBKBKWkbKFNc/fAcirMYvj0ICMkOms6mkGgnpGg2e14x6l8EikyyClOfNG 3dkyU5QZP9NF42UTZvbbJedtpmWlYX4= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-335-uPc4WsY6M6CzWewQL5_Ljg-1; Wed, 19 Jul 2023 05:15:29 -0400 X-MC-Unique: uPc4WsY6M6CzWewQL5_Ljg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D50D51C28CE5; Wed, 19 Jul 2023 09:15:28 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 39A261121314; Wed, 19 Jul 2023 09:15:28 +0000 (UTC) From: Florian Weimer To: Stefan Liebler Cc: libc-alpha@sourceware.org Subject: Re: [PATCH] Fix getting return address in elf/tst-audit28.c. References: <20230713131348.985999-1-stli@linux.ibm.com> Date: Wed, 19 Jul 2023 11:15:26 +0200 In-Reply-To: <20230713131348.985999-1-stli@linux.ibm.com> (Stefan Liebler's message of "Thu, 13 Jul 2023 15:13:48 +0200") Message-ID: <87bkg89s9d.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-10.9 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,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=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: * Stefan Liebler: > Starting with commit 1bcfe0f732066ae5336b252295591ebe7e51c301, the > test was enhanced and the object for __builtin_return_address (0) > is searched with _dl_find_object. > > Unfortunately on e.g. s390 (31bit), a postprocessing step is needed > as the highest bit has to be masked out. This can be done with > __builtin_extract_return_addr. > > Without this postprocessing, _dl_find_object returns with -1 and the > content of dlfo is invalid, which may lead to segfaults in basename. > Therefore those checks are now only done on success. > --- > elf/tst-auditmod28.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/elf/tst-auditmod28.c b/elf/tst-auditmod28.c > index f6dfbbe202..35180208ba 100644 > --- a/elf/tst-auditmod28.c > +++ b/elf/tst-auditmod28.c > @@ -73,12 +73,19 @@ la_version (unsigned int current) > > /* Check _dl_find_object. */ > struct dl_find_object dlfo; > - TEST_COMPARE (_dl_find_object (__builtin_return_address (0), &dlfo), 0); > - /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */ > - if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0) > - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO); > - TEST_COMPARE (_dl_find_object (dlsym (handle, "environ"), &dlfo), 0); > - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO); > + void *ret_addr = __builtin_extract_return_addr (__builtin_return_address (0)); > + int ret_dl_find_object =_dl_find_object (ret_addr, &dlfo); > + TEST_COMPARE (ret_dl_find_object, 0); > + if (ret_dl_find_object == 0) > + { > + /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */ > + if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0) > + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO); > + } > + ret_dl_find_object = _dl_find_object (dlsym (handle, "environ"), &dlfo); > + TEST_COMPARE (ret_dl_find_object, 0); > + if (ret_dl_find_object == 0) > + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO); > TEST_COMPARE (_dl_find_object ((void *) 1, &dlfo), -1); > TEST_COMPARE (_dl_find_object ((void *) -1, &dlfo), -1); Based on the GCC documentation, this should be reasinable portable. Reviewed-by: Florian Weimer Thanks, Florian