From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0667DC2BC61 for ; Tue, 30 Oct 2018 17:40:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC6C42075D for ; Tue, 30 Oct 2018 17:40:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC6C42075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbeJaCew (ORCPT ); Tue, 30 Oct 2018 22:34:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58794 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727621AbeJaCew (ORCPT ); Tue, 30 Oct 2018 22:34:52 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DDFD6307D96B; Tue, 30 Oct 2018 17:40:27 +0000 (UTC) Received: from [10.13.129.51] (dhcp129-51.rdu.redhat.com [10.13.129.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id 79366177A9; Tue, 30 Oct 2018 17:40:27 +0000 (UTC) Subject: Re: [PATCH] ARM: kprobes: Fix false positive with FORTIFY_SOURCE To: Kees Cook , Russell King Cc: Laura Abbott , linux-kernel@vger.kernel.org, Masami Hiramatsu , linux-arm-kernel@lists.infradead.org References: <20181022093023.GA8920@beast> From: William Cohen Message-ID: Date: Tue, 30 Oct 2018 13:40:27 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181022093023.GA8920@beast> Content-Type: text/plain; charset=utf-8 Content-Language: en-MW Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Tue, 30 Oct 2018 17:40:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/18 5:30 AM, Kees Cook wrote: > The arm compiler internally interprets an inline assembly label > as an unsigned long value, not a pointer. As a result, under > CONFIG_FORTIFY_SOURCE, the size of the array pointed to by an address > of a label is 4 bytes, which was tripping the runtime checks. Instead, > we can just cast the label (as done with the size calculations earlier) > to avoid the problem. > > Reported-by: William Cohen > Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions") > Cc: stable@vger.kernel.org > Signed-off-by: Kees Cook > --- > arch/arm/probes/kprobes/opt-arm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c > index b2aa9b32bff2..2c118a6ab358 100644 > --- a/arch/arm/probes/kprobes/opt-arm.c > +++ b/arch/arm/probes/kprobes/opt-arm.c > @@ -247,7 +247,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *or > } > > /* Copy arch-dep-instance from template. */ > - memcpy(code, &optprobe_template_entry, > + memcpy(code, (unsigned char *)optprobe_template_entry, > TMPL_END_IDX * sizeof(kprobe_opcode_t)); > > /* Adjust buffer according to instruction. */ > The patch fixes the issue for kretprobes. It looks good to me. Thanks, -Will