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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBBD6C433F5 for ; Fri, 19 Nov 2021 17:49:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA476611AF for ; Fri, 19 Nov 2021 17:49:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233992AbhKSRwM (ORCPT ); Fri, 19 Nov 2021 12:52:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:57576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231840AbhKSRwF (ORCPT ); Fri, 19 Nov 2021 12:52:05 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BEBF16120F; Fri, 19 Nov 2021 17:49:02 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1mo80T-001NJL-Ta; Fri, 19 Nov 2021 12:49:01 -0500 Message-ID: <20211119174901.749266954@goodmis.org> User-Agent: quilt/0.66 Date: Fri, 19 Nov 2021 12:47:32 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Kees Cook Subject: [for-linus][PATCH 2/3] tracing: Use memset_startat() to zero struct trace_iterator References: <20211119174730.441176580@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Use memset_startat() to avoid confusing memset() about writing beyond the target struct member. Link: https://lkml.kernel.org/r/20211118202217.1285588-1-keescook@chromium.org Signed-off-by: Kees Cook Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f9139dc1262c..e3c80cfd4eec 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6706,9 +6706,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, cnt = PAGE_SIZE - 1; /* reset all but tr, trace, and overruns */ - memset(&iter->seq, 0, - sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + memset_startat(iter, 0, seq); cpumask_clear(iter->started); trace_seq_init(&iter->seq); iter->pos = -1; -- 2.33.0