From patchwork Mon Nov 9 12:55:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 322787 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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 1C4EEC388F7 for ; Mon, 9 Nov 2020 13:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C064A20897 for ; Mon, 9 Nov 2020 13:07:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927251; bh=1TPAtwwuxKFpOsLHBXmFntJ8vxoiEggKfc+Y3QDa4pw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=T3lREwFym/Axj6c8SCWxM8pbmrac3MR3uKNCZ329T4gAD71h4prsePfdEySY65CHf uHu7Q0Xta5Ko4HNKgcomb9dHQ6msl/J83Mi0mxlFAI83X7CQ50/DdmXRfs1x3YT5Ff N3iAi/F9+oj9uG1cPawWHy7pKkjPn+AJF0TcTChE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731321AbgKINHX (ORCPT ); Mon, 9 Nov 2020 08:07:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:60128 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731316AbgKINHW (ORCPT ); Mon, 9 Nov 2020 08:07:22 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 2A0CE20731; Mon, 9 Nov 2020 13:07:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927241; bh=1TPAtwwuxKFpOsLHBXmFntJ8vxoiEggKfc+Y3QDa4pw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iRSIVcnPPo7d6f172XWVy+puifOC0JtTISZycOIv9Y+RFzTBQ6YoxCkfAm70KqUAF K1QylztoO9wAb+jOw40nTzEo5EH7dLggn3HtiY2/Q62+ols6DREjpY7npkxbnNBOCE Qx3DRbbZkpgnyjEtEwx/6e8WBp6pViKfKctt0WEk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qiujun Huang , "Steven Rostedt (VMware)" Subject: [PATCH 4.14 24/48] tracing: Fix out of bounds write in get_trace_buf Date: Mon, 9 Nov 2020 13:55:33 +0100 Message-Id: <20201109125017.946178648@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125016.734107741@linuxfoundation.org> References: <20201109125016.734107741@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qiujun Huang commit c1acb4ac1a892cf08d27efcb964ad281728b0545 upstream. The nesting count of trace_printk allows for 4 levels of nesting. The nesting counter starts at zero and is incremented before being used to retrieve the current context's buffer. But the index to the buffer uses the nesting counter after it was incremented, and not its original number, which in needs to do. Link: https://lkml.kernel.org/r/20201029161905.4269-1-hqjagain@gmail.com Cc: stable@vger.kernel.org Fixes: 3d9622c12c887 ("tracing: Add barrier to trace_printk() buffer nesting modification") Signed-off-by: Qiujun Huang Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2817,7 +2817,7 @@ static char *get_trace_buf(void) /* Interrupts must see nesting incremented before we use the buffer */ barrier(); - return &buffer->buffer[buffer->nesting][0]; + return &buffer->buffer[buffer->nesting - 1][0]; } static void put_trace_buf(void)