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=-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=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 CB21DC388F7 for ; Mon, 9 Nov 2020 13:09:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7095E21D40 for ; Mon, 9 Nov 2020 13:09:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927397; bh=Qig32iJy/AMBo4tI3512+wgkuiXN1kFxWXumB4pjLkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Tn1rejIng/ybF2iNT2RqT6JiO0QLyBXJCrvMJ63vLfSnFIRxQEP4vnREUGclZibaj fhCAMKwolEwJSsDFNQVlxcY7YTLlqPG11jSgfONU+/y3M4/5dEfJvwOIDIBpQFf7on MIUhVu9vBYt1+zxaLd00SPiDSu9GexhoLrsWGGdc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731949AbgKINJ4 (ORCPT ); Mon, 9 Nov 2020 08:09:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:34920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731286AbgKINJv (ORCPT ); Mon, 9 Nov 2020 08:09:51 -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 8BAFD20663; Mon, 9 Nov 2020 13:09:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927391; bh=Qig32iJy/AMBo4tI3512+wgkuiXN1kFxWXumB4pjLkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vCUDSKeCkcBD7s+ngxH9UY7NKHBIGPtnytE9hJIsEqCRItAI+kQjkJ3KCCInQQERw Z/FJqFAMmjcAYbE4G1dLHu6nU08GXkWhWtArCpcQ6aVm4iIQ8LfsvX+YAp+vSnWXPW E1euDsgMYi3/rK9creQ9Mqot0rvfqR08j4QetsD4= 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 4.19 44/71] tracing: Fix out of bounds write in get_trace_buf Date: Mon, 9 Nov 2020 13:55:38 +0100 Message-Id: <20201109125021.968130180@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125019.906191744@linuxfoundation.org> References: <20201109125019.906191744@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -2819,7 +2819,7 @@ 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)