From patchwork Mon Nov 9 12:55:37 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: 322757 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 EBEAFC4741F for ; Mon, 9 Nov 2020 13:13:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AACA121D7F for ; Mon, 9 Nov 2020 13:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927591; bh=4s+s+54s6ztPMdZSnsUCq9B+7cYRD+rien9Avayj+0o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HVduHBRUMnnmbwbrxX7Kq5GOjfSJraf8dG79PrCe7jHVwzAayUfL8NgfF1W6BZjqX YcvtW03AvuRb21wWPm1jK4sxMnXP1RN03l5ZcsDO30kE8kEUK3r5RsUg4kYvP+sr29 A3cyJpJPrUw1O1iNm6SuOxuBvhNT2zMJ3qU0P6mc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731444AbgKINNK (ORCPT ); Mon, 9 Nov 2020 08:13:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:38964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732949AbgKINNJ (ORCPT ); Mon, 9 Nov 2020 08:13:09 -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 6402F20663; Mon, 9 Nov 2020 13:13:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927589; bh=4s+s+54s6ztPMdZSnsUCq9B+7cYRD+rien9Avayj+0o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=goR/b5/zhQU83uZVRO8DKpdkfMMPQPfLeAfJ209/KoSOKo7X101yAsFTdnu60dGOw w+O8y4+SiAEXNTOYOiMqw2n27M0f9qpJhh2RRz4VtnSvwzvAEuyOJy3q6BT9TR0U2C 4JEQtMR78XECVqeYVmvveITVxdaJwjuR3U4mBl68= 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 5.4 40/85] tracing: Fix out of bounds write in get_trace_buf Date: Mon, 9 Nov 2020 13:55:37 +0100 Message-Id: <20201109125024.516578878@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125022.614792961@linuxfoundation.org> References: <20201109125022.614792961@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 @@ -3012,7 +3012,7 @@ 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)