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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 A4CFAC4360F for ; Thu, 28 Feb 2019 15:30:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B4D420C01 for ; Thu, 28 Feb 2019 15:30:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551367859; bh=Y7heQ6sGPC7qDyM2CpigzX2e8ntRSCTu7au0f8DSAyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DXYJGN4OSTS8U6ewTXA0I6ie4b0JNkFqiFi1QbI1J6avNPoxKyBnidFnVRztEkZ7k KJf6FAwXSaM6JGVnZPcuriO3DW/T5cQfxH0JojwZ3yCDoTBZeuYVqcUulOvSbltlqg ui7HqqaR10UGTOMzsn4Q3ql4zQWuiM7Ma8SedyCM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387520AbfB1PJX (ORCPT ); Thu, 28 Feb 2019 10:09:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:41952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387518AbfB1PJW (ORCPT ); Thu, 28 Feb 2019 10:09:22 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C9089218AE; Thu, 28 Feb 2019 15:09:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551366561; bh=Y7heQ6sGPC7qDyM2CpigzX2e8ntRSCTu7au0f8DSAyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l5RFENKP8y6O4Rka9xoJY9f+fVuCKE3LU0UvwgG2dwkXjd1LYynL4nt/DlCQbJFsO mAWnvbqVLPbENI5x5elsZGLyBMkQYazc6gQK5/1onXKximFGZu6SWhOQZD++O69FYK T+mK9FLVte4w9Y9gl8GkanSQK0ikYDc5kNejI0KY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Andrew Morton , David Rientjes , Sasha Levin Subject: [PATCH AUTOSEL 4.20 42/81] relay: check return of create_buf_file() properly Date: Thu, 28 Feb 2019 10:07:34 -0500 Message-Id: <20190228150813.10256-42-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190228150813.10256-1-sashal@kernel.org> References: <20190228150813.10256-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Greg Kroah-Hartman [ Upstream commit 2c1cf00eeacb784781cf1c9896b8af001246d339 ] If create_buf_file() returns an error, don't try to reference it later as a valid dentry pointer. This problem was exposed when debugfs started to return errors instead of just NULL for some calls when they do not succeed properly. Also, the check for WARN_ON(dentry) was just wrong :) Reported-by: Kees Cook Reported-and-tested-by: syzbot+16c3a70e1e9b29346c43@syzkaller.appspotmail.com Reported-by: Tetsuo Handa Cc: Andrew Morton Cc: David Rientjes Fixes: ff9fb72bc077 ("debugfs: return error values, not NULL") Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- kernel/relay.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/relay.c b/kernel/relay.c index 04f248644e065..9e0f52375487d 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -428,6 +428,8 @@ static struct dentry *relay_create_buf_file(struct rchan *chan, dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, buf, &chan->is_global); + if (IS_ERR(dentry)) + dentry = NULL; kfree(tmpname); @@ -461,7 +463,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) dentry = chan->cb->create_buf_file(NULL, NULL, S_IRUSR, buf, &chan->is_global); - if (WARN_ON(dentry)) + if (IS_ERR_OR_NULL(dentry)) goto free_buf; } -- 2.19.1