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,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 2788CC43381 for ; Thu, 28 Feb 2019 15:25:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D10DB2184A for ; Thu, 28 Feb 2019 15:25:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551367504; bh=Y7heQ6sGPC7qDyM2CpigzX2e8ntRSCTu7au0f8DSAyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jT1O+QdSXCqnemn4Vj0aJIWSkopPjrD6pBikFrxhVcNOryBgj2LChHC/GglrB326L qUX/WQdCjCCOKW5OxY7YPDheiSCYNkjTOiuU2RQgoUwlRYaeDt/z2EPW1R26knSCdT rmjMZaw/7r66bmfawFOWIvEqMNkbbyTaGlLnmP98= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389086AbfB1PZC (ORCPT ); Thu, 28 Feb 2019 10:25:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:45600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388195AbfB1PMN (ORCPT ); Thu, 28 Feb 2019 10:12:13 -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 28AB4218C3; Thu, 28 Feb 2019 15:12:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551366732; bh=Y7heQ6sGPC7qDyM2CpigzX2e8ntRSCTu7au0f8DSAyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wqbMTAIQ92+nX20fU7Y6SPbYmiGHxyEpi2TUAcQa3d2zzVSQoIvBYpIE04Rj5PunC Ztvh4LOtiGBPl8tsUztDKVtaIKGgh2P7wekqcZQGkHDl2/G2uJ84UgUHoWJH6/rhPo Aab5Nt44y3c4ZBDOd6IZsYYXmK8uSoylvnEefcDw= 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 4.19 33/64] relay: check return of create_buf_file() properly Date: Thu, 28 Feb 2019 10:10:34 -0500 Message-Id: <20190228151105.11277-33-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190228151105.11277-1-sashal@kernel.org> References: <20190228151105.11277-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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