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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 17A3AC282CE for ; Mon, 11 Feb 2019 15:25:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFF2C21B1A for ; Mon, 11 Feb 2019 15:25:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549898752; bh=nFNLTX0R5C+smZTDbQBKQ6nW982cDG4l+SCvVBFbLL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FGcxlNDapuP6YeLEvOlfIgbhuli4TzJxr6ocbgCCAIQfIMVUgbIx4HtJcRSTpO9Mf pP4xuv8Foz+CGen3SlSd4NFxRV3WRj6Y0iHDaUm2dXyR1gs5puYDwred04LWjE3OjE H6ElDSQGd4UWPHYOMuqDJ9eQ0oYgliU/4hBMa1MM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389471AbfBKPBC (ORCPT ); Mon, 11 Feb 2019 10:01:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:48956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390097AbfBKPA7 (ORCPT ); Mon, 11 Feb 2019 10:00:59 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (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 91220222A4; Mon, 11 Feb 2019 15:00:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549897259; bh=nFNLTX0R5C+smZTDbQBKQ6nW982cDG4l+SCvVBFbLL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E+OnUAs6BnPvCtllFe/Zr2n48t273jE70WVm/Mk/DqLU3mESoBai6drY/VJWTe/C7 AMPMg2RFlSJTmg4IiQPHubOuztQKJvIm+Yi34RvMM1QpsU6Xpi3dnOtg0V4PJHicpt EyZF1bsfkLhMsug6y9wCWmMO2vI8uvYBrHB7x6Iw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ronnie Sahlberg , Steve French , Sasha Levin Subject: [PATCH 4.14 142/205] cifs: check ntwrk_buf_start for NULL before dereferencing it Date: Mon, 11 Feb 2019 15:19:00 +0100 Message-Id: <20190211141837.664712281@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141827.214852402@linuxfoundation.org> References: <20190211141827.214852402@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 59a63e479ce36a3f24444c3a36efe82b78e4a8e0 ] RHBZ: 1021460 There is an issue where when multiple threads open/close the same directory ntwrk_buf_start might end up being NULL, causing the call to smbCalcSize later to oops with a NULL deref. The real bug is why this happens and why this can become NULL for an open cfile, which should not be allowed. This patch tries to avoid a oops until the time when we fix the underlying issue. Signed-off-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/readdir.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c index ef24b4527459..68183872bf8b 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -655,7 +655,14 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos, /* scan and find it */ int i; char *cur_ent; - char *end_of_smb = cfile->srch_inf.ntwrk_buf_start + + char *end_of_smb; + + if (cfile->srch_inf.ntwrk_buf_start == NULL) { + cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n"); + return -EIO; + } + + end_of_smb = cfile->srch_inf.ntwrk_buf_start + server->ops->calc_smb_size( cfile->srch_inf.ntwrk_buf_start); -- 2.19.1