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,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,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 9FCD0C43381 for ; Mon, 18 Feb 2019 14:03:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 712762173C for ; Mon, 18 Feb 2019 14:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498608; bh=7C9Vy6nGxguIIQzZwvbVXwS4zFzaBy7WJXrVmMHhNtg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Oym6O82REFgsjbaU/a2XH3GzB77CIJwY7FofJdz3bDb+eqZwIAxXW/8HnxtaX4V6t T2EKZSZxM1KXqg5nSjyRB5eib8eF6gVBoEfvRaBBgI0JSqKjqsNUpuHNTPDUWQ8pDy vP5JhFHrw2IPHUsxIcs+6u+xb4Em8E02xWsDOe1c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389690AbfBROD1 (ORCPT ); Mon, 18 Feb 2019 09:03:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:45300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388728AbfBRODV (ORCPT ); Mon, 18 Feb 2019 09:03:21 -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 4EA7321904; Mon, 18 Feb 2019 14:03:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498600; bh=7C9Vy6nGxguIIQzZwvbVXwS4zFzaBy7WJXrVmMHhNtg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hvFLYFLbLtP5c2NdlsOG/uo62Xt4VTmjfvyhaUp200hw1ngQoyh+9g6+RKdlZjhwc Efx3es9zsmzW/a61v0hg5tupNLa9NpcoUUHQTMXkU1RaSnc2Y7Lj1HfgrO2CXThZKK Bf5lZjjFWe+iLhiGjB9JJlcb0dmpKA3yNYzYhmIk= 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 4.4 061/143] cifs: check ntwrk_buf_start for NULL before dereferencing it Date: Mon, 18 Feb 2019 14:43:09 +0100 Message-Id: <20190218133531.336795448@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133529.099444112@linuxfoundation.org> References: <20190218133529.099444112@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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-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 57b039ebfb1f..43fa471c88d7 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -652,7 +652,14 @@ 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