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=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 7BA1BC169C4 for ; Thu, 31 Jan 2019 12:46:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 561AE218D3 for ; Thu, 31 Jan 2019 12:46:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733254AbfAaMqO (ORCPT ); Thu, 31 Jan 2019 07:46:14 -0500 Received: from mx2.suse.de ([195.135.220.15]:46664 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732733AbfAaMqO (ORCPT ); Thu, 31 Jan 2019 07:46:14 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6B51BAC4B; Thu, 31 Jan 2019 12:46:13 +0000 (UTC) From: Aurelien Aptel To: linux-cifs@vger.kernel.org Cc: smfrench@gmail.com, Aurelien Aptel , stable@vger.kernel.org Subject: [PATCH] CIFS: fix use-after-free of the lease keys Date: Thu, 31 Jan 2019 13:46:07 +0100 Message-Id: <20190131124607.2458-1-aaptel@suse.com> X-Mailer: git-send-email 2.16.4 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The request buffers are freed right before copying the pointers. Use the func args instead which are identical and still valid. Simple reproducer (requires KASAN enabled) on a cifs mount: echo foo > foo ; tail -f foo & rm foo Cc: # 4.20 Fixes: 179e44d49c2f ("smb3: add tracepoint for sending lease break responses to server") Signed-off-by: Aurelien Aptel --- fs/cifs/smb2pdu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 846e605175bf..54181387a770 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -4435,8 +4435,8 @@ SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon, rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov); cifs_small_buf_release(req); - please_key_low = (__u64 *)req->LeaseKey; - please_key_high = (__u64 *)(req->LeaseKey+8); + please_key_low = (__u64 *)lease_key; + please_key_high = (__u64 *)(lease_key+8); if (rc) { cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE); trace_smb3_lease_err(le32_to_cpu(lease_state), tcon->tid, -- 2.16.4