From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754896AbbJ0WOv (ORCPT ); Tue, 27 Oct 2015 18:14:51 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34740 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753794AbbJ0Van (ORCPT ); Tue, 27 Oct 2015 17:30:43 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jann Horn , Steve French , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 09/86] CIFS: fix type confusion in copy offload ioctl Date: Tue, 27 Oct 2015 14:29:09 -0700 Message-Id: <1445981426-19727-10-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1445981426-19727-1-git-send-email-kamal@canonical.com> References: <1445981426-19727-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit 4c17a6d56bb0cad3066a714e94f7185a24b40f49 upstream. This might lead to local privilege escalation (code execution as kernel) for systems where the following conditions are met: - CONFIG_CIFS_SMB2 and CONFIG_CIFS_POSIX are enabled - a cifs filesystem is mounted where: - the mount option "vers" was used and set to a value >=2.0 - the attacker has write access to at least one file on the filesystem To attack this, an attacker would have to guess the target_tcon pointer (but guessing wrong doesn't cause a crash, it just returns an error code) and win a narrow race. Signed-off-by: Jann Horn Signed-off-by: Steve French Signed-off-by: Kamal Mostafa --- fs/cifs/ioctl.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c index 8b7898b..64a9bca 100644 --- a/fs/cifs/ioctl.c +++ b/fs/cifs/ioctl.c @@ -67,6 +67,12 @@ static long cifs_ioctl_clone(unsigned int xid, struct file *dst_file, goto out_drop_write; } + if (src_file.file->f_op->unlocked_ioctl != cifs_ioctl) { + rc = -EBADF; + cifs_dbg(VFS, "src file seems to be from a different filesystem type\n"); + goto out_fput; + } + if ((!src_file.file->private_data) || (!dst_file->private_data)) { rc = -EBADF; cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n"); -- 1.9.1