From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751501AbcEIT4k (ORCPT ); Mon, 9 May 2016 15:56:40 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54678 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbcEIT4i (ORCPT ); Mon, 9 May 2016 15:56:38 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ignat Korchagin , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 02/59] USB: usbip: fix potential out-of-bounds write Date: Mon, 9 May 2016 12:55:20 -0700 Message-Id: <1462823777-8384-3-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1462823777-8384-1-git-send-email-kamal@canonical.com> References: <1462823777-8384-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt10 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Ignat Korchagin commit b348d7dddb6c4fbfc810b7a0626e8ec9e29f7cbb upstream. Fix potential out-of-bounds write to urb->transfer_buffer usbip handles network communication directly in the kernel. When receiving a packet from its peer, usbip code parses headers according to protocol. As part of this parsing urb->actual_length is filled. Since the input for urb->actual_length comes from the network, it should be treated as untrusted. Any entity controlling the network may put any value in the input and the preallocated urb->transfer_buffer may not be large enough to hold the data. Thus, the malicious entity is able to write arbitrary data to kernel memory. Signed-off-by: Ignat Korchagin Signed-off-by: Greg Kroah-Hartman Reference: CVE-2016-3955 Signed-off-by: Kamal Mostafa --- drivers/usb/usbip/usbip_common.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c index facaaf0..e40da77 100644 --- a/drivers/usb/usbip/usbip_common.c +++ b/drivers/usb/usbip/usbip_common.c @@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb) if (!(size > 0)) return 0; + if (size > urb->transfer_buffer_length) { + /* should not happen, probably malicious packet */ + if (ud->side == USBIP_STUB) { + usbip_event_add(ud, SDEV_EVENT_ERROR_TCP); + return 0; + } else { + usbip_event_add(ud, VDEV_EVENT_ERROR_TCP); + return -EPIPE; + } + } + ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size); if (ret != size) { dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret); -- 2.7.4