Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754104AbcDVLJJ (ORCPT ); Fri, 22 Apr 2016 07:09:09 -0400 Received: from mx2.suse.de ([195.135.220.15]:44217 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753839AbcDVLGh (ORCPT ); Fri, 22 Apr 2016 07:06:37 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ignat Korchagin , Greg Kroah-Hartman , Jiri Slaby Subject: [PATCH 3.12 71/78] USB: usbip: fix potential out-of-bounds write Date: Fri, 22 Apr 2016 13:05:54 +0200 Message-Id: <21f8cf65e09a5fd3a606b7f5c143787256bf9ff0.1461323133.git.jslaby@suse.cz> X-Mailer: git-send-email 2.8.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1811 Lines: 48 From: Ignat Korchagin 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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 Signed-off-by: Jiri Slaby --- drivers/staging/usbip/usbip_common.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/staging/usbip/usbip_common.c b/drivers/staging/usbip/usbip_common.c index e3fc749c1e7e..15aeb41f7c84 100644 --- a/drivers/staging/usbip/usbip_common.c +++ b/drivers/staging/usbip/usbip_common.c @@ -785,6 +785,17 @@ 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); -- 2.8.1