Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754009AbcD0AVy (ORCPT ); Tue, 26 Apr 2016 20:21:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39984 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753901AbcDZXNv (ORCPT ); Tue, 26 Apr 2016 19:13:51 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "Ignat Korchagin" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 184/217] USB: usbip: fix potential out-of-bounds write In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1704 Lines: 45 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings --- drivers/staging/usbip/usbip_common.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/staging/usbip/usbip_common.c +++ b/drivers/staging/usbip/usbip_common.c @@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device 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);