@@ -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);
This is a note to let you know that I have just added a patch titled USB: usbip: fix potential out-of-bounds write to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt10. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 7679a59d1f2269fb08f5cadd6e9e20ff63e29eb7 Mon Sep 17 00:00:00 2001 From: Ignat Korchagin <ignat.korchagin@gmail.com> Date: Thu, 17 Mar 2016 18:00:29 +0000 Subject: USB: usbip: fix potential out-of-bounds write 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 <ignat.korchagin@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reference: CVE-2016-3955 Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/usb/usbip/usbip_common.c | 11 +++++++++++ 1 file changed, 11 insertions(+) -- 2.7.4