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USB: usbip: fix potential out-of-bounds write

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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>
This commit is contained in:
Ignat Korchagin 2016-03-17 18:00:29 +00:00 committed by Greg Kroah-Hartman
parent 8ef34aa5a1
commit b348d7dddb
1 changed files with 11 additions and 0 deletions
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11
drivers/usb/usbip/usbip_common.c
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@ -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);