Commit 7679a59d authored by Ignat Korchagin's avatar Ignat Korchagin Committed by Kamal Mostafa

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

commit b348d7dd 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: default avatarIgnat Korchagin <ignat.korchagin@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reference: CVE-2016-3955
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
parent 861d04db
...@@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb) ...@@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
if (!(size > 0)) if (!(size > 0))
return 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); ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
if (ret != size) { if (ret != size) {
dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret); dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
......
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