From: Ignat Korchagin <[email protected]> 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 <[email protected]> Cc: Sasha Levin <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Willy Tarreau <[email protected]> --- 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 7b97df6..b4f237e 100644 --- a/drivers/staging/usbip/usbip_common.c +++ b/drivers/staging/usbip/usbip_common.c @@ -784,6 +784,17 @@ 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); -- 2.8.0.rc2.1.gbe9624a
