usbnet: ipheth: check that DPE points past NCM header

commit 429fa68b58cefb9aa9de27e4089637298b46b757 upstream.

By definition, a DPE points at the start of a network frame/datagram.
Thus it makes no sense for it to point at anything that's part of the
NCM header. It is not a security issue, but merely an indication of
a malformed DPE.

Enforce that all DPEs point at the data portion of the URB, past the
NCM header.

Fixes: a2d274c62e ("usbnet: ipheth: add CDC NCM support")
Cc: stable@vger.kernel.org
Signed-off-by: Foster Snowhill <forst@pen.gy>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Foster Snowhill
2025-01-26 00:54:04 +01:00
committed by Greg Kroah-Hartman
parent cf1ac7f7cf
commit 387ec9277a
+2 -1
View File
@@ -241,7 +241,8 @@ static int ipheth_rcvbulk_callback_ncm(struct urb *urb)
dpe = ncm0->dpe16;
while (le16_to_cpu(dpe->wDatagramIndex) != 0 &&
le16_to_cpu(dpe->wDatagramLength) != 0) {
if (le16_to_cpu(dpe->wDatagramIndex) >= urb->actual_length ||
if (le16_to_cpu(dpe->wDatagramIndex) < IPHETH_NCM_HEADER_SIZE ||
le16_to_cpu(dpe->wDatagramIndex) >= urb->actual_length ||
le16_to_cpu(dpe->wDatagramLength) > urb->actual_length -
le16_to_cpu(dpe->wDatagramIndex)) {
dev->net->stats.rx_length_errors++;