From: Prasad J Pandit When processing remote NDIS control message packets, the USB Net device emulator uses a fixed length(4096) data buffer. The incoming informationBufferOffset & Length combination could overflow and cross that range. Check control message buffer offsets and length to avoid it. Reported-by: Qinghao Tang Signed-off-by: Prasad J Pandit --- hw/usb/dev-network.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) Update as per review -> https://lists.gnu.org/archive/html/qemu-devel/2016-02/msg03475.html diff --git a/hw/usb/dev-network.c b/hw/usb/dev-network.c index 8a4ff49..180adce 100644 --- a/tools/qemu-xen/hw/usb/dev-network.c +++ b/tools/qemu-xen/hw/usb/dev-network.c @@ -915,8 +915,9 @@ static int rndis_query_response(USBNetState *s, bufoffs = le32_to_cpu(buf->InformationBufferOffset) + 8; buflen = le32_to_cpu(buf->InformationBufferLength); - if (bufoffs + buflen > length) + if (buflen > length || bufoffs >= length || bufoffs + buflen > length) { return USB_RET_STALL; + } infobuflen = ndis_query(s, le32_to_cpu(buf->OID), bufoffs + (uint8_t *) buf, buflen, infobuf, @@ -961,8 +962,9 @@ static int rndis_set_response(USBNetState *s, bufoffs = le32_to_cpu(buf->InformationBufferOffset) + 8; buflen = le32_to_cpu(buf->InformationBufferLength); - if (bufoffs + buflen > length) + if (buflen > length || bufoffs >= length || bufoffs + buflen > length) { return USB_RET_STALL; + } ret = ndis_set(s, le32_to_cpu(buf->OID), bufoffs + (uint8_t *) buf, buflen); @@ -1212,8 +1214,9 @@ static void usb_net_handle_dataout(USBNetState *s, USBPacket *p) if (le32_to_cpu(msg->MessageType) == RNDIS_PACKET_MSG) { uint32_t offs = 8 + le32_to_cpu(msg->DataOffset); uint32_t size = le32_to_cpu(msg->DataLength); - if (offs + size <= len) + if (offs < len && size < len && offs + size <= len) { qemu_send_packet(qemu_get_queue(s->nic), s->out_buf + offs, size); + } } s->out_ptr -= len; memmove(s->out_buf, &s->out_buf[len], s->out_ptr); -- 2.5.0