GeoVision GV-I/O Box DVRSearch buffer overflow vulnerabilities in CMD_IP_SET command

GV-I/O Box 4E is a smart embedded device with 4 input and 4 relays output that can be controlled over Ethernet and RS-485.

DVRSearch is a service running by default on the IOBox listening for UDP messages on port 10001. Any user on the network can send messages to this service and interact with it.

Upon receiving a UDP message, the server reads at most 1460 bytes into a local buffer and a pointer to the buffer is stored in a global variable:

#### Net Mask field stack overflow

The following code is vulnerable to a stack overflow that is attacker-controlled:

v6 = strlen(g_network_config->net_mask);

memcpy(&reply_buf[184], g_network_config->net_mask, v6);