cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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test_blackhole_dev.c (2585B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * This module tests the blackhole_dev that is created during the
      4 * net subsystem initialization. The test this module performs is
      5 * by injecting an skb into the stack with skb->dev as the
      6 * blackhole_dev and expects kernel to behave in a sane manner
      7 * (in other words, *not crash*)!
      8 *
      9 * Copyright (c) 2018, Mahesh Bandewar <maheshb@google.com>
     10 */
     11
     12#include <linux/init.h>
     13#include <linux/module.h>
     14#include <linux/printk.h>
     15#include <linux/skbuff.h>
     16#include <linux/netdevice.h>
     17#include <linux/udp.h>
     18#include <linux/ipv6.h>
     19
     20#include <net/dst.h>
     21
     22#define SKB_SIZE  256
     23#define HEAD_SIZE (14+40+8)	/* Ether + IPv6 + UDP */
     24#define TAIL_SIZE 32		/* random tail-room */
     25
     26#define UDP_PORT 1234
     27
     28static int __init test_blackholedev_init(void)
     29{
     30	struct ipv6hdr *ip6h;
     31	struct sk_buff *skb;
     32	struct ethhdr *ethh;
     33	struct udphdr *uh;
     34	int data_len;
     35	int ret;
     36
     37	skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
     38	if (!skb)
     39		return -ENOMEM;
     40
     41	/* Reserve head-room for the headers */
     42	skb_reserve(skb, HEAD_SIZE);
     43
     44	/* Add data to the skb */
     45	data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);
     46	memset(__skb_put(skb, data_len), 0xf, data_len);
     47
     48	/* Add protocol data */
     49	/* (Transport) UDP */
     50	uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));
     51	skb_set_transport_header(skb, 0);
     52	uh->source = uh->dest = htons(UDP_PORT);
     53	uh->len = htons(data_len);
     54	uh->check = 0;
     55	/* (Network) IPv6 */
     56	ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));
     57	skb_set_network_header(skb, 0);
     58	ip6h->hop_limit = 32;
     59	ip6h->payload_len = data_len + sizeof(struct udphdr);
     60	ip6h->nexthdr = IPPROTO_UDP;
     61	ip6h->saddr = in6addr_loopback;
     62	ip6h->daddr = in6addr_loopback;
     63	/* Ether */
     64	ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
     65	skb_set_mac_header(skb, 0);
     66
     67	skb->protocol = htons(ETH_P_IPV6);
     68	skb->pkt_type = PACKET_HOST;
     69	skb->dev = blackhole_netdev;
     70
     71	/* Now attempt to send the packet */
     72	ret = dev_queue_xmit(skb);
     73
     74	switch (ret) {
     75	case NET_XMIT_SUCCESS:
     76		pr_warn("dev_queue_xmit() returned NET_XMIT_SUCCESS\n");
     77		break;
     78	case NET_XMIT_DROP:
     79		pr_warn("dev_queue_xmit() returned NET_XMIT_DROP\n");
     80		break;
     81	case NET_XMIT_CN:
     82		pr_warn("dev_queue_xmit() returned NET_XMIT_CN\n");
     83		break;
     84	default:
     85		pr_err("dev_queue_xmit() returned UNKNOWN(%d)\n", ret);
     86	}
     87
     88	return 0;
     89}
     90
     91static void __exit test_blackholedev_exit(void)
     92{
     93	pr_warn("test_blackholedev module terminating.\n");
     94}
     95
     96module_init(test_blackholedev_init);
     97module_exit(test_blackholedev_exit);
     98
     99MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");
    100MODULE_LICENSE("GPL");