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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dn_rtmsg.c (3650B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * DECnet       An implementation of the DECnet protocol suite for the LINUX
      4 *              operating system.  DECnet is implemented using the  BSD Socket
      5 *              interface as the means of communication with the user level.
      6 *
      7 *              DECnet Routing Message Grabulator
      8 *
      9 *              (C) 2000 ChyGwyn Limited  -  https://www.chygwyn.com/
     10 *
     11 * Author:      Steven Whitehouse <steve@chygwyn.com>
     12 */
     13#include <linux/module.h>
     14#include <linux/skbuff.h>
     15#include <linux/slab.h>
     16#include <linux/init.h>
     17#include <linux/netdevice.h>
     18#include <linux/netfilter.h>
     19#include <linux/spinlock.h>
     20#include <net/netlink.h>
     21#include <linux/netfilter_decnet.h>
     22
     23#include <net/sock.h>
     24#include <net/flow.h>
     25#include <net/dn.h>
     26#include <net/dn_route.h>
     27
     28static struct sock *dnrmg = NULL;
     29
     30
     31static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp)
     32{
     33	struct sk_buff *skb = NULL;
     34	size_t size;
     35	sk_buff_data_t old_tail;
     36	struct nlmsghdr *nlh;
     37	unsigned char *ptr;
     38	struct nf_dn_rtmsg *rtm;
     39
     40	size = NLMSG_ALIGN(rt_skb->len) +
     41	       NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
     42	skb = nlmsg_new(size, GFP_ATOMIC);
     43	if (!skb) {
     44		*errp = -ENOMEM;
     45		return NULL;
     46	}
     47	old_tail = skb->tail;
     48	nlh = nlmsg_put(skb, 0, 0, 0, size, 0);
     49	if (!nlh) {
     50		kfree_skb(skb);
     51		*errp = -ENOMEM;
     52		return NULL;
     53	}
     54	rtm = (struct nf_dn_rtmsg *)nlmsg_data(nlh);
     55	rtm->nfdn_ifindex = rt_skb->dev->ifindex;
     56	ptr = NFDN_RTMSG(rtm);
     57	skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
     58	nlh->nlmsg_len = skb->tail - old_tail;
     59	return skb;
     60}
     61
     62static void dnrmg_send_peer(struct sk_buff *skb)
     63{
     64	struct sk_buff *skb2;
     65	int status = 0;
     66	int group = 0;
     67	unsigned char flags = *skb->data;
     68
     69	switch (flags & DN_RT_CNTL_MSK) {
     70	case DN_RT_PKT_L1RT:
     71		group = DNRNG_NLGRP_L1;
     72		break;
     73	case DN_RT_PKT_L2RT:
     74		group = DNRNG_NLGRP_L2;
     75		break;
     76	default:
     77		return;
     78	}
     79
     80	skb2 = dnrmg_build_message(skb, &status);
     81	if (skb2 == NULL)
     82		return;
     83	NETLINK_CB(skb2).dst_group = group;
     84	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
     85}
     86
     87
     88static unsigned int dnrmg_hook(void *priv,
     89			struct sk_buff *skb,
     90			const struct nf_hook_state *state)
     91{
     92	dnrmg_send_peer(skb);
     93	return NF_ACCEPT;
     94}
     95
     96
     97#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err), NULL); return; } while (0)
     98
     99static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
    100{
    101	struct nlmsghdr *nlh = nlmsg_hdr(skb);
    102
    103	if (skb->len < sizeof(*nlh) ||
    104	    nlh->nlmsg_len < sizeof(*nlh) ||
    105	    skb->len < nlh->nlmsg_len)
    106		return;
    107
    108	if (!netlink_capable(skb, CAP_NET_ADMIN))
    109		RCV_SKB_FAIL(-EPERM);
    110
    111	/* Eventually we might send routing messages too */
    112
    113	RCV_SKB_FAIL(-EINVAL);
    114}
    115
    116static const struct nf_hook_ops dnrmg_ops = {
    117	.hook		= dnrmg_hook,
    118	.pf		= NFPROTO_DECNET,
    119	.hooknum	= NF_DN_ROUTE,
    120	.priority	= NF_DN_PRI_DNRTMSG,
    121};
    122
    123static int __init dn_rtmsg_init(void)
    124{
    125	int rv = 0;
    126	struct netlink_kernel_cfg cfg = {
    127		.groups	= DNRNG_NLGRP_MAX,
    128		.input	= dnrmg_receive_user_skb,
    129	};
    130
    131	dnrmg = netlink_kernel_create(&init_net, NETLINK_DNRTMSG, &cfg);
    132	if (dnrmg == NULL) {
    133		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
    134		return -ENOMEM;
    135	}
    136
    137	rv = nf_register_net_hook(&init_net, &dnrmg_ops);
    138	if (rv) {
    139		netlink_kernel_release(dnrmg);
    140	}
    141
    142	return rv;
    143}
    144
    145static void __exit dn_rtmsg_fini(void)
    146{
    147	nf_unregister_net_hook(&init_net, &dnrmg_ops);
    148	netlink_kernel_release(dnrmg);
    149}
    150
    151
    152MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
    153MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
    154MODULE_LICENSE("GPL");
    155MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
    156
    157module_init(dn_rtmsg_init);
    158module_exit(dn_rtmsg_fini);