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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sysctl.c (2204B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * File: sysctl.c
      4 *
      5 * Phonet /proc/sys/net/phonet interface implementation
      6 *
      7 * Copyright (C) 2008 Nokia Corporation.
      8 *
      9 * Author: Rémi Denis-Courmont
     10 */
     11
     12#include <linux/seqlock.h>
     13#include <linux/sysctl.h>
     14#include <linux/errno.h>
     15#include <linux/init.h>
     16
     17#include <net/sock.h>
     18#include <linux/phonet.h>
     19#include <net/phonet/phonet.h>
     20
     21#define DYNAMIC_PORT_MIN	0x40
     22#define DYNAMIC_PORT_MAX	0x7f
     23
     24static DEFINE_SEQLOCK(local_port_range_lock);
     25static int local_port_range_min[2] = {0, 0};
     26static int local_port_range_max[2] = {1023, 1023};
     27static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
     28static struct ctl_table_header *phonet_table_hrd;
     29
     30static void set_local_port_range(int range[2])
     31{
     32	write_seqlock(&local_port_range_lock);
     33	local_port_range[0] = range[0];
     34	local_port_range[1] = range[1];
     35	write_sequnlock(&local_port_range_lock);
     36}
     37
     38void phonet_get_local_port_range(int *min, int *max)
     39{
     40	unsigned int seq;
     41
     42	do {
     43		seq = read_seqbegin(&local_port_range_lock);
     44		if (min)
     45			*min = local_port_range[0];
     46		if (max)
     47			*max = local_port_range[1];
     48	} while (read_seqretry(&local_port_range_lock, seq));
     49}
     50
     51static int proc_local_port_range(struct ctl_table *table, int write,
     52				 void *buffer, size_t *lenp, loff_t *ppos)
     53{
     54	int ret;
     55	int range[2] = {local_port_range[0], local_port_range[1]};
     56	struct ctl_table tmp = {
     57		.data = &range,
     58		.maxlen = sizeof(range),
     59		.mode = table->mode,
     60		.extra1 = &local_port_range_min,
     61		.extra2 = &local_port_range_max,
     62	};
     63
     64	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
     65
     66	if (write && ret == 0) {
     67		if (range[1] < range[0])
     68			ret = -EINVAL;
     69		else
     70			set_local_port_range(range);
     71	}
     72
     73	return ret;
     74}
     75
     76static struct ctl_table phonet_table[] = {
     77	{
     78		.procname	= "local_port_range",
     79		.data		= &local_port_range,
     80		.maxlen		= sizeof(local_port_range),
     81		.mode		= 0644,
     82		.proc_handler	= proc_local_port_range,
     83	},
     84	{ }
     85};
     86
     87int __init phonet_sysctl_init(void)
     88{
     89	phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
     90	return phonet_table_hrd == NULL ? -ENOMEM : 0;
     91}
     92
     93void phonet_sysctl_exit(void)
     94{
     95	unregister_net_sysctl_table(phonet_table_hrd);
     96}