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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xt_bpf.c (3729B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Xtables module to match packets using a BPF filter.
      3 * Copyright 2013 Google Inc.
      4 * Written by Willem de Bruijn <willemb@google.com>
      5 */
      6
      7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      8
      9#include <linux/module.h>
     10#include <linux/syscalls.h>
     11#include <linux/skbuff.h>
     12#include <linux/filter.h>
     13#include <linux/bpf.h>
     14
     15#include <linux/netfilter/xt_bpf.h>
     16#include <linux/netfilter/x_tables.h>
     17
     18MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
     19MODULE_DESCRIPTION("Xtables: BPF filter match");
     20MODULE_LICENSE("GPL");
     21MODULE_ALIAS("ipt_bpf");
     22MODULE_ALIAS("ip6t_bpf");
     23
     24static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
     25				   struct bpf_prog **ret)
     26{
     27	struct sock_fprog_kern program;
     28
     29	if (len > XT_BPF_MAX_NUM_INSTR)
     30		return -EINVAL;
     31
     32	program.len = len;
     33	program.filter = insns;
     34
     35	if (bpf_prog_create(ret, &program)) {
     36		pr_info_ratelimited("check failed: parse error\n");
     37		return -EINVAL;
     38	}
     39
     40	return 0;
     41}
     42
     43static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
     44{
     45	struct bpf_prog *prog;
     46
     47	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
     48	if (IS_ERR(prog))
     49		return PTR_ERR(prog);
     50
     51	*ret = prog;
     52	return 0;
     53}
     54
     55static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
     56{
     57	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
     58		return -EINVAL;
     59
     60	*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
     61	return PTR_ERR_OR_ZERO(*ret);
     62}
     63
     64static int bpf_mt_check(const struct xt_mtchk_param *par)
     65{
     66	struct xt_bpf_info *info = par->matchinfo;
     67
     68	return __bpf_mt_check_bytecode(info->bpf_program,
     69				       info->bpf_program_num_elem,
     70				       &info->filter);
     71}
     72
     73static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
     74{
     75	struct xt_bpf_info_v1 *info = par->matchinfo;
     76
     77	if (info->mode == XT_BPF_MODE_BYTECODE)
     78		return __bpf_mt_check_bytecode(info->bpf_program,
     79					       info->bpf_program_num_elem,
     80					       &info->filter);
     81	else if (info->mode == XT_BPF_MODE_FD_ELF)
     82		return __bpf_mt_check_fd(info->fd, &info->filter);
     83	else if (info->mode == XT_BPF_MODE_PATH_PINNED)
     84		return __bpf_mt_check_path(info->path, &info->filter);
     85	else
     86		return -EINVAL;
     87}
     88
     89static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
     90{
     91	const struct xt_bpf_info *info = par->matchinfo;
     92
     93	return bpf_prog_run(info->filter, skb);
     94}
     95
     96static bool bpf_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
     97{
     98	const struct xt_bpf_info_v1 *info = par->matchinfo;
     99
    100	return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
    101}
    102
    103static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
    104{
    105	const struct xt_bpf_info *info = par->matchinfo;
    106
    107	bpf_prog_destroy(info->filter);
    108}
    109
    110static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
    111{
    112	const struct xt_bpf_info_v1 *info = par->matchinfo;
    113
    114	bpf_prog_destroy(info->filter);
    115}
    116
    117static struct xt_match bpf_mt_reg[] __read_mostly = {
    118	{
    119		.name		= "bpf",
    120		.revision	= 0,
    121		.family		= NFPROTO_UNSPEC,
    122		.checkentry	= bpf_mt_check,
    123		.match		= bpf_mt,
    124		.destroy	= bpf_mt_destroy,
    125		.matchsize	= sizeof(struct xt_bpf_info),
    126		.usersize	= offsetof(struct xt_bpf_info, filter),
    127		.me		= THIS_MODULE,
    128	},
    129	{
    130		.name		= "bpf",
    131		.revision	= 1,
    132		.family		= NFPROTO_UNSPEC,
    133		.checkentry	= bpf_mt_check_v1,
    134		.match		= bpf_mt_v1,
    135		.destroy	= bpf_mt_destroy_v1,
    136		.matchsize	= sizeof(struct xt_bpf_info_v1),
    137		.usersize	= offsetof(struct xt_bpf_info_v1, filter),
    138		.me		= THIS_MODULE,
    139	},
    140};
    141
    142static int __init bpf_mt_init(void)
    143{
    144	return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
    145}
    146
    147static void __exit bpf_mt_exit(void)
    148{
    149	xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
    150}
    151
    152module_init(bpf_mt_init);
    153module_exit(bpf_mt_exit);