[mirror_ubuntu-bionic-kernel.git] / net / netfilter / xt_bpf.c

/* Xtables module to match packets using a BPF filter.
 * Copyright 2013 Google Inc.
 * Written by Willem de Bruijn <willemb@google.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/bpf.h>

#include <linux/netfilter/xt_bpf.h>
#include <linux/netfilter/x_tables.h>

MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
MODULE_DESCRIPTION("Xtables: BPF filter match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_bpf");
MODULE_ALIAS("ip6t_bpf");

static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
				   struct bpf_prog **ret)
{
	struct sock_fprog_kern program;

	if (len > XT_BPF_MAX_NUM_INSTR)
		return -EINVAL;

	program.len = len;
	program.filter = insns;

	if (bpf_prog_create(ret, &program)) {
		pr_info("bpf: check failed: parse error\n");
		return -EINVAL;
	}

	return 0;
}

static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
{
	struct bpf_prog *prog;

	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
	if (IS_ERR(prog))
		return PTR_ERR(prog);

	*ret = prog;
	return 0;
}

static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
{
	mm_segment_t oldfs = get_fs();
	int retval, fd;

	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
		return -EINVAL;

	set_fs(KERNEL_DS);
	fd = bpf_obj_get_user(path, 0);
	set_fs(oldfs);
	if (fd < 0)
		return fd;

	retval = __bpf_mt_check_fd(fd, ret);
	sys_close(fd);
	return retval;
}

static int bpf_mt_check(const struct xt_mtchk_param *par)
{
	struct xt_bpf_info *info = par->matchinfo;

	return __bpf_mt_check_bytecode(info->bpf_program,
				       info->bpf_program_num_elem,
				       &info->filter);
}

static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
{
	struct xt_bpf_info_v1 *info = par->matchinfo;

	if (info->mode == XT_BPF_MODE_BYTECODE)
		return __bpf_mt_check_bytecode(info->bpf_program,
					       info->bpf_program_num_elem,
					       &info->filter);
	else if (info->mode == XT_BPF_MODE_FD_ELF)
		return __bpf_mt_check_fd(info->fd, &info->filter);
	else if (info->mode == XT_BPF_MODE_PATH_PINNED)
		return __bpf_mt_check_path(info->path, &info->filter);
	else
		return -EINVAL;
}

static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_bpf_info *info = par->matchinfo;

	return BPF_PROG_RUN(info->filter, skb);
}

static bool bpf_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_bpf_info_v1 *info = par->matchinfo;

	return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
}

static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
{
	const struct xt_bpf_info *info = par->matchinfo;

	bpf_prog_destroy(info->filter);
}

static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
{
	const struct xt_bpf_info_v1 *info = par->matchinfo;

	bpf_prog_destroy(info->filter);
}

static struct xt_match bpf_mt_reg[] __read_mostly = {
	{
		.name		= "bpf",
		.revision	= 0,
		.family		= NFPROTO_UNSPEC,
		.checkentry	= bpf_mt_check,
		.match		= bpf_mt,
		.destroy	= bpf_mt_destroy,
		.matchsize	= sizeof(struct xt_bpf_info),
		.usersize	= offsetof(struct xt_bpf_info, filter),
		.me		= THIS_MODULE,
	},
	{
		.name		= "bpf",
		.revision	= 1,
		.family		= NFPROTO_UNSPEC,
		.checkentry	= bpf_mt_check_v1,
		.match		= bpf_mt_v1,
		.destroy	= bpf_mt_destroy_v1,
		.matchsize	= sizeof(struct xt_bpf_info_v1),
		.usersize	= offsetof(struct xt_bpf_info_v1, filter),
		.me		= THIS_MODULE,
	},
};

static int __init bpf_mt_init(void)
{
	return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
}

static void __exit bpf_mt_exit(void)
{
	xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
}

module_init(bpf_mt_init);
module_exit(bpf_mt_exit);
Commit	Line	Data
e6f30c73 WB	1	/* Xtables module to match packets using a BPF filter.
	2	* Copyright 2013 Google Inc.
	3	* Written by Willem de Bruijn <willemb@google.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/module.h>
98589a09	11	#include <linux/syscalls.h>
e6f30c73 WB	12	#include <linux/skbuff.h>
e6f30c73 WB	13	#include <linux/filter.h>
2c16d603	14	#include <linux/bpf.h>
e6f30c73 WB	15
	16	#include <linux/netfilter/xt_bpf.h>
	17	#include <linux/netfilter/x_tables.h>
	18
	19	MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
	20	MODULE_DESCRIPTION("Xtables: BPF filter match");
	21	MODULE_LICENSE("GPL");
	22	MODULE_ALIAS("ipt_bpf");
	23	MODULE_ALIAS("ip6t_bpf");
	24
2c16d603 WB	25	static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
2c16d603 WB	26	struct bpf_prog **ret)
e6f30c73	27	{
b1fcd35c	28	struct sock_fprog_kern program;
e6f30c73	29
6ab40511 JH	30	if (len > XT_BPF_MAX_NUM_INSTR)
	31	return -EINVAL;
	32
2c16d603 WB	33	program.len = len;
2c16d603 WB	34	program.filter = insns;
b1fcd35c	35
2c16d603	36	if (bpf_prog_create(ret, &program)) {
e6f30c73 WB	37	pr_info("bpf: check failed: parse error\n");
	38	return -EINVAL;
	39	}
	40
	41	return 0;
	42	}
	43
2c16d603 WB	44	static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
	45	{
	46	struct bpf_prog *prog;
	47
	48	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
	49	if (IS_ERR(prog))
	50	return PTR_ERR(prog);
	51
	52	*ret = prog;
	53	return 0;
	54	}
	55
98589a09 SL	56	static int __bpf_mt_check_path(const char path, struct bpf_prog *ret)
	57	{
	58	mm_segment_t oldfs = get_fs();
	59	int retval, fd;
	60
6ab40511 JH	61	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
	62	return -EINVAL;
	63
98589a09	64	set_fs(KERNEL_DS);
6e71b04a	65	fd = bpf_obj_get_user(path, 0);
98589a09 SL	66	set_fs(oldfs);
	67	if (fd < 0)
	68	return fd;
	69
	70	retval = __bpf_mt_check_fd(fd, ret);
	71	sys_close(fd);
	72	return retval;
	73	}
	74
2c16d603 WB	75	static int bpf_mt_check(const struct xt_mtchk_param *par)
	76	{
	77	struct xt_bpf_info *info = par->matchinfo;
	78
	79	return __bpf_mt_check_bytecode(info->bpf_program,
	80	info->bpf_program_num_elem,
	81	&info->filter);
	82	}
	83
	84	static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
	85	{
	86	struct xt_bpf_info_v1 *info = par->matchinfo;
	87
	88	if (info->mode == XT_BPF_MODE_BYTECODE)
	89	return __bpf_mt_check_bytecode(info->bpf_program,
	90	info->bpf_program_num_elem,
	91	&info->filter);
98589a09	92	else if (info->mode == XT_BPF_MODE_FD_ELF)
2c16d603	93	return __bpf_mt_check_fd(info->fd, &info->filter);
98589a09 SL	94	else if (info->mode == XT_BPF_MODE_PATH_PINNED)
98589a09 SL	95	return __bpf_mt_check_path(info->path, &info->filter);
2c16d603 WB	96	else
	97	return -EINVAL;
	98	}
	99
e6f30c73 WB	100	static bool bpf_mt(const struct sk_buff skb, struct xt_action_param par)
	101	{
	102	const struct xt_bpf_info *info = par->matchinfo;
	103
7ae457c1	104	return BPF_PROG_RUN(info->filter, skb);
e6f30c73 WB	105	}
e6f30c73 WB	106
2c16d603 WB	107	static bool bpf_mt_v1(const struct sk_buff skb, struct xt_action_param par)
	108	{
	109	const struct xt_bpf_info_v1 *info = par->matchinfo;
	110
	111	return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
	112	}
	113
e6f30c73 WB	114	static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
	115	{
	116	const struct xt_bpf_info *info = par->matchinfo;
2c16d603 WB	117
	118	bpf_prog_destroy(info->filter);
	119	}
	120
	121	static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
	122	{
	123	const struct xt_bpf_info_v1 *info = par->matchinfo;
	124
7ae457c1	125	bpf_prog_destroy(info->filter);
e6f30c73 WB	126	}
e6f30c73 WB	127
2c16d603 WB	128	static struct xt_match bpf_mt_reg[] __read_mostly = {
	129	{
	130	.name = "bpf",
	131	.revision = 0,
	132	.family = NFPROTO_UNSPEC,
	133	.checkentry = bpf_mt_check,
	134	.match = bpf_mt,
	135	.destroy = bpf_mt_destroy,
	136	.matchsize = sizeof(struct xt_bpf_info),
ec231890	137	.usersize = offsetof(struct xt_bpf_info, filter),
2c16d603 WB	138	.me = THIS_MODULE,
	139	},
	140	{
	141	.name = "bpf",
	142	.revision = 1,
	143	.family = NFPROTO_UNSPEC,
	144	.checkentry = bpf_mt_check_v1,
	145	.match = bpf_mt_v1,
	146	.destroy = bpf_mt_destroy_v1,
	147	.matchsize = sizeof(struct xt_bpf_info_v1),
ec231890	148	.usersize = offsetof(struct xt_bpf_info_v1, filter),
2c16d603 WB	149	.me = THIS_MODULE,
2c16d603 WB	150	},
e6f30c73 WB	151	};
	152
	153	static int __init bpf_mt_init(void)
	154	{
2c16d603	155	return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
e6f30c73 WB	156	}
	157
	158	static void __exit bpf_mt_exit(void)
	159	{
2c16d603	160	xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
e6f30c73 WB	161	}
	162
	163	module_init(bpf_mt_init);
	164	module_exit(bpf_mt_exit);