[linux-2.6-block.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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_ratelimited("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)
{
	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
		return -EINVAL;

	*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
	return PTR_ERR_OR_ZERO(*ret);
}

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
b2606644 FW	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
b2606644 FW	11
e6f30c73	12	#include <linux/module.h>
98589a09	13	#include <linux/syscalls.h>
e6f30c73 WB	14	#include <linux/skbuff.h>
e6f30c73 WB	15	#include <linux/filter.h>
2c16d603	16	#include <linux/bpf.h>
e6f30c73 WB	17
	18	#include <linux/netfilter/xt_bpf.h>
	19	#include <linux/netfilter/x_tables.h>
	20
	21	MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
	22	MODULE_DESCRIPTION("Xtables: BPF filter match");
	23	MODULE_LICENSE("GPL");
	24	MODULE_ALIAS("ipt_bpf");
	25	MODULE_ALIAS("ip6t_bpf");
	26
2c16d603 WB	27	static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
2c16d603 WB	28	struct bpf_prog **ret)
e6f30c73	29	{
b1fcd35c	30	struct sock_fprog_kern program;
e6f30c73	31
6ab40511 JH	32	if (len > XT_BPF_MAX_NUM_INSTR)
	33	return -EINVAL;
	34
2c16d603 WB	35	program.len = len;
2c16d603 WB	36	program.filter = insns;
b1fcd35c	37
2c16d603	38	if (bpf_prog_create(ret, &program)) {
b2606644	39	pr_info_ratelimited("check failed: parse error\n");
e6f30c73 WB	40	return -EINVAL;
	41	}
	42
	43	return 0;
	44	}
	45
2c16d603 WB	46	static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
	47	{
	48	struct bpf_prog *prog;
	49
	50	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
	51	if (IS_ERR(prog))
	52	return PTR_ERR(prog);
	53
	54	*ret = prog;
	55	return 0;
	56	}
	57
98589a09 SL	58	static int __bpf_mt_check_path(const char path, struct bpf_prog *ret)
98589a09 SL	59	{
6ab40511 JH	60	if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
	61	return -EINVAL;
	62
040ee692 AV	63	*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
040ee692 AV	64	return PTR_ERR_OR_ZERO(*ret);
98589a09 SL	65	}
98589a09 SL	66
2c16d603 WB	67	static int bpf_mt_check(const struct xt_mtchk_param *par)
	68	{
	69	struct xt_bpf_info *info = par->matchinfo;
	70
	71	return __bpf_mt_check_bytecode(info->bpf_program,
	72	info->bpf_program_num_elem,
	73	&info->filter);
	74	}
	75
	76	static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
	77	{
	78	struct xt_bpf_info_v1 *info = par->matchinfo;
	79
	80	if (info->mode == XT_BPF_MODE_BYTECODE)
	81	return __bpf_mt_check_bytecode(info->bpf_program,
	82	info->bpf_program_num_elem,
	83	&info->filter);
98589a09	84	else if (info->mode == XT_BPF_MODE_FD_ELF)
2c16d603	85	return __bpf_mt_check_fd(info->fd, &info->filter);
98589a09 SL	86	else if (info->mode == XT_BPF_MODE_PATH_PINNED)
98589a09 SL	87	return __bpf_mt_check_path(info->path, &info->filter);
2c16d603 WB	88	else
	89	return -EINVAL;
	90	}
	91
e6f30c73 WB	92	static bool bpf_mt(const struct sk_buff skb, struct xt_action_param par)
	93	{
	94	const struct xt_bpf_info *info = par->matchinfo;
	95
7ae457c1	96	return BPF_PROG_RUN(info->filter, skb);
e6f30c73 WB	97	}
e6f30c73 WB	98
2c16d603 WB	99	static bool bpf_mt_v1(const struct sk_buff skb, struct xt_action_param par)
	100	{
	101	const struct xt_bpf_info_v1 *info = par->matchinfo;
	102
	103	return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
	104	}
	105
e6f30c73 WB	106	static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
	107	{
	108	const struct xt_bpf_info *info = par->matchinfo;
2c16d603 WB	109
	110	bpf_prog_destroy(info->filter);
	111	}
	112
	113	static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
	114	{
	115	const struct xt_bpf_info_v1 *info = par->matchinfo;
	116
7ae457c1	117	bpf_prog_destroy(info->filter);
e6f30c73 WB	118	}
e6f30c73 WB	119
2c16d603 WB	120	static struct xt_match bpf_mt_reg[] __read_mostly = {
	121	{
	122	.name = "bpf",
	123	.revision = 0,
	124	.family = NFPROTO_UNSPEC,
	125	.checkentry = bpf_mt_check,
	126	.match = bpf_mt,
	127	.destroy = bpf_mt_destroy,
	128	.matchsize = sizeof(struct xt_bpf_info),
ec231890	129	.usersize = offsetof(struct xt_bpf_info, filter),
2c16d603 WB	130	.me = THIS_MODULE,
	131	},
	132	{
	133	.name = "bpf",
	134	.revision = 1,
	135	.family = NFPROTO_UNSPEC,
	136	.checkentry = bpf_mt_check_v1,
	137	.match = bpf_mt_v1,
	138	.destroy = bpf_mt_destroy_v1,
	139	.matchsize = sizeof(struct xt_bpf_info_v1),
ec231890	140	.usersize = offsetof(struct xt_bpf_info_v1, filter),
2c16d603 WB	141	.me = THIS_MODULE,
2c16d603 WB	142	},
e6f30c73 WB	143	};
	144
	145	static int __init bpf_mt_init(void)
	146	{
2c16d603	147	return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
e6f30c73 WB	148	}
	149
	150	static void __exit bpf_mt_exit(void)
	151	{
2c16d603	152	xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
e6f30c73 WB	153	}
	154
	155	module_init(bpf_mt_init);
	156	module_exit(bpf_mt_exit);