提交 0f3cd9b3 编写于 作者: P Pablo Neira Ayuso

netfilter: nf_tables: add range expression

Inverse ranges != [a,b] are not currently possible because rules are
composites of && operations, and we need to express this:

	data < a || data > b

This patch adds a new range expression. Positive ranges can be already
through two cmp expressions:

	cmp(sreg, data, >=)
	cmp(sreg, data, <=)

This new range expression provides an alternative way to express this.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
上级 7a682575
......@@ -28,6 +28,9 @@ extern const struct nft_expr_ops nft_cmp_fast_ops;
int nft_cmp_module_init(void);
void nft_cmp_module_exit(void);
int nft_range_module_init(void);
void nft_range_module_exit(void);
int nft_lookup_module_init(void);
void nft_lookup_module_exit(void);
......
......@@ -546,6 +546,35 @@ enum nft_cmp_attributes {
};
#define NFTA_CMP_MAX (__NFTA_CMP_MAX - 1)
/**
* enum nft_range_ops - nf_tables range operator
*
* @NFT_RANGE_EQ: equal
* @NFT_RANGE_NEQ: not equal
*/
enum nft_range_ops {
NFT_RANGE_EQ,
NFT_RANGE_NEQ,
};
/**
* enum nft_range_attributes - nf_tables range expression netlink attributes
*
* @NFTA_RANGE_SREG: source register of data to compare (NLA_U32: nft_registers)
* @NFTA_RANGE_OP: cmp operation (NLA_U32: nft_cmp_ops)
* @NFTA_RANGE_FROM_DATA: data range from (NLA_NESTED: nft_data_attributes)
* @NFTA_RANGE_TO_DATA: data range to (NLA_NESTED: nft_data_attributes)
*/
enum nft_range_attributes {
NFTA_RANGE_UNSPEC,
NFTA_RANGE_SREG,
NFTA_RANGE_OP,
NFTA_RANGE_FROM_DATA,
NFTA_RANGE_TO_DATA,
__NFTA_RANGE_MAX
};
#define NFTA_RANGE_MAX (__NFTA_RANGE_MAX - 1)
enum nft_lookup_flags {
NFT_LOOKUP_F_INV = (1 << 0),
};
......
......@@ -71,8 +71,9 @@ obj-$(CONFIG_NF_DUP_NETDEV) += nf_dup_netdev.o
# nf_tables
nf_tables-objs += nf_tables_core.o nf_tables_api.o nf_tables_trace.o
nf_tables-objs += nft_immediate.o nft_cmp.o nft_lookup.o nft_dynset.o
nf_tables-objs += nft_immediate.o nft_cmp.o nft_range.o
nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
nf_tables-objs += nft_lookup.o nft_dynset.o
obj-$(CONFIG_NF_TABLES) += nf_tables.o
obj-$(CONFIG_NF_TABLES_INET) += nf_tables_inet.o
......
......@@ -263,8 +263,13 @@ int __init nf_tables_core_module_init(void)
if (err < 0)
goto err7;
return 0;
err = nft_range_module_init();
if (err < 0)
goto err8;
return 0;
err8:
nft_dynset_module_exit();
err7:
nft_payload_module_exit();
err6:
......
/*
* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
struct nft_range_expr {
struct nft_data data_from;
struct nft_data data_to;
enum nft_registers sreg:8;
u8 len;
enum nft_range_ops op:8;
};
static void nft_range_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_range_expr *priv = nft_expr_priv(expr);
bool mismatch;
int d1, d2;
d1 = memcmp(&regs->data[priv->sreg], &priv->data_from, priv->len);
d2 = memcmp(&regs->data[priv->sreg], &priv->data_to, priv->len);
switch (priv->op) {
case NFT_RANGE_EQ:
mismatch = (d1 < 0 || d2 > 0);
break;
case NFT_RANGE_NEQ:
mismatch = (d1 >= 0 && d2 <= 0);
break;
}
if (mismatch)
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
[NFTA_RANGE_SREG] = { .type = NLA_U32 },
[NFTA_RANGE_OP] = { .type = NLA_U32 },
[NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED },
[NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED },
};
static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_range_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc_from, desc_to;
int err;
err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
&desc_from, tb[NFTA_RANGE_FROM_DATA]);
if (err < 0)
return err;
err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
&desc_to, tb[NFTA_RANGE_TO_DATA]);
if (err < 0)
goto err1;
if (desc_from.len != desc_to.len) {
err = -EINVAL;
goto err2;
}
priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]);
err = nft_validate_register_load(priv->sreg, desc_from.len);
if (err < 0)
goto err2;
priv->op = ntohl(nla_get_be32(tb[NFTA_RANGE_OP]));
priv->len = desc_from.len;
return 0;
err2:
nft_data_uninit(&priv->data_to, desc_to.type);
err1:
nft_data_uninit(&priv->data_from, desc_from.type);
return err;
}
static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_range_expr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
NFT_DATA_VALUE, priv->len) < 0 ||
nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_range_type;
static const struct nft_expr_ops nft_range_ops = {
.type = &nft_range_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
.eval = nft_range_eval,
.init = nft_range_init,
.dump = nft_range_dump,
};
static struct nft_expr_type nft_range_type __read_mostly = {
.name = "range",
.ops = &nft_range_ops,
.policy = nft_range_policy,
.maxattr = NFTA_RANGE_MAX,
.owner = THIS_MODULE,
};
int __init nft_range_module_init(void)
{
return nft_register_expr(&nft_range_type);
}
void nft_range_module_exit(void)
{
nft_unregister_expr(&nft_range_type);
}
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