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netfilter: nft_reject: introduce icmp code abstraction for inet and bridge 

This patch introduces the NFT_REJECT_ICMPX_UNREACH type which provides
an abstraction to the ICMP and ICMPv6 codes that you can use from the
inet and bridge tables, they are:

* NFT_REJECT_ICMPX_NO_ROUTE: no route to host - network unreachable
* NFT_REJECT_ICMPX_PORT_UNREACH: port unreachable
* NFT_REJECT_ICMPX_HOST_UNREACH: host unreachable
* NFT_REJECT_ICMPX_ADMIN_PROHIBITED: administratevely prohibited

You can still use the specific codes when restricting the rule to match
the corresponding layer 3 protocol.

I decided to not overload the existing NFT_REJECT_ICMP_UNREACH to have
different semantics depending on the table family and to allow the user
to specify ICMP family specific codes if they restrict it to the
corresponding family.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2014-09-26 14:35:14 +02:00
parent 2c804d0f8f
commit 51b0a5d8c2
7 changed files with 241 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/netfilter/ipv4/nf_reject.h
View File

@ -5,6 +5,7 @@
#include <net/tcp.h>
#include <net/route.h>
#include <net/dst.h>
#include <net/icmp.h>
static inline void nf_send_unreach(struct sk_buff *skb_in, int code)
{

9
include/net/netfilter/nft_reject.h
View File

@ -14,12 +14,7 @@ int nft_reject_init(const struct nft_ctx *ctx,
int nft_reject_dump(struct sk_buff *skb, const struct nft_expr *expr);
void nft_reject_ipv4_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt);
void nft_reject_ipv6_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt);
int nft_reject_icmp_code(u8 code);
int nft_reject_icmpv6_code(u8 code);
#endif

21
include/uapi/linux/netfilter/nf_tables.h
View File

@ -749,12 +749,33 @@ enum nft_queue_attributes {
*
* @NFT_REJECT_ICMP_UNREACH: reject using ICMP unreachable
* @NFT_REJECT_TCP_RST: reject using TCP RST
* @NFT_REJECT_ICMPX_UNREACH: abstracted ICMP unreachable for bridge and inet
*/
enum nft_reject_types {
NFT_REJECT_ICMP_UNREACH,
NFT_REJECT_TCP_RST,
NFT_REJECT_ICMPX_UNREACH,
};
/**
* enum nft_reject_code - Generic reject codes for IPv4/IPv6
*
* @NFT_REJECT_ICMPX_NO_ROUTE: no route to host / network unreachable
* @NFT_REJECT_ICMPX_PORT_UNREACH: port unreachable
* @NFT_REJECT_ICMPX_HOST_UNREACH: host unreachable
* @NFT_REJECT_ICMPX_ADMIN_PROHIBITED: administratively prohibited
*
* These codes are mapped to real ICMP and ICMPv6 codes.
*/
enum nft_reject_inet_code {
NFT_REJECT_ICMPX_NO_ROUTE = 0,
NFT_REJECT_ICMPX_PORT_UNREACH,
NFT_REJECT_ICMPX_HOST_UNREACH,
NFT_REJECT_ICMPX_ADMIN_PROHIBITED,
__NFT_REJECT_ICMPX_MAX
};
#define NFT_REJECT_ICMPX_MAX (__NFT_REJECT_ICMPX_MAX + 1)
/**
* enum nft_reject_attributes - nf_tables reject expression netlink attributes
*

95
net/bridge/netfilter/nft_reject_bridge.c
View File

@ -14,21 +14,106 @@
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_reject.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/ipv6/nf_reject.h>
static void nft_reject_bridge_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
struct nft_reject *priv = nft_expr_priv(expr);
struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
switch (eth_hdr(pkt->skb)->h_proto) {
case htons(ETH_P_IP):
return nft_reject_ipv4_eval(expr, data, pkt);
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
nf_send_unreach(pkt->skb, priv->icmp_code);
break;
case NFT_REJECT_TCP_RST:
nf_send_reset(pkt->skb, pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
nf_send_unreach(pkt->skb,
nft_reject_icmp_code(priv->icmp_code));
break;
}
break;
case htons(ETH_P_IPV6):
return nft_reject_ipv6_eval(expr, data, pkt);
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
nf_send_unreach6(net, pkt->skb, priv->icmp_code,
pkt->ops->hooknum);
break;
case NFT_REJECT_TCP_RST:
nf_send_reset6(net, pkt->skb, pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
nf_send_unreach6(net, pkt->skb,
nft_reject_icmpv6_code(priv->icmp_code),
pkt->ops->hooknum);
break;
}
break;
default:
/* No explicit way to reject this protocol, drop it. */
data[NFT_REG_VERDICT].verdict = NF_DROP;
break;
}
data[NFT_REG_VERDICT].verdict = NF_DROP;
}
static int nft_reject_bridge_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_reject *priv = nft_expr_priv(expr);
int icmp_code;
if (tb[NFTA_REJECT_TYPE] == NULL)
return -EINVAL;
priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
case NFT_REJECT_ICMPX_UNREACH:
if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
return -EINVAL;
icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
icmp_code > NFT_REJECT_ICMPX_MAX)
return -EINVAL;
priv->icmp_code = icmp_code;
break;
case NFT_REJECT_TCP_RST:
break;
default:
return -EINVAL;
}
return 0;
}
static int nft_reject_bridge_dump(struct sk_buff *skb,
const struct nft_expr *expr)
{
const struct nft_reject *priv = nft_expr_priv(expr);
if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
goto nla_put_failure;
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
case NFT_REJECT_ICMPX_UNREACH:
if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
goto nla_put_failure;
break;
}
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_reject_bridge_type;
@ -36,8 +121,8 @@ static const struct nft_expr_ops nft_reject_bridge_ops = {
.type = &nft_reject_bridge_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
.eval = nft_reject_bridge_eval,
.init = nft_reject_init,
.dump = nft_reject_dump,
.init = nft_reject_bridge_init,
.dump = nft_reject_bridge_dump,
};
static struct nft_expr_type nft_reject_bridge_type __read_mostly = {

1
net/ipv4/netfilter/nft_reject_ipv4.c
View File

@ -16,7 +16,6 @@
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/icmp.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/nft_reject.h>

37
net/netfilter/nft_reject.c
View File

@ -17,6 +17,8 @@
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_reject.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
const struct nla_policy nft_reject_policy[NFTA_REJECT_MAX + 1] = {
[NFTA_REJECT_TYPE] = { .type = NLA_U32 },
@ -70,5 +72,40 @@ int nft_reject_dump(struct sk_buff *skb, const struct nft_expr *expr)
}
EXPORT_SYMBOL_GPL(nft_reject_dump);
static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX] = {
[NFT_REJECT_ICMPX_NO_ROUTE] = ICMP_NET_UNREACH,
[NFT_REJECT_ICMPX_PORT_UNREACH] = ICMP_PORT_UNREACH,
[NFT_REJECT_ICMPX_HOST_UNREACH] = ICMP_HOST_UNREACH,
[NFT_REJECT_ICMPX_ADMIN_PROHIBITED] = ICMP_PKT_FILTERED,
};
int nft_reject_icmp_code(u8 code)
{
if (code > NFT_REJECT_ICMPX_MAX)
return -EINVAL;
return icmp_code_v4[code];
}
EXPORT_SYMBOL_GPL(nft_reject_icmp_code);
static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX] = {
[NFT_REJECT_ICMPX_NO_ROUTE] = ICMPV6_NOROUTE,
[NFT_REJECT_ICMPX_PORT_UNREACH] = ICMPV6_PORT_UNREACH,
[NFT_REJECT_ICMPX_HOST_UNREACH] = ICMPV6_ADDR_UNREACH,
[NFT_REJECT_ICMPX_ADMIN_PROHIBITED] = ICMPV6_ADM_PROHIBITED,
};
int nft_reject_icmpv6_code(u8 code)
{
if (code > NFT_REJECT_ICMPX_MAX)
return -EINVAL;
return icmp_code_v6[code];
}
EXPORT_SYMBOL_GPL(nft_reject_icmpv6_code);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");

94
net/netfilter/nft_reject_inet.c
View File

@ -14,17 +14,103 @@
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_reject.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/ipv6/nf_reject.h>
static void nft_reject_inet_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
struct nft_reject *priv = nft_expr_priv(expr);
struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
switch (pkt->ops->pf) {
case NFPROTO_IPV4:
return nft_reject_ipv4_eval(expr, data, pkt);
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
nf_send_unreach(pkt->skb, priv->icmp_code);
break;
case NFT_REJECT_TCP_RST:
nf_send_reset(pkt->skb, pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
nf_send_unreach(pkt->skb,
nft_reject_icmp_code(priv->icmp_code));
break;
}
break;
case NFPROTO_IPV6:
return nft_reject_ipv6_eval(expr, data, pkt);
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
nf_send_unreach6(net, pkt->skb, priv->icmp_code,
pkt->ops->hooknum);
break;
case NFT_REJECT_TCP_RST:
nf_send_reset6(net, pkt->skb, pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
nf_send_unreach6(net, pkt->skb,
nft_reject_icmpv6_code(priv->icmp_code),
pkt->ops->hooknum);
break;
}
break;
}
data[NFT_REG_VERDICT].verdict = NF_DROP;
}
static int nft_reject_inet_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_reject *priv = nft_expr_priv(expr);
int icmp_code;
if (tb[NFTA_REJECT_TYPE] == NULL)
return -EINVAL;
priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
case NFT_REJECT_ICMPX_UNREACH:
if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
return -EINVAL;
icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
icmp_code > NFT_REJECT_ICMPX_MAX)
return -EINVAL;
priv->icmp_code = icmp_code;
break;
case NFT_REJECT_TCP_RST:
break;
default:
return -EINVAL;
}
return 0;
}
static int nft_reject_inet_dump(struct sk_buff *skb,
const struct nft_expr *expr)
{
const struct nft_reject *priv = nft_expr_priv(expr);
if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
goto nla_put_failure;
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
case NFT_REJECT_ICMPX_UNREACH:
if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
goto nla_put_failure;
break;
}
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_reject_inet_type;
@ -32,8 +118,8 @@ static const struct nft_expr_ops nft_reject_inet_ops = {
.type = &nft_reject_inet_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
.eval = nft_reject_inet_eval,
.init = nft_reject_init,
.dump = nft_reject_dump,
.init = nft_reject_inet_init,
.dump = nft_reject_inet_dump,
};
static struct nft_expr_type nft_reject_inet_type __read_mostly = {