/*
* (C) 2012-2013 by 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.
*
* This software has been sponsored by Sophos Astaro <http://www.sophos.com>
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <linux/netfilter/nf_tables_compat.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <asm/uaccess.h> /* for set_fs */
#include <net/netfilter/nf_tables.h>
union nft_entry {
struct ipt_entry e4;
struct ip6t_entry e6;
};
static inline void
nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
{
par->target = xt;
par->targinfo = xt_info;
par->hotdrop = false;
}
static void nft_target_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
void *info = nft_expr_priv(expr);
struct xt_target *target = expr->ops->data;
struct sk_buff *skb = pkt->skb;
int ret;
nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
ret = target->target(skb, &pkt->xt);
if (pkt->xt.hotdrop)
ret = NF_DROP;
switch(ret) {
case XT_CONTINUE:
data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
break;
default:
data[NFT_REG_VERDICT].verdict = ret;
break;
}
return;
}
static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
[NFTA_TARGET_NAME] = { .type = NLA_NUL_STRING },
[NFTA_TARGET_REV] = { .type = NLA_U32 },
[NFTA_TARGET_INFO] = { .type = NLA_BINARY },
};
static void
nft_target_set_tgchk_param(struct xt_tgchk_param *par,
const struct nft_ctx *ctx,
struct xt_target *target, void *info,
union nft_entry *entry, u8 proto, bool inv)
{
par->net = &init_net;
par->table = ctx->table->name;
switch (ctx->afi->family) {
case AF_INET:
entry->e4.ip.proto = proto;
entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
break;
case AF_INET6:
entry->e6.ipv6.proto = proto;
entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
break;
}
par->entryinfo = entry;
par->target = target;
par->targinfo = info;
if (ctx->chain->flags & NFT_BASE_CHAIN) {
const struct nft_base_chain *basechain =
nft_base_chain(ctx->chain);
const struct nf_hook_ops *ops = &basechain->ops;
par->hook_mask = 1 << ops->hooknum;
}
par->family = ctx->afi->family;
}
static void target_compat_from_user(struct xt_target *t, void *in, void *out)
{
#ifdef CONFIG_COMPAT
if (t->compat_from_user) {
int pad;
t->compat_from_user(out, in);
pad = XT_ALIGN(t->targetsize) - t->targetsize;
if (pad > 0)
memset(out + t->targetsize, 0, pad);
} else
#endif
memcpy(out, in, XT_ALIGN(t->targetsize));
}
static inline int nft_compat_target_offset(struct xt_target *target)
{
#ifdef CONFIG_COMPAT
return xt_compat_target_offset(target);
#else
return 0;
#endif
}
static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
[NFTA_RULE_COMPAT_PROTO] = { .type = NLA_U32 },
[NFTA_RULE_COMPAT_FLAGS] = { .type = NLA_U32 },
};
static int nft_parse_compat(const struct nlattr *attr, u8 *proto, bool *inv)
{
struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
u32 flags;
int err;
err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
nft_rule_compat_policy);
if (err < 0)
return err;
if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
return -EINVAL;
flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
if (flags & ~NFT_RULE_COMPAT_F_MASK)
return -EINVAL;
if (flags & NFT_RULE_COMPAT_F_INV)
*inv = true;
*proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
return 0;
}
static int
nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
void *info = nft_expr_priv(expr);
struct xt_target *target = expr->ops->data;
struct xt_tgchk_param par;
size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
u8 proto = 0;
bool inv = false;
union nft_entry e = {};
int ret;
target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
if (ctx->nla[NFTA_RULE_COMPAT]) {
ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
if (ret < 0)
goto err;
}
nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
ret = xt_check_target(&par, size, proto, inv);
if (ret < 0)
goto err;
/* The standard target cannot be used */
if (target->target == NULL) {
ret = -EINVAL;
goto err;
}
return 0;
err:
module_put(target->me);
return ret;
}
static void
nft_target_destroy(const struct nft_expr *expr)
{
struct xt_target *target = expr->ops->data;
module_put(target->me);
}
static int
target_dump_info(struct sk_buff *skb, const struct xt_target *t, const void *in)
{
int ret;
#ifdef CONFIG_COMPAT
if (t->compat_to_user) {
mm_segment_t old_fs;
void *out;
out = kmalloc(XT_ALIGN(t->targetsize), GFP_ATOMIC);
if (out == NULL)
return -ENOMEM;
/* We want to reuse existing compat_to_user */
old_fs = get_fs();
set_fs(KERNEL_DS);
t->compat_to_user(out, in);
set_fs(old_fs);
ret = nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(t->targetsize), out);
kfree(out);
} else
#endif
ret = nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(t->targetsize), in);
return ret;
}
static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct xt_target *target = expr->ops->data;
void *info = nft_expr_priv(expr);
if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
target_dump_info(skb, target, info))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static int nft_target_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
{
struct xt_target *target = expr->ops->data;
unsigned int hook_mask = 0;
if (ctx->chain->flags & NFT_BASE_CHAIN) {
const struct nft_base_chain *basechain =
nft_base_chain(ctx->chain);
const struct nf_hook_ops *ops = &basechain->ops;
hook_mask = 1 << ops->hooknum;
if (hook_mask & target->hooks)
return 0;
/* This target is being called from an invalid chain */
return -EINVAL;
}
return 0;
}
static void nft_match_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
void *info = nft_expr_priv(expr);
struct xt_match *match = expr->ops->data;
struct sk_buff *skb = pkt->skb;
bool ret;
nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
if (pkt->xt.hotdrop) {
data[NFT_REG_VERDICT].verdict = NF_DROP;
return;
}
switch(ret) {
case true:
data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
break;
case false:
data[NFT_REG_VERDICT].verdict = NFT_BREAK;
break;
}
}
static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
[NFTA_MATCH_NAME] = { .type = NLA_NUL_STRING },
[NFTA_MATCH_REV] = { .type = NLA_U32 },
[NFTA_MATCH_INFO] = { .type = NLA_BINARY },
};
/* struct xt_mtchk_param and xt_tgchk_param look very similar */
static void
nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
struct xt_match *match, void *info,
union nft_entry *entry, u8 proto, bool inv)
{
par->net = &init_net;
par->table = ctx->table->name;
switch (ctx->afi->family) {
case AF_INET:
entry->e4.ip.proto = proto;
entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
break;
case AF_INET6:
entry->e6.ipv6.proto = proto;
entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
break;
}
par->entryinfo = entry;
par->match = match;
par->matchinfo = info;
if (ctx->chain->flags &
