blob: 8a779be832fba2d8a86181f8f8f68a445299d626 [file] [log] [blame]
/*
* (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[0];
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_ctx *ctx, 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[0];
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 & NFT_BASE_CHAIN) {
const struct nft_base_chain *basechain =
nft_base_chain(ctx->chain);
const struct nf_hook_ops *ops = &basechain->ops[0];
par->hook_mask = 1 << ops->hooknum;
}
par->family = ctx->afi->family;
}
static void match_compat_from_user(struct xt_match *m, void *in, void *out)
{
#ifdef CONFIG_COMPAT
if (m->compat_from_user) {
int pad;
m->compat_from_user(out, in);
pad = XT_ALIGN(m->matchsize) - m->matchsize;
if (pad > 0)
memset(out + m->matchsize, 0, pad);
} else
#endif
memcpy(out, in, XT_ALIGN(m->matchsize));
}
static int
nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
void *info = nft_expr_priv(expr);
struct xt_match *match = expr->ops->data;
struct xt_mtchk_param par;
size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
u8 proto = 0;
bool inv = false;
union nft_entry e = {};
int ret;
match_compat_from_user(match, nla_data(tb[NFTA_MATCH_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_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
ret = xt_check_match(&par, size, proto, inv);
if (ret < 0)
goto err;
return 0;
err:
module_put(match->me);
return ret;
}
static void
nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
struct xt_match *match = expr->ops->data;
module_put(match->me);
}
static int
match_dump_info(struct sk_buff *skb, const struct xt_match *m, const void *in)
{
int ret;
#ifdef CONFIG_COMPAT
if (m->compat_to_user) {
mm_segment_t old_fs;
void *out;
out = kmalloc(XT_ALIGN(m->matchsize), GFP_ATOMIC);
if (out == NULL)
return -ENOMEM;
/* We want to reuse existing compat_to_user */
old_fs = get_fs();
set_fs(KERNEL_DS);
m->compat_to_user(out, in);
set_fs(old_fs);
ret = nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(m->matchsize), out);
kfree(out);
} else
#endif
ret = nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(m->matchsize), in);
return ret;
}
static inline int nft_compat_match_offset(struct xt_match *match)
{
#ifdef CONFIG_COMPAT
return xt_compat_match_offset(match);
#else
return 0;
#endif
}
static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
void *info = nft_expr_priv(expr);
struct xt_match *match = expr->ops->data;
if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
match_dump_info(skb, match, info))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static int nft_match_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
{
struct xt_match *match = 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[0];
hook_mask = 1 << ops->hooknum;
if (hook_mask & match->hooks)
return 0;
/* This match is being called from an invalid chain */
return -EINVAL;
}
return 0;
}
static int
nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
int event, u16 family, const char *name,
int rev, int target)
{
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
unsigned int flags = portid ? NLM_F_MULTI : 0;
event |= NFNL_SUBSYS_NFT_COMPAT << 8;
nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
if (nlh == NULL)
goto nlmsg_failure;
nfmsg = nlmsg_data(nlh);
nfmsg->nfgen_family = family;
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = 0;
if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
goto nla_put_failure;
nlmsg_end(skb, nlh);
return skb->len;
nlmsg_failure:
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -1;
}
static int
nfnl_compat_get(struct sock *nfnl, struct sk_buff *skb,
const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
int ret = 0, target;
struct nfgenmsg *nfmsg;
const char *fmt;
const char *name;
u32 rev;
struct sk_buff *skb2;
if (tb[NFTA_COMPAT_NAME] == NULL ||
tb[NFTA_COMPAT_REV] == NULL ||
tb[NFTA_COMPAT_TYPE] == NULL)
return -EINVAL;
name = nla_data(tb[NFTA_COMPAT_NAME]);
rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
nfmsg = nlmsg_data(nlh);
switch(nfmsg->nfgen_family) {
case AF_INET:
fmt = "ipt_%s";
break;
case AF_INET6:
fmt = "ip6t_%s";
break;
default:
pr_err("nft_compat: unsupported protocol %d\n",
nfmsg->nfgen_family);
return -EINVAL;
}
try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
rev, target, &ret),
fmt, name);
if (ret < 0)
return ret;
skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (skb2 == NULL)
return -ENOMEM;
/* include the best revision for this extension in the message */
if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
nlh->nlmsg_seq,
NFNL_MSG_TYPE(nlh->nlmsg_type),
NFNL_MSG_COMPAT_GET,
nfmsg->nfgen_family,
name, ret, target) <= 0) {
kfree_skb(skb2);
return -ENOSPC;
}
ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
MSG_DONTWAIT);
if (ret > 0)
ret = 0;
return ret == -EAGAIN ? -ENOBUFS : ret;
}
static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
[NFTA_COMPAT_NAME] = { .type = NLA_NUL_STRING,
.len = NFT_COMPAT_NAME_MAX-1 },
[NFTA_COMPAT_REV] = { .type = NLA_U32 },
[NFTA_COMPAT_TYPE] = { .type = NLA_U32 },
};
static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
[NFNL_MSG_COMPAT_GET] = { .call = nfnl_compat_get,
.attr_count = NFTA_COMPAT_MAX,
.policy = nfnl_compat_policy_get },
};
static const struct nfnetlink_subsystem nfnl_compat_subsys = {
.name = "nft-compat",
.subsys_id = NFNL_SUBSYS_NFT_COMPAT,
.cb_count = NFNL_MSG_COMPAT_MAX,
.cb = nfnl_nft_compat_cb,
};
static LIST_HEAD(nft_match_list);
struct nft_xt {
struct list_head head;
struct nft_expr_ops ops;
};
static struct nft_expr_type nft_match_type;
static const struct nft_expr_ops *
nft_match_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_xt *nft_match;
struct xt_match *match;
char *mt_name;
__u32 rev, family;
if (tb[NFTA_MATCH_NAME] == NULL ||
tb[NFTA_MATCH_REV] == NULL ||
tb[NFTA_MATCH_INFO] == NULL)
return ERR_PTR(-EINVAL);
mt_name = nla_data(tb[NFTA_MATCH_NAME]);
rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
family = ctx->afi->family;
/* Re-use the existing match if it's already loaded. */
list_for_each_entry(nft_match, &nft_match_list, head) {
struct xt_match *match = nft_match->ops.data;
if (strcmp(match->name, mt_name) == 0 &&
match->revision == rev && match->family == family)
return &nft_match->ops;
}
match = xt_request_find_match(family, mt_name, rev);
if (IS_ERR(match))
return ERR_PTR(-ENOENT);
/* This is the first time we use this match, allocate operations */
nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
if (nft_match == NULL)
return ERR_PTR(-ENOMEM);
nft_match->ops.type = &nft_match_type;
nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize) +
nft_compat_match_offset(match));
nft_match->ops.eval = nft_match_eval;
nft_match->ops.init = nft_match_init;
nft_match->ops.destroy = nft_match_destroy;
nft_match->ops.dump = nft_match_dump;
nft_match->ops.validate = nft_match_validate;
nft_match->ops.data = match;
list_add(&nft_match->head, &nft_match_list);
return &nft_match->ops;
}
static void nft_match_release(void)
{
struct nft_xt *nft_match, *tmp;
list_for_each_entry_safe(nft_match, tmp, &nft_match_list, head)
kfree(nft_match);
}
static struct nft_expr_type nft_match_type __read_mostly = {
.name = "match",
.select_ops = nft_match_select_ops,
.policy = nft_match_policy,
.maxattr = NFTA_MATCH_MAX,
.owner = THIS_MODULE,
};
static LIST_HEAD(nft_target_list);
static struct nft_expr_type nft_target_type;
static const struct nft_expr_ops *
nft_target_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_xt *nft_target;
struct xt_target *target;
char *tg_name;
__u32 rev, family;
if (tb[NFTA_TARGET_NAME] == NULL ||
tb[NFTA_TARGET_REV] == NULL ||
tb[NFTA_TARGET_INFO] == NULL)
return ERR_PTR(-EINVAL);
tg_name = nla_data(tb[NFTA_TARGET_NAME]);
rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
family = ctx->afi->family;
/* Re-use the existing target if it's already loaded. */
list_for_each_entry(nft_target, &nft_match_list, head) {
struct xt_target *target = nft_target->ops.data;
if (strcmp(target->name, tg_name) == 0 &&
target->revision == rev && target->family == family)
return &nft_target->ops;
}
target = xt_request_find_target(family, tg_name, rev);
if (IS_ERR(target))
return ERR_PTR(-ENOENT);
/* This is the first time we use this target, allocate operations */
nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
if (nft_target == NULL)
return ERR_PTR(-ENOMEM);
nft_target->ops.type = &nft_target_type;
nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize) +
nft_compat_target_offset(target));
nft_target->ops.eval = nft_target_eval;
nft_target->ops.init = nft_target_init;
nft_target->ops.destroy = nft_target_destroy;
nft_target->ops.dump = nft_target_dump;
nft_target->ops.validate = nft_target_validate;
nft_target->ops.data = target;
list_add(&nft_target->head, &nft_target_list);
return &nft_target->ops;
}
static void nft_target_release(void)
{
struct nft_xt *nft_target, *tmp;
list_for_each_entry_safe(nft_target, tmp, &nft_target_list, head)
kfree(nft_target);
}
static struct nft_expr_type nft_target_type __read_mostly = {
.name = "target",
.select_ops = nft_target_select_ops,
.policy = nft_target_policy,
.maxattr = NFTA_TARGET_MAX,
.owner = THIS_MODULE,
};
static int __init nft_compat_module_init(void)
{
int ret;
ret = nft_register_expr(&nft_match_type);
if (ret < 0)
return ret;
ret = nft_register_expr(&nft_target_type);
if (ret < 0)
goto err_match;
ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
if (ret < 0) {
pr_err("nft_compat: cannot register with nfnetlink.\n");
goto err_target;
}
pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
return ret;
err_target:
nft_unregister_expr(&nft_target_type);
err_match:
nft_unregister_expr(&nft_match_type);
return ret;
}
static void __exit nft_compat_module_exit(void)
{
nfnetlink_subsys_unregister(&nfnl_compat_subsys);
nft_unregister_expr(&nft_target_type);
nft_unregister_expr(&nft_match_type);
nft_match_release();
nft_target_release();
}
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
module_init(nft_compat_module_init);
module_exit(nft_compat_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_EXPR("match");
MODULE_ALIAS_NFT_EXPR("target");