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linux-stable/net/netfilter/nft_compat.c
Johannes Berg 8cb081746c netlink: make validation more configurable for future strictness 
We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:21 -04:00

907 lines
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/*
* (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 <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_arp/arp_tables.h>
#include <net/netfilter/nf_tables.h>
/* Used for matches where *info is larger than X byte */
#define NFT_MATCH_LARGE_THRESH 192
struct nft_xt_match_priv {
void *info;
};
static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
const char *tablename)
{
enum nft_chain_types type = NFT_CHAIN_T_DEFAULT;
const struct nft_chain *chain = ctx->chain;
const struct nft_base_chain *basechain;
if (!tablename ||
!nft_is_base_chain(chain))
return 0;
basechain = nft_base_chain(chain);
if (strcmp(tablename, "nat") == 0) {
if (ctx->family != NFPROTO_BRIDGE)
type = NFT_CHAIN_T_NAT;
if (basechain->type->type != type)
return -EINVAL;
}
return 0;
}
union nft_entry {
struct ipt_entry e4;
struct ip6t_entry e6;
struct ebt_entry ebt;
struct arpt_entry arp;
};
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_xt(const struct nft_expr *expr,
struct nft_regs *regs,
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:
regs->verdict.code = NFT_CONTINUE;
break;
default:
regs->verdict.code = ret;
break;
}
}
static void nft_target_eval_bridge(const struct nft_expr *expr,
struct nft_regs *regs,
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 EBT_ACCEPT:
regs->verdict.code = NF_ACCEPT;
break;
case EBT_DROP:
regs->verdict.code = NF_DROP;
break;
case EBT_CONTINUE:
regs->verdict.code = NFT_CONTINUE;
break;
case EBT_RETURN:
regs->verdict.code = NFT_RETURN;
break;
default:
regs->verdict.code = ret;
break;
}
}
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, u16 proto, bool inv)
{
par->net = ctx->net;
par->table = ctx->table->name;
switch (ctx->family) {
case AF_INET:
entry->e4.ip.proto = proto;
entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
break;
case AF_INET6:
if (proto)
entry->e6.ipv6.flags |= IP6T_F_PROTO;
entry->e6.ipv6.proto = proto;
entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
break;
case NFPROTO_BRIDGE:
entry->ebt.ethproto = (__force __be16)proto;
entry->ebt.invflags = inv ? EBT_IPROTO : 0;
break;
case NFPROTO_ARP:
break;
}
par->entryinfo = entry;
par->target = target;
par->targinfo = info;
if (nft_is_base_chain(ctx->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;
} else {
par->hook_mask = 0;
}
par->family = ctx->family;
par->nft_compat = true;
}
static void target_compat_from_user(struct xt_target *t, void *in, void *out)
{
int pad;
memcpy(out, in, t->targetsize);
pad = XT_ALIGN(t->targetsize) - t->targetsize;
if (pad > 0)
memset(out + t->targetsize, 0, pad);
}
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, u16 *proto, bool *inv)
{
struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
u32 flags;
int err;
err = nla_parse_nested_deprecated(tb, NFTA_RULE_COMPAT_MAX, attr,
nft_rule_compat_policy, NULL);
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]));
u16 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)
return ret;
}
nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
ret = xt_check_target(&par, size, proto, inv);
if (ret < 0)
return ret;
/* The standard target cannot be used */
if (!target->target)
return -EINVAL;
return 0;
}
static void
nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
struct xt_target *target = expr->ops->data;
void *info = nft_expr_priv(expr);
struct module *me = target->me;
struct xt_tgdtor_param par;
par.net = ctx->net;
par.target = target;
par.targinfo = info;
par.family = ctx->family;
if (par.target->destroy != NULL)
par.target->destroy(&par);
module_put(me);
kfree(expr->ops);
}
static int nft_extension_dump_info(struct sk_buff *skb, int attr,
const void *info,
unsigned int size, unsigned int user_size)
{
unsigned int info_size, aligned_size = XT_ALIGN(size);
struct nlattr *nla;
nla = nla_reserve(skb, attr, aligned_size);
if (!nla)
return -1;
info_size = user_size ? : size;
memcpy(nla_data(nla), info, info_size);
memset(nla_data(nla) + info_size, 0, aligned_size - info_size);
return 0;
}
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)) ||
nft_extension_dump_info(skb, NFTA_TARGET_INFO, info,
target->targetsize, target->usersize))
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;
int ret;
if (nft_is_base_chain(ctx->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 (target->hooks && !(hook_mask & target->hooks))
return -EINVAL;
ret = nft_compat_chain_validate_dependency(ctx, target->table);
if (ret < 0)
return ret;
}
return 0;
}
static void __nft_match_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt,
void *info)
{
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) {
regs->verdict.code = NF_DROP;
return;
}
switch (ret ? 1 : 0) {
case 1:
regs->verdict.code = NFT_CONTINUE;
break;
case 0:
regs->verdict.code = NFT_BREAK;
break;
}
}
static void nft_match_large_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_xt_match_priv *priv = nft_expr_priv(expr);
__nft_match_eval(expr, regs, pkt, priv->info);
}
static void nft_match_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
__nft_match_eval(expr, regs, pkt, nft_expr_priv(expr));
}
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, u16 proto, bool inv)
{
par->net = ctx->net;
par->table = ctx->table->name;
switch (ctx->family) {
case AF_INET:
entry->e4.ip.proto = proto;
entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
break;
case AF_INET6:
if (proto)
entry->e6.ipv6.flags |= IP6T_F_PROTO;
entry->e6.ipv6.proto = proto;
entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
break;
case NFPROTO_BRIDGE:
entry->ebt.ethproto = (__force __be16)proto;
entry->ebt.invflags = inv ? EBT_IPROTO : 0;
break;
case NFPROTO_ARP:
break;
}
par->entryinfo = entry;
par->match = match;
par->matchinfo = info;
if (nft_is_base_chain(ctx->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;
} else {
par->hook_mask = 0;
}
par->family = ctx->family;
par->nft_compat = true;
}
static void match_compat_from_user(struct xt_match *m, void *in, void *out)
{
int pad;
memcpy(out, in, m->matchsize);
pad = XT_ALIGN(m->matchsize) - m->matchsize;
if (pad > 0)
memset(out + m->matchsize, 0, pad);
}
static int
__nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[],
void *info)
{
struct xt_match *match = expr->ops->data;
struct xt_mtchk_param par;
size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
u16 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)
return ret;
}
nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
return xt_check_match(&par, size, proto, inv);
}
static int
nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
return __nft_match_init(ctx, expr, tb, nft_expr_priv(expr));
}
static int
nft_match_large_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_xt_match_priv *priv = nft_expr_priv(expr);
struct xt_match *m = expr->ops->data;
int ret;
priv->info = kmalloc(XT_ALIGN(m->matchsize), GFP_KERNEL);
if (!priv->info)
return -ENOMEM;
ret = __nft_match_init(ctx, expr, tb, priv->info);
if (ret)
kfree(priv->info);
return ret;
}
static void
__nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr,
void *info)
{
struct xt_match *match = expr->ops->data;
struct module *me = match->me;
struct xt_mtdtor_param par;
par.net = ctx->net;
par.match = match;
par.matchinfo = info;
par.family = ctx->family;
if (par.match->destroy != NULL)
par.match->destroy(&par);
module_put(me);
kfree(expr->ops);
}
static void
nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
__nft_match_destroy(ctx, expr, nft_expr_priv(expr));
}
static void
nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
struct nft_xt_match_priv *priv = nft_expr_priv(expr);
__nft_match_destroy(ctx, expr, priv->info);
kfree(priv->info);
}
static int __nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr,
void *info)
{
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)) ||
nft_extension_dump_info(skb, NFTA_MATCH_INFO, info,
match->matchsize, match->usersize))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
return __nft_match_dump(skb, expr, nft_expr_priv(expr));
}
static int nft_match_large_dump(struct sk_buff *skb, const struct nft_expr *e)
{
struct nft_xt_match_priv *priv = nft_expr_priv(e);
return __nft_match_dump(skb, e, priv->info);
}
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;
int ret;
if (nft_is_base_chain(ctx->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 (match->hooks && !(hook_mask & match->hooks))
return -EINVAL;
ret = nft_compat_chain_validate_dependency(ctx, match->table);
if (ret < 0)
return ret;
}
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_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
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_rcu(struct net *net, struct sock *nfnl,
struct sk_buff *skb, const struct nlmsghdr *nlh,
const struct nlattr * const tb[],
struct netlink_ext_ack *extack)
{
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;
case NFPROTO_BRIDGE:
fmt = "ebt_%s";
break;
case NFPROTO_ARP:
fmt = "arpt_%s";
break;
default:
pr_err("nft_compat: unsupported protocol %d\n",
nfmsg->nfgen_family);
return -EINVAL;
}
if (!try_module_get(THIS_MODULE))
return -EINVAL;
rcu_read_unlock();
try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
rev, target, &ret),
fmt, name);
if (ret < 0)
goto out_put;
skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (skb2 == NULL) {
ret = -ENOMEM;
goto out_put;
}
/* 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);
goto out_put;
}
ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
MSG_DONTWAIT);
if (ret > 0)
ret = 0;
out_put:
rcu_read_lock();
module_put(THIS_MODULE);
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_rcu = nfnl_compat_get_rcu,
.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 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_expr_ops *ops;
struct xt_match *match;
unsigned int matchsize;
char *mt_name;
u32 rev, family;
int err;
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->family;
match = xt_request_find_match(family, mt_name, rev);
if (IS_ERR(match))
return ERR_PTR(-ENOENT);
if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
err = -EINVAL;
goto err;
}
ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
if (!ops) {
err = -ENOMEM;
goto err;
}
ops->type = &nft_match_type;
ops->eval = nft_match_eval;
ops->init = nft_match_init;
ops->destroy = nft_match_destroy;
ops->dump = nft_match_dump;
ops->validate = nft_match_validate;
ops->data = match;
matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
if (matchsize > NFT_MATCH_LARGE_THRESH) {
matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
ops->eval = nft_match_large_eval;
ops->init = nft_match_large_init;
ops->destroy = nft_match_large_destroy;
ops->dump = nft_match_large_dump;
}
ops->size = matchsize;
return ops;
err:
module_put(match->me);
return ERR_PTR(err);
}
static void nft_match_release_ops(const struct nft_expr_ops *ops)
{
struct xt_match *match = ops->data;
module_put(match->me);
kfree(ops);
}
static struct nft_expr_type nft_match_type __read_mostly = {
.name = "match",
.select_ops = nft_match_select_ops,
.release_ops = nft_match_release_ops,
.policy = nft_match_policy,
.maxattr = NFTA_MATCH_MAX,
.owner = THIS_MODULE,
};
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_expr_ops *ops;
struct xt_target *target;
char *tg_name;
u32 rev, family;
int err;
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->family;
if (strcmp(tg_name, XT_ERROR_TARGET) == 0 ||
strcmp(tg_name, XT_STANDARD_TARGET) == 0 ||
strcmp(tg_name, "standard") == 0)
return ERR_PTR(-EINVAL);
target = xt_request_find_target(family, tg_name, rev);
if (IS_ERR(target))
return ERR_PTR(-ENOENT);
if (!target->target) {
err = -EINVAL;
goto err;
}
if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
err = -EINVAL;
goto err;
}
ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
if (!ops) {
err = -ENOMEM;
goto err;
}
ops->type = &nft_target_type;
ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
ops->init = nft_target_init;
ops->destroy = nft_target_destroy;
ops->dump = nft_target_dump;
ops->validate = nft_target_validate;
ops->data = target;
if (family == NFPROTO_BRIDGE)
ops->eval = nft_target_eval_bridge;
else
ops->eval = nft_target_eval_xt;
return ops;
err:
module_put(target->me);
return ERR_PTR(err);
}
static void nft_target_release_ops(const struct nft_expr_ops *ops)
{
struct xt_target *target = ops->data;
module_put(target->me);
kfree(ops);
}
static struct nft_expr_type nft_target_type __read_mostly = {
.name = "target",
.select_ops = nft_target_select_ops,
.release_ops = nft_target_release_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;
}
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);
}
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");
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