Revision a82c25c366b0963d33ddf699196e6cf57f6d89b1 authored by Florian Westphal on 08 March 2022, 12:52:11 UTC, committed by Florian Westphal on 08 March 2022, 12:52:11 UTC
This reverts commit 878aed8db324bec64f3c3f956e64d5ae7375a5de. This change breaks existing setups where conntrack is used with asymmetric paths. In these cases, the NAT transformation occurs on the syn-ack instead of the syn: 1. SYN x:12345 -> y -> 443 // sent by initiator, receiverd by responder 2. SYNACK y:443 -> x:12345 // First packet seen by conntrack, as sent by responder 3. tuple_force_port_remap() gets called, sees: 'tcp from 443 to port 12345 NAT' -> pick a new source port, inititor receives 4. SYNACK y:$RANDOM -> x:12345 // connection is never established While its possible to avoid the breakage with NOTRACK rules, a kernel update should not break working setups. An alternative to the revert is to augment conntrack to tag mid-stream connections plus more code in the nat core to skip NAT for such connections, however, this leads to more interaction/integration between conntrack and NAT. Therefore, revert, users will need to add explicit nat rules to avoid port shadowing. Link: https://lore.kernel.org/netfilter-devel/20220302105908.GA5852@breakpoint.cc/#R Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2051413 Signed-off-by: Florian Westphal <fw@strlen.de>
1 parent f8e9bd3
nft_cmp.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/if_arp.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables_offload.h>
#include <net/netfilter/nf_tables.h>
struct nft_cmp_expr {
struct nft_data data;
u8 sreg;
u8 len;
enum nft_cmp_ops op:8;
};
void nft_cmp_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
int d;
d = memcmp(®s->data[priv->sreg], &priv->data, priv->len);
switch (priv->op) {
case NFT_CMP_EQ:
if (d != 0)
goto mismatch;
break;
case NFT_CMP_NEQ:
if (d == 0)
goto mismatch;
break;
case NFT_CMP_LT:
if (d == 0)
goto mismatch;
fallthrough;
case NFT_CMP_LTE:
if (d > 0)
goto mismatch;
break;
case NFT_CMP_GT:
if (d == 0)
goto mismatch;
fallthrough;
case NFT_CMP_GTE:
if (d < 0)
goto mismatch;
break;
}
return;
mismatch:
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = {
[NFTA_CMP_SREG] = { .type = NLA_U32 },
[NFTA_CMP_OP] = { .type = NLA_U32 },
[NFTA_CMP_DATA] = { .type = NLA_NESTED },
};
static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_cmp_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc;
int err;
err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return err;
if (desc.type != NFT_DATA_VALUE) {
err = -EINVAL;
nft_data_release(&priv->data, desc.type);
return err;
}
err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len);
if (err < 0)
return err;
priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
priv->len = desc.len;
return 0;
}
static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
union nft_cmp_offload_data {
u16 val16;
u32 val32;
u64 val64;
};
static void nft_payload_n2h(union nft_cmp_offload_data *data,
const u8 *val, u32 len)
{
switch (len) {
case 2:
data->val16 = ntohs(*((u16 *)val));
break;
case 4:
data->val32 = ntohl(*((u32 *)val));
break;
case 8:
data->val64 = be64_to_cpu(*((u64 *)val));
break;
default:
WARN_ON_ONCE(1);
break;
}
}
static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_cmp_expr *priv)
{
struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
union nft_cmp_offload_data _data, _datamask;
u8 *mask = (u8 *)&flow->match.mask;
u8 *key = (u8 *)&flow->match.key;
u8 *data, *datamask;
if (priv->op != NFT_CMP_EQ || priv->len > reg->len)
return -EOPNOTSUPP;
if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) {
nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len);
nft_payload_n2h(&_datamask, (u8 *)®->mask, reg->len);
data = (u8 *)&_data;
datamask = (u8 *)&_datamask;
} else {
data = (u8 *)&priv->data;
datamask = (u8 *)®->mask;
}
memcpy(key + reg->offset, data, reg->len);
memcpy(mask + reg->offset, datamask, reg->len);
flow->match.dissector.used_keys |= BIT(reg->key);
flow->match.dissector.offset[reg->key] = reg->base_offset;
if (reg->key == FLOW_DISSECTOR_KEY_META &&
reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) &&
nft_reg_load16(priv->data.data) != ARPHRD_ETHER)
return -EOPNOTSUPP;
nft_offload_update_dependency(ctx, &priv->data, reg->len);
return 0;
}
static int nft_cmp_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_expr *expr)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
return __nft_cmp_offload(ctx, flow, priv);
}
static const struct nft_expr_ops nft_cmp_ops = {
.type = &nft_cmp_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
.eval = nft_cmp_eval,
.init = nft_cmp_init,
.dump = nft_cmp_dump,
.offload = nft_cmp_offload,
};
static int nft_cmp_fast_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc;
struct nft_data data;
int err;
err = nft_data_init(NULL, &data, sizeof(data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return err;
err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len);
if (err < 0)
return err;
desc.len *= BITS_PER_BYTE;
priv->mask = nft_cmp_fast_mask(desc.len);
priv->data = data.data[0] & priv->mask;
priv->len = desc.len;
priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ;
return 0;
}
static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_expr *expr)
{
const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
struct nft_cmp_expr cmp = {
.data = {
.data = {
[0] = priv->data,
},
},
.sreg = priv->sreg,
.len = priv->len / BITS_PER_BYTE,
.op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ,
};
return __nft_cmp_offload(ctx, flow, &cmp);
}
static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ;
struct nft_data data;
if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op)))
goto nla_put_failure;
data.data[0] = priv->data;
if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
const struct nft_expr_ops nft_cmp_fast_ops = {
.type = &nft_cmp_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
.eval = NULL, /* inlined */
.init = nft_cmp_fast_init,
.dump = nft_cmp_fast_dump,
.offload = nft_cmp_fast_offload,
};
static const struct nft_expr_ops *
nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
{
struct nft_data_desc desc;
struct nft_data data;
enum nft_cmp_ops op;
int err;
if (tb[NFTA_CMP_SREG] == NULL ||
tb[NFTA_CMP_OP] == NULL ||
tb[NFTA_CMP_DATA] == NULL)
return ERR_PTR(-EINVAL);
op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
switch (op) {
case NFT_CMP_EQ:
case NFT_CMP_NEQ:
case NFT_CMP_LT:
case NFT_CMP_LTE:
case NFT_CMP_GT:
case NFT_CMP_GTE:
break;
default:
return ERR_PTR(-EINVAL);
}
err = nft_data_init(NULL, &data, sizeof(data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return ERR_PTR(err);
if (desc.type != NFT_DATA_VALUE)
goto err1;
if (desc.len <= sizeof(u32) && (op == NFT_CMP_EQ || op == NFT_CMP_NEQ))
return &nft_cmp_fast_ops;
return &nft_cmp_ops;
err1:
nft_data_release(&data, desc.type);
return ERR_PTR(-EINVAL);
}
struct nft_expr_type nft_cmp_type __read_mostly = {
.name = "cmp",
.select_ops = nft_cmp_select_ops,
.policy = nft_cmp_policy,
.maxattr = NFTA_CMP_MAX,
.owner = THIS_MODULE,
};
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