net/netfilter/nft_xfrm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *
  * Generic part shared by ipv4 and ipv6 backends.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
 #include <linux/in.h>
 #include <net/xfrm.h>

 static const struct nla_policy nft_xfrm_policy[NFTA_XFRM_MAX + 1] = {
 	[NFTA_XFRM_KEY]		= NLA_POLICY_MAX(NLA_BE32, 255),
 	[NFTA_XFRM_DIR]		= { .type = NLA_U8 },
 	[NFTA_XFRM_SPNUM]	= NLA_POLICY_MAX(NLA_BE32, 255),
 	[NFTA_XFRM_DREG]	= { .type = NLA_U32 },
 };

 struct nft_xfrm {
 	enum nft_xfrm_keys	key:8;
 	u8			dreg;
 	u8			dir;
 	u8			spnum;
 	u8			len;
 };

 static int nft_xfrm_get_init(const struct nft_ctx *ctx,
 			     const struct nft_expr *expr,
 			     const struct nlattr * const tb[])
 {
 	struct nft_xfrm *priv = nft_expr_priv(expr);
 	unsigned int len = 0;
 	u32 spnum = 0;
 	u8 dir;

 	if (!tb[NFTA_XFRM_KEY] || !tb[NFTA_XFRM_DIR] || !tb[NFTA_XFRM_DREG])
 		return -EINVAL;

 	switch (ctx->family) {
 	case NFPROTO_IPV4:
 	case NFPROTO_IPV6:
 	case NFPROTO_INET:
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	priv->key = ntohl(nla_get_be32(tb[NFTA_XFRM_KEY]));
 	switch (priv->key) {
 	case NFT_XFRM_KEY_REQID:
 	case NFT_XFRM_KEY_SPI:
 		len = sizeof(u32);
 		break;
 	case NFT_XFRM_KEY_DADDR_IP4:
 	case NFT_XFRM_KEY_SADDR_IP4:
 		len = sizeof(struct in_addr);
 		break;
 	case NFT_XFRM_KEY_DADDR_IP6:
 	case NFT_XFRM_KEY_SADDR_IP6:
 		len = sizeof(struct in6_addr);
 		break;
 	default:
 		return -EINVAL;
 	}

 	dir = nla_get_u8(tb[NFTA_XFRM_DIR]);
 	switch (dir) {
 	case XFRM_POLICY_IN:
 	case XFRM_POLICY_OUT:
 		priv->dir = dir;
 		break;
 	default:
 		return -EINVAL;
 	}

 	if (tb[NFTA_XFRM_SPNUM])
 		spnum = ntohl(nla_get_be32(tb[NFTA_XFRM_SPNUM]));

 	if (spnum >= XFRM_MAX_DEPTH)
 		return -ERANGE;

 	priv->spnum = spnum;

 	priv->len = len;
 	return nft_parse_register_store(ctx, tb[NFTA_XFRM_DREG], &priv->dreg,
 					NULL, NFT_DATA_VALUE, len);
 }

 /* Return true if key asks for daddr/saddr and current
  * state does have a valid address (BEET, TUNNEL).
  */
 static bool xfrm_state_addr_ok(enum nft_xfrm_keys k, u8 family, u8 mode)
 {
 	switch (k) {
 	case NFT_XFRM_KEY_DADDR_IP4:
 	case NFT_XFRM_KEY_SADDR_IP4:
 		if (family == NFPROTO_IPV4)
 			break;
 		return false;
 	case NFT_XFRM_KEY_DADDR_IP6:
 	case NFT_XFRM_KEY_SADDR_IP6:
 		if (family == NFPROTO_IPV6)
 			break;
 		return false;
 	default:
 		return true;
 	}

 	return mode == XFRM_MODE_BEET || mode == XFRM_MODE_TUNNEL;
 }

 static void nft_xfrm_state_get_key(const struct nft_xfrm *priv,
 				   struct nft_regs *regs,
 				   const struct xfrm_state *state)
 {
 	u32 *dest = &regs->data[priv->dreg];

 	if (!xfrm_state_addr_ok(priv->key,
 				state->props.family,
 				state->props.mode)) {
 		regs->verdict.code = NFT_BREAK;
 		return;
 	}

 	switch (priv->key) {
 	case NFT_XFRM_KEY_UNSPEC:
 	case __NFT_XFRM_KEY_MAX:
 		WARN_ON_ONCE(1);
 		break;
 	case NFT_XFRM_KEY_DADDR_IP4:
 		*dest = (__force __u32)state->id.daddr.a4;
 		return;
 	case NFT_XFRM_KEY_DADDR_IP6:
 		memcpy(dest, &state->id.daddr.in6, sizeof(struct in6_addr));
 		return;
 	case NFT_XFRM_KEY_SADDR_IP4:
 		*dest = (__force __u32)state->props.saddr.a4;
 		return;
 	case NFT_XFRM_KEY_SADDR_IP6:
 		memcpy(dest, &state->props.saddr.in6, sizeof(struct in6_addr));
 		return;
 	case NFT_XFRM_KEY_REQID:
 		*dest = state->props.reqid;
 		return;
 	case NFT_XFRM_KEY_SPI:
 		*dest = (__force __u32)state->id.spi;
 		return;
 	}

 	regs->verdict.code = NFT_BREAK;
 }

 static void nft_xfrm_get_eval_in(const struct nft_xfrm *priv,
 				    struct nft_regs *regs,
 				    const struct nft_pktinfo *pkt)
 {
 	const struct sec_path *sp = skb_sec_path(pkt->skb);
 	const struct xfrm_state *state;

 	if (sp == NULL || sp->len <= priv->spnum) {
 		regs->verdict.code = NFT_BREAK;
 		return;
 	}

 	state = sp->xvec[priv->spnum];
 	nft_xfrm_state_get_key(priv, regs, state);
 }

 static void nft_xfrm_get_eval_out(const struct nft_xfrm *priv,
 				  struct nft_regs *regs,
 				  const struct nft_pktinfo *pkt)
 {
 	const struct dst_entry *dst = skb_dst(pkt->skb);
 	int i;

 	for (i = 0; dst && dst->xfrm;
 	     dst = ((const struct xfrm_dst *)dst)->child, i++) {
 		if (i < priv->spnum)
 			continue;

 		nft_xfrm_state_get_key(priv, regs, dst->xfrm);
 		return;
 	}

 	regs->verdict.code = NFT_BREAK;
 }

 static void nft_xfrm_get_eval(const struct nft_expr *expr,
 			      struct nft_regs *regs,
 			      const struct nft_pktinfo *pkt)
 {
 	const struct nft_xfrm *priv = nft_expr_priv(expr);

 	switch (priv->dir) {
 	case XFRM_POLICY_IN:
 		nft_xfrm_get_eval_in(priv, regs, pkt);
 		break;
 	case XFRM_POLICY_OUT:
 		nft_xfrm_get_eval_out(priv, regs, pkt);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		regs->verdict.code = NFT_BREAK;
 		break;
 	}
 }

 static int nft_xfrm_get_dump(struct sk_buff *skb,
 			     const struct nft_expr *expr, bool reset)
 {
 	const struct nft_xfrm *priv = nft_expr_priv(expr);

 	if (nft_dump_register(skb, NFTA_XFRM_DREG, priv->dreg))
 		return -1;

 	if (nla_put_be32(skb, NFTA_XFRM_KEY, htonl(priv->key)))
 		return -1;
 	if (nla_put_u8(skb, NFTA_XFRM_DIR, priv->dir))
 		return -1;
 	if (nla_put_be32(skb, NFTA_XFRM_SPNUM, htonl(priv->spnum)))
 		return -1;

 	return 0;
 }

 static int nft_xfrm_validate(const struct nft_ctx *ctx, const struct nft_expr *expr)
 {
 	const struct nft_xfrm *priv = nft_expr_priv(expr);
 	unsigned int hooks;

 	if (ctx->family != NFPROTO_IPV4 &&
 	    ctx->family != NFPROTO_IPV6 &&
 	    ctx->family != NFPROTO_INET)
 		return -EOPNOTSUPP;

 	switch (priv->dir) {
 	case XFRM_POLICY_IN:
 		hooks = (1 << NF_INET_FORWARD) |
 			(1 << NF_INET_LOCAL_IN) |
 			(1 << NF_INET_PRE_ROUTING);
 		break;
 	case XFRM_POLICY_OUT:
 		hooks = (1 << NF_INET_FORWARD) |
 			(1 << NF_INET_LOCAL_OUT) |
 			(1 << NF_INET_POST_ROUTING);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}

 	return nft_chain_validate_hooks(ctx->chain, hooks);
 }

 static bool nft_xfrm_reduce(struct nft_regs_track *track,
 			    const struct nft_expr *expr)
 {
 	const struct nft_xfrm *priv = nft_expr_priv(expr);
 	const struct nft_xfrm *xfrm;

 	if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
 		nft_reg_track_update(track, expr, priv->dreg, priv->len);
 		return false;
 	}

 	xfrm = nft_expr_priv(track->regs[priv->dreg].selector);
 	if (priv->key != xfrm->key ||
 	    priv->dreg != xfrm->dreg ||
 	    priv->dir != xfrm->dir ||
 	    priv->spnum != xfrm->spnum) {
 		nft_reg_track_update(track, expr, priv->dreg, priv->len);
 		return false;
 	}

 	if (!track->regs[priv->dreg].bitwise)
 		return true;

 	return nft_expr_reduce_bitwise(track, expr);
 }

 static struct nft_expr_type nft_xfrm_type;
 static const struct nft_expr_ops nft_xfrm_get_ops = {
 	.type		= &nft_xfrm_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_xfrm)),
 	.eval		= nft_xfrm_get_eval,
 	.init		= nft_xfrm_get_init,
 	.dump		= nft_xfrm_get_dump,
 	.validate	= nft_xfrm_validate,
 	.reduce		= nft_xfrm_reduce,
 };

 static struct nft_expr_type nft_xfrm_type __read_mostly = {
 	.name		= "xfrm",
 	.ops		= &nft_xfrm_get_ops,
 	.policy		= nft_xfrm_policy,
 	.maxattr	= NFTA_XFRM_MAX,
 	.owner		= THIS_MODULE,
 };

 static int __init nft_xfrm_module_init(void)
 {
 	return nft_register_expr(&nft_xfrm_type);
 }

 static void __exit nft_xfrm_module_exit(void)
 {
 	nft_unregister_expr(&nft_xfrm_type);
 }

 module_init(nft_xfrm_module_init);
 module_exit(nft_xfrm_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("nf_tables: xfrm/IPSec matching");
 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
 MODULE_AUTHOR("Máté Eckl <ecklm94@gmail.com>");
 MODULE_ALIAS_NFT_EXPR("xfrm");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	*
	* Generic part shared by ipv4 and ipv6 backends.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/netlink.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables_core.h>
	#include <net/netfilter/nf_tables.h>
	#include <linux/in.h>
	#include <net/xfrm.h>

	static const struct nla_policy nft_xfrm_policy[NFTA_XFRM_MAX + 1] = {
	[NFTA_XFRM_KEY] = NLA_POLICY_MAX(NLA_BE32, 255),
	[NFTA_XFRM_DIR] = { .type = NLA_U8 },
	[NFTA_XFRM_SPNUM] = NLA_POLICY_MAX(NLA_BE32, 255),
	[NFTA_XFRM_DREG] = { .type = NLA_U32 },
	};

	struct nft_xfrm {
	enum nft_xfrm_keys key:8;
	u8 dreg;
	u8 dir;
	u8 spnum;
	u8 len;
	};

	static int nft_xfrm_get_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_xfrm *priv = nft_expr_priv(expr);
	unsigned int len = 0;
	u32 spnum = 0;
	u8 dir;

	if (!tb[NFTA_XFRM_KEY] \|\| !tb[NFTA_XFRM_DIR] \|\| !tb[NFTA_XFRM_DREG])
	return -EINVAL;

	switch (ctx->family) {
	case NFPROTO_IPV4:
	case NFPROTO_IPV6:
	case NFPROTO_INET:
	break;
	default:
	return -EOPNOTSUPP;
	}

	priv->key = ntohl(nla_get_be32(tb[NFTA_XFRM_KEY]));
	switch (priv->key) {
	case NFT_XFRM_KEY_REQID:
	case NFT_XFRM_KEY_SPI:
	len = sizeof(u32);
	break;
	case NFT_XFRM_KEY_DADDR_IP4:
	case NFT_XFRM_KEY_SADDR_IP4:
	len = sizeof(struct in_addr);
	break;
	case NFT_XFRM_KEY_DADDR_IP6:
	case NFT_XFRM_KEY_SADDR_IP6:
	len = sizeof(struct in6_addr);
	break;
	default:
	return -EINVAL;
	}

	dir = nla_get_u8(tb[NFTA_XFRM_DIR]);
	switch (dir) {
	case XFRM_POLICY_IN:
	case XFRM_POLICY_OUT:
	priv->dir = dir;
	break;
	default:
	return -EINVAL;
	}

	if (tb[NFTA_XFRM_SPNUM])
	spnum = ntohl(nla_get_be32(tb[NFTA_XFRM_SPNUM]));

	if (spnum >= XFRM_MAX_DEPTH)
	return -ERANGE;

	priv->spnum = spnum;

	priv->len = len;
	return nft_parse_register_store(ctx, tb[NFTA_XFRM_DREG], &priv->dreg,
	NULL, NFT_DATA_VALUE, len);
	}

	/* Return true if key asks for daddr/saddr and current
	* state does have a valid address (BEET, TUNNEL).
	*/
	static bool xfrm_state_addr_ok(enum nft_xfrm_keys k, u8 family, u8 mode)
	{
	switch (k) {
	case NFT_XFRM_KEY_DADDR_IP4:
	case NFT_XFRM_KEY_SADDR_IP4:
	if (family == NFPROTO_IPV4)
	break;
	return false;
	case NFT_XFRM_KEY_DADDR_IP6:
	case NFT_XFRM_KEY_SADDR_IP6:
	if (family == NFPROTO_IPV6)
	break;
	return false;
	default:
	return true;
	}

	return mode == XFRM_MODE_BEET \|\| mode == XFRM_MODE_TUNNEL;
	}

	static void nft_xfrm_state_get_key(const struct nft_xfrm *priv,
	struct nft_regs *regs,
	const struct xfrm_state *state)
	{
	u32 *dest = &regs->data[priv->dreg];

	if (!xfrm_state_addr_ok(priv->key,
	state->props.family,
	state->props.mode)) {
	regs->verdict.code = NFT_BREAK;
	return;
	}

	switch (priv->key) {
	case NFT_XFRM_KEY_UNSPEC:
	case __NFT_XFRM_KEY_MAX:
	WARN_ON_ONCE(1);
	break;
	case NFT_XFRM_KEY_DADDR_IP4:
	*dest = (__force __u32)state->id.daddr.a4;
	return;
	case NFT_XFRM_KEY_DADDR_IP6:
	memcpy(dest, &state->id.daddr.in6, sizeof(struct in6_addr));
	return;
	case NFT_XFRM_KEY_SADDR_IP4:
	*dest = (__force __u32)state->props.saddr.a4;
	return;
	case NFT_XFRM_KEY_SADDR_IP6:
	memcpy(dest, &state->props.saddr.in6, sizeof(struct in6_addr));
	return;
	case NFT_XFRM_KEY_REQID:
	*dest = state->props.reqid;
	return;
	case NFT_XFRM_KEY_SPI:
	*dest = (__force __u32)state->id.spi;
	return;
	}

	regs->verdict.code = NFT_BREAK;
	}

	static void nft_xfrm_get_eval_in(const struct nft_xfrm *priv,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	const struct sec_path *sp = skb_sec_path(pkt->skb);
	const struct xfrm_state *state;

	if (sp == NULL \|\| sp->len <= priv->spnum) {
	regs->verdict.code = NFT_BREAK;
	return;
	}

	state = sp->xvec[priv->spnum];
	nft_xfrm_state_get_key(priv, regs, state);
	}

	static void nft_xfrm_get_eval_out(const struct nft_xfrm *priv,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	const struct dst_entry *dst = skb_dst(pkt->skb);
	int i;

	for (i = 0; dst && dst->xfrm;
	dst = ((const struct xfrm_dst *)dst)->child, i++) {
	if (i < priv->spnum)
	continue;

	nft_xfrm_state_get_key(priv, regs, dst->xfrm);
	return;
	}

	regs->verdict.code = NFT_BREAK;
	}

	static void nft_xfrm_get_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	const struct nft_xfrm *priv = nft_expr_priv(expr);

	switch (priv->dir) {
	case XFRM_POLICY_IN:
	nft_xfrm_get_eval_in(priv, regs, pkt);
	break;
	case XFRM_POLICY_OUT:
	nft_xfrm_get_eval_out(priv, regs, pkt);
	break;
	default:
	WARN_ON_ONCE(1);
	regs->verdict.code = NFT_BREAK;
	break;
	}
	}

	static int nft_xfrm_get_dump(struct sk_buff *skb,
	const struct nft_expr *expr, bool reset)
	{
	const struct nft_xfrm *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_XFRM_DREG, priv->dreg))
	return -1;

	if (nla_put_be32(skb, NFTA_XFRM_KEY, htonl(priv->key)))
	return -1;
	if (nla_put_u8(skb, NFTA_XFRM_DIR, priv->dir))
	return -1;
	if (nla_put_be32(skb, NFTA_XFRM_SPNUM, htonl(priv->spnum)))
	return -1;

	return 0;
	}

	static int nft_xfrm_validate(const struct nft_ctx ctx, const struct nft_expr expr)
	{
	const struct nft_xfrm *priv = nft_expr_priv(expr);
	unsigned int hooks;

	if (ctx->family != NFPROTO_IPV4 &&
	ctx->family != NFPROTO_IPV6 &&
	ctx->family != NFPROTO_INET)
	return -EOPNOTSUPP;

	switch (priv->dir) {
	case XFRM_POLICY_IN:
	hooks = (1 << NF_INET_FORWARD) \|
	(1 << NF_INET_LOCAL_IN) \|
	(1 << NF_INET_PRE_ROUTING);
	break;
	case XFRM_POLICY_OUT:
	hooks = (1 << NF_INET_FORWARD) \|
	(1 << NF_INET_LOCAL_OUT) \|
	(1 << NF_INET_POST_ROUTING);
	break;
	default:
	WARN_ON_ONCE(1);
	return -EINVAL;
	}

	return nft_chain_validate_hooks(ctx->chain, hooks);
	}

	static bool nft_xfrm_reduce(struct nft_regs_track *track,
	const struct nft_expr *expr)
	{
	const struct nft_xfrm *priv = nft_expr_priv(expr);
	const struct nft_xfrm *xfrm;

	if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
	nft_reg_track_update(track, expr, priv->dreg, priv->len);
	return false;
	}

	xfrm = nft_expr_priv(track->regs[priv->dreg].selector);
	if (priv->key != xfrm->key \|\|
	priv->dreg != xfrm->dreg \|\|
	priv->dir != xfrm->dir \|\|
	priv->spnum != xfrm->spnum) {
	nft_reg_track_update(track, expr, priv->dreg, priv->len);
	return false;
	}

	if (!track->regs[priv->dreg].bitwise)
	return true;

	return nft_expr_reduce_bitwise(track, expr);
	}

	static struct nft_expr_type nft_xfrm_type;
	static const struct nft_expr_ops nft_xfrm_get_ops = {
	.type = &nft_xfrm_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_xfrm)),
	.eval = nft_xfrm_get_eval,
	.init = nft_xfrm_get_init,
	.dump = nft_xfrm_get_dump,
	.validate = nft_xfrm_validate,
	.reduce = nft_xfrm_reduce,
	};

	static struct nft_expr_type nft_xfrm_type __read_mostly = {
	.name = "xfrm",
	.ops = &nft_xfrm_get_ops,
	.policy = nft_xfrm_policy,
	.maxattr = NFTA_XFRM_MAX,
	.owner = THIS_MODULE,
	};

	static int __init nft_xfrm_module_init(void)
	{
	return nft_register_expr(&nft_xfrm_type);
	}

	static void __exit nft_xfrm_module_exit(void)
	{
	nft_unregister_expr(&nft_xfrm_type);
	}

	module_init(nft_xfrm_module_init);
	module_exit(nft_xfrm_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("nf_tables: xfrm/IPSec matching");
	MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
	MODULE_AUTHOR("Máté Eckl <ecklm94@gmail.com>");
	MODULE_ALIAS_NFT_EXPR("xfrm");