[linux-block.git] / net / netfilter / nft_exthdr.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 */

#include <asm/unaligned.h>
#include <linux/kernel.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 <net/tcp.h>

struct nft_exthdr {
	u8			type;
	u8			offset;
	u8			len;
	u8			op;
	u8			dreg;
	u8			sreg;
	u8			flags;
};

static unsigned int optlen(const u8 *opt, unsigned int offset)
{
	/* Beware zero-length options: make finite progress */
	if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
		return 1;
	else
		return opt[offset + 1];
}

static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
				 struct nft_regs *regs,
				 const struct nft_pktinfo *pkt)
{
	struct nft_exthdr *priv = nft_expr_priv(expr);
	u32 *dest = &regs->data[priv->dreg];
	unsigned int offset = 0;
	int err;

	err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
		nft_reg_store8(dest, err >= 0);
		return;
	} else if (err < 0) {
		goto err;
	}
	offset += priv->offset;

	dest[priv->len / NFT_REG32_SIZE] = 0;
	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
		goto err;
	return;
err:
	regs->verdict.code = NFT_BREAK;
}

/* find the offset to specified option.
 *
 * If target header is found, its offset is set in *offset and return option
 * number. Otherwise, return negative error.
 *
 * If the first fragment doesn't contain the End of Options it is considered
 * invalid.
 */
static int ipv4_find_option(struct net *net, struct sk_buff *skb,
			    unsigned int *offset, int target)
{
	unsigned char optbuf[sizeof(struct ip_options) + 40];
	struct ip_options *opt = (struct ip_options *)optbuf;
	struct iphdr *iph, _iph;
	unsigned int start;
	bool found = false;
	__be32 info;
	int optlen;

	iph = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
	if (!iph)
		return -EBADMSG;
	start = sizeof(struct iphdr);

	optlen = iph->ihl * 4 - (int)sizeof(struct iphdr);
	if (optlen <= 0)
		return -ENOENT;

	memset(opt, 0, sizeof(struct ip_options));
	/* Copy the options since __ip_options_compile() modifies
	 * the options.
	 */
	if (skb_copy_bits(skb, start, opt->__data, optlen))
		return -EBADMSG;
	opt->optlen = optlen;

	if (__ip_options_compile(net, opt, NULL, &info))
		return -EBADMSG;

	switch (target) {
	case IPOPT_SSRR:
	case IPOPT_LSRR:
		if (!opt->srr)
			break;
		found = target == IPOPT_SSRR ? opt->is_strictroute :
					       !opt->is_strictroute;
		if (found)
			*offset = opt->srr + start;
		break;
	case IPOPT_RR:
		if (!opt->rr)
			break;
		*offset = opt->rr + start;
		found = true;
		break;
	case IPOPT_RA:
		if (!opt->router_alert)
			break;
		*offset = opt->router_alert + start;
		found = true;
		break;
	default:
		return -EOPNOTSUPP;
	}
	return found ? target : -ENOENT;
}

static void nft_exthdr_ipv4_eval(const struct nft_expr *expr,
				 struct nft_regs *regs,
				 const struct nft_pktinfo *pkt)
{
	struct nft_exthdr *priv = nft_expr_priv(expr);
	u32 *dest = &regs->data[priv->dreg];
	struct sk_buff *skb = pkt->skb;
	unsigned int offset;
	int err;

	if (skb->protocol != htons(ETH_P_IP))
		goto err;

	err = ipv4_find_option(nft_net(pkt), skb, &offset, priv->type);
	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
		nft_reg_store8(dest, err >= 0);
		return;
	} else if (err < 0) {
		goto err;
	}
	offset += priv->offset;

	dest[priv->len / NFT_REG32_SIZE] = 0;
	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
		goto err;
	return;
err:
	regs->verdict.code = NFT_BREAK;
}

static void *
nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
		       unsigned int len, void *buffer, unsigned int *tcphdr_len)
{
	struct tcphdr *tcph;

	if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
		return NULL;

	tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buffer);
	if (!tcph)
		return NULL;

	*tcphdr_len = __tcp_hdrlen(tcph);
	if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len)
		return NULL;

	return skb_header_pointer(pkt->skb, pkt->xt.thoff, *tcphdr_len, buffer);
}

static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
				struct nft_regs *regs,
				const struct nft_pktinfo *pkt)
{
	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
	struct nft_exthdr *priv = nft_expr_priv(expr);
	unsigned int i, optl, tcphdr_len, offset;
	u32 *dest = &regs->data[priv->dreg];
	struct tcphdr *tcph;
	u8 *opt;

	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
	if (!tcph)
		goto err;

	opt = (u8 *)tcph;
	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
		optl = optlen(opt, i);

		if (priv->type != opt[i])
			continue;

		if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
			goto err;

		offset = i + priv->offset;
		if (priv->flags & NFT_EXTHDR_F_PRESENT) {
			*dest = 1;
		} else {
			dest[priv->len / NFT_REG32_SIZE] = 0;
			memcpy(dest, opt + offset, priv->len);
		}

		return;
	}

err:
	if (priv->flags & NFT_EXTHDR_F_PRESENT)
		*dest = 0;
	else
		regs->verdict.code = NFT_BREAK;
}

static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
				    struct nft_regs *regs,
				    const struct nft_pktinfo *pkt)
{
	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
	struct nft_exthdr *priv = nft_expr_priv(expr);
	unsigned int i, optl, tcphdr_len, offset;
	struct tcphdr *tcph;
	u8 *opt;

	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
	if (!tcph)
		return;

	opt = (u8 *)tcph;
	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
		union {
			__be16 v16;
			__be32 v32;
		} old, new;

		optl = optlen(opt, i);

		if (priv->type != opt[i])
			continue;

		if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
			return;

		if (skb_ensure_writable(pkt->skb,
					pkt->xt.thoff + i + priv->len))
			return;

		tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
					      &tcphdr_len);
		if (!tcph)
			return;

		offset = i + priv->offset;

		switch (priv->len) {
		case 2:
			old.v16 = get_unaligned((u16 *)(opt + offset));
			new.v16 = (__force __be16)nft_reg_load16(
				&regs->data[priv->sreg]);

			switch (priv->type) {
			case TCPOPT_MSS:
				/* increase can cause connection to stall */
				if (ntohs(old.v16) <= ntohs(new.v16))
					return;
			break;
			}

			if (old.v16 == new.v16)
				return;

			put_unaligned(new.v16, (u16*)(opt + offset));
			inet_proto_csum_replace2(&tcph->check, pkt->skb,
						 old.v16, new.v16, false);
			break;
		case 4:
			new.v32 = regs->data[priv->sreg];
			old.v32 = get_unaligned((u32 *)(opt + offset));

			if (old.v32 == new.v32)
				return;

			put_unaligned(new.v32, (u32*)(opt + offset));
			inet_proto_csum_replace4(&tcph->check, pkt->skb,
						 old.v32, new.v32, false);
			break;
		default:
			WARN_ON_ONCE(1);
			break;
		}

		return;
	}
}

static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
	[NFTA_EXTHDR_DREG]		= { .type = NLA_U32 },
	[NFTA_EXTHDR_TYPE]		= { .type = NLA_U8 },
	[NFTA_EXTHDR_OFFSET]		= { .type = NLA_U32 },
	[NFTA_EXTHDR_LEN]		= { .type = NLA_U32 },
	[NFTA_EXTHDR_FLAGS]		= { .type = NLA_U32 },
	[NFTA_EXTHDR_OP]		= { .type = NLA_U32 },
	[NFTA_EXTHDR_SREG]		= { .type = NLA_U32 },
};

static int nft_exthdr_init(const struct nft_ctx *ctx,
			   const struct nft_expr *expr,
			   const struct nlattr * const tb[])
{
	struct nft_exthdr *priv = nft_expr_priv(expr);
	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
	int err;

	if (!tb[NFTA_EXTHDR_DREG] ||
	    !tb[NFTA_EXTHDR_TYPE] ||
	    !tb[NFTA_EXTHDR_OFFSET] ||
	    !tb[NFTA_EXTHDR_LEN])
		return -EINVAL;

	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
	if (err < 0)
		return err;

	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
	if (err < 0)
		return err;

	if (tb[NFTA_EXTHDR_FLAGS]) {
		err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
		if (err < 0)
			return err;

		if (flags & ~NFT_EXTHDR_F_PRESENT)
			return -EINVAL;
	}

	if (tb[NFTA_EXTHDR_OP]) {
		err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
		if (err < 0)
			return err;
	}

	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
	priv->offset = offset;
	priv->len    = len;
	priv->flags  = flags;
	priv->op     = op;

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

static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
				   const struct nft_expr *expr,
				   const struct nlattr * const tb[])
{
	struct nft_exthdr *priv = nft_expr_priv(expr);
	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
	int err;

	if (!tb[NFTA_EXTHDR_SREG] ||
	    !tb[NFTA_EXTHDR_TYPE] ||
	    !tb[NFTA_EXTHDR_OFFSET] ||
	    !tb[NFTA_EXTHDR_LEN])
		return -EINVAL;

	if (tb[NFTA_EXTHDR_DREG] || tb[NFTA_EXTHDR_FLAGS])
		return -EINVAL;

	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
	if (err < 0)
		return err;

	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
	if (err < 0)
		return err;

	if (offset < 2)
		return -EOPNOTSUPP;

	switch (len) {
	case 2: break;
	case 4: break;
	default:
		return -EOPNOTSUPP;
	}

	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
	if (err < 0)
		return err;

	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
	priv->offset = offset;
	priv->len    = len;
	priv->flags  = flags;
	priv->op     = op;

	return nft_parse_register_load(tb[NFTA_EXTHDR_SREG], &priv->sreg,
				       priv->len);
}

static int nft_exthdr_ipv4_init(const struct nft_ctx *ctx,
				const struct nft_expr *expr,
				const struct nlattr * const tb[])
{
	struct nft_exthdr *priv = nft_expr_priv(expr);
	int err = nft_exthdr_init(ctx, expr, tb);

	if (err < 0)
		return err;

	switch (priv->type) {
	case IPOPT_SSRR:
	case IPOPT_LSRR:
	case IPOPT_RR:
	case IPOPT_RA:
		break;
	default:
		return -EOPNOTSUPP;
	}
	return 0;
}

static int nft_exthdr_dump_common(struct sk_buff *skb, const struct nft_exthdr *priv)
{
	if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	const struct nft_exthdr *priv = nft_expr_priv(expr);

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

	return nft_exthdr_dump_common(skb, priv);
}

static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr)
{
	const struct nft_exthdr *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg))
		return -1;

	return nft_exthdr_dump_common(skb, priv);
}

static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
	.type		= &nft_exthdr_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	.eval		= nft_exthdr_ipv6_eval,
	.init		= nft_exthdr_init,
	.dump		= nft_exthdr_dump,
};

static const struct nft_expr_ops nft_exthdr_ipv4_ops = {
	.type		= &nft_exthdr_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	.eval		= nft_exthdr_ipv4_eval,
	.init		= nft_exthdr_ipv4_init,
	.dump		= nft_exthdr_dump,
};

static const struct nft_expr_ops nft_exthdr_tcp_ops = {
	.type		= &nft_exthdr_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	.eval		= nft_exthdr_tcp_eval,
	.init		= nft_exthdr_init,
	.dump		= nft_exthdr_dump,
};

static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
	.type		= &nft_exthdr_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	.eval		= nft_exthdr_tcp_set_eval,
	.init		= nft_exthdr_tcp_set_init,
	.dump		= nft_exthdr_dump_set,
};

static const struct nft_expr_ops *
nft_exthdr_select_ops(const struct nft_ctx *ctx,
		      const struct nlattr * const tb[])
{
	u32 op;

	if (!tb[NFTA_EXTHDR_OP])
		return &nft_exthdr_ipv6_ops;

	if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG])
		return ERR_PTR(-EOPNOTSUPP);

	op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP]));
	switch (op) {
	case NFT_EXTHDR_OP_TCPOPT:
		if (tb[NFTA_EXTHDR_SREG])
			return &nft_exthdr_tcp_set_ops;
		if (tb[NFTA_EXTHDR_DREG])
			return &nft_exthdr_tcp_ops;
		break;
	case NFT_EXTHDR_OP_IPV6:
		if (tb[NFTA_EXTHDR_DREG])
			return &nft_exthdr_ipv6_ops;
		break;
	case NFT_EXTHDR_OP_IPV4:
		if (ctx->family != NFPROTO_IPV6) {
			if (tb[NFTA_EXTHDR_DREG])
				return &nft_exthdr_ipv4_ops;
		}
		break;
	}

	return ERR_PTR(-EOPNOTSUPP);
}

struct nft_expr_type nft_exthdr_type __read_mostly = {
	.name		= "exthdr",
	.select_ops	= nft_exthdr_select_ops,
	.policy		= nft_exthdr_policy,
	.maxattr	= NFTA_EXTHDR_MAX,
	.owner		= THIS_MODULE,
};
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
96518518 PM	2	/*
	3	* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
	4	*
96518518 PM	5	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	6	*/
	7
99d1712b	8	#include <asm/unaligned.h>
96518518	9	#include <linux/kernel.h>
96518518 PM	10	#include <linux/netlink.h>
	11	#include <linux/netfilter.h>
	12	#include <linux/netfilter/nf_tables.h>
d0103158	13	#include <net/netfilter/nf_tables_core.h>
96518518	14	#include <net/netfilter/nf_tables.h>
935b7f64	15	#include <net/tcp.h>
96518518 PM	16
	17	struct nft_exthdr {
	18	u8 type;
	19	u8 offset;
	20	u8 len;
935b7f64	21	u8 op;
345023b0	22	u8 dreg;
4f16d25c	23	u8 sreg;
c078ca3b	24	u8 flags;
96518518 PM	25	};
96518518 PM	26
935b7f64 MM	27	static unsigned int optlen(const u8 *opt, unsigned int offset)
	28	{
	29	/* Beware zero-length options: make finite progress */
	30	if (opt[offset] <= TCPOPT_NOP \|\| opt[offset + 1] == 0)
	31	return 1;
	32	else
	33	return opt[offset + 1];
	34	}
	35
	36	static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
	37	struct nft_regs *regs,
	38	const struct nft_pktinfo *pkt)
96518518 PM	39	{
96518518 PM	40	struct nft_exthdr *priv = nft_expr_priv(expr);
49499c3e	41	u32 *dest = &regs->data[priv->dreg];
540436c8	42	unsigned int offset = 0;
96518518 PM	43	int err;
	44
	45	err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
c078ca3b	46	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
b4283366	47	nft_reg_store8(dest, err >= 0);
c078ca3b PS	48	return;
c078ca3b PS	49	} else if (err < 0) {
96518518	50	goto err;
c078ca3b	51	}
96518518 PM	52	offset += priv->offset;
96518518 PM	53
49499c3e	54	dest[priv->len / NFT_REG32_SIZE] = 0;
fad136ea	55	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
96518518 PM	56	goto err;
	57	return;
	58	err:
a55e22e9	59	regs->verdict.code = NFT_BREAK;
96518518 PM	60	}
96518518 PM	61
dbb5281a SS	62	/* find the offset to specified option.
	63	*
	64	* If target header is found, its offset is set in *offset and return option
	65	* number. Otherwise, return negative error.
	66	*
	67	* If the first fragment doesn't contain the End of Options it is considered
	68	* invalid.
	69	*/
	70	static int ipv4_find_option(struct net net, struct sk_buff skb,
	71	unsigned int *offset, int target)
	72	{
	73	unsigned char optbuf[sizeof(struct ip_options) + 40];
	74	struct ip_options opt = (struct ip_options )optbuf;
	75	struct iphdr *iph, _iph;
	76	unsigned int start;
	77	bool found = false;
	78	__be32 info;
	79	int optlen;
	80
	81	iph = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
	82	if (!iph)
	83	return -EBADMSG;
	84	start = sizeof(struct iphdr);
	85
	86	optlen = iph->ihl * 4 - (int)sizeof(struct iphdr);
	87	if (optlen <= 0)
	88	return -ENOENT;
	89
	90	memset(opt, 0, sizeof(struct ip_options));
	91	/* Copy the options since __ip_options_compile() modifies
	92	* the options.
	93	*/
	94	if (skb_copy_bits(skb, start, opt->__data, optlen))
	95	return -EBADMSG;
	96	opt->optlen = optlen;
	97
	98	if (__ip_options_compile(net, opt, NULL, &info))
	99	return -EBADMSG;
	100
	101	switch (target) {
	102	case IPOPT_SSRR:
	103	case IPOPT_LSRR:
	104	if (!opt->srr)
	105	break;
	106	found = target == IPOPT_SSRR ? opt->is_strictroute :
	107	!opt->is_strictroute;
	108	if (found)
	109	*offset = opt->srr + start;
	110	break;
	111	case IPOPT_RR:
	112	if (!opt->rr)
	113	break;
	114	*offset = opt->rr + start;
	115	found = true;
	116	break;
	117	case IPOPT_RA:
	118	if (!opt->router_alert)
	119	break;
	120	*offset = opt->router_alert + start;
	121	found = true;
	122	break;
	123	default:
	124	return -EOPNOTSUPP;
	125	}
126	return found ? target : -ENOENT;
127	}
128
129	static void nft_exthdr_ipv4_eval(const struct nft_expr *expr,
130	struct nft_regs *regs,
131	const struct nft_pktinfo *pkt)
132	{
133	struct nft_exthdr *priv = nft_expr_priv(expr);
134	u32 *dest = &regs->data[priv->dreg];
135	struct sk_buff *skb = pkt->skb;
136	unsigned int offset;
137	int err;
138
139	if (skb->protocol != htons(ETH_P_IP))
140	goto err;
141
142	err = ipv4_find_option(nft_net(pkt), skb, &offset, priv->type);
143	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
b4283366	144	nft_reg_store8(dest, err >= 0);
dbb5281a SS	145	return;
	146	} else if (err < 0) {
	147	goto err;
	148	}
	149	offset += priv->offset;
	150
	151	dest[priv->len / NFT_REG32_SIZE] = 0;
	152	if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
	153	goto err;
	154	return;
	155	err:
	156	regs->verdict.code = NFT_BREAK;
	157	}
	158
a1817700 FW	159	static void *
	160	nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
	161	unsigned int len, void buffer, unsigned int tcphdr_len)
	162	{
	163	struct tcphdr *tcph;
	164
	165	if (!pkt->tprot_set \|\| pkt->tprot != IPPROTO_TCP)
	166	return NULL;
	167
	168	tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buffer);
	169	if (!tcph)
	170	return NULL;
	171
	172	*tcphdr_len = __tcp_hdrlen(tcph);
	173	if (tcphdr_len < sizeof(tcph) \|\| *tcphdr_len > len)
	174	return NULL;
	175
	176	return skb_header_pointer(pkt->skb, pkt->xt.thoff, *tcphdr_len, buffer);
	177	}
	178
935b7f64 MM	179	static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
	180	struct nft_regs *regs,
	181	const struct nft_pktinfo *pkt)
	182	{
	183	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
	184	struct nft_exthdr *priv = nft_expr_priv(expr);
	185	unsigned int i, optl, tcphdr_len, offset;
	186	u32 *dest = &regs->data[priv->dreg];
	187	struct tcphdr *tcph;
	188	u8 *opt;
	189
a1817700	190	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
935b7f64 MM	191	if (!tcph)
	192	goto err;
	193
	194	opt = (u8 *)tcph;
	195	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
	196	optl = optlen(opt, i);
	197
	198	if (priv->type != opt[i])
	199	continue;
	200
	201	if (i + optl > tcphdr_len \|\| priv->len + priv->offset > optl)
	202	goto err;
	203
	204	offset = i + priv->offset;
3c1fece8 PS	205	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
	206	*dest = 1;
	207	} else {
	208	dest[priv->len / NFT_REG32_SIZE] = 0;
	209	memcpy(dest, opt + offset, priv->len);
	210	}
935b7f64 MM	211
	212	return;
	213	}
	214
	215	err:
3c1fece8 PS	216	if (priv->flags & NFT_EXTHDR_F_PRESENT)
	217	*dest = 0;
	218	else
	219	regs->verdict.code = NFT_BREAK;
935b7f64 MM	220	}
935b7f64 MM	221
99d1712b FW	222	static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
	223	struct nft_regs *regs,
	224	const struct nft_pktinfo *pkt)
	225	{
	226	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
	227	struct nft_exthdr *priv = nft_expr_priv(expr);
	228	unsigned int i, optl, tcphdr_len, offset;
	229	struct tcphdr *tcph;
	230	u8 *opt;
99d1712b FW	231
	232	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
	233	if (!tcph)
	234	return;
	235
	236	opt = (u8 *)tcph;
	237	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
	238	union {
99d1712b FW	239	__be16 v16;
	240	__be32 v32;
	241	} old, new;
	242
	243	optl = optlen(opt, i);
	244
	245	if (priv->type != opt[i])
	246	continue;
	247
	248	if (i + optl > tcphdr_len \|\| priv->len + priv->offset > optl)
	249	return;
	250
7418ee4c FW	251	if (skb_ensure_writable(pkt->skb,
7418ee4c FW	252	pkt->xt.thoff + i + priv->len))
99d1712b FW	253	return;
	254
	255	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
	256	&tcphdr_len);
	257	if (!tcph)
	258	return;
	259
99d1712b FW	260	offset = i + priv->offset;
	261
	262	switch (priv->len) {
	263	case 2:
	264	old.v16 = get_unaligned((u16 *)(opt + offset));
2e34328b SM	265	new.v16 = (__force __be16)nft_reg_load16(
2e34328b SM	266	&regs->data[priv->sreg]);
99d1712b FW	267
	268	switch (priv->type) {
	269	case TCPOPT_MSS:
	270	/* increase can cause connection to stall */
	271	if (ntohs(old.v16) <= ntohs(new.v16))
	272	return;
	273	break;
	274	}
	275
	276	if (old.v16 == new.v16)
	277	return;
	278
	279	put_unaligned(new.v16, (u16*)(opt + offset));
	280	inet_proto_csum_replace2(&tcph->check, pkt->skb,
	281	old.v16, new.v16, false);
	282	break;
	283	case 4:
2e34328b	284	new.v32 = regs->data[priv->sreg];
99d1712b FW	285	old.v32 = get_unaligned((u32 *)(opt + offset));
	286
	287	if (old.v32 == new.v32)
	288	return;
	289
	290	put_unaligned(new.v32, (u32*)(opt + offset));
	291	inet_proto_csum_replace4(&tcph->check, pkt->skb,
	292	old.v32, new.v32, false);
	293	break;
	294	default:
	295	WARN_ON_ONCE(1);
	296	break;
	297	}
	298
	299	return;
	300	}
	301	}
	302
96518518 PM	303	static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
	304	[NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
	305	[NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
	306	[NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
	307	[NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
c078ca3b	308	[NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 },
f5b5702a FW	309	[NFTA_EXTHDR_OP] = { .type = NLA_U32 },
f5b5702a FW	310	[NFTA_EXTHDR_SREG] = { .type = NLA_U32 },
96518518 PM	311	};
	312
	313	static int nft_exthdr_init(const struct nft_ctx *ctx,
	314	const struct nft_expr *expr,
	315	const struct nlattr * const tb[])
	316	{
	317	struct nft_exthdr *priv = nft_expr_priv(expr);
935b7f64	318	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
21a9e0f1	319	int err;
96518518	320
935b7f64 MM	321	if (!tb[NFTA_EXTHDR_DREG] \|\|
	322	!tb[NFTA_EXTHDR_TYPE] \|\|
	323	!tb[NFTA_EXTHDR_OFFSET] \|\|
	324	!tb[NFTA_EXTHDR_LEN])
96518518 PM	325	return -EINVAL;
96518518 PM	326
36b701fa LGL	327	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
	328	if (err < 0)
	329	return err;
4da449ae	330
36b701fa LGL	331	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
	332	if (err < 0)
	333	return err;
4da449ae	334
c078ca3b PS	335	if (tb[NFTA_EXTHDR_FLAGS]) {
	336	err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
	337	if (err < 0)
	338	return err;
	339
	340	if (flags & ~NFT_EXTHDR_F_PRESENT)
	341	return -EINVAL;
	342	}
	343
935b7f64 MM	344	if (tb[NFTA_EXTHDR_OP]) {
	345	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
	346	if (err < 0)
	347	return err;
	348	}
	349
96518518	350	priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
4da449ae LGL	351	priv->offset = offset;
4da449ae LGL	352	priv->len = len;
c078ca3b	353	priv->flags = flags;
935b7f64	354	priv->op = op;
96518518	355
345023b0 PNA	356	return nft_parse_register_store(ctx, tb[NFTA_EXTHDR_DREG],
	357	&priv->dreg, NULL, NFT_DATA_VALUE,
	358	priv->len);
96518518 PM	359	}
96518518 PM	360
99d1712b FW	361	static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
	362	const struct nft_expr *expr,
	363	const struct nlattr * const tb[])
	364	{
	365	struct nft_exthdr *priv = nft_expr_priv(expr);
	366	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
	367	int err;
	368
	369	if (!tb[NFTA_EXTHDR_SREG] \|\|
	370	!tb[NFTA_EXTHDR_TYPE] \|\|
	371	!tb[NFTA_EXTHDR_OFFSET] \|\|
	372	!tb[NFTA_EXTHDR_LEN])
	373	return -EINVAL;
	374
	375	if (tb[NFTA_EXTHDR_DREG] \|\| tb[NFTA_EXTHDR_FLAGS])
	376	return -EINVAL;
	377
	378	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
	379	if (err < 0)
	380	return err;
	381
	382	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
	383	if (err < 0)
	384	return err;
	385
	386	if (offset < 2)
	387	return -EOPNOTSUPP;
	388
	389	switch (len) {
	390	case 2: break;
	391	case 4: break;
	392	default:
	393	return -EOPNOTSUPP;
	394	}
	395
	396	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
	397	if (err < 0)
	398	return err;
	399
	400	priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
	401	priv->offset = offset;
	402	priv->len = len;
99d1712b FW	403	priv->flags = flags;
	404	priv->op = op;
	405
4f16d25c PNA	406	return nft_parse_register_load(tb[NFTA_EXTHDR_SREG], &priv->sreg,
4f16d25c PNA	407	priv->len);
99d1712b FW	408	}
99d1712b FW	409
dbb5281a SS	410	static int nft_exthdr_ipv4_init(const struct nft_ctx *ctx,
	411	const struct nft_expr *expr,
	412	const struct nlattr * const tb[])
	413	{
	414	struct nft_exthdr *priv = nft_expr_priv(expr);
	415	int err = nft_exthdr_init(ctx, expr, tb);
	416
	417	if (err < 0)
	418	return err;
	419
	420	switch (priv->type) {
	421	case IPOPT_SSRR:
	422	case IPOPT_LSRR:
	423	case IPOPT_RR:
	424	case IPOPT_RA:
	425	break;
	426	default:
	427	return -EOPNOTSUPP;
	428	}
	429	return 0;
	430	}
	431
5e7d695a	432	static int nft_exthdr_dump_common(struct sk_buff skb, const struct nft_exthdr priv)
96518518	433	{
96518518 PM	434	if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
	435	goto nla_put_failure;
	436	if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
	437	goto nla_put_failure;
	438	if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
	439	goto nla_put_failure;
c078ca3b PS	440	if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
c078ca3b PS	441	goto nla_put_failure;
935b7f64 MM	442	if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
935b7f64 MM	443	goto nla_put_failure;
96518518 PM	444	return 0;
	445
	446	nla_put_failure:
	447	return -1;
	448	}
	449
5e7d695a FW	450	static int nft_exthdr_dump(struct sk_buff skb, const struct nft_expr expr)
	451	{
	452	const struct nft_exthdr *priv = nft_expr_priv(expr);
	453
	454	if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
	455	return -1;
	456
	457	return nft_exthdr_dump_common(skb, priv);
	458	}
	459
99d1712b FW	460	static int nft_exthdr_dump_set(struct sk_buff skb, const struct nft_expr expr)
	461	{
	462	const struct nft_exthdr *priv = nft_expr_priv(expr);
	463
	464	if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg))
	465	return -1;
	466
	467	return nft_exthdr_dump_common(skb, priv);
	468	}
	469
935b7f64 MM	470	static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
	471	.type = &nft_exthdr_type,
	472	.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	473	.eval = nft_exthdr_ipv6_eval,
	474	.init = nft_exthdr_init,
	475	.dump = nft_exthdr_dump,
	476	};
	477
dbb5281a SS	478	static const struct nft_expr_ops nft_exthdr_ipv4_ops = {
	479	.type = &nft_exthdr_type,
	480	.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	481	.eval = nft_exthdr_ipv4_eval,
	482	.init = nft_exthdr_ipv4_init,
	483	.dump = nft_exthdr_dump,
	484	};
	485
935b7f64	486	static const struct nft_expr_ops nft_exthdr_tcp_ops = {
ef1f7df9	487	.type = &nft_exthdr_type,
96518518	488	.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
935b7f64	489	.eval = nft_exthdr_tcp_eval,
96518518 PM	490	.init = nft_exthdr_init,
96518518 PM	491	.dump = nft_exthdr_dump,
ef1f7df9 PM	492	};
ef1f7df9 PM	493
99d1712b FW	494	static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
	495	.type = &nft_exthdr_type,
	496	.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
	497	.eval = nft_exthdr_tcp_set_eval,
	498	.init = nft_exthdr_tcp_set_init,
	499	.dump = nft_exthdr_dump_set,
	500	};
	501
935b7f64 MM	502	static const struct nft_expr_ops *
	503	nft_exthdr_select_ops(const struct nft_ctx *ctx,
	504	const struct nlattr * const tb[])
	505	{
	506	u32 op;
	507
	508	if (!tb[NFTA_EXTHDR_OP])
	509	return &nft_exthdr_ipv6_ops;
	510
99d1712b FW	511	if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG])
	512	return ERR_PTR(-EOPNOTSUPP);
	513
5fd02ebe	514	op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP]));
935b7f64 MM	515	switch (op) {
935b7f64 MM	516	case NFT_EXTHDR_OP_TCPOPT:
99d1712b FW	517	if (tb[NFTA_EXTHDR_SREG])
	518	return &nft_exthdr_tcp_set_ops;
	519	if (tb[NFTA_EXTHDR_DREG])
	520	return &nft_exthdr_tcp_ops;
	521	break;
935b7f64	522	case NFT_EXTHDR_OP_IPV6:
99d1712b FW	523	if (tb[NFTA_EXTHDR_DREG])
	524	return &nft_exthdr_ipv6_ops;
	525	break;
dbb5281a SS	526	case NFT_EXTHDR_OP_IPV4:
	527	if (ctx->family != NFPROTO_IPV6) {
	528	if (tb[NFTA_EXTHDR_DREG])
	529	return &nft_exthdr_ipv4_ops;
	530	}
	531	break;
935b7f64 MM	532	}
	533
	534	return ERR_PTR(-EOPNOTSUPP);
	535	}
	536
d0103158	537	struct nft_expr_type nft_exthdr_type __read_mostly = {
ef1f7df9	538	.name = "exthdr",
d4ef3835	539	.select_ops = nft_exthdr_select_ops,
96518518 PM	540	.policy = nft_exthdr_policy,
96518518 PM	541	.maxattr = NFTA_EXTHDR_MAX,
ef1f7df9	542	.owner = THIS_MODULE,
96518518	543	};