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Commit 22c7652c authored by Fernando Fernandez Mancera's avatar Fernando Fernandez Mancera Committed by Pablo Neira Ayuso
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netfilter: nft_osf: Add version option support 



Add version option support to the nftables "osf" expression.

Signed-off-by: default avatarFernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 6978cdb1

include/linux/netfilter/nfnetlink_osf.h

+8 −3
Original line number Diff line number Diff line
@@ -21,13 +21,18 @@ struct nf_osf_finger { 
	struct nf_osf_user_finger	finger;

};



struct nf_osf_data {

	const char *genre;

	const char *version;

};



bool nf_osf_match(const struct sk_buff *skb, u_int8_t family,

		  int hooknum, struct net_device *in, struct net_device *out,

		  const struct nf_osf_info *info, struct net *net,

		  const struct list_head *nf_osf_fingers);



const char *nf_osf_find(const struct sk_buff *skb,

bool nf_osf_find(const struct sk_buff *skb,

		 const struct list_head *nf_osf_fingers,

			const int ttl_check);

		 const int ttl_check, struct nf_osf_data *data);



#endif /* _NFOSF_H */

include/uapi/linux/netfilter/nf_tables.h

+6 −0
Original line number Diff line number Diff line
@@ -1522,15 +1522,21 @@ enum nft_flowtable_hook_attributes { 
 *

 * @NFTA_OSF_DREG: destination register (NLA_U32: nft_registers)

 * @NFTA_OSF_TTL: Value of the TTL osf option (NLA_U8)

 * @NFTA_OSF_FLAGS: flags (NLA_U32)

 */

enum nft_osf_attributes {

	NFTA_OSF_UNSPEC,

	NFTA_OSF_DREG,

	NFTA_OSF_TTL,

	NFTA_OSF_FLAGS,

	__NFTA_OSF_MAX,

};

#define NFTA_OSF_MAX (__NFTA_OSF_MAX - 1)



enum nft_osf_flags {

	NFT_OSF_F_VERSION = (1 << 0),

};



/**

 * enum nft_device_attributes - nf_tables device netlink attributes

 *

net/netfilter/nfnetlink_osf.c

+7 −7
Original line number Diff line number Diff line
@@ -255,9 +255,9 @@ nf_osf_match(const struct sk_buff *skb, u_int8_t family, 
}

EXPORT_SYMBOL_GPL(nf_osf_match);



const char *nf_osf_find(const struct sk_buff *skb,

bool nf_osf_find(const struct sk_buff *skb,

		 const struct list_head *nf_osf_fingers,

			const int ttl_check)

		 const int ttl_check, struct nf_osf_data *data)

{

	const struct iphdr *ip = ip_hdr(skb);

	const struct nf_osf_user_finger *f;
@@ -265,24 +265,24 @@ const char *nf_osf_find(const struct sk_buff *skb, 
	const struct nf_osf_finger *kf;

	struct nf_osf_hdr_ctx ctx;

	const struct tcphdr *tcp;

	const char *genre = NULL;



	memset(&ctx, 0, sizeof(ctx));



	tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts);

	if (!tcp)

		return NULL;

		return false;



	list_for_each_entry_rcu(kf, &nf_osf_fingers[ctx.df], finger_entry) {

		f = &kf->finger;

		if (!nf_osf_match_one(skb, f, ttl_check, &ctx))

			continue;



		genre = f->genre;

		data->genre = f->genre;

		data->version = f->version;

		break;

	}



	return genre;

	return true;

}

EXPORT_SYMBOL_GPL(nf_osf_find);

net/netfilter/nft_osf.c

+25 −5
Original line number Diff line number Diff line
@@ -7,11 +7,13 @@ 
struct nft_osf {

	enum nft_registers	dreg:8;

	u8			ttl;

	u32			flags;

};



static const struct nla_policy nft_osf_policy[NFTA_OSF_MAX + 1] = {

	[NFTA_OSF_DREG]		= { .type = NLA_U32 },

	[NFTA_OSF_TTL]		= { .type = NLA_U8 },

	[NFTA_OSF_FLAGS]	= { .type = NLA_U32 },

};



static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
@@ -20,9 +22,10 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs, 
	struct nft_osf *priv = nft_expr_priv(expr);

	u32 *dest = &regs->data[priv->dreg];

	struct sk_buff *skb = pkt->skb;

	char os_match[NFT_OSF_MAXGENRELEN + 1];

	const struct tcphdr *tcp;

	struct nf_osf_data data;

	struct tcphdr _tcph;

	const char *os_name;



	tcp = skb_header_pointer(skb, ip_hdrlen(skb),

				 sizeof(struct tcphdr), &_tcph);
@@ -35,11 +38,17 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs, 
		return;

	}



	os_name = nf_osf_find(skb, nf_osf_fingers, priv->ttl);

	if (!os_name)

	if (!nf_osf_find(skb, nf_osf_fingers, priv->ttl, &data)) {

		strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);

	} else {

		if (priv->flags & NFT_OSF_F_VERSION)

			snprintf(os_match, NFT_OSF_MAXGENRELEN, "%s:%s",

				 data.genre, data.version);

		else

		strncpy((char *)dest, os_name, NFT_OSF_MAXGENRELEN);

			strlcpy(os_match, data.genre, NFT_OSF_MAXGENRELEN);



		strncpy((char *)dest, os_match, NFT_OSF_MAXGENRELEN);

	}

}



static int nft_osf_init(const struct nft_ctx *ctx,
@@ -47,6 +56,7 @@ static int nft_osf_init(const struct nft_ctx *ctx, 
			const struct nlattr * const tb[])

{

	struct nft_osf *priv = nft_expr_priv(expr);

	u32 flags;

	int err;

	u8 ttl;
@@ -57,6 +67,13 @@ static int nft_osf_init(const struct nft_ctx *ctx, 
		priv->ttl = ttl;

	}



	if (tb[NFTA_OSF_FLAGS]) {

		flags = ntohl(nla_get_be32(tb[NFTA_OSF_FLAGS]));

		if (flags != NFT_OSF_F_VERSION)

			return -EINVAL;

		priv->flags = flags;

	}



	priv->dreg = nft_parse_register(tb[NFTA_OSF_DREG]);

	err = nft_validate_register_store(ctx, priv->dreg, NULL,

					  NFT_DATA_VALUE, NFT_OSF_MAXGENRELEN);
@@ -73,6 +90,9 @@ static int nft_osf_dump(struct sk_buff *skb, const struct nft_expr *expr) 
	if (nla_put_u8(skb, NFTA_OSF_TTL, priv->ttl))

		goto nla_put_failure;



	if (nla_put_be32(skb, NFTA_OSF_FLAGS, ntohl(priv->flags)))

		goto nla_put_failure;



	if (nft_dump_register(skb, NFTA_OSF_DREG, priv->dreg))

		goto nla_put_failure;