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Commit 053d20f5 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nft_payload: mangle ckecksum if NFT_PAYLOAD_L4CSUM_PSEUDOHDR is set 



If the NFT_PAYLOAD_L4CSUM_PSEUDOHDR flag is set, then mangle layer 4
checksum. This should not depend on csum_type NFT_PAYLOAD_CSUM_INET
since IPv6 header has no checksum field, but still an update of any of
the pseudoheader fields may trigger a layer 4 checksum update.

Fixes: 18140969 ("netfilter: nft_payload: layer 4 checksum adjustment for pseudoheader fields")
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 3e38df13

net/netfilter/nft_payload.c

+19 −8
Original line number Diff line number Diff line
@@ -250,6 +250,22 @@ static int nft_payload_l4csum_update(const struct nft_pktinfo *pkt, 
	return 0;

}



static int nft_payload_csum_inet(struct sk_buff *skb, const u32 *src,

				 __wsum fsum, __wsum tsum, int csum_offset)

{

	__sum16 sum;



	if (skb_copy_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)

		return -1;



	nft_csum_replace(&sum, fsum, tsum);

	if (!skb_make_writable(skb, csum_offset + sizeof(sum)) ||

	    skb_store_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)

		return -1;



	return 0;

}



static void nft_payload_set_eval(const struct nft_expr *expr,

				 struct nft_regs *regs,

				 const struct nft_pktinfo *pkt)
@@ -259,7 +275,6 @@ static void nft_payload_set_eval(const struct nft_expr *expr, 
	const u32 *src = &regs->data[priv->sreg];

	int offset, csum_offset;

	__wsum fsum, tsum;

	__sum16 sum;



	switch (priv->base) {

	case NFT_PAYLOAD_LL_HEADER:
@@ -282,18 +297,14 @@ static void nft_payload_set_eval(const struct nft_expr *expr, 
	csum_offset = offset + priv->csum_offset;

	offset += priv->offset;



	if (priv->csum_type == NFT_PAYLOAD_CSUM_INET &&

	if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) &&

	    (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER ||

	     skb->ip_summed != CHECKSUM_PARTIAL)) {

		if (skb_copy_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)

			goto err;



		fsum = skb_checksum(skb, offset, priv->len, 0);

		tsum = csum_partial(src, priv->len, 0);

		nft_csum_replace(&sum, fsum, tsum);



		if (!skb_make_writable(skb, csum_offset + sizeof(sum)) ||

		    skb_store_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)

		if (priv->csum_type == NFT_PAYLOAD_CSUM_INET &&

		    nft_payload_csum_inet(skb, src, fsum, tsum, csum_offset))

			goto err;



		if (priv->csum_flags &&