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netfilter: nft_ct: fix unconditional dump of 'dir' attr

PATCH Applied Arturo Borrero Gonzalez 2 participants 2 messages Jan 17, 2014 – Jan 29, 2014

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Networking netfilter
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Arturo Borrero Gonzalez

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#0 lore raw

PATCH 1/1 netfilter: nft_ct: fix unconditional dump of 'dir' attr

We want to make sure that the information that we get from the kernel can be reinjected without troubles.

The kernel shouldn't return an attribute that is not required, or even prohibited.

Dump unconditionally NFTA_CT_DIRECTION could lead an application in userspace to interpret that the attribute was originally set, while it was not.

Signed-off-by Arturo Borrero Gonzalez <[email protected]>
---
 net/netfilter/nft_ct.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)
net/netfilter/nft_ct.c +13 -2
index 917052e..feaf0f3 100644
@@ -311,8 +311,19 @@ static int nft_ct_get_dump(struct sk_buff *skb, const struct nft_expr *expr)
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key)))
 		goto nla_put_failure;
-	if (nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir))
-		goto nla_put_failure;
+
+	switch (priv->key) {
+	case NFT_CT_PROTOCOL:
+	case NFT_CT_SRC:
+	case NFT_CT_DST:
+	case NFT_CT_PROTO_SRC:
+	case NFT_CT_PROTO_DST:
+		if (nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir))
+			goto nla_put_failure;
+	default:
+		break;
+	}
+
 	return 0;
 
 nla_put_failure:
maintainer Applied
#1 lore raw
Quoted 8 lines · Arturo Borrero Gonzalez

We want to make sure that the information that we get from the kernel can be reinjected without troubles.

The kernel shouldn't return an attribute that is not required, or even prohibited.

Dump unconditionally NFTA_CT_DIRECTION could lead an application in userspace to interpret that the attribute was originally set, while it was not.

Applied, thanks Arturo.