[PATCH net-next 02/10] netfilter: nf_tables: reduce nft_pktinfo by 8 bytes

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

From: Florian Westphal <fw@xxxxxxxxx>

structure is reduced from 32 to 24 bytes.  While at it, also check
that iphdrlen is sane, this is guaranteed for NFPROTO_IPV4 but not
for ingress or bridge, so add checks for this.

Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 include/net/netfilter/nf_tables.h      | 4 ++--
 include/net/netfilter/nf_tables_ipv4.h | 4 ++++
 include/net/netfilter/nf_tables_ipv6.h | 6 +++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index cdb7db9b0e25..f6db510689a8 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -32,8 +32,8 @@ struct nft_pktinfo {
 	u8				flags;
 	u8				tprot;
 	u16				fragoff;
-	unsigned int			thoff;
-	unsigned int			inneroff;
+	u16				thoff;
+	u16				inneroff;
 };
 
 static inline struct sock *nft_sk(const struct nft_pktinfo *pkt)
diff --git a/include/net/netfilter/nf_tables_ipv4.h b/include/net/netfilter/nf_tables_ipv4.h
index c4a6147b0ef8..112708f7a6b4 100644
--- a/include/net/netfilter/nf_tables_ipv4.h
+++ b/include/net/netfilter/nf_tables_ipv4.h
@@ -35,6 +35,8 @@ static inline int __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt)
 		return -1;
 	else if (len < thoff)
 		return -1;
+	else if (thoff < sizeof(*iph))
+		return -1;
 
 	pkt->flags = NFT_PKTINFO_L4PROTO;
 	pkt->tprot = iph->protocol;
@@ -69,6 +71,8 @@ static inline int nft_set_pktinfo_ipv4_ingress(struct nft_pktinfo *pkt)
 		return -1;
 	} else if (len < thoff) {
 		goto inhdr_error;
+	} else if (thoff < sizeof(*iph)) {
+		return -1;
 	}
 
 	pkt->flags = NFT_PKTINFO_L4PROTO;
diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h
index ec7eaeaf4f04..467d59b9e533 100644
--- a/include/net/netfilter/nf_tables_ipv6.h
+++ b/include/net/netfilter/nf_tables_ipv6.h
@@ -13,7 +13,7 @@ static inline void nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt)
 	unsigned short frag_off;
 
 	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags);
-	if (protohdr < 0) {
+	if (protohdr < 0 || thoff > U16_MAX) {
 		nft_set_pktinfo_unspec(pkt);
 		return;
 	}
@@ -47,7 +47,7 @@ static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt)
 		return -1;
 
 	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags);
-	if (protohdr < 0)
+	if (protohdr < 0 || thoff > U16_MAX)
 		return -1;
 
 	pkt->flags = NFT_PKTINFO_L4PROTO;
@@ -93,7 +93,7 @@ static inline int nft_set_pktinfo_ipv6_ingress(struct nft_pktinfo *pkt)
 	}
 
 	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags);
-	if (protohdr < 0)
+	if (protohdr < 0 || thoff > U16_MAX)
 		goto inhdr_error;
 
 	pkt->flags = NFT_PKTINFO_L4PROTO;
-- 
2.30.2