From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Subject: [PATCH nf-next 3/5] netfilter: introduce nft_set_pktinfo_{ipv4,ipv6}_validate()
Date: Fri, 9 Sep 2016 12:42:51 +0200 [thread overview]
Message-ID: <1473417773-9840-3-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1473417773-9840-1-git-send-email-pablo@netfilter.org>
These functions are extracted from the netdev family, they initialize
the pktinfo structure and validate that the IPv4 and IPv6 headers are
well-formed given that these functions are called from a path where
layer 3 sanitization did not happen yet.
These functions are placed in include/net/netfilter/nf_tables_ipv{4,6}.h
so they can be reused by a follow up patch to use them from the bridge
family too.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
include/net/netfilter/nf_tables_ipv4.h | 42 ++++++++++++++++++
include/net/netfilter/nf_tables_ipv6.h | 49 +++++++++++++++++++++
net/netfilter/nf_tables_netdev.c | 79 +---------------------------------
3 files changed, 93 insertions(+), 77 deletions(-)
diff --git a/include/net/netfilter/nf_tables_ipv4.h b/include/net/netfilter/nf_tables_ipv4.h
index af952f7..968f00b 100644
--- a/include/net/netfilter/nf_tables_ipv4.h
+++ b/include/net/netfilter/nf_tables_ipv4.h
@@ -20,6 +20,48 @@ nft_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
}
+static inline int
+__nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
+ struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ struct iphdr *iph, _iph;
+ u32 len, thoff;
+
+ iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
+ &_iph);
+ if (!iph)
+ return -1;
+
+ iph = ip_hdr(skb);
+ if (iph->ihl < 5 || iph->version != 4)
+ return -1;
+
+ len = ntohs(iph->tot_len);
+ thoff = iph->ihl * 4;
+ if (skb->len < len)
+ return -1;
+ else if (len < thoff)
+ return -1;
+
+ pkt->tprot_set = true;
+ pkt->tprot = iph->protocol;
+ pkt->xt.thoff = thoff;
+ pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
+
+ return 0;
+}
+
+static inline void
+nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
+ struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ nft_set_pktinfo(pkt, skb, state);
+ if (__nft_set_pktinfo_ipv4_validate(pkt, skb, state) < 0)
+ nft_set_pktinfo_proto_unspec(pkt, skb);
+}
+
extern struct nft_af_info nft_af_ipv4;
#endif
diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h
index 1e0ffd5..39b7b71 100644
--- a/include/net/netfilter/nf_tables_ipv6.h
+++ b/include/net/netfilter/nf_tables_ipv6.h
@@ -28,6 +28,55 @@ nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
return 0;
}
+static inline int
+__nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt,
+ struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+ struct ipv6hdr *ip6h, _ip6h;
+ unsigned int thoff = 0;
+ unsigned short frag_off;
+ int protohdr;
+ u32 pkt_len;
+
+ ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
+ &_ip6h);
+ if (!ip6h)
+ return -1;
+
+ if (ip6h->version != 6)
+ return -1;
+
+ pkt_len = ntohs(ip6h->payload_len);
+ if (pkt_len + sizeof(*ip6h) > skb->len)
+ return -1;
+
+ protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
+ if (protohdr < 0)
+ return -1;
+
+ pkt->tprot_set = true;
+ pkt->tprot = protohdr;
+ pkt->xt.thoff = thoff;
+ pkt->xt.fragoff = frag_off;
+
+ return 0;
+#else
+ return -1;
+#endif
+}
+
+static inline void
+nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt,
+ struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ nft_set_pktinfo(pkt, skb, state);
+ if (__nft_set_pktinfo_ipv6_validate(pkt, skb, state) < 0)
+ nft_set_pktinfo_proto_unspec(pkt, skb);
+}
+
extern struct nft_af_info nft_af_ipv6;
#endif
diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c
index 8de502b..3e5475a 100644
--- a/net/netfilter/nf_tables_netdev.c
+++ b/net/netfilter/nf_tables_netdev.c
@@ -15,81 +15,6 @@
#include <net/netfilter/nf_tables_ipv4.h>
#include <net/netfilter/nf_tables_ipv6.h>
-static inline void
-nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- struct iphdr *iph, _iph;
- u32 len, thoff;
-
- nft_set_pktinfo(pkt, skb, state);
-
- iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
- &_iph);
- if (!iph)
- return;
-
- iph = ip_hdr(skb);
- if (iph->ihl < 5 || iph->version != 4)
- return;
-
- len = ntohs(iph->tot_len);
- thoff = iph->ihl * 4;
- if (skb->len < len)
- return;
- else if (len < thoff)
- return;
-
- pkt->tprot_set = true;
- pkt->tprot = iph->protocol;
- pkt->xt.thoff = thoff;
- pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
-}
-
-static inline void
-__nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
-#if IS_ENABLED(CONFIG_IPV6)
- struct ipv6hdr *ip6h, _ip6h;
- unsigned int thoff = 0;
- unsigned short frag_off;
- int protohdr;
- u32 pkt_len;
-
- ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
- &_ip6h);
- if (!ip6h)
- return;
-
- if (ip6h->version != 6)
- return;
-
- pkt_len = ntohs(ip6h->payload_len);
- if (pkt_len + sizeof(*ip6h) > skb->len)
- return;
-
- protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
- if (protohdr < 0)
- return;
-
- pkt->tprot_set = true;
- pkt->tprot = protohdr;
- pkt->xt.thoff = thoff;
- pkt->xt.fragoff = frag_off;
-#endif
-}
-
-static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
- struct sk_buff *skb,
- const struct nf_hook_state *state)
-{
- nft_set_pktinfo(pkt, skb, state);
- __nft_netdev_set_pktinfo_ipv6(pkt, skb, state);
-}
-
static unsigned int
nft_do_chain_netdev(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
@@ -98,10 +23,10 @@ nft_do_chain_netdev(void *priv, struct sk_buff *skb,
switch (skb->protocol) {
case htons(ETH_P_IP):
- nft_netdev_set_pktinfo_ipv4(&pkt, skb, state);
+ nft_set_pktinfo_ipv4_validate(&pkt, skb, state);
break;
case htons(ETH_P_IPV6):
- nft_netdev_set_pktinfo_ipv6(&pkt, skb, state);
+ nft_set_pktinfo_ipv6_validate(&pkt, skb, state);
break;
default:
nft_set_pktinfo_unspec(&pkt, skb, state);
--
2.1.4
next prev parent reply other threads:[~2016-09-09 10:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-09 10:42 [PATCH nf-next 1/5] netfilter: nf_tables: ensure proper initialization of nft_pktinfo fields Pablo Neira Ayuso
2016-09-09 10:42 ` [PATCH nf-next 2/5] netfilter: nf_tables_ipv6: setup pktinfo transport field on failure to parse Pablo Neira Ayuso
2016-09-09 10:42 ` Pablo Neira Ayuso [this message]
2016-09-09 10:42 ` [PATCH nf-next 4/5] netfilter: nf_tables_bridge: use nft_set_pktinfo_ipv{4,6}_validate Pablo Neira Ayuso
2016-09-09 10:42 ` [PATCH nf-next 5/5] netfilter: nf_tables: don't drop IPv6 packets that cannot parse transport Pablo Neira Ayuso
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