netfilter: introduce nft_set_pktinfo_{ipv4, ipv6}_validate()
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>
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@ -20,6 +20,48 @@ nft_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
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pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
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pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
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}
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}
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static inline int
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__nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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struct iphdr *iph, _iph;
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u32 len, thoff;
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iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
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&_iph);
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if (!iph)
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return -1;
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iph = ip_hdr(skb);
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if (iph->ihl < 5 || iph->version != 4)
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return -1;
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len = ntohs(iph->tot_len);
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thoff = iph->ihl * 4;
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if (skb->len < len)
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return -1;
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else if (len < thoff)
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return -1;
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pkt->tprot_set = true;
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pkt->tprot = iph->protocol;
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pkt->xt.thoff = thoff;
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pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
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return 0;
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}
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static inline void
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nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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nft_set_pktinfo(pkt, skb, state);
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if (__nft_set_pktinfo_ipv4_validate(pkt, skb, state) < 0)
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nft_set_pktinfo_proto_unspec(pkt, skb);
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}
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extern struct nft_af_info nft_af_ipv4;
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extern struct nft_af_info nft_af_ipv4;
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#endif
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#endif
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@ -28,6 +28,55 @@ nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
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return 0;
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return 0;
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}
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}
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static inline int
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__nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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#if IS_ENABLED(CONFIG_IPV6)
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struct ipv6hdr *ip6h, _ip6h;
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unsigned int thoff = 0;
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unsigned short frag_off;
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int protohdr;
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u32 pkt_len;
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ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
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&_ip6h);
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if (!ip6h)
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return -1;
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if (ip6h->version != 6)
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return -1;
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pkt_len = ntohs(ip6h->payload_len);
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if (pkt_len + sizeof(*ip6h) > skb->len)
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return -1;
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protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
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if (protohdr < 0)
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return -1;
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pkt->tprot_set = true;
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pkt->tprot = protohdr;
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pkt->xt.thoff = thoff;
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pkt->xt.fragoff = frag_off;
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return 0;
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#else
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return -1;
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#endif
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}
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static inline void
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nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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nft_set_pktinfo(pkt, skb, state);
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if (__nft_set_pktinfo_ipv6_validate(pkt, skb, state) < 0)
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nft_set_pktinfo_proto_unspec(pkt, skb);
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}
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extern struct nft_af_info nft_af_ipv6;
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extern struct nft_af_info nft_af_ipv6;
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#endif
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#endif
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@ -15,81 +15,6 @@
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#include <net/netfilter/nf_tables_ipv4.h>
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#include <net/netfilter/nf_tables_ipv4.h>
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#include <net/netfilter/nf_tables_ipv6.h>
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#include <net/netfilter/nf_tables_ipv6.h>
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static inline void
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nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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struct iphdr *iph, _iph;
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u32 len, thoff;
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nft_set_pktinfo(pkt, skb, state);
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iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
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&_iph);
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if (!iph)
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return;
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iph = ip_hdr(skb);
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if (iph->ihl < 5 || iph->version != 4)
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return;
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len = ntohs(iph->tot_len);
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thoff = iph->ihl * 4;
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if (skb->len < len)
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return;
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else if (len < thoff)
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return;
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pkt->tprot_set = true;
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pkt->tprot = iph->protocol;
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pkt->xt.thoff = thoff;
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pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
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}
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static inline void
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__nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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#if IS_ENABLED(CONFIG_IPV6)
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struct ipv6hdr *ip6h, _ip6h;
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unsigned int thoff = 0;
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unsigned short frag_off;
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int protohdr;
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u32 pkt_len;
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ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h),
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&_ip6h);
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if (!ip6h)
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return;
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if (ip6h->version != 6)
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return;
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pkt_len = ntohs(ip6h->payload_len);
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if (pkt_len + sizeof(*ip6h) > skb->len)
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return;
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protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
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if (protohdr < 0)
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return;
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pkt->tprot_set = true;
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pkt->tprot = protohdr;
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pkt->xt.thoff = thoff;
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pkt->xt.fragoff = frag_off;
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#endif
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}
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static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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nft_set_pktinfo(pkt, skb, state);
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__nft_netdev_set_pktinfo_ipv6(pkt, skb, state);
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}
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static unsigned int
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static unsigned int
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nft_do_chain_netdev(void *priv, struct sk_buff *skb,
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nft_do_chain_netdev(void *priv, struct sk_buff *skb,
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const struct nf_hook_state *state)
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const struct nf_hook_state *state)
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@ -98,10 +23,10 @@ nft_do_chain_netdev(void *priv, struct sk_buff *skb,
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switch (skb->protocol) {
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switch (skb->protocol) {
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case htons(ETH_P_IP):
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case htons(ETH_P_IP):
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nft_netdev_set_pktinfo_ipv4(&pkt, skb, state);
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nft_set_pktinfo_ipv4_validate(&pkt, skb, state);
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break;
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break;
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case htons(ETH_P_IPV6):
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case htons(ETH_P_IPV6):
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nft_netdev_set_pktinfo_ipv6(&pkt, skb, state);
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nft_set_pktinfo_ipv6_validate(&pkt, skb, state);
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break;
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break;
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default:
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default:
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nft_set_pktinfo_unspec(&pkt, skb, state);
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nft_set_pktinfo_unspec(&pkt, skb, state);
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