From ddc8b6027ad08d145a6d7a6a6abc00e43f315bd1 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 9 Sep 2016 12:42:51 +0200 Subject: [PATCH] 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 --- 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 af952f7843ee..968f00b82fb5 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 1e0ffd5aea47..39b7b717b540 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 8de502b0c37b..3e5475a833a5 100644 --- a/net/netfilter/nf_tables_netdev.c +++ b/net/netfilter/nf_tables_netdev.c @@ -15,81 +15,6 @@ #include #include -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); -- 2.20.1