diff options
| -rw-r--r-- | net/bridge/netfilter/nft_reject_bridge.c | 84 |
1 files changed, 66 insertions, 18 deletions
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index 3244aead0926..5c6c96585acd 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -21,6 +21,7 @@ #include <net/ip.h> #include <net/ip6_checksum.h> #include <linux/netfilter_bridge.h> +#include <linux/netfilter_ipv6.h> #include "../br_private.h" static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, @@ -36,7 +37,12 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, skb_pull(nskb, ETH_HLEN); } -static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook) +/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT) + * or the bridge port (NF_BRIDGE PREROUTING). + */ +static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, + const struct net_device *dev, + int hook) { struct sk_buff *nskb; struct iphdr *niph; @@ -65,11 +71,12 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook) nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } -static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, - u8 code) +static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) { struct sk_buff *nskb; struct iphdr *niph; @@ -77,8 +84,9 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, unsigned int len; void *payload; __wsum csum; + u8 proto; - if (!nft_bridge_iphdr_validate(oldskb)) + if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb)) return; /* IP header checks: fragment. */ @@ -91,7 +99,17 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, if (!pskb_may_pull(oldskb, len)) return; - if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), 0)) + if (pskb_trim_rcsum(oldskb, htons(ip_hdr(oldskb)->tot_len))) + return; + + if (ip_hdr(oldskb)->protocol == IPPROTO_TCP || + ip_hdr(oldskb)->protocol == IPPROTO_UDP) + proto = ip_hdr(oldskb)->protocol; + else + proto = 0; + + if (!skb_csum_unnecessary(oldskb) && + nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto)) return; nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) + @@ -120,11 +138,13 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } static void nft_reject_br_send_v6_tcp_reset(struct net *net, - struct sk_buff *oldskb, int hook) + struct sk_buff *oldskb, + const struct net_device *dev, + int hook) { struct sk_buff *nskb; const struct tcphdr *oth; @@ -152,12 +172,37 @@ static void nft_reject_br_send_v6_tcp_reset(struct net *net, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); +} + +static bool reject6_br_csum_ok(struct sk_buff *skb, int hook) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + int thoff; + __be16 fo; + u8 proto = ip6h->nexthdr; + + if (skb->csum_bad) + return false; + + if (skb_csum_unnecessary(skb)) + return true; + + if (ip6h->payload_len && + pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h))) + return false; + + thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo); + if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0) + return false; + + return nf_ip6_checksum(skb, hook, thoff, proto) == 0; } static void nft_reject_br_send_v6_unreach(struct net *net, - struct sk_buff *oldskb, int hook, - u8 code) + struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) { struct sk_buff *nskb; struct ipv6hdr *nip6h; @@ -176,6 +221,9 @@ static void nft_reject_br_send_v6_unreach(struct net *net, if (!pskb_may_pull(oldskb, len)) return; + if (!reject6_br_csum_ok(oldskb, hook)) + return; + nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) + LL_MAX_HEADER + len, GFP_ATOMIC); if (!nskb) @@ -205,7 +253,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } static void nft_reject_bridge_eval(const struct nft_expr *expr, @@ -224,16 +272,16 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr, case htons(ETH_P_IP): switch (priv->type) { case NFT_REJECT_ICMP_UNREACH: - nft_reject_br_send_v4_unreach(pkt->skb, + nft_reject_br_send_v4_unreach(pkt->skb, pkt->in, pkt->ops->hooknum, priv->icmp_code); break; case NFT_REJECT_TCP_RST: - nft_reject_br_send_v4_tcp_reset(pkt->skb, + nft_reject_br_send_v4_tcp_reset(pkt->skb, pkt->in, pkt->ops->hooknum); break; case NFT_REJECT_ICMPX_UNREACH: - nft_reject_br_send_v4_unreach(pkt->skb, + nft_reject_br_send_v4_unreach(pkt->skb, pkt->in, pkt->ops->hooknum, nft_reject_icmp_code(priv->icmp_code)); break; @@ -242,16 +290,16 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr, case htons(ETH_P_IPV6): switch (priv->type) { case NFT_REJECT_ICMP_UNREACH: - nft_reject_br_send_v6_unreach(net, pkt->skb, + nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in, pkt->ops->hooknum, priv->icmp_code); break; case NFT_REJECT_TCP_RST: - nft_reject_br_send_v6_tcp_reset(net, pkt->skb, + nft_reject_br_send_v6_tcp_reset(net, pkt->skb, pkt->in, pkt->ops->hooknum); break; case NFT_REJECT_ICMPX_UNREACH: - nft_reject_br_send_v6_unreach(net, pkt->skb, + nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in, pkt->ops->hooknum, nft_reject_icmpv6_code(priv->icmp_code)); break; |