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-rw-r--r--net/bridge/br_forward.c1
-rw-r--r--net/bridge/netfilter/nft_reject_bridge.c263
2 files changed, 254 insertions, 10 deletions
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 992ec49a96aa..44cb786b925a 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -112,6 +112,7 @@ void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
kfree_skb(skb);
}
+EXPORT_SYMBOL_GPL(br_deliver);
/* called with rcu_read_lock */
void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index a76479535df2..31b27e1bab9f 100644
--- a/net/bridge/netfilter/nft_reject_bridge.c
+++ b/net/bridge/netfilter/nft_reject_bridge.c
@@ -16,6 +16,237 @@
#include <net/netfilter/nft_reject.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/ipv6/nf_reject.h>
+#include <linux/ip.h>
+#include <net/ip.h>
+#include "../br_private.h"
+
+static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
+ struct sk_buff *nskb)
+{
+ struct ethhdr *eth;
+
+ eth = (struct ethhdr *)skb_push(nskb, ETH_HLEN);
+ skb_reset_mac_header(nskb);
+ ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest);
+ ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source);
+ eth->h_proto = eth_hdr(oldskb)->h_proto;
+ skb_pull(nskb, ETH_HLEN);
+}
+
+static int nft_reject_iphdr_validate(struct sk_buff *oldskb)
+{
+ struct iphdr *iph;
+ u32 len;
+
+ if (!pskb_may_pull(oldskb, sizeof(struct iphdr)))
+ return 0;
+
+ iph = ip_hdr(oldskb);
+ if (iph->ihl < 5 || iph->version != 4)
+ return 0;
+
+ len = ntohs(iph->tot_len);
+ if (oldskb->len < len)
+ return 0;
+ else if (len < (iph->ihl*4))
+ return 0;
+
+ if (!pskb_may_pull(oldskb, iph->ihl*4))
+ return 0;
+
+ return 1;
+}
+
+static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)
+{
+ struct sk_buff *nskb;
+ struct iphdr *niph;
+ const struct tcphdr *oth;
+ struct tcphdr _oth;
+
+ if (!nft_reject_iphdr_validate(oldskb))
+ return;
+
+ oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
+ if (!oth)
+ return;
+
+ nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
+ LL_MAX_HEADER, GFP_ATOMIC);
+ if (!nskb)
+ return;
+
+ skb_reserve(nskb, LL_MAX_HEADER);
+ niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
+ sysctl_ip_default_ttl);
+ nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
+ niph->ttl = sysctl_ip_default_ttl;
+ niph->tot_len = htons(nskb->len);
+ ip_send_check(niph);
+
+ nft_reject_br_push_etherhdr(oldskb, nskb);
+
+ br_deliver(br_port_get_rcu(oldskb->dev), nskb);
+}
+
+static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
+ u8 code)
+{
+ struct sk_buff *nskb;
+ struct iphdr *niph;
+ struct icmphdr *icmph;
+ unsigned int len;
+ void *payload;
+ __wsum csum;
+
+ if (!nft_reject_iphdr_validate(oldskb))
+ return;
+
+ /* IP header checks: fragment. */
+ if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
+ return;
+
+ /* RFC says return as much as we can without exceeding 576 bytes. */
+ len = min_t(unsigned int, 536, oldskb->len);
+
+ if (!pskb_may_pull(oldskb, len))
+ return;
+
+ if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), 0))
+ return;
+
+ nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
+ LL_MAX_HEADER + len, GFP_ATOMIC);
+ if (!nskb)
+ return;
+
+ skb_reserve(nskb, LL_MAX_HEADER);
+ niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
+ sysctl_ip_default_ttl);
+
+ skb_reset_transport_header(nskb);
+ icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
+ memset(icmph, 0, sizeof(*icmph));
+ icmph->type = ICMP_DEST_UNREACH;
+ icmph->code = code;
+
+ payload = skb_put(nskb, len);
+ memcpy(payload, skb_network_header(oldskb), len);
+
+ csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
+ icmph->checksum = csum_fold(csum);
+
+ niph->tot_len = htons(nskb->len);
+ ip_send_check(niph);
+
+ nft_reject_br_push_etherhdr(oldskb, nskb);
+
+ br_deliver(br_port_get_rcu(oldskb->dev), nskb);
+}
+
+static int nft_reject_ip6hdr_validate(struct sk_buff *oldskb)
+{
+ struct ipv6hdr *hdr;
+ u32 pkt_len;
+
+ if (!pskb_may_pull(oldskb, sizeof(struct ipv6hdr)))
+ return 0;
+
+ hdr = ipv6_hdr(oldskb);
+ if (hdr->version != 6)
+ return 0;
+
+ pkt_len = ntohs(hdr->payload_len);
+ if (pkt_len + sizeof(struct ipv6hdr) > oldskb->len)
+ return 0;
+
+ return 1;
+}
+
+static void nft_reject_br_send_v6_tcp_reset(struct net *net,
+ struct sk_buff *oldskb, int hook)
+{
+ struct sk_buff *nskb;
+ const struct tcphdr *oth;
+ struct tcphdr _oth;
+ unsigned int otcplen;
+ struct ipv6hdr *nip6h;
+
+ if (!nft_reject_ip6hdr_validate(oldskb))
+ return;
+
+ oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
+ if (!oth)
+ return;
+
+ nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
+ LL_MAX_HEADER, GFP_ATOMIC);
+ if (!nskb)
+ return;
+
+ skb_reserve(nskb, LL_MAX_HEADER);
+ nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
+ net->ipv6.devconf_all->hop_limit);
+ nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
+ nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
+
+ nft_reject_br_push_etherhdr(oldskb, nskb);
+
+ br_deliver(br_port_get_rcu(oldskb->dev), nskb);
+}
+
+static void nft_reject_br_send_v6_unreach(struct net *net,
+ struct sk_buff *oldskb, int hook,
+ u8 code)
+{
+ struct sk_buff *nskb;
+ struct ipv6hdr *nip6h;
+ struct icmp6hdr *icmp6h;
+ unsigned int len;
+ void *payload;
+
+ if (!nft_reject_ip6hdr_validate(oldskb))
+ return;
+
+ /* Include "As much of invoking packet as possible without the ICMPv6
+ * packet exceeding the minimum IPv6 MTU" in the ICMP payload.
+ */
+ len = min_t(unsigned int, 1220, oldskb->len);
+
+ if (!pskb_may_pull(oldskb, len))
+ return;
+
+ nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
+ LL_MAX_HEADER + len, GFP_ATOMIC);
+ if (!nskb)
+ return;
+
+ skb_reserve(nskb, LL_MAX_HEADER);
+ nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
+ net->ipv6.devconf_all->hop_limit);
+
+ skb_reset_transport_header(nskb);
+ icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
+ memset(icmp6h, 0, sizeof(*icmp6h));
+ icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
+ icmp6h->icmp6_code = code;
+
+ payload = skb_put(nskb, len);
+ memcpy(payload, skb_network_header(oldskb), len);
+ nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
+
+ icmp6h->icmp6_cksum =
+ csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
+ nskb->len - sizeof(struct ipv6hdr),
+ IPPROTO_ICMPV6,
+ csum_partial(icmp6h,
+ nskb->len - sizeof(struct ipv6hdr),
+ 0));
+
+ nft_reject_br_push_etherhdr(oldskb, nskb);
+
+ br_deliver(br_port_get_rcu(oldskb->dev), nskb);
+}
static void nft_reject_bridge_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
@@ -23,35 +254,46 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr,
{
struct nft_reject *priv = nft_expr_priv(expr);
struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
+ const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
+
+ if (is_broadcast_ether_addr(dest) ||
+ is_multicast_ether_addr(dest))
+ goto out;
switch (eth_hdr(pkt->skb)->h_proto) {
case htons(ETH_P_IP):
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
- nf_send_unreach(pkt->skb, priv->icmp_code);
+ nft_reject_br_send_v4_unreach(pkt->skb,
+ pkt->ops->hooknum,
+ priv->icmp_code);
break;
case NFT_REJECT_TCP_RST:
- nf_send_reset(pkt->skb, pkt->ops->hooknum);
+ nft_reject_br_send_v4_tcp_reset(pkt->skb,
+ pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
- nf_send_unreach(pkt->skb,
- nft_reject_icmp_code(priv->icmp_code));
+ nft_reject_br_send_v4_unreach(pkt->skb,
+ pkt->ops->hooknum,
+ nft_reject_icmp_code(priv->icmp_code));
break;
}
break;
case htons(ETH_P_IPV6):
switch (priv->type) {
case NFT_REJECT_ICMP_UNREACH:
- nf_send_unreach6(net, pkt->skb, priv->icmp_code,
- pkt->ops->hooknum);
+ nft_reject_br_send_v6_unreach(net, pkt->skb,
+ pkt->ops->hooknum,
+ priv->icmp_code);
break;
case NFT_REJECT_TCP_RST:
- nf_send_reset6(net, pkt->skb, pkt->ops->hooknum);
+ nft_reject_br_send_v6_tcp_reset(net, pkt->skb,
+ pkt->ops->hooknum);
break;
case NFT_REJECT_ICMPX_UNREACH:
- nf_send_unreach6(net, pkt->skb,
- nft_reject_icmpv6_code(priv->icmp_code),
- pkt->ops->hooknum);
+ nft_reject_br_send_v6_unreach(net, pkt->skb,
+ pkt->ops->hooknum,
+ nft_reject_icmpv6_code(priv->icmp_code));
break;
}
break;
@@ -59,6 +301,7 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr,
/* No explicit way to reject this protocol, drop it. */
break;
}
+out:
data[NFT_REG_VERDICT].verdict = NF_DROP;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 13:34:56 +0100