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path: root/net/bridge/netfilter/nft_reject_bridge.c
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Diffstat (limited to 'net/bridge/netfilter/nft_reject_bridge.c')
-rw-r--r--net/bridge/netfilter/nft_reject_bridge.c92
1 files changed, 71 insertions, 21 deletions
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index 3244aead0926..858d848564ee 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, ntohs(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)
@@ -205,12 +253,12 @@ 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,
- struct nft_data data[NFT_REG_MAX + 1],
- const struct nft_pktinfo *pkt)
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
{
struct nft_reject *priv = nft_expr_priv(expr);
struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
@@ -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;
@@ -262,7 +310,7 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr,
break;
}
out:
- data[NFT_REG_VERDICT].verdict = NF_DROP;
+ regs->verdict.code = NF_DROP;
}
static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
@@ -323,6 +371,8 @@ static int nft_reject_bridge_dump(struct sk_buff *skb,
if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
goto nla_put_failure;
break;
+ default:
+ break;
}
return 0;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.