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-rw-r--r--net/bridge/br_device.c5
-rw-r--r--net/bridge/br_forward.c4
-rw-r--r--net/bridge/br_netfilter.c78
-rw-r--r--net/bridge/br_private.h5
-rw-r--r--net/bridge/netfilter/nft_reject_bridge.c84
5 files changed, 147 insertions, 29 deletions
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index ffd379db5938..294cbcc49263 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -36,13 +36,10 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
u16 vid = 0;
rcu_read_lock();
-#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
- if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
- br_nf_pre_routing_finish_bridge_slow(skb);
+ if (br_nf_prerouting_finish_bridge(skb)) {
rcu_read_unlock();
return NETDEV_TX_OK;
}
-#endif
u64_stats_update_begin(&brstats->syncp);
brstats->tx_packets++;
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 1238fabff874..3304a5442331 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -37,9 +37,7 @@ static inline int should_deliver(const struct net_bridge_port *p,
int br_dev_queue_push_xmit(struct sk_buff *skb)
{
- /* ip_fragment doesn't copy the MAC header */
- if (nf_bridge_maybe_copy_header(skb) ||
- !is_skb_forwardable(skb->dev, skb)) {
+ if (!is_skb_forwardable(skb->dev, skb)) {
kfree_skb(skb);
} else {
skb_push(skb, ETH_HLEN);
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 0ee453fad3de..a8361c7cdf81 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -239,6 +239,14 @@ drop:
return -1;
}
+static void nf_bridge_update_protocol(struct sk_buff *skb)
+{
+ if (skb->nf_bridge->mask & BRNF_8021Q)
+ skb->protocol = htons(ETH_P_8021Q);
+ else if (skb->nf_bridge->mask & BRNF_PPPoE)
+ skb->protocol = htons(ETH_P_PPP_SES);
+}
+
/* PF_BRIDGE/PRE_ROUTING *********************************************/
/* Undo the changes made for ip6tables PREROUTING and continue the
* bridge PRE_ROUTING hook. */
@@ -764,23 +772,53 @@ static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops,
}
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
+static bool nf_bridge_copy_header(struct sk_buff *skb)
+{
+ int err;
+ unsigned int header_size;
+
+ nf_bridge_update_protocol(skb);
+ header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
+ err = skb_cow_head(skb, header_size);
+ if (err)
+ return false;
+
+ skb_copy_to_linear_data_offset(skb, -header_size,
+ skb->nf_bridge->data, header_size);
+ __skb_push(skb, nf_bridge_encap_header_len(skb));
+ return true;
+}
+
+static int br_nf_push_frag_xmit(struct sk_buff *skb)
+{
+ if (!nf_bridge_copy_header(skb)) {
+ kfree_skb(skb);
+ return 0;
+ }
+
+ return br_dev_queue_push_xmit(skb);
+}
+
static int br_nf_dev_queue_xmit(struct sk_buff *skb)
{
int ret;
int frag_max_size;
+ unsigned int mtu_reserved;
+ if (skb_is_gso(skb) || skb->protocol != htons(ETH_P_IP))
+ return br_dev_queue_push_xmit(skb);
+
+ mtu_reserved = nf_bridge_mtu_reduction(skb);
/* This is wrong! We should preserve the original fragment
* boundaries by preserving frag_list rather than refragmenting.
*/
- if (skb->protocol == htons(ETH_P_IP) &&
- skb->len + nf_bridge_mtu_reduction(skb) > skb->dev->mtu &&
- !skb_is_gso(skb)) {
+ if (skb->len + mtu_reserved > skb->dev->mtu) {
frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
if (br_parse_ip_options(skb))
/* Drop invalid packet */
return NF_DROP;
IPCB(skb)->frag_max_size = frag_max_size;
- ret = ip_fragment(skb, br_dev_queue_push_xmit);
+ ret = ip_fragment(skb, br_nf_push_frag_xmit);
} else
ret = br_dev_queue_push_xmit(skb);
@@ -854,6 +892,38 @@ static unsigned int ip_sabotage_in(const struct nf_hook_ops *ops,
return NF_ACCEPT;
}
+/* This is called when br_netfilter has called into iptables/netfilter,
+ * and DNAT has taken place on a bridge-forwarded packet.
+ *
+ * neigh->output has created a new MAC header, with local br0 MAC
+ * as saddr.
+ *
+ * This restores the original MAC saddr of the bridged packet
+ * before invoking bridge forward logic to transmit the packet.
+ */
+static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
+{
+ struct nf_bridge_info *nf_bridge = skb->nf_bridge;
+
+ skb_pull(skb, ETH_HLEN);
+ nf_bridge->mask &= ~BRNF_BRIDGED_DNAT;
+
+ skb_copy_to_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN),
+ skb->nf_bridge->data, ETH_HLEN-ETH_ALEN);
+ skb->dev = nf_bridge->physindev;
+ br_handle_frame_finish(skb);
+}
+
+int br_nf_prerouting_finish_bridge(struct sk_buff *skb)
+{
+ if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
+ br_nf_pre_routing_finish_bridge_slow(skb);
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(br_nf_prerouting_finish_bridge);
+
void br_netfilter_enable(void)
{
}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index c32e279c62f8..f0a0438dbd6d 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -765,10 +765,15 @@ static inline int br_vlan_enabled(struct net_bridge *br)
/* br_netfilter.c */
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+int br_nf_prerouting_finish_bridge(struct sk_buff *skb);
int br_nf_core_init(void);
void br_nf_core_fini(void);
void br_netfilter_rtable_init(struct net_bridge *);
#else
+static inline int br_nf_prerouting_finish_bridge(struct sk_buff *skb)
+{
+ return 0;
+}
static inline int br_nf_core_init(void) { return 0; }
static inline void br_nf_core_fini(void) {}
#define br_netfilter_rtable_init(x)
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;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.