Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 248 insertions, 0 deletions

diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c
new file mode 100644
index 000000000..cd24ab9bb
--- /dev/null
+++ b/net/bridge/br_netfilter_ipv6.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Handle firewalling
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ *	Bart De Schuymer		<bdschuym@pandora.be>
+ *
+ *	Lennert dedicates this file to Kerstin Wurdinger.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/ip.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <linux/if_pppox.h>
+#include <linux/ppp_defs.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter_arp.h>
+#include <linux/in_route.h>
+#include <linux/inetdevice.h>
+
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/addrconf.h>
+#include <net/route.h>
+#include <net/netfilter/br_netfilter.h>
+
+#include <linux/uaccess.h>
+#include "br_private.h"
+#ifdef CONFIG_SYSCTL
+#include <linux/sysctl.h>
+#endif
+
+/* We only check the length. A bridge shouldn't do any hop-by-hop stuff
+ * anyway
+ */
+static int br_nf_check_hbh_len(struct sk_buff *skb)
+{
+	unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1);
+	u32 pkt_len;
+	const unsigned char *nh = skb_network_header(skb);
+	int off = raw - nh;
+	int len = (raw[1] + 1) << 3;
+
+	if ((raw + len) - skb->data > skb_headlen(skb))
+		goto bad;
+
+	off += 2;
+	len -= 2;
+
+	while (len > 0) {
+		int optlen = nh[off + 1] + 2;
+
+		switch (nh[off]) {
+		case IPV6_TLV_PAD1:
+			optlen = 1;
+			break;
+
+		case IPV6_TLV_PADN:
+			break;
+
+		case IPV6_TLV_JUMBO:
+			if (nh[off + 1] != 4 || (off & 3) != 2)
+				goto bad;
+			pkt_len = ntohl(*(__be32 *)(nh + off + 2));
+			if (pkt_len <= IPV6_MAXPLEN ||
+			    ipv6_hdr(skb)->payload_len)
+				goto bad;
+			if (pkt_len > skb->len - sizeof(struct ipv6hdr))
+				goto bad;
+			if (pskb_trim_rcsum(skb,
+					    pkt_len + sizeof(struct ipv6hdr)))
+				goto bad;
+			nh = skb_network_header(skb);
+			break;
+		default:
+			if (optlen > len)
+				goto bad;
+			break;
+		}
+		off += optlen;
+		len -= optlen;
+	}
+	if (len == 0)
+		return 0;
+bad:
+	return -1;
+}
+
+int br_validate_ipv6(struct net *net, struct sk_buff *skb)
+{
+	const struct ipv6hdr *hdr;
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
+	u32 pkt_len;
+	u8 ip6h_len = sizeof(struct ipv6hdr);
+
+	if (!pskb_may_pull(skb, ip6h_len))
+		goto inhdr_error;
+
+	if (skb->len < ip6h_len)
+		goto drop;
+
+	hdr = ipv6_hdr(skb);
+
+	if (hdr->version != 6)
+		goto inhdr_error;
+
+	pkt_len = ntohs(hdr->payload_len);
+
+	if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
+		if (pkt_len + ip6h_len > skb->len) {
+			__IP6_INC_STATS(net, idev,
+					IPSTATS_MIB_INTRUNCATEDPKTS);
+			goto drop;
+		}
+		if (pskb_trim_rcsum(skb, pkt_len + ip6h_len)) {
+			__IP6_INC_STATS(net, idev,
+					IPSTATS_MIB_INDISCARDS);
+			goto drop;
+		}
+		hdr = ipv6_hdr(skb);
+	}
+	if (hdr->nexthdr == NEXTHDR_HOP && br_nf_check_hbh_len(skb))
+		goto drop;
+
+	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
+	/* No IP options in IPv6 header; however it should be
+	 * checked if some next headers need special treatment
+	 */
+	return 0;
+
+inhdr_error:
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+drop:
+	return -1;
+}
+
+static inline bool
+br_nf_ipv6_daddr_was_changed(const struct sk_buff *skb,
+			     const struct nf_bridge_info *nf_bridge)
+{
+	return memcmp(&nf_bridge->ipv6_daddr, &ipv6_hdr(skb)->daddr,
+		      sizeof(ipv6_hdr(skb)->daddr)) != 0;
+}
+
+/* PF_BRIDGE/PRE_ROUTING: Undo the changes made for ip6tables
+ * PREROUTING and continue the bridge PRE_ROUTING hook. See comment
+ * for br_nf_pre_routing_finish(), same logic is used here but
+ * equivalent IPv6 function ip6_route_input() called indirectly.
+ */
+static int br_nf_pre_routing_finish_ipv6(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct rtable *rt;
+	struct net_device *dev = skb->dev, *br_indev;
+	const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
+
+	br_indev = nf_bridge_get_physindev(skb, net);
+	if (!br_indev) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
+
+	if (nf_bridge->pkt_otherhost) {
+		skb->pkt_type = PACKET_OTHERHOST;
+		nf_bridge->pkt_otherhost = false;
+	}
+	nf_bridge->in_prerouting = 0;
+	if (br_nf_ipv6_daddr_was_changed(skb, nf_bridge)) {
+		skb_dst_drop(skb);
+		v6ops->route_input(skb);
+
+		if (skb_dst(skb)->error) {
+			kfree_skb(skb);
+			return 0;
+		}
+
+		if (skb_dst(skb)->dev == dev) {
+			skb->dev = br_indev;
+			nf_bridge_update_protocol(skb);
+			nf_bridge_push_encap_header(skb);
+			br_nf_hook_thresh(NF_BR_PRE_ROUTING,
+					  net, sk, skb, skb->dev, NULL,
+					  br_nf_pre_routing_finish_bridge);
+			return 0;
+		}
+		ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
+		skb->pkt_type = PACKET_HOST;
+	} else {
+		rt = bridge_parent_rtable(br_indev);
+		if (!rt) {
+			kfree_skb(skb);
+			return 0;
+		}
+		skb_dst_drop(skb);
+		skb_dst_set_noref(skb, &rt->dst);
+	}
+
+	skb->dev = br_indev;
+	nf_bridge_update_protocol(skb);
+	nf_bridge_push_encap_header(skb);
+	br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb,
+			  skb->dev, NULL, br_handle_frame_finish);
+
+	return 0;
+}
+
+/* Replicate the checks that IPv6 does on packet reception and pass the packet
+ * to ip6tables.
+ */
+unsigned int br_nf_pre_routing_ipv6(void *priv,
+				    struct sk_buff *skb,
+				    const struct nf_hook_state *state)
+{
+	struct nf_bridge_info *nf_bridge;
+
+	if (br_validate_ipv6(state->net, skb))
+		return NF_DROP;
+
+	nf_bridge = nf_bridge_alloc(skb);
+	if (!nf_bridge)
+		return NF_DROP;
+	if (!setup_pre_routing(skb, state->net))
+		return NF_DROP;
+
+	nf_bridge = nf_bridge_info_get(skb);
+	nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr;
+
+	skb->protocol = htons(ETH_P_IPV6);
+	skb->transport_header = skb->network_header + sizeof(struct ipv6hdr);
+
+	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
+		skb->dev, NULL,
+		br_nf_pre_routing_finish_ipv6);
+
+	return NF_STOLEN;
+}