linux/net/bridge
Harsh Modi d047283a70 netfilter: br_netfilter: Drop dst references before setting.
The IPv6 path already drops dst in the daddr changed case, but the IPv4
path does not. This change makes the two code paths consistent.

Further, it is possible that there is already a metadata_dst allocated from
ingress that might already be attached to skbuff->dst while following
the bridge path. If it is not released before setting a new
metadata_dst, it will be leaked. This is similar to what is done in
bpf_set_tunnel_key() or ip6_route_input().

It is important to note that the memory being leaked is not the dst
being set in the bridge code, but rather memory allocated from some
other code path that is not being freed correctly before the skb dst is
overwritten.

An example of the leakage fixed by this commit found using kmemleak:

unreferenced object 0xffff888010112b00 (size 256):
  comm "softirq", pid 0, jiffies 4294762496 (age 32.012s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 80 16 f1 83 ff ff ff ff  ................
    e1 4e f6 82 ff ff ff ff 00 00 00 00 00 00 00 00  .N..............
  backtrace:
    [<00000000d79567ea>] metadata_dst_alloc+0x1b/0xe0
    [<00000000be113e13>] udp_tun_rx_dst+0x174/0x1f0
    [<00000000a36848f4>] geneve_udp_encap_recv+0x350/0x7b0
    [<00000000d4afb476>] udp_queue_rcv_one_skb+0x380/0x560
    [<00000000ac064aea>] udp_unicast_rcv_skb+0x75/0x90
    [<000000009a8ee8c5>] ip_protocol_deliver_rcu+0xd8/0x230
    [<00000000ef4980bb>] ip_local_deliver_finish+0x7a/0xa0
    [<00000000d7533c8c>] __netif_receive_skb_one_core+0x89/0xa0
    [<00000000a879497d>] process_backlog+0x93/0x190
    [<00000000e41ade9f>] __napi_poll+0x28/0x170
    [<00000000b4c0906b>] net_rx_action+0x14f/0x2a0
    [<00000000b20dd5d4>] __do_softirq+0xf4/0x305
    [<000000003a7d7e15>] __irq_exit_rcu+0xc3/0x140
    [<00000000968d39a2>] sysvec_apic_timer_interrupt+0x9e/0xc0
    [<000000009e920794>] asm_sysvec_apic_timer_interrupt+0x16/0x20
    [<000000008942add0>] native_safe_halt+0x13/0x20

Florian Westphal says: "Original code was likely fine because nothing
ever did set a skb->dst entry earlier than bridge in those days."

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Harsh Modi <harshmodi@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-08-31 12:12:32 +02:00
..
netfilter netfilter: ebtables: reject blobs that don't provide all entry points 2022-08-23 18:23:15 +02:00
br_arp_nd_proxy.c net: bridge: Use netif_rx(). 2022-03-04 12:02:19 +00:00
br_cfm_netlink.c bridge: cfm: Netlink Notifications. 2020-10-29 18:39:44 -07:00
br_cfm.c bridge: cfm: remove redundant return 2021-06-22 10:35:15 -07:00
br_device.c net: bridge: fdb: add ndo_fdb_del_bulk 2022-04-13 12:46:26 +01:00
br_fdb.c rtnetlink: add extack support in fdb del handlers 2022-05-09 11:58:20 +01:00
br_forward.c net: Add skb_clear_tstamp() to keep the mono delivery_time 2022-03-03 14:38:48 +00:00
br_if.c net: rename reference+tracking helpers 2022-06-09 21:52:55 -07:00
br_input.c net: bridge: Clear offload_fwd_mark when passing frame up bridge interface. 2022-05-19 09:20:44 +02:00
br_ioctl.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
br_mdb.c net: bridge: allow add/remove permanent mdb entries on disabled ports 2022-06-15 09:35:21 +01:00
br_mrp_netlink.c bridge: mrp: Use hlist_head instead of list_head for mrp 2020-11-09 16:42:12 -08:00
br_mrp_switchdev.c bridge: mrp: Extend br_mrp_switchdev to detect better the errors 2021-02-16 14:47:46 -08:00
br_mrp.c net: bridge: mrp: Update the Test frames for MRA 2021-06-28 15:46:10 -07:00
br_mst.c net: bridge: mst: Add helper to query a port's MST state 2022-03-17 16:49:58 -07:00
br_multicast_eht.c net: bridge: multicast: use multicast contexts instead of bridge or port 2021-07-20 05:41:19 -07:00
br_multicast.c net: bridge: multicast: notify switchdev driver whenever MC processing gets disabled 2022-02-16 20:35:00 -08:00
br_netfilter_hooks.c netfilter: br_netfilter: Drop dst references before setting. 2022-08-31 12:12:32 +02:00
br_netfilter_ipv6.c netfilter: br_netfilter: Drop dst references before setting. 2022-08-31 12:12:32 +02:00
br_netlink_tunnel.c net: bridge: notify on vlan tunnel changes done via the old api 2020-07-12 15:18:24 -07:00
br_netlink.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-07-28 18:21:16 -07:00
br_nf_core.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00
br_private_cfm.h bridge: cfm: Kernel space implementation of CFM. CCM frame RX added. 2020-10-29 18:39:43 -07:00
br_private_mcast_eht.h net: bridge: multicast: use multicast contexts instead of bridge or port 2021-07-20 05:41:19 -07:00
br_private_mrp.h net: bridge: mrp: Update the Test frames for MRA 2021-06-28 15:46:10 -07:00
br_private_stp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_private_tunnel.h net: bridge: change return type of br_handle_ingress_vlan_tunnel 2021-08-24 16:51:09 -07:00
br_private.h rtnetlink: add extack support in fdb del handlers 2022-05-09 11:58:20 +01:00
br_stp_bpdu.c net: bridge: add STP xstats 2019-12-14 20:02:36 -08:00
br_stp_if.c net: use eth_hw_addr_set() 2021-10-02 14:18:25 +01:00
br_stp_timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_stp.c net: bridge: mst: Multiple Spanning Tree (MST) mode 2022-03-17 16:49:57 -07:00
br_switchdev.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-04-28 13:02:01 -07:00
br_sysfs_br.c net: bridge: fdb: add support for fine-grained flushing 2022-04-13 12:46:26 +01:00
br_sysfs_if.c net: bridge: mcast: br_multicast_set_port_router takes multicast context as argument 2021-08-20 15:00:35 +01:00
br_vlan_options.c net: bridge: mst: Allow changing a VLAN's MSTI 2022-03-17 16:49:57 -07:00
br_vlan_tunnel.c net: bridge: change return type of br_handle_ingress_vlan_tunnel 2021-08-24 16:51:09 -07:00
br_vlan.c net: adopt u64_stats_t in struct pcpu_sw_netstats 2022-06-09 21:53:11 -07:00
br.c net: bridge: mst: Multiple Spanning Tree (MST) mode 2022-03-17 16:49:57 -07:00
Kconfig bridge: cfm: Add BRIDGE_CFM to Kconfig. 2020-10-29 18:39:43 -07:00
Makefile net: bridge: mst: Multiple Spanning Tree (MST) mode 2022-03-17 16:49:57 -07:00