Eyal Birger 9ef33d23f8 bpf, lwt: Fix crash when using bpf_skb_set_tunnel_key() from bpf_xmit lwt hook ...

[ Upstream commit b02d196c44ead1a5949729be9ff08fe781c3e48a ]

xmit_check_hhlen() observes the dst for getting the device hard header
length to make sure a modified packet can fit. When a helper which changes
the dst - such as bpf_skb_set_tunnel_key() - is called as part of the
xmit program the accessed dst is no longer valid.

This leads to the following splat:

 BUG: kernel NULL pointer dereference, address: 00000000000000de
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 0 PID: 798 Comm: ping Not tainted 5.18.0-rc2+ #103
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 RIP: 0010:bpf_xmit+0xfb/0x17f
 Code: c6 c0 4d cd 8e 48 c7 c7 7d 33 f0 8e e8 42 09 fb ff 48 8b 45 58 48 8b 95 c8 00 00 00 48 2b 95 c0 00 00 00 48 83 e0 fe 48 8b 00 <0f> b7 80 de 00 00 00 39 c2 73 22 29 d0 b9 20 0a 00 00 31 d2 48 89
 RSP: 0018:ffffb148c0bc7b98 EFLAGS: 00010282
 RAX: 0000000000000000 RBX: 0000000000240008 RCX: 0000000000000000
 RDX: 0000000000000010 RSI: 00000000ffffffea RDI: 00000000ffffffff
 RBP: ffff922a828a4e00 R08: ffffffff8f1350e8 R09: 00000000ffffdfff
 R10: ffffffff8f055100 R11: ffffffff8f105100 R12: 0000000000000000
 R13: ffff922a828a4e00 R14: 0000000000000040 R15: 0000000000000000
 FS:  00007f414e8f0080(0000) GS:ffff922afdc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000000000de CR3: 0000000002d80006 CR4: 0000000000370ef0
 Call Trace:
  <TASK>
  lwtunnel_xmit.cold+0x71/0xc8
  ip_finish_output2+0x279/0x520
  ? __ip_finish_output.part.0+0x21/0x130

Fix by fetching the device hard header length before running the BPF code.

Fixes: 3a0af8fd61 ("bpf: BPF for lightweight tunnel infrastructure")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420165219.1755407-1-eyal.birger@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

2022-05-09 09:05:02 +02:00

..

bpf_sk_storage.c

bpf: Change bpf_sk_storage_*() to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON

2020-09-25 13:58:01 -07:00

datagram.c

udp: fix skb_copy_and_csum_datagram with odd segment sizes

2021-02-17 11:02:28 +01:00

datagram.h

net/core: Allow the compiler to verify declaration and definition consistency

2019-03-27 13:49:44 -07:00

dev_addr_lists.c

net: core: add nested_level variable in net_device

2020-09-28 15:00:15 -07:00

dev_ioctl.c

net: fix dev_ifsioc_locked() race condition

2021-03-07 12:34:07 +01:00

dev.c

xdp: check prog type before updating BPF link

2022-01-27 10:54:30 +01:00

devlink.c

devlink: Remove misleading internal_flags from health reporter dump

2022-01-27 10:54:34 +01:00

drop_monitor.c

drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hit

2022-02-23 12:01:02 +01:00

dst_cache.c

wireguard: device: reset peer src endpoint when netns exits

2021-12-08 09:03:22 +01:00

dst.c

net, bpf: Fix ip6ip6 crash with collect_md populated skbs

2021-03-30 14:32:05 +02:00

failover.c

failover: allow name change on IFF_UP slave interfaces

2019-04-10 22:12:26 -07:00

fib_notifier.c

net: fib_notifier: propagate extack down to the notifier block callback

2019-10-04 11:10:56 -07:00

fib_rules.c

ipv6: fix memory leak in fib6_rule_suppress

2021-12-08 09:03:21 +01:00

filter.c

bpf: Support dual-stack sockets in bpf_tcp_check_syncookie

2022-04-13 21:01:06 +02:00

flow_dissector.c

net/sched: flower: fix parsing of ethertype following VLAN header

2022-04-20 09:23:11 +02:00

flow_offload.c

net: Fix offloading indirect devices dependency on qdisc order creation

2021-09-18 13:40:30 +02:00

gen_estimator.c

net_sched: gen_estimator: support large ewma log

2021-01-27 11:55:23 +01:00

gen_stats.c

docs: networking: convert gen_stats.txt to ReST

2020-04-28 14:39:46 -07:00

gro_cells.c

gro_cells: reduce number of synchronize_net() calls

2020-11-25 11:28:12 -08:00

hwbm.c

net: hwbm: Make the hwbm_pool lock a mutex

2019-06-09 19:40:10 -07:00

link_watch.c

net: linkwatch: fix failure to restore device state across suspend/resume

2021-08-18 08:59:13 +02:00

lwt_bpf.c

bpf, lwt: Fix crash when using bpf_skb_set_tunnel_key() from bpf_xmit lwt hook

2022-05-09 09:05:02 +02:00

lwtunnel.c

lwtunnel: Validate RTA_ENCAP_TYPE attribute length

2022-01-11 15:25:00 +01:00

Makefile

ethtool: move to its own directory

2019-12-12 17:07:05 -08:00

neighbour.c

net, neigh: clear whole pneigh_entry at alloc time

2021-12-14 11:32:43 +01:00

net_namespace.c

netns: add schedule point in ops_exit_list()

2022-01-27 10:54:33 +01:00

net-procfs.c

net-procfs: show net devices bound packet types

2022-02-01 17:25:44 +01:00

net-sysfs.c

net-sysfs: add check for netdevice being present to speed_show

2022-03-16 14:16:00 +01:00

net-sysfs.h

net-sysfs: add netdev_change_owner()

2020-02-26 20:07:25 -08:00

net-traces.c

page_pool: add tracepoints for page_pool with details need by XDP

2019-06-19 11:23:13 -04:00

netclassid_cgroup.c

cgroup, netclassid: remove double cond_resched

2020-04-21 15:44:30 -07:00

netevent.c

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30 11:26:32 -07:00

netpoll.c

net: Have netpoll bring-up DSA management interface

2020-11-18 11:04:11 -08:00

netprio_cgroup.c

netprio_cgroup: Fix unlimited memory leak of v2 cgroups

2020-05-09 20:59:21 -07:00

page_pool.c

mm: fix struct page layout on 32-bit systems

2021-05-19 10:13:17 +02:00

pktgen.c

pktgen: fix misuse of BUG_ON() in pktgen_thread_worker()

2021-03-07 12:34:09 +01:00

ptp_classifier.c

ptp: Add generic ptp v2 header parsing function

2020-08-19 16:07:49 -07:00

request_sock.c

tcp: add rcu protection around tp->fastopen_rsk

2019-10-13 10:13:08 -07:00

rtnetlink.c

net: limit altnames to 64k total

2022-04-13 21:01:00 +02:00

scm.c

fs: Add receive_fd() wrapper for __receive_fd()

2020-07-13 11:03:44 -07:00

secure_seq.c

crypto: lib/sha1 - remove unnecessary includes of linux/cryptohash.h

2020-05-08 15:32:17 +10:00

skbuff.c

net: fix up skbs delta_truesize in UDP GRO frag_list

2022-03-08 19:09:32 +01:00

skmsg.c

bpf, sockmap: Fix memleak in tcp_bpf_sendmsg while sk msg is full

2022-04-08 14:40:21 +02:00

sock_diag.c

bpf, net: Rework cookie generator as per-cpu one

2020-09-30 11:50:35 -07:00

sock_map.c

bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc

2021-12-17 10:14:41 +01:00

sock_reuseport.c

udp: Prevent reuseport_select_sock from reading uninitialized socks

2021-01-23 16:03:59 +01:00

sock.c

sock: fix /proc/net/sockstat underflow in sk_clone_lock()

2021-11-26 10:39:14 +01:00

stream.c

net: stream: don't purge sk_error_queue in sk_stream_kill_queues()

2021-11-18 14:04:08 +01:00

sysctl_net_core.c

bpf: Prevent increasing bpf_jit_limit above max

2021-11-18 14:03:42 +01:00

timestamping.c

net: Introduce a new MII time stamping interface.

2019-12-25 19:51:33 -08:00

tso.c

net: tso: add UDP segmentation support

2020-06-18 20:46:23 -07:00

utils.c

net: Fix skb->csum update in inet_proto_csum_replace16().

2020-01-24 20:54:30 +01:00

xdp.c

xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model

2021-04-14 08:42:09 +02:00