In the Linux kernel, the following vulnerability has been resolved:

udp: clear skb->dev before running a sockmap verdict

On the UDP receive path skb->dev is repurposed as dev_scratch (the
truesize/state cache set by udp_set_dev_scratch()), through the
union { struct net_device *dev; unsigned long dev_scratch; } in sk_buff.

When a UDP socket is in a sockmap, sk_data_ready is
sk_psock_verdict_data_ready(), which calls udp_read_skb() -> recv_actor()
(sk_psock_verdict_recv) to run the attached SK_SKB verdict program in softirq.
If that program calls a socket-lookup helper (bpf_sk_lookup_tcp/udp,
bpf_skc_lookup_tcp), bpf_skc_lookup() does:

	if (skb->dev)
		caller_net = dev_net(skb->dev);

skb->dev still holds the dev_scratch value (a non-NULL integer), so dev_net()
dereferences it as a struct net_device * and the kernel takes a general
protection fault on a non-canonical address in softirq:

  Oops: general protection fault, probably for non-canonical address 0x1010000800004a0
  CPU: 1 UID: 0 PID: 1406 Comm: syz.2.19 Not tainted 7.1.0-rc6 #1 PREEMPT(full)
  RIP: 0010:bpf_skc_lookup net/core/filter.c:7033 [inline]
  RIP: 0010:bpf_sk_lookup+0x45/0x160 net/core/filter.c:7047
  Call Trace:
   <IRQ>
   bpf_prog_4675cb904b7071f8+0x12e/0x14e
   bpf_prog_run_pin_on_cpu+0xc6/0x1f0
   sk_psock_verdict_recv+0x1ba/0x350
   udp_read_skb+0x31a/0x370
   sk_psock_verdict_data_ready+0x2e3/0x600
   __udp_enqueue_schedule_skb+0x4c8/0x650
   udpv6_queue_rcv_one_skb+0x3ec/0x740
   udp6_unicast_rcv_skb+0x11d/0x140
   ip6_protocol_deliver_rcu+0x61e/0x950
   ip6_input_finish+0xa9/0x150
   NF_HOOK+0x286/0x2f0
   ip6_input+0x117/0x220
   NF_HOOK+0x286/0x2f0
   __netif_receive_skb+0x85/0x200
   process_backlog+0x374/0x9a0
   __napi_poll+0x4f/0x1c0
   net_rx_action+0x3b0/0x770
   handle_softirqs+0x15a/0x460
   do_softirq+0x57/0x80
   </IRQ>

The rmem charge that dev_scratch accounted for is released by skb_recv_udp() on
dequeue, just above, so the scratch is dead by the time recv_actor() runs. Clear
skb->dev so bpf_skc_lookup() falls back to sock_net(skb->sk), which
skb_set_owner_sk_safe() set just above.

https://git.kernel.org/stable/c/1b585673a2249f13678e7ac443ac683ba767e0b6

https://git.kernel.org/stable/c/263779a6beff03b8b06f6d25566cb0f45af361f2

https://git.kernel.org/stable/c/3c94f241f776562c489876ff506f366224565c21

https://git.kernel.org/stable/c/6822eed69572000a181fa4e31fceacc60918c471

https://git.kernel.org/stable/c/7d6d92d000ebe3a845a17c165c1d3a70c5d84fe1

https://git.kernel.org/stable/c/90d35188aaa92b8f8b23f66335e0e91bf60103a3

[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","programFiles":["net/ipv4/udp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"263779a6beff03b8b06f6d25566cb0f45af361f2","versionType":"git","status":"affected"},{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"1b585673a2249f13678e7ac443ac683ba767e0b6","versionType":"git","status":"affected"},{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"90d35188aaa92b8f8b23f66335e0e91bf60103a3","versionType":"git","status":"affected"},{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"6822eed69572000a181fa4e31fceacc60918c471","versionType":"git","status":"affected"},{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"7d6d92d000ebe3a845a17c165c1d3a70c5d84fe1","versionType":"git","status":"affected"},{"version":"965b57b469a589d64d81b1688b38dcb537011bb0","lessThan":"3c94f241f776562c489876ff506f366224565c21","versionType":"git","status":"affected"}]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","programFiles":["net/ipv4/udp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"6.0","status":"affected"},{"version":"0","lessThan":"6.0","versionType":"semver","status":"unaffected"},{"version":"6.1.176","lessThanOrEqual":"6.1.*","versionType":"semver","status":"unaffected"},{"version":"6.6.143","lessThanOrEqual":"6.6.*","versionType":"semver","status":"unaffected"},{"version":"6.12.94","lessThanOrEqual":"6.12.*","versionType":"semver","status":"unaffected"},{"version":"6.18.36","lessThanOrEqual":"6.18.*","versionType":"semver","status":"unaffected"},{"version":"7.0.13","lessThanOrEqual":"7.0.*","versionType":"semver","status":"unaffected"},{"version":"7.1","lessThanOrEqual":"*","versionType":"original_commit_for_fix","status":"unaffected"}]}]