CVE-2024-46770: NULL Pointer Dereference

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

ice: Add netif_device_attach/detach into PF reset flow

Ethtool callbacks can be executed while reset is in progress and try to access deleted resources, e.g. getting coalesce settings can result in a NULL pointer dereference seen below.

Reproduction steps: Once the driver is fully initialized, trigger reset: # echo 1 > /sys/class/net/<interface>/device/reset when reset is in progress try to get coalesce settings using ethtool: # ethtool -c <interface>

BUG: kernel NULL pointer dereference, address: 0000000000000020 PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 11 PID: 19713 Comm: ethtool Tainted: G S 6.10.0-rc7+ #7 RIP: 0010:ice_get_q_coalesce+0x2e/0xa0 [ice] RSP: 0018:ffffbab1e9bcf6a8 EFLAGS: 00010206 RAX: 000000000000000c RBX: ffff94512305b028 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9451c3f2e588 RDI: ffff9451c3f2e588 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffff9451c3f2e580 R11: 000000000000001f R12: ffff945121fa9000 R13: ffffbab1e9bcf760 R14: 0000000000000013 R15: ffffffff9e65dd40 FS: 00007faee5fbe740(0000) GS:ffff94546fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 0000000106c2e005 CR4: 00000000001706f0 Call Trace: <TASK> ice_get_coalesce+0x17/0x30 [ice] coalesce_prepare_data+0x61/0x80 ethnl_default_doit+0xde/0x340 genl_family_rcv_msg_doit+0xf2/0x150 genl_rcv_msg+0x1b3/0x2c0 netlink_rcv_skb+0x5b/0x110 genl_rcv+0x28/0x40 netlink_unicast+0x19c/0x290 netlink_sendmsg+0x222/0x490 __sys_sendto+0x1df/0x1f0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x82/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7faee60d8e27

Calling netif_device_detach() before reset makes the net core not call the driver when ethtool command is issued, the attempt to execute an ethtool command during reset will result in the following message:

netlink error: No such device

instead of NULL pointer dereference. Once reset is done and ice_rebuild() is executing, the netif_device_attach() is called to allow for ethtool operations to occur again in a safe manner.