Linux/Unix ホストには、ベンダーが提供するパッチが利用できない脆弱性の影響を受ける複数のパッケージがインストールされています。

  - Linux カーネルでは、以下の脆弱性が解決されています: ibmvnic: fix race between xmit and reset There is a race between reset and the transmit paths that can lead to ibmvnic_xmit() accessing an scrq after it has been freed in the reset path. It can result in a crash like: Kernel attempted to read user page (0) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000000 Faulting instruction address: 0xc0080000016189f8 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c0080000016189f8] ibmvnic_xmit+0x60/0xb60 [ibmvnic] LR [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 Call Trace: [c008000001618f08] ibmvnic_xmit+0x570/0xb60 [ibmvnic] (unreliable) [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c9cfcc] sch_direct_xmit+0xec/0x330 [c000000000bfe640]
    __dev_xmit_skb+0x3a0/0x9d0 [c000000000c00ad4] __dev_queue_xmit+0x394/0x730 [c008000002db813c]
    __bond_start_xmit+0x254/0x450 [bonding] [c008000002db8378] bond_start_xmit+0x40/0xc0 [bonding] [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c00ca4] __dev_queue_xmit+0x564/0x730 [c000000000cf97e0] neigh_hh_output+0xd0/0x180 [c000000000cfa69c] ip_finish_output2+0x31c/0x5c0 [c000000000cfd244] __ip_queue_xmit+0x194/0x4f0 [c000000000d2a3c4] __tcp_transmit_skb+0x434/0x9b0 [c000000000d2d1e0] __tcp_retransmit_skb+0x1d0/0x6a0 [c000000000d2d984] tcp_retransmit_skb+0x34/0x130 [c000000000d310e8] tcp_retransmit_timer+0x388/0x6d0 [c000000000d315ec] tcp_write_timer_handler+0x1bc/0x330 [c000000000d317bc] tcp_write_timer+0x5c/0x200 [c000000000243270] call_timer_fn+0x50/0x1c0 [c000000000243704] __run_timers.part.0+0x324/0x460 [c000000000243894] run_timer_softirq+0x54/0xa0 [c000000000ea713c] __do_softirq+0x15c/0x3e0 [c000000000166258] __irq_exit_rcu+0x158/0x190 [c000000000166420] irq_exit+0x20/0x40 [c00000000002853c] timer_interrupt+0x14c/0x2b0 [c000000000009a00] decrementer_common_virt+0x210/0x220 --- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x2c The immediate cause of the crash is the access of tx_scrq in the following snippet during a reset, where the tx_scrq can be either NULL or an address that will soon be invalid: ibmvnic_xmit() { ... tx_scrq = adapter->tx_scrq[queue_num]; txq = netdev_get_tx_queue(netdev, queue_num); ind_bufp = &tx_scrq->ind_buf;
    if (test_bit(0, &adapter->resetting)) { ... } But beyond that, the call to ibmvnic_xmit() itself is not safe during a reset and the reset path attempts to avoid this by stopping the queue in ibmvnic_cleanup().
    However just after the queue was stopped, an in-flight ibmvnic_complete_tx() could have restarted the queue even as the reset is progressing. Since the queue was restarted we could get a call to ibmvnic_xmit() which can then access the bad tx_scrq (or other fields). We cannot however simply have ibmvnic_complete_tx() check the ->resetting bit and skip starting the queue. This can race at the back-end of a good reset which just restarted the queue but has not cleared the ->resetting bit yet. If we skip restarting the queue due to ->resetting being true, the queue would remain stopped indefinitely potentially leading to transmit timeouts. IOW ->resetting is too broad for this purpose. Instead use a new flag that indicates whether or not the queues are active. Only the open/ reset paths control when the queues are active. ibmvnic_complete_tx() and others wake up the queue only if the queue is marked active.
    So we will have: A. reset/open thread in ibmvnic_cleanup() and __ibmvnic_open() ->resetting = true
    ->tx_queues_active = false disable tx queues ... ->tx_queues_active = true start tx queues B. Tx interrupt in ibmvnic_complete_tx(): if (->tx_queues_active) netif_wake_subqueue(); To ensure that ->tx_queues_active and state of the queues are consistent, we need a lock which: - must also be taken in the interrupt path (ibmvnic_complete_tx()) - shared across the multiple ---truncated--- (CVE-2022-49201)

Nessus は、ベンダーによって報告されたパッケージの存在に依存していることに注意してください。

検出

Linux Distros のパッチ未適用の脆弱性: CVE-2022-49201

medium Nessus プラグイン ID 225514

バージョン 1.17