CVE-2024-35971
In the Linux kernel, the following vulnerability has been resolved: net: ks8851: Handle softirqs at the end of IRQ thread to fix hang The ks8851_irq() thread may call ks8851_rx_pkts() in case there are any packets in the MAC FIFO, which calls netif_rx().
Does this matter?
Lower severity and a low EPSS score (0.69%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: net: ks8851: Handle softirqs at the end of IRQ thread to fix hang The ks8851_irq() thread may call ks8851_rx_pkts() in case there are any packets in the MAC FIFO, which calls netif_rx(). This netif_rx() implementation is guarded by local_bh_disable() and local_bh_enable(). The local_bh_enable() may call do_softirq() to run softirqs in case any are pending. One of the softirqs is net_rx_action, which ultimately reaches the driver .start_xmit callback. If that happens, the system hangs. The entire call chain is below: ks8851_start_xmit_par from netdev_start_xmit netdev_start_xmit from dev_hard_start_xmit dev_hard_start_xmit from sch_direct_xmit sch_direct_xmit from __dev_queue_xmit __dev_queue_xmit from __neigh_update __neigh_update from neigh_update neigh_update from arp_process.constprop.0 arp_process.constprop.0 from __netif_receive_skb_one_core __netif_receive_skb_one_core from process_backlog process_backlog from __napi_poll.constprop.0 __napi_poll.constprop.0 from net_rx_action net_rx_action from __do_softirq __do_softirq from call_with_stack call_with_stack from do_softirq do_softirq from __local_bh_enable_ip __local_bh_enable_ip from netif_rx netif_rx from ks8851_irq ks8851_irq from irq_thread_fn irq_thread_fn from irq_thread irq_thread from kthread kthread from ret_from_fork The hang happens because ks8851_irq() first locks a spinlock in ks8851_par.c ks8851_lock_par() spin_lock_irqsave(&ksp->lock, ...) and with that spinlock locked, calls netif_rx(). Once the execution reaches ks8851_start_xmit_par(), it calls ks8851_lock_par() again which attempts to claim the already locked spinlock again, and the hang happens. Move the do_softirq() call outside of the spinlock protected section of ks8851_irq() by disabling BHs around the entire spinlock protected section of ks8851_irq() handler. Place local_bh_enable() outside of the spinlock protected section, so that it can trigger do_softirq() without the ks8851_par.c ks8851_lock_par() spinlock being held, and safely call ks8851_start_xmit_par() without attempting to lock the already locked spinlock. Since ks8851_irq() is protected by local_bh_disable()/local_bh_enable() now, replace netif_rx() with __netif_rx() which is not duplicating the local_bh_disable()/local_bh_enable() calls.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.69% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-667
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/492337a4fbd1421b42df684ee9b34be2a2722540Patch
- https://git.kernel.org/stable/c/49d5d70538b6b8f2a3f8f1ac30c1f921d4a0929bPatch
- https://git.kernel.org/stable/c/be0384bf599cf1eb8d337517feeb732d71f75a6fPatch
- https://git.kernel.org/stable/c/cba376eb036c2c20077b41d47b317d8218fe754fPatch
- http://www.openwall.com/lists/oss-security/2024/05/30/1Mailing List
- http://www.openwall.com/lists/oss-security/2024/05/30/2Mailing List
- https://git.kernel.org/stable/c/492337a4fbd1421b42df684ee9b34be2a2722540Patch
- https://git.kernel.org/stable/c/49d5d70538b6b8f2a3f8f1ac30c1f921d4a0929bPatch
- https://git.kernel.org/stable/c/be0384bf599cf1eb8d337517feeb732d71f75a6fPatch
- https://git.kernel.org/stable/c/cba376eb036c2c20077b41d47b317d8218fe754fPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.