CVE-2022-50476

/// Technical description

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

ntb_netdev: Use dev_kfree_skb_any() in interrupt context

TX/RX callback handlers (ntb_netdev_tx_handler(),

ntb_netdev_rx_handler()) can be called in interrupt

context via the DMA framework when the respective

DMA operations have completed. As such, any calls

by these routines to free skb's, should use the

interrupt context safe dev_kfree_skb_any() function.

Previously, these callback handlers would call the

interrupt unsafe version of dev_kfree_skb(). This has

not presented an issue on Intel IOAT DMA engines as

that driver utilizes tasklets rather than a hard

interrupt handler, like the AMD PTDMA DMA driver.

On AMD systems, a kernel WARNING message is

encountered, which is being issued from

skb_release_head_state() due to in_hardirq()

being true.

Besides the user visible WARNING from the kernel,

the other symptom of this bug was that TCP/IP performance

across the ntb_netdev interface was very poor, i.e.

approximate

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References