CVE-2022-50476

Summary

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. approximately an order of magnitude below what was expected. With the repair to use dev_kfree_skb_any(), kernel WARNINGs from skb_release_head_state() ceased and TCP/IP performance, as measured by iperf, was on par with expected results, approximately 20 Gb/s on AMD Milan based server. Note that this performance is comparable with Intel based servers.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < d4460c82177899751975180c268f352893302221affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < dd860b39aa7c7b82e6c99b6fdb99d4610ce49d67affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 8b78493968ed3cef0326183ed059c55e42f24d5baffected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < a6b9e09403102bdf8402dae734800e4916c7ea58affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 13286ad1c7c49c606fdcba4cf66f953a1a16c1caaffected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 21296a52caa6a6bad6debdfe40ad81d4f1a27e69affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 14d245da57a11e80277ab455aa9b6dcc5ed38a19affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 07e28a8f450217db679802ebd4de0915556ce846affected
LinuxLinux548c237c0a9972df5d1afaca38aa733ee577128d < 5f7d78b2b12a9d561f48fa00bab29b40f4616dadaffected
LinuxLinux3.9affected
LinuxLinux0 < 3.9unaffected
LinuxLinux4.9.337 <= 4.9.*unaffected
LinuxLinux4.14.303 <= 4.14.*unaffected
LinuxLinux4.19.270 <= 4.19.*unaffected
LinuxLinux5.4.229 <= 5.4.*unaffected
LinuxLinux5.10.163 <= 5.10.*unaffected
LinuxLinux5.15.86 <= 5.15.*unaffected
LinuxLinux6.0.16 <= 6.0.*unaffected
LinuxLinux6.1.2 <= 6.1.*unaffected
LinuxLinux6.2 <= *unaffected

Weaknesses

References