net: sparx5: skip ptp deinit if init was skipped

Overview

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

net: sparx5: skip ptp deinit if init was skipped

sparx5_ptp_init() returns early on the base lan969x variants because they do not have the SPX5_FEATURE_PTP flag. It also returns early when no "ptp" interrupt is described. Unbinding the driver then causes a NULL pointer dereference when cleaning up uninitialized tx_skbs queues:

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000008
Call trace:
skb_queue_purge_reason+0x68/0x120 (P)
sparx5_ptp_deinit+0x64/0xc0
mchp_sparx5_remove+0x38/0x70
platform_remove+0x20/0x30
device_remove+0x4c/0x80

Before per-port tx_skbs were added, a NULL dereference would have happened when calling ptp_clock_unregister() on the never-registered PTP clocks.

Fix by returning early in sparx5_ptp_deinit() if PTP is not used.

Affected

• Linux >= 0933bd04047c3b96ba49545a8f91e7e6f8f666ff < 35c706d6eb1963735814c5f5bb2674a96eacf3cc
• Linux >= 0933bd04047c3b96ba49545a8f91e7e6f8f666ff < 2879b65bfa548e10d59c5fba91d17f8a00cd7029
• Linux >= 0933bd04047c3b96ba49545a8f91e7e6f8f666ff < 0d2c49915bc3aea4521cda5e4d42f24f63b94585
• Linux 5.18

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.