wifi: mt76: mt7996: fix use-after-free bugs in mt7996_mac_dump_work()

Overview

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

wifi: mt76: mt7996: fix use-after-free bugs in mt7996_mac_dump_work()

When the mt7996 pci chip is detaching, the mt7996_crash_data is released in mt7996_coredump_unregister(). However, the work item dump_work may still be running or pending, leading to UAF bugs when the already freed crash_data is dereferenced again in mt7996_mac_dump_work().

The race condition can occur as follows:

CPU 0 (removal path) | CPU 1 (workqueue) mt7996_pci_remove() | mt7996_sys_recovery_set() mt7996_unregister_device() | mt7996_reset() mt7996_coredump_unregister() | queue_work() vfree(dev->coredump.crash_data) | mt7996_mac_dump_work() | crash_data-> // UAF

Fix this by ensuring dump_work is properly canceled before the crash_data is deallocated. Add cancel_work_sync() in mt7996_unregister_device() to synchronize with any pending or executing dump work.

Affected

• Linux >= 878161d5d4a469a6ef7f3fb4fe9f676bc508ee99 < 533b1a9fa0128c75e40dd2d2c38a32b4e660741f
• Linux >= 878161d5d4a469a6ef7f3fb4fe9f676bc508ee99 < 180182a3f23ff79430a32ca2c4c1885368ceab48
• Linux >= 878161d5d4a469a6ef7f3fb4fe9f676bc508ee99 < aa4a31cd89f4fde5043ac613fe0e27014a60a60b
• Linux >= 878161d5d4a469a6ef7f3fb4fe9f676bc508ee99 < 188e10f9ea3109d23c6b7643aa6ec2f5cb0faa6d
• Linux >= 878161d5d4a469a6ef7f3fb4fe9f676bc508ee99 < c8f62f73bbced3a79894655bdb0b625462d956fc
• Linux 6.4

Remediation

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