Description
In the Linux kernel, the following vulnerability has been resolved: net: dsa: mxl862xx: fix use-after-free of DSA ports in crc_err_work Upon an MDIO CRC error mxl862xx_crc_err_work_fn() walks the DSA ports and closes the CPU port conduits: dsa_switch_for_each_cpu_port(dp, priv->ds) dev_close(dp->conduit); mxl862xx_remove() unregisters the switch before cancelling this work: set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags); cancel_delayed_work_sync(&priv->stats_work); dsa_unregister_switch(ds); mxl862xx_host_shutdown(priv); dsa_unregister_switch() frees the dsa_port objects. If a CRC error schedules the work during teardown it can run after the ports have been freed and dereference freed memory. Guard the port walk with MXL862XX_FLAG_WORK_STOPPED, which is already set before dsa_unregister_switch(). DSA tears the ports down under rtnl_lock(), so checking the flag under rtnl_lock() means the work either runs before teardown and sees valid ports, or runs afterwards, observes the flag and skips the walk. This mirrors the host_flood_work handler, which skips torn-down ports under rtnl_lock().
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
a319d0c8c8cede3b63538c9f111f84651d078bf6 to < cf52622fbc274eb4ca9a2066b258da2ae3dc7406affecteda319d0c8c8cede3b63538c9f111f84651d078bf6 to < bcb3b8314611ed9cb4ff4bff484ef9b154fd1b83affected
Linux Linux
Default version status: affected
7.1affected0 to < 7.1unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected