In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: disconnect on CSA to channel 0 The refactor for the CS

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

wifi: mac80211: disconnect on CSA to channel 0

The refactor for the CSA parsing erroneously equates channel
zero and no information present, leading it to ignore a CSA
on an AP that advertises a switch to that (invalid) channel.
This leads to not disconnecting, which we should. For Intel
devices, this can lead to a firmware crash.

Fix this by using an int type for the channel number as well
as the opclass, and using a (negative) value that cannot be
encoded in the element to indicate it's not present.