wifi: mac80211: validate TX status rate metadata

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

wifi: mac80211: validate TX status rate metadata

minstrel_ht_tx_status() converts the HT/VHT rate reported in a TX status
into a group and rate index and uses those to index the minstrel_ht rate
tables. The existing validation only checked that an entry was present
and had tries recorded; it did not check that the reported MCS, spatial
stream count and bandwidth are representable by the tables, so malformed
metadata passed to minstrel_ht_get_stats() or
minstrel_ht_ri_get_stats() could be used as an out-of-bounds index.

Validate the rate metadata in the common TX status path instead of only
in minstrel_ht, since the values are used by more than rate control.
The legacy ieee80211_tx_rate array and the rate_info based entries are
sanitized in ieee80211_tx_status_ext() and ieee80211_tx_rate_update()
before any consumer runs: an entry that does not describe a valid rate
for its encoding is dropped. minstrel_ht keeps the checks that depend
on its own tables, i.e. the supported number of spatial streams, the MCS
group size and the supported bandwidths.

This does not take away the driver's responsibility to report sane
values, it only prevents a single bad report from corrupting mac80211
state. No WARN_ON() is added: with panic_on_warn a driver bug would
otherwise turn into a denial of service.