wifi: mac80211_hwsim: reject undersized HWSIM_ATTR_TX_INFO

wifi: mac80211_hwsim: reject undersized HWSIM_ATTR_TX_INFO

hwsim_tx_info_frame_received_nl() casts the HWSIM_ATTR_TX_INFO payload
to a struct hwsim_tx_rate * and unconditionally reads
IEEE80211_TX_MAX_RATES entries (8 bytes) from it. The policy only bounds
the attribute from above (NLA_BINARY .len is a maximum) and the op sets
GENL_DONT_VALIDATE_STRICT, so a short or zero-length attribute is
accepted and the loop reads past the payload.

Require the exact length in the policy, so a malformed attribute is
rejected before the handler runs.

Signed-off-by: Ibrahim Hashimov <security@auditcode.ai>
Assisted-by: AuditCode-AI:2026.07
Link: https://patch.msgid.link/20260721115346.17236-1-security@auditcode.ai
Signed-off-by: Johannes Berg <johannes.berg@intel.com>