wifi: iwlwifi: mvm: check n_ssids before accessing the ssids

In some versions of cfg80211, the ssids poinet might be a valid one even
though n_ssids is 0. Accessing the pointer in this case will cuase an
out-of-bound access. Fix this by checking n_ssids first.

Fixes: c1a75153 ("iwlwifi: mvm: add adaptive dwell support")
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240513132416.6e4d1762bf0d.I5a0e6cc8f02050a766db704d15594c61fe583d45@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/scan.c

@@ -1313,7 +1313,7 @@ static void iwl_mvm_scan_umac_dwell(struct iwl_mvm *mvm,
 		if (IWL_MVM_ADWELL_MAX_BUDGET)
 			cmd->v7.adwell_max_budget =
 				cpu_to_le16(IWL_MVM_ADWELL_MAX_BUDGET);
-		else if (params->ssids && params->ssids[0].ssid_len)
+		else if (params->n_ssids && params->ssids[0].ssid_len)
 			cmd->v7.adwell_max_budget =
 				cpu_to_le16(IWL_SCAN_ADWELL_MAX_BUDGET_DIRECTED_SCAN);
 		else
@@ -1418,7 +1418,7 @@ iwl_mvm_scan_umac_dwell_v11(struct iwl_mvm *mvm,
 	if (IWL_MVM_ADWELL_MAX_BUDGET)
 		general_params->adwell_max_budget =
 			cpu_to_le16(IWL_MVM_ADWELL_MAX_BUDGET);
-	else if (params->ssids && params->ssids[0].ssid_len)
+	else if (params->n_ssids && params->ssids[0].ssid_len)
 		general_params->adwell_max_budget =
 			cpu_to_le16(IWL_SCAN_ADWELL_MAX_BUDGET_DIRECTED_SCAN);
 	else