[PATCH 5.15.y,6.1.y,6.6.y] wifi: iwlwifi: mvm: fix 6 GHz scan construction

[Johannes Berg <johannes@sipsolutions.net>]

From: Johannes Berg <johannes.berg@intel.com>

Upstream commit 7245012f0f496162dd95d888ed2ceb5a35170f1a.

If more than 255 colocated APs exist for the set of all
APs found during 2.4/5 GHz scanning, then the 6 GHz scan
construction will loop forever since the loop variable
has type u8, which can never reach the number found when
that's bigger than 255, and is stored in a u32 variable.
Also move it into the loops to have a smaller scope.

Using a u32 there is fine, we limit the number of APs in
the scan list and each has a limit on the number of RNR
entries due to the frame size. With a limit of 1000 scan
results, a frame size upper bound of 4096 (really it's
more like ~2300) and a TBTT entry size of at least 11,
we get an upper bound for the number of ~372k, well in
the bounds of a u32.

Cc: stable@vger.kernel.org
Fixes: eae94cf82d74 ("iwlwifi: mvm: add support for 6GHz")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219375
Link: https://patch.msgid.link/20241023091744.f4baed5c08a1.I8b417148bbc8c5d11c101e1b8f5bf372e17bf2a7@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
index aa6ef6491205..16818dcdae22 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
@@ -1753,7 +1753,8 @@ iwl_mvm_umac_scan_cfg_channels_v6_6g(struct iwl_mvm_scan_params *params,
 			&cp->channel_config[i];
 
 		u32 s_ssid_bitmap = 0, bssid_bitmap = 0, flags = 0;
-		u8 j, k, s_max = 0, b_max = 0, n_used_bssid_entries;
+		u8 k, s_max = 0, b_max = 0, n_used_bssid_entries;
+		u32 j;
 		bool force_passive, found = false, allow_passive = true,
 		     unsolicited_probe_on_chan = false, psc_no_listen = false;
 
-- 
2.47.0