[PATCH v2] wifi: nl80211: fix bounds checker error in nl80211_parse_sched_scan

[Aleksei Vetrov]

The channels array in the cfg80211_scan_request has a __counted_by
attribute attached to it, which points to the n_channels variable. This
attribute is used in bounds checking, and if it is not set before the
array is filled, then the bounds sanitizer will issue a warning or a
kernel panic if CONFIG_UBSAN_TRAP is set.

This patch sets the size of allocated memory as the initial value for
n_channels. It is updated with the actual number of added elements after
the array is filled.

Fixes: aa4ec06c455d ("wifi: cfg80211: use __counted_by where appropriate")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Aleksei Vetrov <vvvvvv@xxxxxxxxxx>
---
Changes in v2:
- Added Fixes tag and added stable to CC
- Link to v1: https://lore.kernel.org/r/20241028-nl80211_parse_sched_scan-bounds-checker-fix-v1-1-bb640be0ebb7@xxxxxxxxxx
---
 net/wireless/nl80211.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d7d099f7118ab5d5c745905abdea85d246c2b7b2..9b1b9dc5a7eb2a864da7b0212bc6a156b7757a9d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -9776,6 +9776,7 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 	request = kzalloc(size, GFP_KERNEL);
 	if (!request)
 		return ERR_PTR(-ENOMEM);
+	request->n_channels = n_channels;
 
 	if (n_ssids)
 		request->ssids = (void *)request +

---
base-commit: 81983758430957d9a5cb3333fe324fd70cf63e7e
change-id: 20241028-nl80211_parse_sched_scan-bounds-checker-fix-c5842f41b863

Best regards,
-- 
Aleksei Vetrov <vvvvvv@xxxxxxxxxx>