[PATCH net] wifi: cfg80211: Fix out-of-bounds in cfg80211_wext_siwscan

[Jeongjun Park]

In the process of searching for matching hardware channels, wreq and 
wreq->num_channels are checked to see if they are NULL. However, 
if the value of wreq->num_channels is greater than IW_MAX_FREQUENCIES,
an out-of-bounds vulnerability occurs.

Therefore, you must also add code to check whether the value of 
wreq->num_channels is within the range.

Reguards.

Signed-by-off: Jeongjun Park <aha310510@xxxxxxxxx>
---
 net/wireless/scan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 0222ede0feb6..f253dee041d1 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -3460,6 +3460,10 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 			if (wreq && wreq->num_channels) {
 				int k;
 				int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
+
+				if (wreq->num_channels > IW_MAX_FREQUENCIES)
+					wreq->num_channels = IW_MAX_FREQUENCIES;
+
 				for (k = 0; k < wreq->num_channels; k++) {
 					struct iw_freq *freq =
 						&wreq->channel_list[k];
-- 
2.34.1