[PATCH] wifi: cfg80211: validate chandef before calling cfg80211_set_monitor_channel

From: Kartik Nair

Date: Sun May 10 2026 - 16:25:15 EST


cfg80211_wext_siwfreq() constructs a channel definition for monitor
mode but passes it to cfg80211_set_monitor_channel() without first
validating it with cfg80211_chandef_valid(). This causes a WARN_ON
in cfg80211_chandef_dfs_required() when it receives an invalid chandef.

Add the missing cfg80211_chandef_valid() check before calling
cfg80211_set_monitor_channel() to return -EINVAL early on invalid
channel definitions, consistent with how other callers handle this.

Reported-by: syzbot+02a1a03b8622d3c7d1c9@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Kartik Nair <contact.kartikn@xxxxxxxxx>
---
net/wireless/wext-compat.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index 22d9d9bae..63d145b52 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -789,6 +789,8 @@ static int cfg80211_wext_siwfreq(struct net_device *dev,
chandef.chan = ieee80211_get_channel(&rdev->wiphy, freq);
if (!chandef.chan)
return -EINVAL;
+ if (!cfg80211_chandef_valid(&chandef))
+ return -EINVAL;
return cfg80211_set_monitor_channel(rdev, dev, &chandef);
case NL80211_IFTYPE_MESH_POINT:
freq = cfg80211_wext_freq(wextfreq);
--
2.50.0