netdev - [PATCH v4 wireless] mac80211: fix NULL pointer dereference in monitor mode Crash trace: RIP: iwlagn_bss_info_changed+0x19d/0x640 [iwldvm] Code: 49 8b 46 10 <8b> 10 RAX: 0000000000000000 (NULL link->conf->bss) wifi: mac80211: fix NULL pointer deref regression in link notify Commit c57e5b974514 ("wifi: mac80211: fix WARN_ON for monitor mode on some devices") reorganized link change notifications. This caused a regression for hardware using IEEE80211_HW_WANT_MONITOR_VIF. In monitor mode, link->conf->bss is uninitialized, but current logic allows these notifications to reach driver callbacks, causing a deterministic NULL dereference in drivers like iwldvm. Fix this by validating the BSS context before driver notification. Device: Intel Centrino Advanced-n 6205 Fixes: c57e5b974514 ("wifi: mac80211: fix WARN_ON for monitor mode on some devices") Cc: stable@...r.kernel.org Cc: netdev@...r.kernel.org Cc: linux-wireless@...r.kernel.org Cc: Johannes Berg <johannes@...solutions.net> Signed-off-by: Dhyan K Prajapati <dhyaan19022009@...il.com>

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20260205174419.4467-1-dhyaan19022009@gmail.com>
Date: Thu,  5 Feb 2026 23:14:19 +0530
From: Dhyan K Prajapati <dhyan19022009@...il.com>
To: Johannes Berg <johannes.berg@...el.com>
Cc: linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org,
	stable@...r.kernel.org,
	dhyaan19022009-hue <dhyaan19022009@...il.com>
Subject: [PATCH v4 wireless] mac80211: fix NULL pointer dereference in monitor
 mode Crash trace:   RIP: iwlagn_bss_info_changed+0x19d/0x640 [iwldvm]   Code:
 49 8b 46 10 <8b> 10   RAX: 0000000000000000 (NULL link->conf->bss) wifi:
 mac80211: fix NULL pointer deref regression in link notify Commit
 c57e5b974514 ("wifi: mac80211: fix WARN_ON for monitor mode on some devices")
 reorganized link change notifications. This caused a regression for hardware
 using IEEE80211_HW_WANT_MONITOR_VIF. In monitor mode, link->conf->bss is
 uninitialized, but current logic allows these notifications to reach driver
 callbacks, causing a deterministic NULL dereference in drivers like iwldvm.
 Fix this by validating the BSS context before driver notification. Device:
 Intel Centrino Advanced-n 6205 Fixes: c57e5b974514 ("wifi: mac80211: fix
 WARN_ON for monitor mode on some devices") Cc: stable@...r.kernel.org Cc:
 netdev@...r.kernel.org Cc: linux-wireless@...r.kernel.org Cc: Johannes Berg
 <johannes@...solutions.net> Signed-off-by: Dhyan K Prajapati <dhyaan19022009@...il.com>

From: dhyaan19022009-hue <dhyaan19022009@...il.com>

---
 net/mac80211/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index b05e313c7..190222c26 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -416,6 +416,8 @@ void ieee80211_link_info_change_notify(struct ieee80211_sub_if_data *sdata,
 	case NL80211_IFTYPE_MONITOR:
 		if (!ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
 			return;
+		if (!link->conf->bss)
+			return;
 		break;
 	default:
 		break;
-- 
2.43.0