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([27.59.86.235]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8241d1c08e8sm6367697b3a.22.2026.02.05.06.20.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Feb 2026 06:20:15 -0800 (PST) From: dhyaan19022009-hue X-Google-Original-From: dhyaan19022009-hue To: Johannes Berg Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, Dhyan K Prajapati Subject: [PATCH v2] mac80211: fix NULL pointer dereference in monitor mode Date: Thu, 5 Feb 2026 19:49:57 +0530 Message-ID: <20260205141957.8527-1-dhyaan19022009@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Dhyan K Prajapati When switching an interface to monitor mode on drivers that set the IEEE80211_HW_WANT_MONITOR_VIF flag, ieee80211_link_info_change_notify() can pass BSS change notifications to the driver callback even though monitor interfaces have no associated BSS context (link->conf->bss is NULL) This triggers a NULL pointer dereference in drivers like iwldvm when they access BSS-specific fields without checking for NULL. Example crash on Intel Centrino Advanced-N 6205 (iwldvm): BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 5295.13= 5825] fixed the issue by adding a NULL check for link->conf->bss before proceedin= g to driver notification Tested on Intel Centrino Advanced-N 6205 [Taylor Peak] (rev 34) Signed-off-by: Dhyan K Prajapati --- 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; --=20 2.43.0