linux-kernel - [PATCH] wifi: iwlwifi: fix potential use after free in iwl_mld_remove

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: <aNKCcKlbSkkS4_gO@stanley.mountain>
Date: Tue, 23 Sep 2025 14:20:16 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Miri Korenblit <miriam.rachel.korenblit@...el.com>
Cc: Johannes Berg <johannes.berg@...el.com>,
	Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
	Somashekhar Puttagangaiah <somashekhar.puttagangaiah@...el.com>,
	Pagadala Yesu Anjaneyulu <pagadala.yesu.anjaneyulu@...el.com>,
	Daniel Gabay <daniel.gabay@...el.com>,
	Avraham Stern <avraham.stern@...el.com>,
	Shaul Triebitz <shaul.triebitz@...el.com>,
	linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH] wifi: iwlwifi: fix potential use after free in
 iwl_mld_remove_link()

This code frees "link" by calling kfree_rcu(link, rcu_head) and then it
dereferences "link" to get the "link->fw_id".  Save the "link->fw_id"
first to avoid a potential use after free.

Fixes: d1e879ec600f ("wifi: iwlwifi: add iwlmld sub-driver")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
 drivers/net/wireless/intel/iwlwifi/mld/link.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/link.c b/drivers/net/wireless/intel/iwlwifi/mld/link.c
index 738f80fe0c50..60d814bf5779 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/link.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/link.c
@@ -501,6 +501,7 @@ void iwl_mld_remove_link(struct iwl_mld *mld,
 	struct iwl_mld_vif *mld_vif = iwl_mld_vif_from_mac80211(bss_conf->vif);
 	struct iwl_mld_link *link = iwl_mld_link_from_mac80211(bss_conf);
 	bool is_deflink = link == &mld_vif->deflink;
+	u8 fw_id = link->fw_id;
 
 	if (WARN_ON(!link || link->active))
 		return;
@@ -513,10 +514,10 @@ void iwl_mld_remove_link(struct iwl_mld *mld,
 
 	RCU_INIT_POINTER(mld_vif->link[bss_conf->link_id], NULL);
 
-	if (WARN_ON(link->fw_id >= mld->fw->ucode_capa.num_links))
+	if (WARN_ON(fw_id >= mld->fw->ucode_capa.num_links))
 		return;
 
-	RCU_INIT_POINTER(mld->fw_id_to_bss_conf[link->fw_id], NULL);
+	RCU_INIT_POINTER(mld->fw_id_to_bss_conf[fw_id], NULL);
 }
 
 void iwl_mld_handle_missed_beacon_notif(struct iwl_mld *mld,
-- 
2.51.0