From: Dan Carpenter Date: Tue, 23 Sep 2025 11:20:16 +0000 (+0300) Subject: wifi: iwlwifi: fix potential use after free in iwl_mld_remove_link() X-Git-Tag: v6.18-rc4~24^2~32^2^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=77e67d5daaf155f7d0f99f4e797c4842169ec19e;p=thirdparty%2Flinux.git 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 Link: https://patch.msgid.link/aNKCcKlbSkkS4_gO@stanley.mountain Signed-off-by: Miri Korenblit --- diff --git a/drivers/net/wireless/intel/iwlwifi/mld/link.c b/drivers/net/wireless/intel/iwlwifi/mld/link.c index 782fc41aa1c31..960dcd208f005 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,