Commit 77e67d5d authored by Dan Carpenter's avatar Dan Carpenter Committed by Miri Korenblit
Browse files

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: d1e879ec ("wifi: iwlwifi: add iwlmld sub-driver")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/aNKCcKlbSkkS4_gO@stanley.mountain


Signed-off-by: default avatarMiri Korenblit <miriam.rachel.korenblit@intel.com>
parent 4ff71af0

drivers/net/wireless/intel/iwlwifi/mld/link.c

+3 −2
Original line number Diff line number Diff line
@@ -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,