From 9161ae1c04cd1f5a84008d1f75608d899c3177b4 Mon Sep 17 00:00:00 2001 From: Xiaomeng Tong Date: Mon, 28 Mar 2022 20:28:20 +0800 Subject: [PATCH] carl9170: tx: fix an incorrect use of list iterator commit 54a6f29522da3c914da30e50721dedf51046449a upstream. If the previous list_for_each_entry_continue_rcu() don't exit early (no goto hit inside the loop), the iterator 'cvif' after the loop will be a bogus pointer to an invalid structure object containing the HEAD (&ar->vif_list). As a result, the use of 'cvif' after that will lead to a invalid memory access (i.e., 'cvif->id': the invalid pointer dereference when return back to/after the callsite in the carl9170_update_beacon()). The original intention should have been to return the valid 'cvif' when found in list, NULL otherwise. So just return NULL when no entry found, to fix this bug. Cc: stable@vger.kernel.org Fixes: 1f1d9654e183c ("carl9170: refactor carl9170_update_beacon") Signed-off-by: Xiaomeng Tong Acked-by: Christian Lamparter Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20220328122820.1004-1-xiam0nd.tong@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/ath/carl9170/tx.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c index 88444fe6d1c64..f9e1306ac74fe 100644 --- a/drivers/net/wireless/ath/carl9170/tx.c +++ b/drivers/net/wireless/ath/carl9170/tx.c @@ -1558,6 +1558,9 @@ static struct carl9170_vif_info *carl9170_pick_beaconing_vif(struct ar9170 *ar) goto out; } } while (ar->beacon_enabled && i--); + + /* no entry found in list */ + return NULL; } out: