Subject: [PATCH 11/24] NFC: st21nfca: fix double free

From: Pan Bian <[email-masked]>
Date: Thu, 7 Nov 2019 09:33:20 +0800

[ Upstream commit 99a8efbb6e30b72ac98cecf81103f847abffb1e5 ]

The variable nfcid_skb is not changed in the callee nfc_hci_get_param()
if error occurs. Consequently, the freed variable nfcid_skb will be
freed again, resulting in a double free bug. Set nfcid_skb to NULL after
releasing it to fix the bug.

Signed-off-by: Pan Bian <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/nfc/st21nfca/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/nfc/st21nfca/core.c b/drivers/nfc/st21nfca/core.c
index f9ac176cf257..2ce17932a073 100644
--- a/drivers/nfc/st21nfca/core.c
+++ b/drivers/nfc/st21nfca/core.c
@@ -708,6 +708,7 @@ static int st21nfca_hci_complete_target_discovered(struct nfc_hci_dev *hdev,
 							NFC_PROTO_FELICA_MASK;
 		} else {
 			kfree_skb(nfcid_skb);
+			nfcid_skb = NULL;
 			/* P2P in type A */
 			r = nfc_hci_get_param(hdev, ST21NFCA_RF_READER_F_GATE,
 					ST21NFCA_RF_READER_F_NFCID1,
-- 
2.20.1