NFC: st21nfca: fix double free

[ 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 <bianpan2016@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nfc/st21nfca/core.c b/drivers/nfc/st21nfca/core.c
index e803fdf..f37069b 100644 (file)
--- a/drivers/nfc/st21nfca/core.c
+++ b/drivers/nfc/st21nfca/core.c
@@ -719,6 +719,7 @@ 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,