[PATCH 5.11 583/601] net:nfc:digital: Fix a double free in digital_tg_recv_dep_req

Greg Kroah-Hartman
2021-05-12T18:03:30Z

From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

[ Upstream commit 75258586793efc521e5dd52a5bf6c7a4cf7002be ]

In digital_tg_recv_dep_req, it calls nfc_tm_data_received(..,resp).
If nfc_tm_data_received() failed, the callee will free the resp via
kfree_skb() and return error. But in the exit branch, the resp
will be freed again.

My patch sets resp to NULL if nfc_tm_data_received() failed, to
avoid the double free.

Fixes: 1c7a4c24fbfd9 ("NFC Digital: Add target NFC-DEP support")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/nfc/digital_dep.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index 5971fb6f51cc..dc21b4141b0a 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -1273,6 +1273,8 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
}

rc = nfc_tm_data_received(ddev->nfc_dev, resp);
+ if (rc)
+ resp = NULL;

exit:
kfree_skb(ddev->chaining_skb);
--
2.30.2