From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Date: Tue, 27 Apr 2021 16:22:58 +0000 (-0700)
Subject: net:nfc:digital: Fix a double free in digital_tg_recv_dep_req
X-Git-Tag: v4.4.269~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5ef149f289ca0ab607971f981ce07a52187613c2;p=thirdparty%2Fkernel%2Fstable.git

net:nfc:digital: Fix a double free in digital_tg_recv_dep_req

[ 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>
---

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index f72be7433df35..46375ff214c03 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -1187,6 +1187,8 @@ 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);