From c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d Mon Sep 17 00:00:00 2001

From: Xiaoming Ni <nixiaoming@huawei.com>

Date: Thu, 25 Mar 2021 11:51:10 +0800

Subject: [PATCH] nfc: fix refcount leak in llcp_sock_bind()

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Git-commit: c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d

Patch-mainline: v5.12-rc7

References: CVE-2020-25670 bsc#1178181

nfc_llcp_local_get() is invoked in llcp_sock_bind(),

but nfc_llcp_local_put() is not invoked in subsequent failure branches.

As a result, refcount leakage occurs.

To fix it, add calling nfc_llcp_local_put().

fix CVE-2020-25670

Fixes: c7aa12252f51 ("NFC: Take a reference on the LLCP local pointer when creating a socket")

Reported-by: "kiyin(尹亮)" <kiyin@tencent.com>

Link: https://www.openwall.com/lists/oss-security/2020/11/01/1

Cc: <stable@vger.kernel.org> #v3.6

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 net/nfc/llcp_sock.c | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c

index d257ed3b732a..68832ee4b9f8 100644

--- a/net/nfc/llcp_sock.c

+++ b/net/nfc/llcp_sock.c

@@ -108,11 +108,13 @@ static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)

 					  llcp_sock->service_name_len,

 					  GFP_KERNEL);

 	if (!llcp_sock->service_name) {

+		nfc_llcp_local_put(llcp_sock->local);

 		ret = -ENOMEM;

 		goto put_dev;

 	}

 	llcp_sock->ssap = nfc_llcp_get_sdp_ssap(local, llcp_sock);

 	if (llcp_sock->ssap == LLCP_SAP_MAX) {

+		nfc_llcp_local_put(llcp_sock->local);

 		kfree(llcp_sock->service_name);

 		llcp_sock->service_name = NULL;

 		ret = -EADDRINUSE;

-- 

2.26.2