From: Xiaoming Ni <nixiaoming@huawei.com>
Date: Thu, 25 Mar 2021 03:51:11 +0000 (+0800)
Subject: nfc: fix refcount leak in llcp_sock_connect()
X-Git-Tag: v4.4.267~35
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a524eabb5e309e49ee2d8422a771c5cedef003c4;p=thirdparty%2Fkernel%2Fstable.git

nfc: fix refcount leak in llcp_sock_connect()

commit 8a4cd82d62b5ec7e5482333a72b58a4eea4979f0 upstream.

nfc_llcp_local_get() is invoked in llcp_sock_connect(),
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-2020-25671
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c
index 2c5dbb797c779..79ca5e60dc94e 100644
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -710,6 +710,7 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
 	llcp_sock->local = nfc_llcp_local_get(local);
 	llcp_sock->ssap = nfc_llcp_get_local_ssap(local);
 	if (llcp_sock->ssap == LLCP_SAP_MAX) {
+		nfc_llcp_local_put(llcp_sock->local);
 		ret = -ENOMEM;
 		goto put_dev;
 	}
@@ -747,6 +748,7 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
 
 sock_unlink:
 	nfc_llcp_put_ssap(local, llcp_sock->ssap);
+	nfc_llcp_local_put(llcp_sock->local);
 
 	nfc_llcp_sock_unlink(&local->connecting_sockets, sk);