[PATCH 5.11 008/210] nfc: fix refcount leak in llcp_sock_connect()

Greg Kroah-Hartman
2021-04-12T09:19:51Z

From: Xiaoming Ni <nixiaoming@huawei.com>

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>
---
net/nfc/llcp_sock.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -704,6 +704,7 @@ static int llcp_sock_connect(struct sock
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;
}
@@ -748,6 +749,7 @@ sock_unlink:

sock_llcp_release:
nfc_llcp_put_ssap(local, llcp_sock->ssap);
+ nfc_llcp_local_put(llcp_sock->local);

put_dev:
nfc_put_device(dev);