nfc: fix memory leak in llcp_sock_connect()

commit 7574fcdbdcb335763b6b322f6928dc0fd5730451 upstream.

In llcp_sock_connect(), use kmemdup to allocate memory for
 "llcp_sock->service_name". The memory is not released in the sock_unlink
label of the subsequent failure branch.
As a result, memory leakage occurs.

fix CVE-2020-25672

Fixes: d646960f7986 ("NFC: Initial LLCP support")
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> #v3.3
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 79ca5e60dc94ebc77a46020652eea249d632e04e..7632593975449814713707fb825cf1be8d86a1f7 100644 (file)
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -751,6 +751,8 @@ sock_unlink:
        nfc_llcp_local_put(llcp_sock->local);
 
        nfc_llcp_sock_unlink(&local->connecting_sockets, sk);
+       kfree(llcp_sock->service_name);
+       llcp_sock->service_name = NULL;
 
 put_dev:
        nfc_put_device(dev);