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 --- 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 68832ee4b9f8..9e2799ee1595 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -704,6 +704,7 @@ 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; } @@ -748,6 +749,7 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
sock_llcp_release: nfc_llcp_put_ssap(local, llcp_sock->ssap); + nfc_llcp_local_put(llcp_sock->local);
put_dev: nfc_put_device(dev);