tcp: cookie transactions setsockopt memory leak

There is a bug in do_tcp_setsockopt(net/ipv4/tcp.c),
TCP_COOKIE_TRANSACTIONS case.
In some cases (when tp->cookie_values == NULL) new tcp_cookie_values
structure can be allocated (at cvp), but not bound to
tp->cookie_values. So a memory leak occurs.

Signed-off-by: Dmitry Popov <dp@highloadlab.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 65afeaec15b7..c259714c5596 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2176,6 +2176,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
                                       GFP_KERNEL);
                         if (cvp == NULL)
                                 return -ENOMEM;
+
+                        kref_init(&cvp->kref);
                 }
                 lock_sock(sk);
                 tp->rx_opt.cookie_in_always =
@@ -2190,12 +2192,11 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
                                  */
                                 kref_put(&tp->cookie_values->kref,
                                          tcp_cookie_values_release);
-                                kref_init(&cvp->kref);
-                                tp->cookie_values = cvp;
                         } else {
                                 cvp = tp->cookie_values;
                         }
                 }
+
                 if (cvp != NULL) {
                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
 
@@ -2209,6 +2210,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
                                 cvp->s_data_constant = 0; /* false */
                         }
+
+                        tp->cookie_values = cvp;
                 }
                 release_sock(sk);
                 return err;