4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <[email protected]>


[ Upstream commit 1f3b359f1004bd34b7b0bad70b93e3c7af92a37b ]

While the cited commit fixed a possible deadlock, it added a leak
of the request socket, since reqsk_put() must be called if the BPF
filter decided the ACK packet must be dropped.

Fixes: d624d276d1dd ("tcp: fix possible deadlock in TCP stack vs BPF filter")
Signed-off-by: Eric Dumazet <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/ipv4/tcp_ipv4.c |    6 +++---
 net/ipv6/tcp_ipv6.c |    6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1722,9 +1722,9 @@ process:
                 */
                sock_hold(sk);
                refcounted = true;
-               if (tcp_filter(sk, skb))
-                       goto discard_and_relse;
-               nsk = tcp_check_req(sk, skb, req, false);
+               nsk = NULL;
+               if (!tcp_filter(sk, skb))
+                       nsk = tcp_check_req(sk, skb, req, false);
                if (!nsk) {
                        reqsk_put(req);
                        goto discard_and_relse;
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1456,9 +1456,9 @@ process:
                }
                sock_hold(sk);
                refcounted = true;
-               if (tcp_filter(sk, skb))
-                       goto discard_and_relse;
-               nsk = tcp_check_req(sk, skb, req, false);
+               nsk = NULL;
+               if (!tcp_filter(sk, skb))
+                       nsk = tcp_check_req(sk, skb, req, false);
                if (!nsk) {
                        reqsk_put(req);
                        goto discard_and_relse;


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