From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tommi Rantala Subject: [PATCH net v3] sctp: fix dst refcnt leak in sctp_v4_get_dst Date: Mon, 5 Feb 2018 21:48:14 +0200 Message-ID: <20180205194814.14006-1-tommi.t.rantala@nokia.com> Mime-Version: 1.0 Content-Type: text/plain Cc: linux-sctp@vger.kernel.org, Neil Horman , Alexey Kodanev , Marcelo Ricardo Leitner , Tommi Rantala To: netdev@vger.kernel.org Return-path: Received: from mail-eopbgr10136.outbound.protection.outlook.com ([40.107.1.136]:9591 "EHLO EUR02-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750846AbeBETtt (ORCPT ); Mon, 5 Feb 2018 14:49:49 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Fix dst reference count leak in sctp_v4_get_dst() introduced in commit 410f03831 ("sctp: add routing output fallback"): When walking the address_list, successive ip_route_output_key() calls may return the same rt->dst with the reference incremented on each call. The code would not decrement the dst refcount when the dst pointer was identical from the previous iteration, causing the dst refcnt leak. Testcase: ip netns add TEST ip netns exec TEST ip link set lo up ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add dummy2 type dummy ip link set dev dummy0 netns TEST ip link set dev dummy1 netns TEST ip link set dev dummy2 netns TEST ip netns exec TEST ip addr add 192.168.1.1/24 dev dummy0 ip netns exec TEST ip link set dummy0 up ip netns exec TEST ip addr add 192.168.1.2/24 dev dummy1 ip netns exec TEST ip link set dummy1 up ip netns exec TEST ip addr add 192.168.1.3/24 dev dummy2 ip netns exec TEST ip link set dummy2 up ip netns exec TEST sctp_test -H 192.168.1.2 -P 20002 -h 192.168.1.1 -p 20000 -s -B 192.168.1.3 ip netns del TEST In 4.4 and 4.9 kernels this results to: [ 354.179591] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 364.419674] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 374.663664] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 384.903717] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 395.143724] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 405.383645] unregister_netdevice: waiting for lo to become free. Usage count = 1 ... Fixes: 410f03831 ("sctp: add routing output fallback") Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") Signed-off-by: Tommi Rantala --- v2: unconditional dst_release() before breaking out of the loop: - if dst == NULL, then dst_release() is no-op. - if dst != &rt->dst, then drop reference to the first dst, we do not need it after all. - if dst == &rt->dst, then the refcnt was incremented twice for this dst, so drop the second ref. net/sctp/protocol.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index ba28d270eb24..aba2381d3cf9 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -509,22 +509,20 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (IS_ERR(rt)) continue; - if (!dst) - dst = &rt->dst; - /* Ensure the src address belongs to the output * interface. */ odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, false); if (!odev || odev->ifindex != fl4->flowi4_oif) { - if (&rt->dst != dst) + if (!dst) + dst = &rt->dst; + else dst_release(&rt->dst); continue; } - if (dst != &rt->dst) - dst_release(dst); + dst_release(dst); dst = &rt->dst; break; } -- 2.15.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tommi Rantala Date: Mon, 05 Feb 2018 19:48:14 +0000 Subject: [PATCH net v3] sctp: fix dst refcnt leak in sctp_v4_get_dst Message-Id: <20180205194814.14006-1-tommi.t.rantala@nokia.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Cc: linux-sctp@vger.kernel.org, Neil Horman , Alexey Kodanev , Marcelo Ricardo Leitner , Tommi Rantala Fix dst reference count leak in sctp_v4_get_dst() introduced in commit 410f03831 ("sctp: add routing output fallback"): When walking the address_list, successive ip_route_output_key() calls may return the same rt->dst with the reference incremented on each call. The code would not decrement the dst refcount when the dst pointer was identical from the previous iteration, causing the dst refcnt leak. Testcase: ip netns add TEST ip netns exec TEST ip link set lo up ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add dummy2 type dummy ip link set dev dummy0 netns TEST ip link set dev dummy1 netns TEST ip link set dev dummy2 netns TEST ip netns exec TEST ip addr add 192.168.1.1/24 dev dummy0 ip netns exec TEST ip link set dummy0 up ip netns exec TEST ip addr add 192.168.1.2/24 dev dummy1 ip netns exec TEST ip link set dummy1 up ip netns exec TEST ip addr add 192.168.1.3/24 dev dummy2 ip netns exec TEST ip link set dummy2 up ip netns exec TEST sctp_test -H 192.168.1.2 -P 20002 -h 192.168.1.1 -p 20000 -s -B 192.168.1.3 ip netns del TEST In 4.4 and 4.9 kernels this results to: [ 354.179591] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 364.419674] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 374.663664] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 384.903717] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 395.143724] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 405.383645] unregister_netdevice: waiting for lo to become free. Usage count = 1 ... Fixes: 410f03831 ("sctp: add routing output fallback") Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") Signed-off-by: Tommi Rantala --- v2: unconditional dst_release() before breaking out of the loop: - if dst = NULL, then dst_release() is no-op. - if dst != &rt->dst, then drop reference to the first dst, we do not need it after all. - if dst = &rt->dst, then the refcnt was incremented twice for this dst, so drop the second ref. net/sctp/protocol.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index ba28d270eb24..aba2381d3cf9 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -509,22 +509,20 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (IS_ERR(rt)) continue; - if (!dst) - dst = &rt->dst; - /* Ensure the src address belongs to the output * interface. */ odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, false); if (!odev || odev->ifindex != fl4->flowi4_oif) { - if (&rt->dst != dst) + if (!dst) + dst = &rt->dst; + else dst_release(&rt->dst); continue; } - if (dst != &rt->dst) - dst_release(dst); + dst_release(dst); dst = &rt->dst; break; } -- 2.15.1