--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Dan Streetman <ddstreet@ieee.org>
+Date: Thu, 18 Jan 2018 16:14:26 -0500
+Subject: [PATCH] net: tcp: close sock if net namespace is exiting
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When a tcp socket is closed, if it detects that its net namespace is
+exiting, close immediately and do not wait for FIN sequence.
+
+For normal sockets, a reference is taken to their net namespace, so it will
+never exit while the socket is open. However, kernel sockets do not take a
+reference to their net namespace, so it may begin exiting while the kernel
+socket is still open. In this case if the kernel socket is a tcp socket,
+it will stay open trying to complete its close sequence. The sock's dst(s)
+hold a reference to their interface, which are all transferred to the
+namespace's loopback interface when the real interfaces are taken down.
+When the namespace tries to take down its loopback interface, it hangs
+waiting for all references to the loopback interface to release, which
+results in messages like:
+
+unregister_netdevice: waiting for lo to become free. Usage count = 1
+
+These messages continue until the socket finally times out and closes.
+Since the net namespace cleanup holds the net_mutex while calling its
+registered pernet callbacks, any new net namespace initialization is
+blocked until the current net namespace finishes exiting.
+
+After this change, the tcp socket notices the exiting net namespace, and
+closes immediately, releasing its dst(s) and their reference to the
+loopback interface, which lets the net namespace continue exiting.
+
+Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407
+Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811
+Signed-off-by: Dan Streetman <ddstreet@canonical.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
+---
+ include/net/net_namespace.h | 10 ++++++++++
+ net/ipv4/tcp.c | 3 +++
+ net/ipv4/tcp_timer.c | 15 +++++++++++++++
+ 3 files changed, 28 insertions(+)
+
+diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
+index 1c401bd4c2e0..a5d023fa78db 100644
+--- a/include/net/net_namespace.h
++++ b/include/net/net_namespace.h
+@@ -221,6 +221,11 @@ int net_eq(const struct net *net1, const struct net *net2)
+ return net1 == net2;
+ }
+
++static inline int check_net(const struct net *net)
++{
++ return atomic_read(&net->count) != 0;
++}
++
+ void net_drop_ns(void *);
+
+ #else
+@@ -245,6 +250,11 @@ int net_eq(const struct net *net1, const struct net *net2)
+ return 1;
+ }
+
++static inline int check_net(const struct net *net)
++{
++ return 1;
++}
++
+ #define net_drop_ns NULL
+ #endif
+
+diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
+index a3e91b552edc..fd2a086da910 100644
+--- a/net/ipv4/tcp.c
++++ b/net/ipv4/tcp.c
+@@ -2258,6 +2258,9 @@ void tcp_close(struct sock *sk, long timeout)
+ tcp_send_active_reset(sk, GFP_ATOMIC);
+ __NET_INC_STATS(sock_net(sk),
+ LINUX_MIB_TCPABORTONMEMORY);
++ } else if (!check_net(sock_net(sk))) {
++ /* Not possible to send reset; just close */
++ tcp_set_state(sk, TCP_CLOSE);
+ }
+ }
+
+diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
+index e906014890b6..ec1e5de41653 100644
+--- a/net/ipv4/tcp_timer.c
++++ b/net/ipv4/tcp_timer.c
+@@ -50,11 +50,19 @@ static void tcp_write_err(struct sock *sk)
+ * to prevent DoS attacks. It is called when a retransmission timeout
+ * or zero probe timeout occurs on orphaned socket.
+ *
++ * Also close if our net namespace is exiting; in that case there is no
++ * hope of ever communicating again since all netns interfaces are already
++ * down (or about to be down), and we need to release our dst references,
++ * which have been moved to the netns loopback interface, so the namespace
++ * can finish exiting. This condition is only possible if we are a kernel
++ * socket, as those do not hold references to the namespace.
++ *
+ * Criteria is still not confirmed experimentally and may change.
+ * We kill the socket, if:
+ * 1. If number of orphaned sockets exceeds an administratively configured
+ * limit.
+ * 2. If we have strong memory pressure.
++ * 3. If our net namespace is exiting.
+ */
+ static int tcp_out_of_resources(struct sock *sk, bool do_reset)
+ {
+@@ -83,6 +91,13 @@ static int tcp_out_of_resources(struct sock *sk, bool do_reset)
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONMEMORY);
+ return 1;
+ }
++
++ if (!check_net(sock_net(sk))) {
++ /* Not possible to send reset; just close */
++ tcp_done(sk);
++ return 1;
++ }
++
+ return 0;
+ }
+
+--
+2.14.2
+
--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tommi Rantala <tommi.t.rantala@nokia.com>
+Date: Mon, 5 Feb 2018 21:48:14 +0200
+Subject: [PATCH] sctp: fix dst refcnt leak in sctp_v4_get_dst
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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 <tommi.t.rantala@nokia.com>
+Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+Acked-by: Neil Horman <nhorman@tuxdriver.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
+---
+ 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 989a900383b5..e1a3ae4f3cab 100644
+--- a/net/sctp/protocol.c
++++ b/net/sctp/protocol.c
+@@ -514,22 +514,20 @@ 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;
+ }
+--
+2.14.2
+
--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Alexey Kodanev <alexey.kodanev@oracle.com>
+Date: Mon, 5 Feb 2018 15:10:35 +0300
+Subject: [PATCH] sctp: fix dst refcnt leak in sctp_v6_get_dst()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When going through the bind address list in sctp_v6_get_dst() and
+the previously found address is better ('matchlen > bmatchlen'),
+the code continues to the next iteration without releasing currently
+held destination.
+
+Fix it by releasing 'bdst' before continue to the next iteration, and
+instead of introducing one more '!IS_ERR(bdst)' check for dst_release(),
+move the already existed one right after ip6_dst_lookup_flow(), i.e. we
+shouldn't proceed further if we get an error for the route lookup.
+
+Fixes: dbc2b5e9a09e ("sctp: fix src address selection if using secondary addresses for ipv6")
+Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
+Acked-by: Neil Horman <nhorman@tuxdriver.com>
+Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
+---
+ net/sctp/ipv6.c | 10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
+
+diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
+index a4b6ffb61495..c5a5ad8ac00f 100644
+--- a/net/sctp/ipv6.c
++++ b/net/sctp/ipv6.c
+@@ -326,8 +326,10 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
+ final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
+ bdst = ip6_dst_lookup_flow(sk, fl6, final_p);
+
+- if (!IS_ERR(bdst) &&
+- ipv6_chk_addr(dev_net(bdst->dev),
++ if (IS_ERR(bdst))
++ continue;
++
++ if (ipv6_chk_addr(dev_net(bdst->dev),
+ &laddr->a.v6.sin6_addr, bdst->dev, 1)) {
+ if (!IS_ERR_OR_NULL(dst))
+ dst_release(dst);
+@@ -336,8 +338,10 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
+ }
+
+ bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
+- if (matchlen > bmatchlen)
++ if (matchlen > bmatchlen) {
++ dst_release(bdst);
+ continue;
++ }
+
+ if (!IS_ERR_OR_NULL(dst))
+ dst_release(dst);
+--
+2.14.2
+
projects / pve-kernel.git / commitdiff