From 6029760ee4df99529def0c1718f49bf33566c43b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= Date: Mon, 18 Sep 2017 10:38:27 +0200 Subject: [PATCH] cherry-pick tcp reset bug fix --- ...cp-reset-sk_rx_dst-in-tcp_disconnect.patch | 43 +++++++++++++++++++ Makefile | 1 + 2 files changed, 44 insertions(+) create mode 100644 0001-tcp-reset-sk_rx_dst-in-tcp_disconnect.patch diff --git a/0001-tcp-reset-sk_rx_dst-in-tcp_disconnect.patch b/0001-tcp-reset-sk_rx_dst-in-tcp_disconnect.patch new file mode 100644 index 0000000..8c0648b --- /dev/null +++ b/0001-tcp-reset-sk_rx_dst-in-tcp_disconnect.patch @@ -0,0 +1,43 @@ +From d747a7a51b00984127a88113cdbbc26f91e9d815 Mon Sep 17 00:00:00 2001 +From: WANG Cong +Date: Sat, 24 Jun 2017 23:50:30 -0700 +Subject: [PATCH] tcp: reset sk_rx_dst in tcp_disconnect() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +We have to reset the sk->sk_rx_dst when we disconnect a TCP +connection, because otherwise when we re-connect it this +dst reference is simply overridden in tcp_finish_connect(). + +This fixes a dst leak which leads to a loopback dev refcnt +leak. It is a long-standing bug, Kevin reported a very similar +(if not same) bug before. Thanks to Andrei for providing such +a reliable reproducer which greatly narrows down the problem. + +Fixes: 41063e9dd119 ("ipv4: Early TCP socket demux.") +Reported-by: Andrei Vagin +Reported-by: Kevin Xu +Signed-off-by: Cong Wang +Signed-off-by: David S. Miller +Signed-off-by: Fabian Grünbichler +--- + net/ipv4/tcp.c | 2 ++ + 1 file changed, 2 insertions(+) + +diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c +index b5ea036ca781..40aca7803cf2 100644 +--- a/net/ipv4/tcp.c ++++ b/net/ipv4/tcp.c +@@ -2330,6 +2330,8 @@ int tcp_disconnect(struct sock *sk, int flags) + tcp_init_send_head(sk); + memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); + __sk_dst_reset(sk); ++ dst_release(sk->sk_rx_dst); ++ sk->sk_rx_dst = NULL; + tcp_saved_syn_free(tp); + + /* Clean up fastopen related fields */ +-- +2.11.0 + diff --git a/Makefile b/Makefile index ce2bdca..adf8c59 100644 --- a/Makefile +++ b/Makefile @@ -246,6 +246,7 @@ ${KERNEL_SRC}/README: ${KERNEL_SRC_SUBMODULE} | submodules cd ${KERNEL_SRC}; patch -p1 < ../cgroup-cpuset-add-cpuset.remap_cpus.patch cd ${KERNEL_SRC}; patch -p1 < ../0001-netfilter-nft_set_rbtree-handle-re-addition-element-.patch # DoS from within (unpriv) containers cd ${KERNEL_SRC}; patch -p1 < ../0001-block-fix-bio_will_gap-for-first-bvec-with-offset.patch + cd ${KERNEL_SRC}; patch -p1 < ../0001-tcp-reset-sk_rx_dst-in-tcp_disconnect.patch sed -i ${KERNEL_SRC}/Makefile -e 's/^EXTRAVERSION.*$$/EXTRAVERSION=${EXTRAVERSION}/' touch $@