The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 03a3ca37e4c6478e3a84f04c8429dd5889e107fd Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw(a)strlen.de>
Date: Wed, 24 Feb 2021 17:23:19 +0100
Subject: [PATCH] netfilter: nf_nat: undo erroneous tcp edemux lookup
Under extremely rare conditions TCP early demux will retrieve the wrong
socket.
1. local machine establishes a connection to a remote server, S, on port
p.
This gives:
laddr:lport -> S:p
... both in tcp and conntrack.
2. local machine establishes a connection to host H, on port p2.
2a. TCP stack choses same laddr:lport, so we have
laddr:lport -> H:p2 from TCP point of view.
2b). There is a destination NAT rewrite in place, translating
H:p2 to S:p. This results in following conntrack entries:
I) laddr:lport -> S:p (origin) S:p -> laddr:lport (reply)
II) laddr:lport -> H:p2 (origin) S:p -> laddr:lport2 (reply)
NAT engine has rewritten laddr:lport to laddr:lport2 to map
the reply packet to the correct origin.
When server sends SYN/ACK to laddr:lport2, the PREROUTING hook
will undo-the SNAT transformation, rewriting IP header to
S:p -> laddr:lport
This causes TCP early demux to associate the skb with the TCP socket
of the first connection.
The INPUT hook will then reverse the DNAT transformation, rewriting
the IP header to H:p2 -> laddr:lport.
Because packet ends up with the wrong socket, the new connection
never completes: originator stays in SYN_SENT and conntrack entry
remains in SYN_RECV until timeout, and responder retransmits SYN/ACK
until it gives up.
To resolve this, orphan the skb after the input rewrite:
Because the source IP address changed, the socket must be incorrect.
We can't move the DNAT undo to prerouting due to backwards
compatibility, doing so will make iptables/nftables rules to no longer
match the way they did.
After orphan, the packet will be handed to the next protocol layer
(tcp, udp, ...) and that will repeat the socket lookup just like as if
early demux was disabled.
Fixes: 41063e9dd1195 ("ipv4: Early TCP socket demux.")
Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1427
Signed-off-by: Florian Westphal <fw(a)strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org>
diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c
index e87b6bd6b3cd..4731d21fc3ad 100644
--- a/net/netfilter/nf_nat_proto.c
+++ b/net/netfilter/nf_nat_proto.c
@@ -646,8 +646,8 @@ nf_nat_ipv4_fn(void *priv, struct sk_buff *skb,
}
static unsigned int
-nf_nat_ipv4_in(void *priv, struct sk_buff *skb,
- const struct nf_hook_state *state)
+nf_nat_ipv4_pre_routing(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
{
unsigned int ret;
__be32 daddr = ip_hdr(skb)->daddr;
@@ -659,6 +659,23 @@ nf_nat_ipv4_in(void *priv, struct sk_buff *skb,
return ret;
}
+static unsigned int
+nf_nat_ipv4_local_in(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ __be32 saddr = ip_hdr(skb)->saddr;
+ struct sock *sk = skb->sk;
+ unsigned int ret;
+
+ ret = nf_nat_ipv4_fn(priv, skb, state);
+
+ if (ret == NF_ACCEPT && sk && saddr != ip_hdr(skb)->saddr &&
+ !inet_sk_transparent(sk))
+ skb_orphan(skb); /* TCP edemux obtained wrong socket */
+
+ return ret;
+}
+
static unsigned int
nf_nat_ipv4_out(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
@@ -736,7 +753,7 @@ nf_nat_ipv4_local_fn(void *priv, struct sk_buff *skb,
static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
/* Before packet filtering, change destination */
{
- .hook = nf_nat_ipv4_in,
+ .hook = nf_nat_ipv4_pre_routing,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_PRE_ROUTING,
.priority = NF_IP_PRI_NAT_DST,
@@ -757,7 +774,7 @@ static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
},
/* After packet filtering, change source */
{
- .hook = nf_nat_ipv4_fn,
+ .hook = nf_nat_ipv4_local_in,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_IN,
.priority = NF_IP_PRI_NAT_SRC,
The patch below does not apply to the 5.11-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 417789df4a03bc820b082bcc503f0d4c5e4704b9 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni(a)redhat.com>
Date: Thu, 4 Mar 2021 13:32:15 -0800
Subject: [PATCH] mptcp: fix missing wakeup
__mptcp_clean_una() can free write memory and should wake-up
user-space processes when needed.
When such function is invoked by the MPTCP receive path, the wakeup
is not needed, as the TCP stack will later trigger subflow_write_space
which will do the wakeup as needed.
Other __mptcp_clean_una() call sites need an additional wakeup check
Let's bundle the relevant code in a new helper and use it.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/165
Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks")
Fixes: 64b9cea7a0af ("mptcp: fix spurious retransmissions")
Tested-by: Matthieu Baerts <matthieu.baerts(a)tessares.net>
Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d2a2169e6d9e..76958570ae7f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1061,6 +1061,12 @@ static void __mptcp_clean_una(struct sock *sk)
}
}
+static void __mptcp_clean_una_wakeup(struct sock *sk)
+{
+ __mptcp_clean_una(sk);
+ mptcp_write_space(sk);
+}
+
static void mptcp_enter_memory_pressure(struct sock *sk)
{
struct mptcp_subflow_context *subflow;
@@ -2270,7 +2276,7 @@ static void __mptcp_retrans(struct sock *sk)
struct sock *ssk;
int ret;
- __mptcp_clean_una(sk);
+ __mptcp_clean_una_wakeup(sk);
dfrag = mptcp_rtx_head(sk);
if (!dfrag)
return;
@@ -2983,7 +2989,7 @@ static void mptcp_release_cb(struct sock *sk)
}
if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags))
- __mptcp_clean_una(sk);
+ __mptcp_clean_una_wakeup(sk);
if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))
__mptcp_error_report(sk);
The patch below does not apply to the 5.11-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e0be4931f3fee2e04dec4013ea4f27ec2db8556f Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw(a)strlen.de>
Date: Thu, 4 Mar 2021 13:32:08 -0800
Subject: [PATCH] mptcp: reset last_snd on subflow close
Send logic caches last active subflow in the msk, so it needs to be
cleared when the cached subflow is closed.
Fixes: d5f49190def61c ("mptcp: allow picking different xmit subflows")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/155
Reported-by: Christoph Paasch <cpaasch(a)apple.com>
Acked-by: Paolo Abeni <pabeni(a)redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts(a)tessares.net>
Signed-off-by: Florian Westphal <fw(a)strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c5d5e68940ea..7362a536cbc0 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2126,6 +2126,8 @@ static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
struct mptcp_subflow_context *subflow)
{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
list_del(&subflow->node);
lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
@@ -2154,6 +2156,9 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
release_sock(ssk);
sock_put(ssk);
+
+ if (ssk == msk->last_snd)
+ msk->last_snd = NULL;
}
void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e0be4931f3fee2e04dec4013ea4f27ec2db8556f Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw(a)strlen.de>
Date: Thu, 4 Mar 2021 13:32:08 -0800
Subject: [PATCH] mptcp: reset last_snd on subflow close
Send logic caches last active subflow in the msk, so it needs to be
cleared when the cached subflow is closed.
Fixes: d5f49190def61c ("mptcp: allow picking different xmit subflows")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/155
Reported-by: Christoph Paasch <cpaasch(a)apple.com>
Acked-by: Paolo Abeni <pabeni(a)redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts(a)tessares.net>
Signed-off-by: Florian Westphal <fw(a)strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c5d5e68940ea..7362a536cbc0 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2126,6 +2126,8 @@ static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
struct mptcp_subflow_context *subflow)
{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
list_del(&subflow->node);
lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
@@ -2154,6 +2156,9 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
release_sock(ssk);
sock_put(ssk);
+
+ if (ssk == msk->last_snd)
+ msk->last_snd = NULL;
}
void mptcp_close_ssk(struct sock *sk, struct sock *ssk,