[PATCH net-next 0/3] mptcp: A few fixes

[PATCH net-next 0/3] mptcp: A few fixes

[Mat Martineau]

This set has three separate changes for the net-next tree:

Patch 1 guarantees safe handling and a warning if a NULL value is
encountered when gathering subflow data for the MPTCP_SUBFLOW_ADDRS
socket option.

Patch 2 increases the default number of subflows allowed per MPTCP
connection.

Patch 3 makes an existing function 'static'.


Mat Martineau (1):
  mptcp: Make mptcp_pm_nl_mp_prio_send_ack() static

Paolo Abeni (1):
  mptcp: increase default max additional subflows to 2

Tim Gardner (1):
  mptcp: Avoid NULL dereference in mptcp_getsockopt_subflow_addrs()

 net/mptcp/pm_netlink.c                          | 9 ++++++---
 net/mptcp/protocol.h                            | 3 ---
 net/mptcp/sockopt.c                             | 3 +++
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 5 ++++-
 tools/testing/selftests/net/mptcp/pm_netlink.sh | 6 +++---
 5 files changed, 16 insertions(+), 10 deletions(-)


base-commit: 295711fa8fec42a55623bf6997d05a21d7855132
-- 
2.33.1

[PATCH net-next 1/3] mptcp: Avoid NULL dereference in mptcp_getsockopt_subflow_addrs()

[Mat Martineau]

From: Tim Gardner <tim.gardner@canonical.com>

Coverity complains of a possible NULL dereference in
mptcp_getsockopt_subflow_addrs():

 861       } else if (sk->sk_family == AF_INET6) {
    	3. returned_null: inet6_sk returns NULL. [show details]
    	4. var_assigned: Assigning: np = NULL return value from inet6_sk.
 862                const struct ipv6_pinfo *np = inet6_sk(sk);

Fix this by checking for NULL.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/231
Fixes: c11c5906bc0a ("mptcp: add MPTCP_SUBFLOW_ADDRS getsockopt support")
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
[mjm: Added WARN_ON_ONCE() to the unexpected case]
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/sockopt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8137cc3a4296..0f1e661c2032 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -861,6 +861,9 @@ static void mptcp_get_sub_addrs(const struct sock *sk, struct mptcp_subflow_addr
 	} else if (sk->sk_family == AF_INET6) {
 		const struct ipv6_pinfo *np = inet6_sk(sk);
 
+		if (WARN_ON_ONCE(!np))
+			return;
+
 		a->sin6_local.sin6_family = AF_INET6;
 		a->sin6_local.sin6_port = inet->inet_sport;
 
-- 
2.33.1

[PATCH net-next 2/3] mptcp: increase default max additional subflows to 2

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

The current default does not allowing additional subflows, mostly
as a safety restriction to avoid uncontrolled resource consumption
on busy servers.

Still the system admin and/or the application have to opt-in to
MPTCP explicitly. After that, they need to change (increase) the
default maximum number of additional subflows.

Let set that to reasonable default, and make end-users life easier.

Additionally we need to update some self-tests accordingly.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c                          | 3 +++
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 5 ++++-
 tools/testing/selftests/net/mptcp/pm_netlink.sh | 6 +++---
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 050eea231528..f7d33a9abd57 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -2052,6 +2052,9 @@ static int __net_init pm_nl_init_net(struct net *net)
 	struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
 
 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
+
+	/* Cit. 2 subflows ought to be enough for anybody. */
+	pernet->subflows_max = 2;
 	pernet->next_id = 1;
 	pernet->stale_loss_cnt = 4;
 	spin_lock_init(&pernet->lock);
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 255793c5ac4f..293d349e21fe 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -945,12 +945,15 @@ subflows_tests()
 
 	# subflow limited by client
 	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 0
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 0
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
 	run_tests $ns1 $ns2 10.0.1.1
 	chk_join_nr "single subflow, limited by client" 0 0 0
 
 	# subflow limited by server
 	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 0
 	ip netns exec $ns2 ./pm_nl_ctl limits 0 1
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
 	run_tests $ns1 $ns2 10.0.1.1
@@ -973,7 +976,7 @@ subflows_tests()
 	run_tests $ns1 $ns2 10.0.1.1
 	chk_join_nr "multiple subflows" 2 2 2
 
-	# multiple subflows limited by serverf
+	# multiple subflows limited by server
 	reset
 	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
 	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index 3c741abe034e..cbacf9f6538b 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -70,7 +70,7 @@ check()
 
 check "ip netns exec $ns1 ./pm_nl_ctl dump" "" "defaults addr list"
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "defaults limits"
+subflows 2" "defaults limits"
 
 ip netns exec $ns1 ./pm_nl_ctl add 10.0.1.1
 ip netns exec $ns1 ./pm_nl_ctl add 10.0.1.2 flags subflow dev lo
@@ -118,11 +118,11 @@ check "ip netns exec $ns1 ./pm_nl_ctl dump" "" "flush addrs"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 9 1
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "rcv addrs above hard limit"
+subflows 2" "rcv addrs above hard limit"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 1 9
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 0
-subflows 0" "subflows above hard limit"
+subflows 2" "subflows above hard limit"
 
 ip netns exec $ns1 ./pm_nl_ctl limits 8 8
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "accept 8
-- 
2.33.1

[PATCH net-next 3/3] mptcp: Make mptcp_pm_nl_mp_prio_send_ack() static

[Mat Martineau]

This function is only used within pm_netlink.c now.

Fixes: 067065422fcd ("mptcp: add the outgoing MP_PRIO support")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c | 6 +++---
 net/mptcp/protocol.h   | 3 ---
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index f7d33a9abd57..7b96be1e9f14 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -654,9 +654,9 @@ void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
 	}
 }
 
-int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
-				 struct mptcp_addr_info *addr,
-				 u8 bkup)
+static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
+					struct mptcp_addr_info *addr,
+					u8 bkup)
 {
 	struct mptcp_subflow_context *subflow;
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 7379ab580a7e..284fdcec067e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -736,9 +736,6 @@ void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 			       const struct mptcp_rm_list *rm_list);
 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
-int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
-				 struct mptcp_addr_info *addr,
-				 u8 bkup);
 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
-- 
2.33.1

Re: [PATCH net-next 0/3] mptcp: A few fixes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri, 15 Oct 2021 16:05:49 -0700 you wrote:
> This set has three separate changes for the net-next tree:
> 
> Patch 1 guarantees safe handling and a warning if a NULL value is
> encountered when gathering subflow data for the MPTCP_SUBFLOW_ADDRS
> socket option.
> 
> Patch 2 increases the default number of subflows allowed per MPTCP
> connection.
> 
> [...]

Here is the summary with links:
  - [net-next,1/3] mptcp: Avoid NULL dereference in mptcp_getsockopt_subflow_addrs()
    https://git.kernel.org/netdev/net-next/c/29211e7db28a
  - [net-next,2/3] mptcp: increase default max additional subflows to 2
    https://git.kernel.org/netdev/net-next/c/72bcbc46a5c3
  - [net-next,3/3] mptcp: Make mptcp_pm_nl_mp_prio_send_ack() static
    https://git.kernel.org/netdev/net-next/c/3828c514726f

You are awesome, thank you!
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