FAILED: patch "[PATCH] mptcp: pm: fullmesh: select the right ID later" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] mptcp: pm: fullmesh: select the right ID later" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-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@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 09355f7abb9fbfc1a240be029837921ea417bf4f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024082641-cauterize-slum-9eb2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

09355f7abb9f ("mptcp: pm: fullmesh: select the right ID later")
b9d69db87fb7 ("mptcp: let the in-kernel PM use mixed IPv4 and IPv6 addresses")
837cf45df163 ("mptcp: fix race in incoming ADD_ADDR option processing")
a88c9e496937 ("mptcp: do not block subflows creation on errors")
86e39e04482b ("mptcp: keep track of local endpoint still available for each msk")
f7d6a237d742 ("mptcp: fix per socket endpoint accounting")
b29fcfb54cd7 ("mptcp: full disconnect implementation")
59060a47ca50 ("mptcp: clean up harmless false expressions")
3ce0852c86b9 ("mptcp: enforce HoL-blocking estimation")
6511882cdd82 ("mptcp: allocate fwd memory separately on the rx and tx path")
765ff425528f ("mptcp: use lockdep_assert_held_once() instead of open-coding it")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 09355f7abb9fbfc1a240be029837921ea417bf4f Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Mon, 19 Aug 2024 21:45:30 +0200
Subject: [PATCH] mptcp: pm: fullmesh: select the right ID later

When reacting upon the reception of an ADD_ADDR, the in-kernel PM first
looks for fullmesh endpoints. If there are some, it will pick them,
using their entry ID.

It should set the ID 0 when using the endpoint corresponding to the
initial subflow, it is a special case imposed by the MPTCP specs.

Note that msk->mpc_endpoint_id might not be set when receiving the first
ADD_ADDR from the server. So better to compare the addresses.

Fixes: 1a0d6136c5f0 ("mptcp: local addresses fullmesh")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-12-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index d0a80f537fc3..a2e37ab1c40f 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -636,6 +636,7 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 {
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_addr_info mpc_addr;
 	struct pm_nl_pernet *pernet;
 	unsigned int subflows_max;
 	int i = 0;
@@ -643,6 +644,8 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	pernet = pm_nl_get_pernet_from_msk(msk);
 	subflows_max = mptcp_pm_get_subflows_max(msk);
 
+	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
@@ -653,7 +656,13 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 
 		if (msk->pm.subflows < subflows_max) {
 			msk->pm.subflows++;
-			addrs[i++] = entry->addr;
+			addrs[i] = entry->addr;
+
+			/* Special case for ID0: set the correct ID */
+			if (mptcp_addresses_equal(&entry->addr, &mpc_addr, entry->addr.port))
+				addrs[i].id = 0;
+
+			i++;
 		}
 	}
 	rcu_read_unlock();

[PATCH 5.15.y] mptcp: pm: fullmesh: select the right ID later

[Matthieu Baerts (NGI0)]

commit 09355f7abb9fbfc1a240be029837921ea417bf4f upstream.

When reacting upon the reception of an ADD_ADDR, the in-kernel PM first
looks for fullmesh endpoints. If there are some, it will pick them,
using their entry ID.

It should set the ID 0 when using the endpoint corresponding to the
initial subflow, it is a special case imposed by the MPTCP specs.

Note that msk->mpc_endpoint_id might not be set when receiving the first
ADD_ADDR from the server. So better to compare the addresses.

Fixes: 1a0d6136c5f0 ("mptcp: local addresses fullmesh")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-12-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in pm_netlink.c, because the new 'mpc_addr' variable is
  added where the 'local' one was, before commit b9d69db87fb7 ("mptcp:
  let the in-kernel PM use mixed IPv4 and IPv6 addresses"), that is not
  a candidate for the backports. This 'local' variable has been moved to
  the new place to reduce the scope, and help with possible future
  backports.
  Note that addresses_equal() has been used instead of
  mptcp_addresses_equal(), renamed in commit 4638de5aefe5 ("mptcp:
  handle local addrs announced by userspace PMs"), not in this version. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index ceeb5fbe8d35..1914c553a9ad 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -554,7 +554,7 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 {
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry;
-	struct mptcp_addr_info local;
+	struct mptcp_addr_info mpc_addr;
 	struct pm_nl_pernet *pernet;
 	unsigned int subflows_max;
 	int i = 0;
@@ -562,6 +562,8 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
 	subflows_max = mptcp_pm_get_subflows_max(msk);
 
+	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+
 	rcu_read_lock();
 	__mptcp_flush_join_list(msk);
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
@@ -580,7 +582,13 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 
 		if (msk->pm.subflows < subflows_max) {
 			msk->pm.subflows++;
-			addrs[i++] = entry->addr;
+			addrs[i] = entry->addr;
+
+			/* Special case for ID0: set the correct ID */
+			if (addresses_equal(&entry->addr, &mpc_addr, entry->addr.port))
+				addrs[i].id = 0;
+
+			i++;
 		}
 	}
 	rcu_read_unlock();
@@ -589,6 +597,8 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	 * 'IPADDRANY' local address
 	 */
 	if (!i) {
+		struct mptcp_addr_info local;
+
 		memset(&local, 0, sizeof(local));
 		local.family = msk->pm.remote.family;
 
-- 
2.45.2