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

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 <[email protected]>.

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 '<[email protected]>' --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)" <[email protected]>
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.

index d0a80f537fc3..a2e37ab1c40f 100644
@@ -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();

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.

[ 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. ]

---
 net/mptcp/pm_netlink.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

index ceeb5fbe8d35..1914c553a9ad 100644
@@ -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

This is a note to let you know that I've just added the patch titled

mptcp: pm: fullmesh: select the right ID later

to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mptcp-pm-fullmesh-select-the-right-id-later.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Fri Sep 6 10:31:36 2024
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Fri, 6 Sep 2024 10:31:24 +0200
Subject: mptcp: pm: fullmesh: select the right ID later
To: [email protected], [email protected]
Cc: MPTCP Upstream <[email protected]>, "Matthieu Baerts (NGI0)" <[email protected]>, Mat Martineau <[email protected]>, Jakub Kicinski <[email protected]>
Message-ID: <[email protected]>

From: "Matthieu Baerts (NGI0)" <[email protected]>

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.

[ 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. ]

---
 net/mptcp/pm_netlink.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

@@ -554,7 +554,7 @@ static unsigned int fill_local_addresses
 {
 	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
 	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
 
 		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
 	 * 'IPADDRANY' local address
 	 */
 	if (!i) {
+		struct mptcp_addr_info local;
+
 		memset(&local, 0, sizeof(local));
 		local.family = msk->pm.remote.family;
 

Patches currently in stable-queue which might be from [email protected] are

queue-5.15/mptcp-pm-avoid-possible-uaf-when-selecting-endp.patch queue-5.15/mptcp-pm-only-decrement-add_addr_accepted-for-mpj-req.patch queue-5.15/mptcp-pm-fullmesh-select-the-right-id-later.patch queue-5.15/mptcp-pm-skip-connecting-to-already-established-sf.patch queue-5.15/mptcp-pm-re-using-id-of-unused-flushed-subflows.patch queue-5.15/mptcp-pm-add_addr-0-is-not-a-new-address.patch queue-5.15/mptcp-constify-a-bunch-of-of-helpers.patch queue-5.15/mptcp-pm-do-not-remove-already-closed-subflows.patch queue-5.15/mptcp-pr_debug-add-missing-n-at-the-end.patch queue-5.15/mptcp-pm-check-add_addr_accept_max-before-accepting-new-add_addr.patch queue-5.15/mptcp-close-subflow-when-receiving-tcp-fin.patch queue-5.15/mptcp-avoid-duplicated-sub_closed-events.patch queue-5.15/mptcp-pm-send-ack-on-an-active-subflow.patch