FAILED: patch "[PATCH] Revert "mptcp: add needs_id for netlink appending addr"" failed to apply to 5.15-stable tree

PATCH New [email protected] 2 participants 2 messages Apr 12

Subsystems (3)

Networking Stable branch Networking MPTCP

lore

Share & tools

lore

[email protected]

author maintainer

2026-04-12 05:17 UTC #0 lore raw

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 8e2760eaab778494fc1fa257031e0e1799647f46
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026041226-animating-improve-ed02@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 8e2760eaab778494fc1fa257031e0e1799647f46 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 7 Apr 2026 10:41:41 +0200
Subject: [PATCH] Revert "mptcp: add needs_id for netlink appending addr"

This commit was originally adding the ability to add MPTCP endpoints with ID 0 by accident. The in-kernel PM, handling MPTCP endpoints at the net namespace level, is not supposed to handle endpoints with such ID, because this ID 0 is reserved to the initial subflow, as mentioned in the MPTCPv1 protocol [1], a per-connection setting.

Note that 'ip mptcp endpoint add id 0' stops early with an error, but other tools might still request the in-kernel PM to create MPTCP endpoints with this restricted ID 0.

In other words, it was wrong to call the mptcp_pm_has_addr_attr_id helper to check whether the address ID attribute is set: if it was set to 0, a new MPTCP endpoint would be created with ID 0, which is not expected, and might cause various issues later.

Fixes 584f38942626 ("mptcp: add needs_id for netlink appending addr")

Cc [email protected]

Link https://datatracker.ietf.org/doc/html/rfc8684#section-3.2-9 [1]

Reviewed-by Geliang Tang <[email protected]>

Signed-off-by Matthieu Baerts (NGI0) <[email protected]>

Link https://patch.msgid.link/20260407-net-mptcp-revert-pm-needs-id-v2-1-7a25cbc324f8@kernel.org open here

Signed-off-by Jakub Kicinski <[email protected]>

net/mptcp/pm_kernel.c +5 ~~-19~~

index 82e59f9c6dd9..0ebf43be9939 100644
@@ -720,7 +720,7 @@ static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
 
 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 					     struct mptcp_pm_addr_entry *entry,
-					     bool needs_id, bool replace)
+					     bool replace)
 {
 	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
 	int ret = -EINVAL;

@@ -779,7 +779,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		}
 	}
 
-	if (!entry->addr.id && needs_id) {
+	if (!entry->addr.id) {
 find_next:
 		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
 						    MPTCP_PM_MAX_ADDR_ID + 1,

@@ -790,7 +790,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		}
 	}
 
-	if (!entry->addr.id && needs_id)
+	if (!entry->addr.id)
 		goto out;
 
 	__set_bit(entry->addr.id, pernet->id_bitmap);

@@ -923,7 +923,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
 		return -ENOMEM;
 
 	entry->addr.port = 0;
-	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true, false);
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, false);
 	if (ret < 0)
 		kfree(entry);

@@ -977,18 +977,6 @@ static int mptcp_nl_add_subflow_or_signal_addr(struct net *net,
 	return 0;
 }
 
-static bool mptcp_pm_has_addr_attr_id(const struct nlattr *attr,
-				      struct genl_info *info)
-{
-	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
-
-	if (!nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
-					 mptcp_pm_address_nl_policy, info->extack) &&
-	    tb[MPTCP_PM_ADDR_ATTR_ID])
-		return true;
-	return false;
-}
-
 /* Add an MPTCP endpoint */
 int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
 {

@@ -1037,9 +1025,7 @@ int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
 			goto out_free;
 		}
 	}
-	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry,
-						!mptcp_pm_has_addr_attr_id(attr, info),
-						true);
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true);
 	if (ret < 0) {
 		GENL_SET_ERR_MSG_FMT(info, "too many addresses or duplicate one: %d", ret);
 		goto out_free;

Sasha Levin

maintainer

2026-04-12 22:52 UTC #1 lore raw

PATCH 1/1 Revert "mptcp: add needs_id for netlink appending addr"

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

[ Upstream commit 8e2760eaab778494fc1fa257031e0e1799647f46 ]

Note that 'ip mptcp endpoint add id 0' stops early with an error, but other tools might still request the in-kernel PM to create MPTCP endpoints with this restricted ID 0.

Fixes 584f38942626 ("mptcp: add needs_id for netlink appending addr")

Cc [email protected]

Link https://datatracker.ietf.org/doc/html/rfc8684#section-3.2-9 [1]

Reviewed-by Geliang Tang <[email protected]>

Signed-off-by Matthieu Baerts (NGI0) <[email protected]>

Link https://patch.msgid.link/20260407-net-mptcp-revert-pm-needs-id-v2-1-7a25cbc324f8@kernel.org open here

Signed-off-by Jakub Kicinski <[email protected]>

[ adapted changes from pm_kernel.c to pm_netlink.c ]

Signed-off-by Sasha Levin <[email protected]>

---
 net/mptcp/pm_netlink.c | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

net/mptcp/pm_netlink.c +5 ~~-19~~

index 1c8aabce33a6a..8190efa19a595 100644
@@ -937,8 +937,7 @@ static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 }
 
 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
-					     struct mptcp_pm_addr_entry *entry,
-					     bool needs_id)
+					     struct mptcp_pm_addr_entry *entry)
 {
 	struct mptcp_pm_addr_entry *cur;
 	unsigned int addr_max;

@@ -965,7 +964,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 			goto out;
 	}
 
-	if (!entry->addr.id && needs_id) {
+	if (!entry->addr.id) {
 find_next:
 		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
 						    MAX_ADDR_ID + 1,

@@ -976,7 +975,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 		}
 	}
 
-	if (!entry->addr.id && needs_id)
+	if (!entry->addr.id)
 		goto out;
 
 	__set_bit(entry->addr.id, pernet->id_bitmap);

@@ -1117,7 +1116,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	entry->ifindex = 0;
 	entry->flags = 0;
 	entry->lsk = NULL;
-	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true);
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0)
 		kfree(entry);

@@ -1339,18 +1338,6 @@ static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
 	return 0;
 }
 
-static bool mptcp_pm_has_addr_attr_id(const struct nlattr *attr,
-				      struct genl_info *info)
-{
-	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
-
-	if (!nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
-					 mptcp_pm_addr_policy, info->extack) &&
-	    tb[MPTCP_PM_ADDR_ATTR_ID])
-		return true;
-	return false;
-}
-
 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];

@@ -1377,8 +1364,7 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 			return ret;
 		}
 	}
-	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry,
-						!mptcp_pm_has_addr_attr_id(attr, info));
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0) {
 		GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
 		if (entry->lsk)

Signature · 1 line

2.53.0