From: Geliang Tang tanggeliang@kylinos.cn

Just like in-kernel pm, when userspace pm does set_flags, it needs to send out MP_PRIO signal, and also modify the flags of the corresponding address entry in the local address list. This patch implements the missing logic.

Traverse all address entries on userspace_pm_local_addr_list to find the local address entry, if bkup is true, set the flags of this entry with FLAG_BACKUP, otherwise, clear FLAG_BACKUP.

Fixes: 892f396c8e68 ("mptcp: netlink: issue MP_PRIO signals from userspace PMs") Cc: stable@vger.kernel.org Signed-off-by: Geliang Tang tanggeliang@kylinos.cn Reviewed-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/pm_userspace.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c index 56dfea9862b7b24dd0eaa8bbedcf22a7f6829ccf..3f888bfe1462ee3c75a3fb6eefe29cb712471410 100644 --- a/net/mptcp/pm_userspace.c +++ b/net/mptcp/pm_userspace.c @@ -560,6 +560,7 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info) struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN]; struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR]; struct net *net = sock_net(skb->sk); + struct mptcp_pm_addr_entry *entry; struct mptcp_sock *msk; int ret = -EINVAL; struct sock *sk; @@ -601,6 +602,17 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info) if (loc.flags & MPTCP_PM_ADDR_FLAG_BACKUP) bkup = 1;

+ spin_lock_bh(&msk->pm.lock); + list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) { + if (mptcp_addresses_equal(&entry->addr, &loc.addr, false)) { + if (bkup) + entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP; + else + entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP; + } + } + spin_unlock_bh(&msk->pm.lock); + lock_sock(sk); ret = mptcp_pm_nl_mp_prio_send_ack(msk, &loc.addr, &rem.addr, bkup); release_sock(sk);

In mptcp_pm_create_subflow_or_signal_addr(), rcu_read_(un)lock() are used as expected to iterate over the list of local addresses, but list_for_each_entry() was used instead of list_for_each_entry_rcu() in __lookup_addr(). It is important to use this variant which adds the required READ_ONCE() (and diagnostic checks if enabled).

Because __lookup_addr() is also used in mptcp_pm_nl_set_flags() where it is called under the pernet->lock and not rcu_read_lock(), an extra condition is then passed to help the diagnostic checks making sure either the associated spin lock or the RCU lock is held.

Fixes: 86e39e04482b ("mptcp: keep track of local endpoint still available for each msk") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang geliang@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/pm_netlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index db586a5b3866f66a24431d7f2cab566f89102885..45a2b5f05d38b0e7f334578f5ee6923a8ff8f7b2 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -524,7 +524,8 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info) { struct mptcp_pm_addr_entry *entry;

- list_for_each_entry(entry, &pernet->local_addr_list, list) { + list_for_each_entry_rcu(entry, &pernet->local_addr_list, list, + lockdep_is_held(&pernet->lock)) { if (mptcp_addresses_equal(&entry->addr, info, entry->addr.port)) return entry; }