commit 8e9eacad7ec7a9cbf262649ebf1fa6e6f6cc7d82 upstream.

The upstream commit had to handle a lookup_by_id variable that is only present in 5.17. This version of the patch removes that variable, so the __lookup_addr() function only handles the lookup as it is implemented in 5.15 and 5.16. It also removes one 'const' keyword to prevent a warning due to differing const-ness in the 5.17 version of addresses_equal().

The MPTCP endpoint list is under RCU protection, guarded by the pernet spinlock. mptcp_nl_cmd_set_flags() traverses the list without acquiring the spin-lock nor under the RCU critical section.

This change addresses the issue performing the lookup and the endpoint update under the pernet spinlock.

Cc: stable@vger.kernel.org # 5.15.x Cc: stable@vger.kernel.org # 5.16.x Fixes: 0f9f696a502e ("mptcp: add set_flags command in PM netlink") Acked-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com --- net/mptcp/pm_netlink.c | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 65764c8171b3..5d305fafd0e9 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -459,6 +459,18 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullm return i; }

+static struct mptcp_pm_addr_entry * +__lookup_addr(struct pm_nl_pernet *pernet, struct mptcp_addr_info *info) +{ + struct mptcp_pm_addr_entry *entry; + + list_for_each_entry(entry, &pernet->local_addr_list, list) { + if (addresses_equal(&entry->addr, info, true)) + return entry; + } + return NULL; +} + static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; @@ -1725,17 +1737,21 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info) if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP) bkup = 1;

- list_for_each_entry(entry, &pernet->local_addr_list, list) { - if (addresses_equal(&entry->addr, &addr.addr, true)) { - mptcp_nl_addr_backup(net, &entry->addr, bkup); - - if (bkup) - entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP; - else - entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP; - } + spin_lock_bh(&pernet->lock); + entry = __lookup_addr(pernet, &addr.addr); + if (!entry) { + spin_unlock_bh(&pernet->lock); + return -EINVAL; }

+ if (bkup) + entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP; + else + entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP; + addr = *entry; + spin_unlock_bh(&pernet->lock); + + mptcp_nl_addr_backup(net, &addr.addr, bkup); return 0; }